WO2009088094A1

WO2009088094A1 - Mould release film

Info

Publication number: WO2009088094A1
Application number: PCT/JP2009/050495
Authority: WO
Inventors: Shinya Watanabe
Original assignee: Teijin Dupont Films Japan Limited
Priority date: 2008-01-11
Filing date: 2009-01-08
Publication date: 2009-07-16

Abstract

Provided is a mould release film which has a suitable rate of dimensional change under thermal tension when a ceramic sheet is produced, and which also has an excellent thermal contraction balance when ceramic slurry is dried, the performance of the film being sufficient to satisfy the requirements as a mould release film which is used in the production of ceramic sheets. The film has a specific rate of elongation under a specific load, and a specific rate of thermal elongation in the absence of a load.

Description

Meiji Seiki Release Film Technical Field

The present invention relates to a release film. More specifically, the present invention relates to a release film that can sufficiently satisfy the performance required as a release film used in the production of ceramic sheets. Background art

A release film based on a polyester film is used as a carrier film for manufacturing ceramic sheets (green sheets) used for manufacturing various ceramic electronic parts such as multilayer ceramic capacitors and ceramic substrates.

For example, a ceramic sheet used for manufacturing a multilayer ceramic capacitor is obtained by applying a ceramic slurry in which a ceramic powder and a binder agent are dispersed in a solvent on a carrier film by a reverse roll method or the like, and heating the solvent. After forming a ceramic layer by drying and removing, a metal film serving as an internal electrode is formed on the ceramic layer by vapor deposition or printing to create a metal film / ceramic layer no-carrier film composite, and a powerful composite It is manufactured by peeling off the carrier film.

The multilayer ceramic capacitor is obtained by laminating the metal film ceramic layer composite produced as described above in a desired size, and after hot pressing, cutting into a rectangular shape to obtain a chip-shaped multilayer body. It can be obtained by firing a chip-like laminate and forming external electrodes on a predetermined surface of the fired body.

By the way, in recent years, in the field of capacitors such as monolithic ceramic capacitors, there has been a demand for higher density circuit components due to downsizing and larger capacity. Therefore, the thickness of the ceramic sheet to be used is made thinner and the internal electrodes are further multilayered. There is a need to do that.

However, if the thickness of the ceramic sheet is reduced or the number of stacked layers is increased, even a slight unevenness in the thickness of the ceramic sheet will cause the displacement of the internal electrodes.

Thus, it has been proposed to reduce the thermal deformation of the carrier film during the production of the ceramic sheet and reduce the thickness variation of the produced ceramic sheet (see Patent Document 1). In Patent Document 1, if the release film has an absolute value of a dimensional change rate under a stress of 1.47 MPa at 120, which is 0.3% or less in both the longitudinal direction and the width direction, heating is performed. It is described that since the thermal deformation at the time of treatment becomes very small, it is possible to suppress the uneven thickness of the ceramic paste obtained.

However, the ceramic sheet is dried without being gripped in the width direction, usually at a temperature around 100.degree. For this reason, the carrier film used in the production of the ceramic sheet shrinks with little tension in the width direction when the ceramic is dried. Therefore, as described in Patent Document 1, using only a release film having a low thermal shrinkage rate in the longitudinal direction and the width direction in a state where tension is applied, all the processes up to drying of the ceramic are performed. Even the shrinkage unevenness of the carrier film in the process could not be resolved, and there still remained a problem that the manufactured ceramic sheet had thickness unevenness and the internal electrodes were displaced during lamination.

In addition, when the ceramic sheet is thin, if the surface roughness of the carrier film is high, defects due to the occurrence of pinholes, or breakage of the ceramic sheet when the ceramic sheet is peeled off, can reduce productivity. cause. In other words, when the ceramic sheet is thin, even fine surface defects such as scratches and foreign matter on the surface of the carrier film, which were not a problem in the past, are manifested as causes of pinhole defects in the obtained ceramic sheet. End up.

Therefore, with the recent miniaturization of the capacitor field and the increase in capacity, the carrier film for manufacturing ceramic sheets has an even higher level of dimensional stability and a higher level of surface roughness. Is required. On the other hand, if the surface of the carrier film is smoothed, the peeling charge tends to increase. For example, if the coating speed of the ceramic slurry is increased to improve productivity, sparks are generated in the process of unwinding the carrier film. The problem is that it is more likely to occur, which in turn makes a fire more likely. In addition, when the ceramic sheet is peeled off from the carrier film, the ceramic sheet is charged, and when the ceramic sheet is laminated in the subsequent process, the internal electrode is displaced due to the charging. Therefore, as a carrier film having a smoother surface, it is strongly required to suppress peeling electrification.

Especially in the production of thin ceramic sheets (less than 1 m), not only the high-precision dimensional stability and high-level smoothing (so-called surface roughness) as described above, but also the flatness of the film (flatness) It is important to control the level of the above. In other words, when the flatness of the carrier film is poor, the uneven coating thickness of the ceramic slurry applied on the carrier film becomes poor, resulting in poor thickness unevenness of the ceramic sheet, and the capacitance is not uniform in the multilayer ceramic capacitor. It will become something.

By the way, the carrier film as described above is generally used in the form of being wound in a roll shape, but since it has a release layer on the surface, it is slippery and is wound during winding or transporting of the roll. Problems such as misalignment are likely to occur. Therefore, conventionally, when winding the carrier film as described above in a roll shape, it is common to employ a condition that the roll hardness is high so that no winding deviation occurs. However, if the roll hardness is too high, the carrier film easily follows the roll shape, and the carrier film is stretched due to a fine roll shape defect, resulting in poor flatness.

In addition, it is important to control film thickness unevenness to a higher degree, especially in the manufacture of thin ceramic sheets (less than 1 zm). That is, if the carrier film has poor thickness unevenness, the coating thickness unevenness of the ceramic slurry applied thereon becomes poor, resulting in poor thickness unevenness of the ceramic sheet, and the capacity of the multilayer ceramic capacitor is not good. It will be uniform. (Patent Document 1) Japanese Unexamined Patent Publication No. 2000-343663 Disclosure of Invention

The object of the present invention has been made in view of such a conventional technique, and has an appropriate dimensional change rate under heating tension when producing a ceramic sheet, and heat shrinkage when drying the ceramic slurry. An object of the present invention is to provide a release film that is excellent in balance and can sufficiently satisfy the performance required as a release film used in the manufacture of ceramics.

The present inventor has intensively studied to solve the above problems. As a result, a release film having a specific elongation under a specific load and having a specific thermal elongation under no load has the performance required for a release film used in manufacturing a ceramic sheet. The inventors have found that they can be satisfied and have completed the present invention. That is, the present invention is a release film having a release layer on at least one surface of a polyester film,

Elongation rate in the longitudinal direction at 100 (S _MD ) when a tension of 0.2 MPa or more and 4.0 MPa or less is applied in the longitudinal direction of the release film. The elongation rate (S _TD ) in the direction perpendicular to the longitudinal direction at 100 when a tension of 0.0 IMP a is applied in the direction perpendicular to the longitudinal direction satisfies the following formula (2):

The longitudinal thermal expansion rate (HS _MD ) at 100 under no load of the release film satisfies the following formula (3),

The thermal expansion rate (HS _TD ) in the direction perpendicular to the longitudinal direction at 100 under no load of the release film satisfies the following formula (4),

A release film satisfying the following formula (5): the thermal elongation rate in the longitudinal direction (HS _MD ), the thermal elongation rate in the direction perpendicular to the longitudinal direction (HS _TD ), and the force.

0. 0961X-0. 45≤S _MD ≤0. 0961X—0. 25 (1) (In formula (1), X is the tension (MP a) applied to the film unit area, and X is 0. 2MPa or more 4. Shows a value of OMPa or less. )

0. 6≤S _TD ≤- 0. 2 (2)

0. 4≤HS _MD ≤-0. 1 (3)

0. 6≤HS _TD ≤— 0. 2 (4)

I " ¹ ° MD ° TD (5)

Furthermore, the release film of the present invention preferably has a maximum height (Rmax) measured with a contact-type three-dimensional surface roughness meter on the surface of the release layer in the range of 100 nm to 600 nm. In addition, the maximum height (Rma X) measured with a contact-type three-dimensional surface roughness meter on the surface of the release layer and the surface not having the release layer is preferably 100 nm or more and 600 nm or less, respectively. The release layer preferably contains a surfactant in an amount of 0.5% by mass or more and 10% by mass or less based on the weight of the release layer. Further, it is preferable that the vertical thickness unevenness is 3.0% or less, and the horizontal thickness unevenness is 3.0% or less. The release layer is preferably formed by applying a release layer forming composition to a polyester film stretched in one direction.

The release film of the present invention is preferably used for producing a ceramic sheet. In particular, it is preferably used for producing a ceramic capacitor.

The present invention includes a film roll obtained by winding the release film into a roll, wherein the roll surface layer has a Vickers hardness (Hv) of 0 or more and 450 or less. The present invention includes a method of using a film having the characteristics of the above formulas (1) to (5) as a release film for a ceramic sheet. BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the machine axis direction in film formation may be referred to as a longitudinal direction or a longitudinal direction. In addition, a direction perpendicular to the longitudinal direction may be referred to as a width direction or a lateral direction.

Release film>

The release film of the present invention is a release film having a release layer on at least one surface of a polyester film, having a specific elongation under a specific load, It has a specific thermal elongation under no load. The physical properties and structure of the release film of the present invention will be described below.

[Elongation ratio (S _MD )]

The release film of the present invention has a longitudinal elongation ratio at 100 (S _MD ) i when the tension of 0.2 MPa or more and 4.0 MPa or less is applied in the longitudinal direction of the release film (S _MD ) i Meet. Ceramic layer release film composites are usually transported under tension at temperatures around 100 ° C. Therefore, by selecting 100 as the temperature condition, it is possible to judge the situation more in line with the actual process.

0. 0961 X- 0. 45≤S _MD ≤0. 0961 X- 0.25 (1)

(In formula (1), X is the tension (MP a) applied to the film unit area, and X is a value of 0.2 MPa or more and 4. OMP a or less.)

If the elongation in the longitudinal direction (S _MD ) is smaller than the value on the left side of the above formula (1), the contraction stress in the longitudinal direction of the film increases with respect to the transport tension of the ceramic layer / release film composite, As a result, it shrinks unevenly in the longitudinal direction, causing uneven thickness of the ceramic sheet. On the other hand, if the elongation ratio (S _MD ) in the longitudinal direction is larger than the value on the right side of the above formula (1), the contraction stress in the longitudinal direction of the film is small relative to the transport tension of the ceramic layer / release film composite. The flatness of the film deteriorates, causing uneven thickness of the ceramic sheet. If the elongation in the longitudinal direction (S _MD ) is within the range that satisfies the above formula (1), the contraction stress in the longitudinal direction has an appropriate balance with respect to the conveying tension of the ceramic layer release film composite, The thickness variation in the longitudinal direction of the obtained ceramic sheet can be suppressed. From this point of view, the release film of the present invention has a longitudinal elongation ratio at 100 (S) when a tension of 0.3 MPa or more and 2.5 MPa or less is applied in the longitudinal direction of the release film. _MD ) force An embodiment that satisfies the above formula (1) is more preferable.

In addition, the elongation rate in the longitudinal direction (S _MD ) and the elongation rate in the width direction (S _TD ), which will be described later, are obtained by the following equations. Where M. Is the length in the longitudinal or width direction of the film before the start of heating, and M is the same direction of the film when it reaches 10 O: Indicates the length. That is, when the elongation rate (S _MD ) and the elongation rate (S _TD ) are negative, the film is contracted, and when it is positive, the film is stretched.

Elongation rate (S _MD , S _TD ) = (ΔΜΖΜ.) XI 00 (%)

ΔΜ = Μ-Μ ₀

[Elongation rate in the direction perpendicular to the longitudinal direction (width direction) (S _TD )]

In the release film of the present invention, the elongation (S _TD ) in the width direction at 100 when a tension of 0. 1 MPa is applied in the width direction of the release film satisfies the following formula (2). Here, by selecting 10 as the temperature condition, it becomes possible to judge the situation more in line with the actual process as described above. The elongation ratio (S _TD ) is determined from the length in the width direction of the film before and after the heat treatment according to the above formula.

—0. 6≤S _XD ≤- 0. 2 (2)

When the elongation in the width direction (S _TD ) is less than -0.6%, the shrinkage in the width direction of the film is large in the transport process of the ceramic layer Z release film composite, and the thickness variation of the ceramic sheet is reduced. It will cause. On the other hand, when the elongation in the width direction (S _TD ) is greater than –0.2%, if the elongation (S _TD ) is greater than the force SO (the film stretches), the ceramic layer Z release film composite During the transportation of the body, the flatness of the film is lost due to the stretching in the width direction of the film, causing thick spots on the ceramic sheet. In addition, the balance between the shrinkage of the ceramic layer and the elongation of the release film is poor, causing problems such as partial peeling of the ceramic layer and floating. When the elongation ratio (S _TD ) is more than 0.2% and less than 0%, the balance between the shrinkage of the ceramic layer and the shrinkage of the release film is poor, and the ceramic layer partially peels from the release film. Problems such as floating.

[Thermal expansion rate in the longitudinal direction (HS _MD ) and the thermal elongation rate in the direction perpendicular to the longitudinal direction (width direction) (HS _TD )]

Release film of the present invention, the longitudinal direction of 100 under no load thermal elongation (HS _MD) force the following formula satisfies the (3), at the same time, in the width direction that put on at 100 under no load Thermal elongation rate (HS _TD ) force The following formula (4) is satisfied, and the longitudinal direction The thermal expansion rate (HS _MD ) and the thermal expansion rate in the width direction (HS _TD ) satisfy the following formula (5).

-0. 4≤HS _MD ≤-0. 1 (3)

—0. 6≤HS _XD ≤-0. 2 (4)

ri ^) _MO ^ S _TD (o)

Longitudinal thermal expansion of the film (HS _MD) that there is a thermal expansion rate in the width direction (HS _TD) is within the above range, respectively, and longitudinal thermal expansion rate (HS _MD) thermal elongation of the width direction to be greater than (HS _TD), at the time of heat drying and removing the solvent contained in the ceramic layer after the ceramic slurry coating, taken in the longitudinal direction of the balance of contraction of the contraction in the width direction of the release film, as a result Thus, the thickness unevenness of the obtained dry ceramic layer can be reduced.

In addition, the thermal expansion rate in the longitudinal direction (HS _MD ) and the thermal expansion rate in the width direction (HS _TD ) are obtained by the following formulas. Where L. Is the length in the longitudinal or width direction of the film before heat treatment, and L is the length in the same direction of the film after heat treatment. That is, when the thermal elongation rate (HS _MD ) and thermal elongation rate (HS _TD ) are negative, it indicates that the film is contracted, and when it is positive, it indicates that the film is stretched.

Thermal elongation (HS _MD , HS _TD ) = (AL NO L.) XI 00 (%)

△ L = L

[Maximum height (Rmax)]

The release film of the present invention preferably has a maximum height (Rmax) of 100 nm or more and 600 nm or less measured with a contact-type three-dimensional surface roughness meter on the surface of the release layer. The maximum height (Rmax) is more preferably not less than 200 nm and not more than 550 nm, particularly preferably not less than 300 nm and not more than 500 nm.

Maximum height (Rma X) conforms to JIS standard (B 0601—2001: Surface roughness—Definition and display, B0651—2001: Contact surface roughness measuring instrument) and uses a 3D surface roughness meter. This is the maximum height of the part where the reference length is extracted from the roughness curve. The maximum height (Rmax) is the maximum height of the contour curve (maximum height of profile), which is the sum of the maximum value of the peak height of the contour curve and the maximum value of the valley depth at the reference length. B 065 1— 200 1

The (stylus instrument) is a measuring instrument that can measure the deviation of the contour shape of the surface as the stylus moves on the surface, calculate the parameters, and record the contour curve.

J I S B0601—2001 corresponds to I SO 4287: 1997. J IS B0651-2001 corresponds to ISO 3274: 1996. The maximum height (Rmax) indicates the maximum protrusion height and is an indicator of pinhole defects in ceramic sheets. Specifically, when the maximum height (Rmax) of the release layer surface exceeds 60 Onm, the thickness of the ceramic sheet formed in the part where the maximum height (Rmax) exceeds 600 nm is reduced. As a result, pinhole defects are likely to occur. On the other hand, when Rma X on the surface of the release layer is less than 100 nm, the slipping property cannot be obtained and the winding property is deteriorated and the productivity tends to be deteriorated.

That is, when the maximum height (Rmax) of the surface of the release layer of the release film of the present invention is in the above numerical range, the surface smoothness and slipperiness are excellent, so that the uneven shape of the resulting ceramic sea ridge is suppressed. Thus, a ceramic sheet with suppressed thickness unevenness can be obtained. As a result, when a ceramic capacitor is manufactured using the obtained ceramic sheet, a capacitor in which the displacement of the internal electrodes is further suppressed can be obtained.

In addition, the release film of the present invention has a maximum height (Rmax) of 100 nm measured with a contact-type three-dimensional surface roughness meter on the surface on the side having no release layer simultaneously with the release layer surface. The thickness is preferably 600 nm or more. The maximum height (Rmax) is more preferably from 200 nm to 550 nm, particularly preferably from 300 nm to 500 nm.

The maximum height (Rmax) indicates the maximum protrusion height on the surface having no release layer, and is an index of the pinhole defect of the ceramic sheet. Specifically, if the maximum height (Rmax) of the surface that does not have a release layer exceeds 600 nm, the maximum height (Rmax) will be reduced when the ceramic slurry is applied and wound up after drying. The part exceeding 600 nm is pressed against the ceramic sheet. A concave portion is formed on the surface of the groove, and the concave portion becomes thin. As a result, pinhole defects are likely to occur. Even if these do not lead to a pinhole defect, an extremely thin portion is formed in the ceramic sheet, which becomes a defect of the ceramic capacitor.

That is, by making the maximum height (Rmax) of the release layer surface and the surface on the side having no release layer of the release film of the present invention simultaneously within the above numerical range, the surface smoothness is more excellent. Therefore, the uneven surface shape of the obtained ceramic sheet can be further suppressed, and a ceramic sheet in which thickness unevenness is further suppressed can be obtained. As a result, when a ceramic capacitor is manufactured using the obtained ceramic sheet, the displacement of the internal electrodes can be further suppressed. Moreover, pinhole generation in the ceramic sheet can be suppressed. Furthermore, the peelability of the ceramic sea cocoon is good.

The maximum height (Rmax) can be achieved by adjusting the conditions for filtering the molten polymer, the mode of particles contained in the polyester film, and the like.

[Vertical thickness variation and lateral thickness variation]

The release film of the present invention preferably has a vertical thickness unevenness of 3.0% or less. In addition, the release film of the present invention has a lateral thickness unevenness of 3.0% or less. It is preferable. In the release film of the present invention, it is preferable that the longitudinal thickness unevenness and the lateral thickness unevenness are simultaneously in the above numerical range. In particular, by using a release film having excellent thickness unevenness, the thickness unevenness of the obtained ceramic sheet can be further suppressed. When a ceramic sheet is manufactured using such a release film and a ceramic capacitor is manufactured using such a ceramic sheet, a ceramic capacitor having a more uniform capacity can be obtained. From this point of view, the vertical thickness unevenness is preferably 2.9% or less, more preferably 2.5% or less, and particularly preferably 2.0% or less. Further, the thickness unevenness in the lateral direction is preferably 2.8% or less, more preferably 2.6% or less, and particularly preferably 2.5% or less. The thickness unevenness in the longitudinal direction can be adjusted by the longitudinal draw ratio. It is also important to adjust the auxiliary heating temperature and stretching temperature in the longitudinal stretching process. The thickness variation in the transverse direction can be adjusted by the longitudinal draw ratio and the transverse draw ratio. It is also important to adjust the auxiliary heating temperature and stretching temperature in the transverse stretching process.

The method for producing the release film of the present invention having the above physical properties will be described below. The release film of the present invention is produced by an unstretched polyester film forming process, a primary stretching process, an in-line coating process, a secondary stretching process, and a heat setting process described below.

[Unstretched polyester film forming process]

In obtaining the release film of the present invention, first, in an unstretched polyester film forming step, a polyester raw material described later is extruded to obtain an unstretched polyester film.

In extrusion molding, an unstretched polyester film is obtained by cooling and solidifying the molten sheet extruded from the die with a cooling roll using an extruder. At this time, in order to reduce coarse particles in the polymer, prior to melt extrusion, a non-woven filter having an average opening of stainless steel fine wires with a wire diameter of 15 zm or less of 10 // m or more and 30 zm or less, preferably It is preferable to filter the molten polymer using a non-woven type film having a diameter of 10 m or more and 20 atm or less. In this way, by reducing the number of coarse particles in the polymer, the maximum height (Rm ax) of the release layer surface and the surface on the side without the release layer of the release film can be reduced to 100 °. It can be in the numerical range between nm and 60 nm.

Further, after such filtration treatment, the molten polymer is filtered using a filter with an average opening of 10 // m or more and 5 or less, preferably 15 zm or more and 30 m or less, immediately before the die base. However, it is preferable from the viewpoint that the heat-degraded product of the polyester can be further removed, and the maximum height (Rmax) value can be set to a more preferable numerical range.

In addition, in terms of improving the flatness of the unstretched polyester film It is preferable to improve the adhesion between the molten sheet extruded from the die and the cooling roll. For example, an electrostatic application adhesion method and a Z or liquid application adhesion method are preferably employed.

[Primary stretching process]

In the primary stretching step, the unstretched polyester film obtained by the above-described unstretched polyester film forming step is stretched in the longitudinal direction (hereinafter, sometimes referred to as longitudinal stretching). Get a film.

At this time, prior to the primary stretching step, preheating under (Tg-10) and above (Tg-2) under the following temperature conditions has a uniform thickness and a desired longitudinal elongation ratio. (S _MD) and preferred in order to obtain the release Fi Lum having thermal expansion rate (HS _MD). Here, Tg represents the glass transition temperature (unit: in) of the unstretched polyester film.

In the primary stretching process, an unstretched polyester film that has been preheated arbitrarily is (Tg + 2) or more and (Tg + 40) at the following temperature conditions: 3.3 to 4.0 times in the longitudinal direction Stretch in the following range.

When the draw ratio is less than 3.3 times, the thermal expansion rate HS _{MD in the} longitudinal direction tends to be a positive value, that is, the film tends to be stretched, which is not preferable. On the other hand, when the draw ratio is larger than 4.0 times, the longitudinal elongation rate (S _MD ;. Tends to be too small), which is not preferable. Also, the longitudinal thermal elongation rate (HS _MD ) is small. It is not preferable because the stretching ratio is 3.3 times or more and 4.0 times or less, and the elongation ratio (S _MD ) and thermal elongation ratio (HS _MD ) in the longitudinal direction are set within the desired numerical range. It is also important to do.

When an unstretched polyester film is stretched in the range of (Tg + 2) or more and (Tg + 40) or less and (Tg + 40) in the range of 3.7 times or more and 4.0 times or less in the longitudinal direction, Thickness unevenness can be reduced to 3.0% or less. If the draw ratio in the longitudinal direction is too low, the thickness unevenness in the longitudinal direction tends to deteriorate. From such a viewpoint, the lower limit of the draw ratio in the longitudinal direction is more preferably 3.8 times or more. On the other hand, the longitudinal extension If the draw ratio is too high, in the longitudinal uniaxially stretched polyester film obtained in the longitudinal stretching step, the thickness unevenness in the transverse direction tends to deteriorate, and a partially oriented crystallized portion is formed. It tends to be difficult to improve the lateral thickness unevenness of the mold film.

[Inline coating process]

In the in-line coating process, a release layer forming composition (hereinafter sometimes referred to as a coating agent) is applied inline to at least one surface of the uniaxially stretched polyester film in the longitudinal direction. A polyester film having a coating film is obtained. That is, the release layer is formed by applying the release layer forming composition to a polyester film stretched in one direction.

As the coating agent used in the in-line coating process, it is preferable to use an aqueous coating liquid containing an aqueous thermosetting silicone resin composition described later.

Also, the coating method is not particularly limited, and any known coating technique can be used as a coating method for aqueous emulsion. For example, the coating can be applied on the longitudinally uniaxially stretched polyester film obtained in the primary stretching process by methods such as roller coating, spray coating, gravure coating, reverse gravure coating, or slot coating. .

The release film of the present invention is characterized in that the coating agent is applied in-line. In the release film of the present invention, the coating agent is applied in-line, the second axis is then stretched, and the heat treatment is performed to complete the heat treatment for the release film. And after that, there is no heat off-line. For this reason, the physical properties set as the target values for the release film production, in particular, the longitudinal elongation rate (S _MD ), the transverse elongation rate (S _TD ), and the longitudinal thermal elongation rate (HS _MD) ), It can be used for actual use while maintaining the thermal expansion rate (HS _TD ) in the width direction. That is, in the release film of the present invention, by applying the coating agent in-line, the target value of the physical properties in producing the release film becomes the final physical property of the release film, so that the dimensional stability is improved. It becomes an excellent release film. On the other hand, in the method of applying a coating agent for forming a release layer off-line using a polyester film once formed, the solvent contained in the coating agent is removed by drying, and the resin that becomes the release layer is removed. It is necessary to go through a curing step. In the process of curing the resin to be the release layer, it is necessary to apply a temperature around 1550, so the release film with the release layer formed off-line is both in the longitudinal and width directions of the release film. However, the elongation rate is increased, and the film is undesirably stretched in the conveying process of the ceramic layer Z release film composite.

In the release film of the present invention, after the coating agent is applied in-line to obtain a coating film, the heat applied in the preheating, second-axis stretching, and heat setting steps after coating. Only to remove the solvent from the coating film and harden the resin contained in the coating.

And resin which becomes a mold release layer can be stuck to a polyester film. Therefore, it is not necessary to provide a special process for drying and curing the coating film, and therefore, a release film having excellent dimensional stability can be obtained, and the process for obtaining the release film is not complicated. .

In addition, the release film of the present invention is characterized in that the coating agent is applied to a uniaxially stretched polyester film in-line. By setting it as such an aspect, the adhesiveness of a mold release layer and a polyester film can be made higher. In addition, it becomes easy to adjust the type and amount of the surfactant contained in the release layer, and the effect of improving the peel-off antistatic property can be enhanced.

The solid content concentration of the coating is preferably 0.5% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and particularly preferably 1.5% by mass or more and 10% by mass or less. preferable. When the solid content concentration of the coating is less than 0.5% by mass, when the coating is applied to the surface of the polyester film, the coating tends to be repelled on the surface of the polyester film and cannot be applied uniformly. It is in. On the other hand, if it exceeds 30% by mass, the resulting release layer may become cloudy, or the coating may be easily gelled, or the cost may be low and the effect may be reduced. There is.

[Secondary stretching process] In the secondary stretching process, the polyester film having the coating film obtained by the in-line coating process is stretched in the width direction (hereinafter, sometimes referred to as lateral stretching), whereby a biaxially stretched polyester film is obtained. obtain. -At this time, prior to the secondary stretching process, (Tg + 10) X: or more (Tg + 30): If auxiliary heating is performed under the following temperature conditions, the solvent contained in the coating will be sufficiently dried. It is preferable because it can be uniformly stretched in the subsequent secondary stretching step.

In the secondary stretching process, (Tg + 10) or more (Tg + 80) or less, preferably the auxiliary heating temperature or more (Tg + 70) or less, and the following temperature conditions, 3.0 times or more in the width direction. 5. Stretch in the range of 0 times or less. When the draw ratio in the width direction is in the above numerical range, the thickness unevenness in the transverse direction is excellent. When the draw ratio in the width direction is too low, the thickness unevenness in the transverse direction tends to deteriorate. On the other hand, when the draw ratio in the width direction is too high, the film tends to break during production. From such a viewpoint, the draw ratio in the width direction is more preferably 3.5 times or more and 4.5 times or less, further preferably 3.9 times or more and 4.3 times or less, and particularly preferably 4.0 times or more 4 Less than 2 times.

In the present invention, the surface draw ratio (longitudinal draw ratio X transverse draw ratio) is preferably 15 or more, and thickness spots in the machine direction and the transverse direction can be improved. The surface draw ratio is more preferably 16 or more.

The relationship between the stretching ratio in the primary stretching step in the present invention (hereinafter sometimes referred to as the longitudinal stretching ratio) and the stretching ratio in the secondary stretching step (hereinafter sometimes referred to as the lateral stretching ratio). The longitudinal draw ratio is preferably equal to or less than the transverse draw ratio. If the relationship of longitudinal stretch ratio ≤ lateral stretch ratio, the longitudinal stretch ratio (S _MD ), the lateral stretch ratio (S _TD ), and the longitudinal thermal stretch ratio (HS _MD ), the lateral thermal stretch It becomes easy to control the rate (HS _T _D ) to a desired value.

[Heat setting process]

In the heat setting step, a release film is obtained by heat setting the biaxially stretched polyester film obtained in the secondary stretching step.

The temperature condition for heat setting depends on the type of polyester that makes up the polyester film. Although it is more different, in general, it is preferable that the temperature is (T g +70) or more and (Tm) in the following temperature range. For example, when the polyester is polyethylene terephthalate, it is preferably heat-set in a temperature range of 1800 to 235. In addition, when the polyester is polyethylene-2,6-naphthalate, it is preferably heat-set in a temperature range of 1 85 to 2 40. By heat-setting within this temperature range, desired elongation rates (S _MD and S _TD ) and thermal elongation rates (HS _MD and HS _TD ) can be obtained. Here, Tm represents the melting point (in units) of polyester.

In addition, heat fixation is not performed in only one zone, but is preferably performed in stages divided into a plurality of zones. Preferably, the temperature is controlled in three or more zones. For example, when heat setting is performed in three zones, the first zone should be between 1800 and 210, the second zone should be higher than the first zone, and the maximum temperature among the three zones. Set. The third zone is preferably set to a temperature lower than that of the second zone, and is set to 1 80 or more and 2 0 or less. In this way, the second zone is set to the maximum temperature, and the third zone is set to a lower temperature and heat-fixed, so that the flatness of the obtained release film is kept good and the thickness variation of the ceramic sheet is reduced. Can do. The heat setting time is not particularly limited, and for example, it is preferably about 1 second or more and 60 seconds or less.

In addition, in order to obtain the desired thermal expansion rate (HS _TD ) in the width direction of the release film, the film is relaxed by reducing the rail width by about 2% to 5% in the last zone of the heat setting process. It is preferable to do.

[Cooling process] (Optional process)

The release film of the present invention may optionally be provided with a cooling step after the heat setting step. By providing a cooling step, the flatness of the obtained release film can be kept good, and the thickness unevenness of the ceramic sheet can be reduced.

In the cooling process, the cooling temperature is preferably (T g−30) t: or more and (T g +20) in the following range. In the same manner as in the heat setting process, a plurality of zones are used. It is preferable to carry out separately. If the cooling temperature is lower than the above range, heat 1

Both elongation ratios (HS _MD and HS _TD ) may be too small. On the other hand, when the cooling temperature is higher than the above numerical range, even in the vicinity of the center line in the longitudinal direction of the film, even if the physical properties are uniform in each direction, a phenomenon occurs in which the oblique orientation becomes stronger at the side edges in the longitudinal direction. Therefore, it is not preferable. The phenomenon that the side edge in the longitudinal direction is obliquely oriented can occur on the lower limit side of the preferred range of the heat setting temperature, but the degree is relatively small. <Polyester film>

[Polyester] It may be a homopolyester or a copolyester.

In the case where the polyester film used in the present invention is made of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Here, examples of the aromatic dicarboxylic acid to be used include terephthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of the aliphatic glycol used include ethylene glycol, diethylene glycol, 1,4-cyclohexane dimethanol, and the like. Typical examples of the homopolyester of the polyester film used in the present invention include polyethylene terephthalate (PET), polyethylene-2,6-naphthalate (PEN), and the like.

On the other hand, when the polyester forming the polyester film used in the present invention is a copolymerized polyester, 20 mol% or less of a dicarboxylic acid and Z or glycol as the third component are copolymerized with respect to the total acid component. It is preferable to be a copolymer.

Examples of the dicarboxylic acid that is a monomer component of the copolyester include isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, P-oxybenzoic acid, etc.) ) And the like, and one or more of these can be used. In addition, glycols that are monomer components of the copolymerized polyester include ethylene glycol, polyethylene glycol, propylene glycol, butanediol, 1,4-cyclohexane. Examples thereof include xanthanimethanol and neopentyl glycol, and one or more of these can be used.

As a material of the polyester film used in the present invention, among these,

80 mol% or more, preferably 90 mol% or more of polyethylene terephthalate having ethylene terephthalate units, or 80 mol% or more, preferably 90 mol% or more of ethylene terephthalate. Polyethylene 1, 2 -naphtholate, which is a naphtholate unit, is preferred, and polyethyleneterephrate rate is particularly preferred. Generally, Tg of polyethylene terephthalate is around 78 and low, so when using polyethylene terephthalate film as a carrier film for manufacturing ceramic sheets processed at around 100 ° C. In particular, dimensional stability during the process was a particular problem. On the other hand, since the release film of the present invention is excellent in dimensional stability, the performance as a release film can be sufficiently exerted even when used at a temperature far exceeding Tg. .

[Additives] It is preferable to blend particles mainly for the purpose of imparting slipperiness when used as a film. The type of particles to be blended is not particularly limited as long as it can impart lubricity, and specifically, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate. And particles of magnesium phosphate, kaolin, aluminum oxide, titanium oxide, and the like.

Further, heat-resistant organic particles such as those described in Japanese Patent Publication No. 5-9-5 2 16 and Japanese Patent Application Laid-Open No. 59-2 1 7 75 5 may be used. Other examples of the heat-resistant organic particles include particles made of silicone resin, thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin, and the like. Furthermore, it is possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed during the production process of the polyester.

The shape of the particles for imparting the slipperiness as described above is not particularly limited, and any of a spherical shape, a lump shape, a rod shape, a flat shape, and the like may be used. Also its hardness, ratio The weight, color, etc. are not particularly limited. Furthermore, two or more kinds of these particles can be used in combination as required.

The average particle size of the particles is preferably from 0.1 zzm to 1 zzm, and more preferably from 0.2 / m to 0.5 / zm. When the average particle size is less than 0.1 m, the particles tend to aggregate and dispersibility may be insufficient. On the other hand, if it exceeds l zm, the surface roughness of the resulting polyester film becomes too rough, and the release film has a maximum release layer surface height (Rmax) and no release layer. It is difficult to make the maximum height (Rm ax) of the side surface 10 0 nm or more and 60 0 nm or less.

Further, the content of the particles to be blended for imparting slidability is preferably from 0.1 to 2% by mass, preferably from 0.1 to 1% by mass in the polyester film. Is more preferable. If the content of the particles is less than 0.01% by mass, the slipperiness of the film tends to be insufficient. On the other hand, if it exceeds 2% by mass, the smoothness of the film surface tends to be insufficient.

The method for incorporating the particles in the polyester film is not particularly limited, and conventionally known methods can be employed. For example, in any stage of producing polyester, it is preferable to add particles to be mixed, or to mix the particles after completion of the transesterification reaction, and then proceed to the polycondensation reaction. . 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 dried particle and a polyester raw material using a kneading extruder It can also be performed by a method of blending and the like.

[Layer structure]

The structure of the polyester film in the present invention is not particularly limited, and may be a single layer structure or a laminated structure. Further, in the case of a laminated structure, other than the two-layer or three-layer structure, a multilayer having four layers or more may be used as long as the gist of the present invention is not exceeded. The laminated structure is not particularly limited, and examples thereof include laminated structures such as A / B, A / B / A, AZBZC, and -A / B / A '. it can. Here, A, B, and C each represent a layer made of the above-described polyester, and may be the same or different. A 'represents a layer of polyester, which is especially similar in structure to A.

[Thickness of polyester film]

The total thickness of the polyester film in the present invention is not particularly limited, but preferably 9 // m or more and 50 m or less, more preferably 15 m or more and 38 m or less, particularly preferably 25 zm or more. 3 1 / m or less.

Release layer>

[Silicone resin composition]

Since the release layer in the present invention is stable as an emulsion, it is preferably formed mainly from a silicone resin composition. What is a silicone resin composition?

A main agent composed of a polysiloxane having at least two unsaturated groups or hydroxyl groups in one molecule, and a hydrogen having at least two hydrogen atoms directly bonded to a silicon atom in one molecule. It contains a cross-linking agent made of polysiloxane as a constituent component. In the present invention, an aqueous coating liquid (coating agent) containing such a silicone resin composition is applied to form a coating film, and the coating film is cured to form a release layer.

The silicone resin composition in the present invention is preferably an aqueous silicone resin composition. Since the aqueous silicone resin composition is excellent in stability when it is emulsified, the stability of the coating material can be increased as a result. In addition, there are a wide range of surfactant options to be described later. For example, a surfactant containing more hydroxyl groups can be used, and the effect of improving the antistatic property of peeling can be increased. In addition

From the viewpoint of the environment, it is preferable to use a water-based coating agent.

In the present invention, examples of the method for curing the silicone resin composition include thermal curing, ultraviolet curing, electron beam curing, etc., among which thermal curing is preferable. That is, as the silicone resin composition, A thermosetting silicone resin composition is preferred. In the present invention, as described above, a polyester film having a coating film is obtained in the in-line coating process, and heat treatment is performed in the subsequent heat setting process. Is made. If the silicone resin composition is a thermosetting silicone resin composition, the crosslinking reaction can be accelerated by heat treatment in the heat setting step, and the curing of the silicone resin composition can be sufficiently progressed. A release layer having excellent properties such as excellent properties can be obtained.

From the above, as the silicone resin composition in the present invention, an aqueous thermosetting silicone resin composition is particularly preferable. Here, “mainly” means that 75% by mass or more is formed from the silicone resin composition with respect to the weight of the release layer.

Silicone resin compositions include addition polymerization types (when the main agent is made of polysiloxane having at least two unsaturated groups in one molecule) and condensation types (the main agent has at least two hydroxyl groups in one molecule). In the case of an addition polymerization type, the coating material contains platinum as a catalyst, and in the case of a condensation type, the coating material contains tin as a catalyst. Is preferred. Of these, the addition polymerization type is preferable from the viewpoint of excellent peeling properties. Further, as the crosslinking agent, those recommended by the manufacturer of the main agent used at the same time can be preferably used.

Specific examples of the water-based thermosetting silicone resin composition that can be suitably used in the present invention are shown below.

1) Water-based 400 E silicone resin composition of Wacker Silicone (Adrian, Michigan). V 20 crosslinker system comprising polysiloxane, platinum catalyst, and methylhydrogen polysiloxane.

2) Aqueous X2 1 7720 silicone resin composition of Dow Cornining (Mid 1 a n d, Michigan). Methylvinylpolysiloxane, and methylhydrogenpolysiloxane containing X2-7721 crosslinker system consisting of platinum polysiloxane.

3) Aqueous PC-105 silicone resin composition of PCL (Phone-Pou 1 en c Inc., Roc Hill, South Carolina). PC_95 catalyst component consisting of methyl vinyl polysiloxane and platinum polysiloxane It consists of methyl hydrogen polysiloxane.

4) P C L P C—10 7 Water-based silicone resin composition (similar to P C—10 5). Contains the above P C-9 5 crosslinker.

5) P C L P C— 1 8 8 Water-based silicone resin composition (similar to P C—1 0 5). Contains the above P C-9 5 crosslinker.

These water-based thermosetting silicone resin compositions can be used as a coating agent with the solid content concentration adjusted as appropriate by adding deionized water or the like.

[Silane coupling agent]

Furthermore, the release layer in the present invention preferably contains a silane coupling agent. As the silane coupling agent, either a polyester resin or a silicone resin composition, or an organic silicon low molecular weight compound having a reactive group bonded to both, is preferable, and as such a reactive group, a methoxy group, an ethoxy group, Organic low molecular weight compounds having at least one kind such as silanol group, vinyl group, epoxy group, (meth) acrylic group, amino group, mercapto group, chloro group, hydroxyl group, strong lpoxyl group preferable.

The content of the silane coupling agent is preferably 0.1% by mass or more and 20% by mass, more preferably 1% by mass or more and 10% by mass or less, with respect to the solid content weight of the release layer. % Or more and 7% by mass or less is particularly preferable. By making the content within the above numerical range, the adhesion of the release layer can be enhanced.

[Surfactant]

The release layer in the present invention preferably contains 0.5% by mass or more and 10% by mass or less surfactant based on the solid content weight of the release layer. When the release layer contains the surfactant in an amount in the above numerical range, the release charge when unwinding the roll release film and the release when peeling the ceramic sheet from the release film Charging can be suppressed. In addition, when manufacturing the multilayer ceramic capacitor, it is possible to suppress the displacement of the internal electrodes. Furthermore, in the coating agent, by adding a surfactant, the wettability of the coating agent on the surface of the polyester film is improved. As a result, local repellency defects of the coating agent are suppressed, and a uniform coating film is formed. obtain As much as possible, it can suppress the pinhole defect generated when peeling the ceramic sheet.

From such a viewpoint, the content of the surfactant is more preferably 1.0% by mass or more and 7.0% by mass or less, and particularly preferably 2.0% by mass, based on the total dry weight of the release layer. More than 5.0% by mass. When the content is less than 0.5% by mass, the peeling charge becomes high. In addition, the wettability of the coating tends to be insufficient with respect to the polyester film surface. On the other hand, when it exceeds 10% by mass, the peeling force on the ceramic sheet tends to be heavy peeling, which is not preferable.

Examples of surfactants include ionic surfactants (anionic surfactants, cationic surfactants, zwitterionic surfactants), and nonionic surfactants (nonionic surfactants). Can do. Of these, nonionic surfactants are preferred. When an ionic surfactant such as an anionic surfactant, a cationic surfactant, or an amphoteric surfactant is used, a silicone resin composition for these surfactants to form a release layer As a result, the silicone resin composition may not be sufficiently cured.

Nonionic surfactants include polyoxyethylene, polyhydric alcohol fatty acid ester, polyhydric alcohol alkyl ether, nitrogen-containing surfactants, nonionic silicone surfactants, nonionic surfactants, and the like. Examples thereof include fluorine-based surfactants.

Polyoxyethylene surfactants include poly (oxyethylene) alkyl ether, poly (oxyethylene) alkylphenyl ether, poly (oxyethylene) poly (oxypropylene) alkyl ether, poly (oxyethylene) fatty acid ester, poly (oxyethylene) ) Examples include sorbin fatty acid esters. Among them, as poly (oxyethylene) alkyl ether, polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, etc. having 12 or more carbon atoms Preferred examples include poly (oxyethylene) alkyl ethers having an alkyl group. . Such an alkyl group may be linear or branched. Examples of the polyhydric alcohol fatty acid ester type surfactant include propylene dallicol fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester. Examples of the polyvalent alcohol alkyl ether type surfactant include alkyl polyglycoxide. Examples of the nitrogen-containing surfactant include alkyl ether amides and alkyl amine oxides.

Examples of the silicone surfactant include polyether-modified silicone and polyglycerin-modified silicone. In addition, the structure of such modified silicone includes: side chain modified type, both end modified type (ABA type), one end modified type (AB type), both end side chain modified type, linear block type (AB n type), Although it is classified as a branched type, it may be of any structure.

Of these, polyoxyethylene surfactants and silicone surfactants are preferred as the surfactant in the present invention. These are less likely to be a catalyst poison of the silicone resin composition, and can exhibit sufficient wettability. Particularly preferred is a silicone-based surfactant, which is less likely to be a catalyst poison, can have a more excellent release property, and can further enhance the effect of improving the antistatic properties of peeling.

The thickness of the release layer (that is, the thickness after drying) in the present invention is not particularly limited, but is preferably 20 nm or more and 90 nm or less. In general, if it is less than 20 nm, it is difficult to exert the effect as a release layer such as a light peeling force. On the other hand, if it exceeds 90 nm, the effect obtained for the cost is reduced.

The release film of the present invention can be used as a separator for sheet forming films such as resin sheets and ceramic sheets, or adhesive films for labels, medical use, office supplies and the like.

In particular, the release film of the present invention sufficiently satisfies the performance required for the release film during the production of the ceramic sheet. It can be suitably used as a carrier film. When a ceramic sheet is produced by using the release film of the present invention, a thin ceramic sheet can be obtained with high precision, and the obtained thin ceramic sheet can be multilayered with internal electrodes as the size and capacity increase. Therefore, it can be suitably used for multilayer ceramic capacitors that are required to be made.

In the production of the ceramic sheet, the prepared ceramic slurry may be applied to the surface of the release layer of the release film of the present invention, and the solvent contained in the ceramic slurry may be removed by drying. The method for applying the ceramic slurry is not particularly limited, and a conventionally known application method can be used. For example, a ceramic slurry in which ceramic powder and a binder agent are dispersed in a solvent can be applied by a reverse roll method, and the solvent can be removed by heat drying. It does not specifically limit as a binder agent to be used, For example, a polyvinyl butyral etc. can be used. Further, the solvent to be used is not particularly limited, and for example, ethanol, toluene and the like can be used.

Gu film roll>

The film roll of the present invention is obtained by winding the release film obtained above in a roll shape. The release film roll may be a parent roll obtained directly by the above-described release film manufacturing process, or a slit roll obtained by slitting the parent roll to the width and length required by the customer. Also good.

The film roll of the present invention has a Vickers hardness (H v) of a roll surface layer of 0 or more and 45 or less. By setting the Vickers hardness (H v) of the roll surface layer within the above numerical range, a release film having excellent flatness can be obtained. In addition, in the release film roll, winding deviation and wrinkle hardly occur.

Vickers force is a diamond square indenter with a diagonal angle of 1 to 36 degrees, and the load when a pyramid-shaped dent is attached to the test surface is divided by the surface area obtained from the diagonal length of the permanent dent. The quotient is calculated by the following formula.

H v = (2 · Ρ · sin (a / 2)) / ά ²

P: Load (kg), d: Average length of diagonal lines (mm), a: Diagonal angle Since α = 136 degrees, the above equation becomes

Ην = 1. 8 δ 4 XP / d ²

In general, when a film is wound into a roll shape, a portion where the film thickness is thick is tightened as the winding diameter increases, which may be a so-called band-shaped defect. In such areas, the film stretches and the flatness of the film is impaired. This tendency becomes more remarkable as the picker hardness (Hv) of the roll surface layer increases. That is, when the Vickers hardness (Hv) of the roll surface layer exceeds 450, the tightening is too strong, the film is stretched too much, and the flatness of the film is inferior. From such a viewpoint, the upper limit of the pickers hardness (Hv) of the roll surface layer is preferably 430 or less, more preferably 420 or less, and particularly preferably 410 or less. On the other hand, when the Vickers hardness (Hv) of the roll surface layer is too low, winding deviation tends to occur, but it is preferable that the roll surface layer is low as long as such a problem does not occur. From such a viewpoint, the lower limit of the pickers hardness (HV) of the roll surface layer is preferably 340 or more, more preferably 360 or more, and particularly preferably 380 or more.

The picker hardness (Hv) of the roll surface as described above can be achieved by adjusting the winding conditions such as the winding tension and the nipping pressure when winding the release film.

The initial tension must be 49 NZm or less as the winding tension. By setting the initial tension within the above numerical range, the Vickers hardness (Hv) of the roll surface layer can be made 450 or less. Further, the amount of air taken in during winding becomes an appropriate amount, and the influence of film thickness unevenness can be reduced, that is, winding tightening can be suppressed, and flatness is excellent. Moreover, winding deviation can be suppressed. When the initial tension is too high, the Vickers hardness (Hv) of the roll surface layer tends to be too high. In addition, the amount of air entrained during winding tends to decrease, and the flatness tends to be poor. From such a viewpoint, the upper limit of the initial tension is preferably 48 NZm or less, more preferably 47 N / m or less. On the other hand, if the initial tension is too low, the winding becomes unstable and the film tends to meander. Force that tends to cause uneven roll end faces, wrinkles, or slit failure. Low force is preferable unless these problems occur. From such a viewpoint, the lower limit of the initial tension is preferably 3 O NZm or more. The initial tension means a tension when the release film as a product is substantially wound in a roll shape, and does not necessarily indicate a tension immediately after starting to roll on the core. That is, in general, for the purpose of reducing the influence of foreign matter, scratches, etc. on the core surface, a method is used in which the take-up tension from several meters to several tens of meters is particularly high immediately after starting to be wound around the core. However, it does not indicate the winding tension in such a part. In addition, it is necessary to provide a tension taper to make the final tension lower than the initial tension. Specifically, the ratio of final tension to initial tension (tensile taper ratio) must be 80% or less. By setting the tension taper ratio within the above numerical range, it is possible to suppress the winding slip while keeping the Vickers hardness (H v) of the surface of the tool low. When the tension taper ratio is too high, the Vickers hardness (Η V) of the roll surface layer tends to be too high. From such a viewpoint, the upper limit of the tension taper rate is preferably 70% or less, and more preferably 60% or less. On the other hand, from the viewpoint of roll hardness, it is preferable that the tension taper rate is low. However, if the tension taper rate is too low, the final tension tends to be too low and problems such as roll end face misalignment tend to occur. From such a viewpoint, the lower limit of the tension taper rate is preferably 30% or more. In the present invention, there may be a portion where the winding tension increases from the initial tension to the final tension as long as the winding tension does not exceed 49 N / m, but in the main part of the roll, A mode in which the winding tension is gradually decreased continuously is preferable, and a mode in which the winding tension is gradually decreased at a constant rate is preferable. By adopting the tension taper as described above, the internal stress in the winding direction can always be 0 or more in the roll, and there is a problem such as lateral crease defects (T bars) Can be suppressed. Here, the main part of the roll means a part 5 mm or more outside the core surface layer and 5 mm or more inside the roll surface layer in the roll radial direction.

From the above initial tension and tension taper ratio, the final tension is less than 39 NZm It is necessary to. By setting the final tension within the above numerical range, the Vickers hardness (H v) of the roll surface layer can be made 4500 or less. When the final tension is too high, the Vickers hardness (H v) of the roll surface layer tends to be too high. From such a viewpoint, the upper limit of the final tension is preferably 3 8 NZm or less, and more preferably 3 O NZm or less. On the other hand, from the viewpoint of roll hardness, it is preferable that the final tension is low. However, if the final tension is too low, the winding becomes unstable and the film tends to meander, and problems such as roll end face misalignment occur. Tend to occur. From such a viewpoint, the lower limit of the final tension is preferably 1 O NZm or more, more preferably 1 S NZm or more.

As the nip pressure, the initial nip pressure needs to be 20 O NZm or less. By setting the initial nip pressure within the above numerical range, the picker hardness (Hv) of the roll surface layer can be reduced to 4500 or less. In addition, the amount of air entrained during winding becomes an appropriate amount, which can reduce the influence of uneven thickness of the film, that is, it can suppress the tightening of the film, and is excellent in flatness. Moreover, winding deviation can be suppressed. When the initial nip pressure is too high, the Vickers hardness (H v) of the roll surface layer tends to be too high. In addition, the amount of air entrained during winding tends to decrease, and the flatness tends to be poor. From such a viewpoint, the upper limit of the initial nip pressure is preferably 1 8 O NZm or less, more preferably 1600 NZm or less, and particularly preferably 1 2 O NZm or less. On the other hand, when the initial nip pressure is too low, the winding tends to be unstable, and winding misalignment and wrinkles tend to occur. From such a viewpoint, the lower limit of the initial nip pressure is preferably 50 NZm or more, more preferably 80 NZm or more.

Also, the nip pressure taper does not have to be attached, but it is possible to generate wrinkles and pin pulls and roll rolls by applying a two-up pressure taper with a two-up pressure taper ratio of 10% to 10%. End face shift can be suppressed.

From the above initial nip pressure and nip pressure taper ratio, the final nip pressure should be 2 2 O NZm or less, but if the final nip pressure is too high, the Vickers hardness (H v) of the roll surface layer will be It tends to be too high. Such a perspective Therefore, the upper limit of the final nip pressure is preferably 17 ONZm or less, more preferably 150 NZm or less, and particularly preferably 14 ONZm or less. On the other hand, if the final nip pressure is too low, the winding tends to be unstable. From such a viewpoint, the lower limit of the final nip pressure is preferably 5 ONZm or more, more preferably 70 N / m or more, and particularly preferably 90 NZm or more. Example

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these unless it exceeds the gist.

In the examples and comparative examples, the following items were measured and evaluated by the following methods.

(1) Average particle size

Made by Shimadzu Corp., trade name: Cp 50 type centrifudal particle size analyzer (Cen tri fuga 1 Par t c i c e S ize A n a 1 y ze r) was used for measurement. From the integrated curve of the particles of each particle size calculated based on the centrifugal sedimentation curve obtained by measurement and their abundance, read the “equivalent sphere diameter”, which is the particle size equivalent to 50 mass percent, and use this value as the particle size. (Refer to Book “Particle Size Measurement Technology” published by Nikkan Kogyo Shimbun, 1975, pages 242 to 247).

(2) Maximum height (Rmax)

Compliant with JIS standards (B 0601: Definition and display of surface roughness, B 0651: Probe surface roughness measuring instrument), 3D surface roughness meter (trade name: SE-3AK manufactured by Kosaka Laboratory) , Magnification: 20,000 times, Scanning pitch: 2 / _im, Scanning length: lmm, Scanning number: 100, Cut-off: 0.25mm, and find the maximum height of the area, 10 The average value of the point measurement results was defined as Rmax (unit: nm).

(3) Elongation rate under load (S _MD , S _TD )

Using TMA (Seiko Instruments Inc., trade name: SS 6000) Humidity: Under 50% RH, sample width: 4mm, between chucks: 2 Omm, in the longitudinal direction, with a load of 0.3MPa, 1.0MPa and 2.5MPa respectively. The temperature was increased from a starting temperature of 30 to a heating rate of 10: Z minutes. From the expansion and contraction behavior of the film when reaching 100, the following formula was used to calculate the elongation rate (S _MD ) (unit:%) under each load condition of 0.3MPa, 1. OMPa, 2.5MPa. It was. Similarly, measurement was performed with a load of 0.0 IMP a in the width direction, and the elongation rate (S _TD ) (unit:%) under the load condition was determined. The elongation ratios ( _SMD and _STD ) were obtained from 10 samples each and the average value was obtained.

Elongation rate (S _MD , S _TD ) = (厶 MZM ₀ ) XI 00 ()

△ M = M— M _Q

In the above formula, M. Is the length in the longitudinal or width direction of the film before heat treatment, and M is the length in the same direction of the film after heat treatment. That is, when the elongation rate (S _MD ) and the elongation rate (S _TD ) are negative, the film is contracted, and when it is positive, the film is stretched.

(4) Thermal elongation rate under no load (HS _MD , HS _TD )

In an oven set at a temperature of 100, a film sample having a length of about 30 cm, which had been accurately measured in advance, was suspended and held for 30 minutes under no load. After 30 minutes, remove the film sample from the oven, return to room temperature, measure its dimensional change, and calculate the thermal elongation rate (HS _MD , _ HS _TD ) (unit:%) using the following formula. It was. The elongation rate (HS _MD , HS _TD ) was obtained for each of 10 samples, and the average value was obtained.

Thermal expansion rate (HS _MD , HS _TD ) = (AL / L ₀ ) XI 00 () AL = LL ₀

In the above formula, L. Is the length in the longitudinal direction or width direction of the film before heat treatment, and L is the length in the same direction of the film after heat treatment. That is, when the thermal elongation rate (HS _MD ) and the thermal elongation rate (HS _TD ) are negative, the film is contracted, and when it is positive, the film is expanded. (5) Evaluation of surface smoothness of ceramic sheet (Practical property substitution evaluation)

(Condition 1) On the release layer side surface of the release film, a ceramic slurry having the following composition was applied using a Dyco overnight to form a ceramic layer with a thickness of 5 tm after drying. Rolled up.

(Condition 2) A release film roll having a width of 450 mm and a length of 2,000 m was prepared. A ceramic rally having the following composition is applied to the surface of the release layer of such a release film at a film transport speed of 6 OmZ using Daiko Yui, and the thickness after drying becomes 5 zm. A ceramic layer was formed, and a ceramic layer release film composite having a length of 1,900 m was obtained and wound into a roll.

Thereafter, in the ceramic layer release film composite obtained from Conditions 1 and 2, the ceramic layer was peeled from the release film to obtain a ceramic sheet. The surface of the obtained ceramic sheet (measurement area: lm ² ) is observed on both sides using a scanning laser microscope (made by Lasertec), and the surface smoothness is evaluated according to the following evaluation criteria. did.

[Ceramic slurry composition]

• Barium titanate (manufactured by Fuji Titanium Co., Ltd., average particle size: 0.7 ^ m): 100 parts • Polyvinyl petital resin (manufactured by Sekisui Chemical Co., Ltd., trade name: S-REC BM—S): 30 parts

• Plasticizer (dioctyl phthalate): 5 parts

· Toluene ethanol mixed solvent (mixing ratio: 6: 4): 200 parts

[Surface smoothness evaluation criteria]

◯: 2 craters (dents) of depth of 0.05 ^ m or more Zm ² or less

(Practical, no problem level)

: 0.5 m or more craters (dents) exceeding 2 Zm ² and 6 and less than Zm ²

(Practical level that may cause problems)

X: 6 craters (recesses) with a depth of 0.5 im or more m ² or more

(Practical problem level) (6) Release charge evaluation of release film

When carrying out the evaluation of (5) (Condition 2) above, the peel charge amount when unrolling the release film roll was measured. Concentrated potential meter (made by Kasuga Denki Co., Ltd., product name: electrostatic potential) from the release film surface immediately after unwinding from the roll (on the roll, the inner surface of the roll) vertically upward, at a distance of 5 cm A measuring instrument SV-10) was installed, and the peel charge amount was measured in an atmosphere with a temperature of 22 and a humidity of 44% RH. While unrolling the entire length of the release film roll of 2,000m, measure the peel charge amount at least 15 points every 100m, and use the average value as the peel charge amount (unit: kV) of the release film. did. Alternatively, the evaluation was performed according to the following evaluation criteria.

[Evaluation criteria for release film peeling electrification]

○: Peeling charge amount is 2.0 kV or less

X: Peeling charge exceeds 2. O kV (Peeling charge failure)

(7) Evaluation of peeling electrification of ceramic sheet

A ceramic layer Z release film composite was obtained in the same manner as in (5) (Condition 2) above. On the surface of the ceramic layer of the obtained ceramic layer Z release film composite, a patterned Ni electrode printed layer having a thickness of 3 m after drying was formed as a metal film by screen printing. Next, the obtained metal film / ceramic layer / release film composite was cut into a size of 30 Omm × 30 Omm to obtain a single-wafer sample. With respect to the obtained single wafer sample, the metal film Z ceramic layer composite was peeled from the release film at a peeling speed of 2 Om, and the peel charge amount in the peeling was measured. Concentrated potential measuring device (manufactured by Kasuga Electric Co., Ltd., trade name: electrostatic potential measuring device SV-10) is installed at a distance of 5 cm from the surface of the ceramic layer of the peeled metal film / ceramic layer composite. The peel charge amount was measured in an atmosphere of temperature: 22 and humidity: 44% RH. The measurement was carried out on 100 single-wafer samples, and the average value was taken as the peel charge amount (unit: kV) of the ceramic sheet. Or, the evaluation was performed according to the following evaluation criteria.

[Ceramic sheet peeling charge evaluation criteria]

○: Peeling charge amount is 20 kV or less (Peeling charge is good) X: Peeling charge amount exceeds 20 kV (Peeling charge failure)

(8) Evaluation of peeling of ceramic sheet

Regarding the single-wafer sample in (7) above, when the metal film no ceramic layer composite was peeled from the release film, the state of the peeling was evaluated according to the following evaluation criteria.

[Peeling evaluation criteria]

◎: Peeling force is moderate, metal film Z ceramic layer does not break, and no residual ceramic layer is seen in the release film (a level that causes no problem in practical use)

◯: Slightly heavy peeling force, slight breakage in the metal film Z ceramic layer, or a slight residual ceramic layer in the release film (no problem in practical use)

X: The peel force was too heavy, the metal film was broken in the ceramic layer, or the ceramic layer remained in the release film (practically problematic level)

(9-1) Lamination evaluation of ceramic sheets 1 (Practical property substitution evaluation)

On the ceramic sheet obtained in (5) (Condition 1) above, a patterned Ni electrode printed layer (thickness after drying was 3 / m) was laminated. Using the obtained ceramic sheet electrode laminate, 10 layers were stacked based on the edge of one side, and the displacement evaluation was performed according to the following evaluation criteria for the degree of displacement of the electrode printing layer. did.

[Position evaluation criteria]

◎: Misalignment is less than 200 m (a level where there is no practical problem)

○: Misalignment is 200 zm or more and less than 400 // m (Practical problem level) X: Misalignment is 400 im or more (Practical problem level)

(9-2) Lamination evaluation of ceramic sheets 2 (Practical property substitution evaluation)

The metal film Z ceramic layer composite after cutting and peeling, obtained by the same method as in (7) above, is laminated into 10 layers using a swinging machine that detects the position with a CCD camera. Got. About the obtained laminated body, the amount of deviation of each layer was measured using a microscope with reference to the first metal film ceramic layer composite. The obtained value was defined as a positional deviation (unit: / m). The evaluation was conducted according to the following evaluation criteria. Lamination was performed immediately after the release film was peeled off.

[Position evaluation criteria]

: Misalignment is less than 200 Atm (a level where there is no practical problem)

○: Misalignment of 200 / zm or more and less than 400 m

X: Misalignment of 400 / zm or more (practical problem level)

(10) Vickers hardness of roll surface layer (Hv)

Measurement was carried out by the following method according to the method of J I S Z2244 (1961). In the surface layer of the release film roll obtained in the example, 10 points were measured in the width direction excluding the 5 mm portion from the end face, and the maximum value was defined as the Vickers hardness (Hv) of the roll surface layer.

(11) Slip

About the release film roll obtained in the Example, the condition of the end face winding deviation was evaluated according to the following evaluation criteria.

[Evaluation criteria for winding slip]

◎: Winding deviation is lmm or less (level that can be used suitably without any problem) ○: Winding deviation exceeds 1 mm and 2 mm or less (level that can be used without problems) △: Winding deviation exceeds 2 mm and 3 mm or less (slightly There is a problem with the level that can be used)

X: Winding deviation exceeds 3 mm (Unusable level due to problems)

(12) Flatness

Take a 2m long film sample from the release film roll and spread it on a flat, flat table with the side that was the surface of the roll when it was wound on the roll facing up. After standing for 10 minutes, observe the entire surface of the film sample, measure the length (unit: cm) of ridges (flutes, the part where the film is floating above the base) remaining on the surface, and measure the total The flatness (unit: cm ² / m ² ) was calculated by dividing by the area (unit: m ² ). The flatness was evaluated according to the following evaluation criteria.

[Flatness evaluation criteria] ◎: Flatness is 28 cmZm ² or less (no problem for practical use) ○: Flatness exceeds 28 cmZm ² and 33 cm / m ² or less (no problem for practical use)

X: Flatness exceeds 33 cmZm ² (Practical problem level) (13) Thickness unevenness of film

Using a micrometer (manufactured by Anritsu Co., Ltd., trade name “K-I 402B” type), 10 points are measured at 10 cm intervals in the longitudinal direction of the film, and 10 measurements are taken at 10 cm intervals in the longitudinal direction. The film thickness of 100 points in total was measured, and the average value of the obtained film thicknesses of 100 points was calculated as the film thickness (unit: am). Next, using an electronic micrometer (Anritsu Co., Ltd., product name “K-312A” type), the length of the film was lm and the horizontal direction was 450 mm at a needle pressure of 30 g and a running speed of 25 mmZ seconds. Read the maximum thickness (unit: / m) and the minimum thickness (unit: m) in the vertical and horizontal directions from the obtained thickness, and match it with the above film thickness. Thickness spots (unit:%) were obtained from the following formula.

Thickness unevenness (%) = ((maximum thickness minus minimum thickness) Z film thickness) X I 00 (14) Ceramic sheet thickness unevenness

For the ceramic layer Z release film composite obtained in (5) (Condition 2) above, the thickness was measured using Micromechiichi (trade name “K_402 B”, manufactured by Anritsu Corporation) Next, the ceramic layer at the location where the thickness was measured was completely peeled off, the thickness was measured again at the same location, and the difference between them was determined as the thickness of the ceramic sheet. This operation was carried out for 10 points in the vertical direction at 10 lm intervals, 10 points in the vertical direction, and 10 rows in the horizontal direction at 10 cm intervals in total, 100 points in total. Was the ceramic sheet thickness (unit: / m). Next, among the above 100 measurements, the maximum thickness was the maximum thickness (unit: minimum thickness was the minimum thickness (unit: / m), and thickness spots (unit:%) were determined from the following formula.

Thickness unevenness (%) = ((maximum thickness minus minimum thickness) Z ceramic sheet thickness) XI 00 Evaluation was carried out according to the following evaluation criteria.

[Thickness spot evaluation standard]

◎: Thickness unevenness is 2.0% or less (excellent thickness unevenness, no problem in practical use)

○: Thickness unevenness exceeds 2.0% and 3.0% or less (excellent thickness unevenness, practically no problem)

X: Thickness unevenness exceeds 3.0% (Inferior thickness unevenness, practically problematic level) Example 1

[Production of polyester]

Manganese oxalate 'tetrahydrate as a transesterification catalyst was added to a mixture of 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol so that the amount of mangan element in the resulting polyester was 80 ppm. The transesterification was carried out while gradually raising the internal temperature from 150. When the transesterification reached 95%, 0.01 part of phosphorous acid was added as a stabilizer, and after sufficient stirring, 0.03 part of antimony trioxide was added. Subsequently, after sufficiently distilling water mixed in the system, synthetic calcium carbonate particles having an average particle size of 0.6 z ^ rn as an internal filler (sliding agent) with respect to the mass of the obtained polyester 0.2% by mass was added and stirred thoroughly. The reaction product is then transferred to a polymerization reactor and subjected to polycondensation under a high temperature vacuum (final internal temperature of 295), thereby producing a polyethylene terephthalate composition having an intrinsic viscosity of 0.65 (35 in orthochlorophenol). I got a thing.

[Preparation of paint]

88. 5 parts deionized water, 10 parts silicone emulsion 400 E (from Wacker Silicones, silicone: methylpolysiloxane with vinyl group, platinum catalyst if crosslinker is added) ), 1 part of the cross-linking agent V 72 (Wacker Si 1 ic one s, methyl hydrogen polysiloxane emulsion, methyl siloxane Reacts with a double bond in) and 0.5 parts of a silane coupling agent A coating agent was obtained by adding Koshi Silicone Co., Ltd., trade name: KBM—40 3). The solid content was 5% by mass.

[Unstretched polyester film forming process]

The polyethylene terephthalate composition obtained above was dried for 5 hours until the water content of the polymer at 170 was 0.05% by mass. Continuing with the bow I, the dried polyethylene terephthalate composition was fed to the extruder and melted at a melting temperature of 28.degree. To 30.000, using a steel wire filter with an average opening of 11.1 .mu..eta. After high-precision filtration, an unstretched polyester film having a thickness of 4500 m was obtained by using an extrusion die and rapidly cooling the cooling drum by electrostatic contact.

[Primary stretching process]

The resulting unstretched polyester film is preheated at 75, and subsequently stretched 3.6 times in the longitudinal direction at a film temperature of 105 between low-speed and high-speed rolls, and then rapidly cooled. Thus, a stretched polyester film was obtained in the longitudinal direction (longitudinal direction).

[Inline coating process]

Next, a polyester film having a coating film was obtained by applying the coating agent prepared above to the obtained longitudinally stretched polyester film so that the thickness after drying was 40 nm.

[Secondary stretching process]

Subsequently, a polyester film having the obtained coating film was supplied to the stainless steel, and after preheating for 2 seconds each in two zones at 1 0 5 and 1 15, 1 2 0, 1 3 0, 1 4 5: In 4 zones of 1 5 5, stretched uniformly so that the stretching ratio (transverse stretching ratio) in the direction perpendicular to the longitudinal direction (width direction) is 4.1 times in total for 2 seconds each. A biaxially stretched polyester film was obtained.

[Heat setting process]

The obtained biaxially stretched polyester film was heat-fixed at 2 1 0, 2 2 5 and 3 zones of 1 9 5 for 2 seconds each for a total of 6 seconds, and the final heat fix of 1 95 5 In the zone, a release film having a total thickness of 31 m was obtained by performing 2.δ% relaxation treatment in the direction (width direction) perpendicular to the longitudinal direction. Gain Various measurements and evaluations were performed using the obtained release film. The results are shown in Table 1. Example 2

In the secondary stretching process, the stretching ratio in the direction perpendicular to the longitudinal direction (width direction) was 4.5 times, and the amount of relaxation in the third zone of the heat setting process was 4.0%. A release film was obtained in the same manner. Table 1 shows the results of various measurements and evaluations using the obtained release film.

Comparative Example 1

Biaxially stretched polyester without a release layer in the same manner as in Example 1 except that in the production of the release film, a release agent coating solution that is a water-based thermosetting silicone composition is applied in-line. A film was obtained.

In addition, a toluene solution (solid content concentration: 3% by mass) of an addition-type silicone compound (Toshiba Silicone, trade name: TPR-6 7 2 1) is mixed with a Pt catalyst (Toshiba Silicone, trade name: CM 6700) was added so as to be 1 part by mass with respect to 100 parts by mass of the solid content of the addition-type silicone compound to prepare a release agent coating solution.

Subsequently, the biaxially stretched polyester film mouth having no release layer obtained above was unwound, and the biaxially stretched polyester film unwound in the center in the direction (width direction) perpendicular to the longitudinal direction, Apply the release agent coating solution adjusted as described above to a coating amount (wet) of 6 g Zm ² and use an air levitation conveyor type drying device in which the distance between the lower and upper air flow outlets is 38 cm. Then, the release tension is 2,100 kPa, the drying temperature is 160, and the release layer is formed by drying for 16 seconds. The weight of the release layer after drying and curing is 0.2 g. A release film of Zm ² was obtained. Table 1 shows the results of various measurements and evaluations using the obtained release film.

Comparative Example 2

A release film was obtained in the same manner as in Example 1 except that in the primary stretching step, the stretching ratio in the longitudinal direction (longitudinal direction) was 3.0. Table 1 shows the results of various measurements and evaluations using the obtained release film.

Comparative Example 3

The stretching ratio in the longitudinal direction (longitudinal direction) in the primary stretching process is 4.8 times, secondary stretching A release film was obtained in the same manner as in Example 1 except that the draw ratio in the direction perpendicular to the longitudinal direction (width direction) was 3.0. Table 1 shows the results of various measurements and evaluations using the obtained release film.

table 1

0 Example 3

[Production of polyester]

In the same manner as in Example 1, a polyethylene terephthalate composition having an intrinsic viscosity of 0.65 (35, in orthoclonal phenol) was obtained.

[Preparation of paint]

In 87 parts of deionized water, with stirring, 10 parts of silicone emulsion 400E (manufactured by Wacker Silicones, silicone: methylpolysiloxane having vinyl group, crosslinking agent added) Is used in combination with a platinum catalyst and an inhibitor to prevent premature reaction, solid content 50 mass%), 1 part of cross-linking agent V 72 (made by Wacker Si 1 icones, methyl hydrogen poly Siloxane emulsion, which reacts with double bonds in methylsiloxane, solid content concentration 50% by mass), 0.3 part silane coupling agent (manufactured by Shin-Etsu Silicon Co., Ltd., trade name: KBM— 403), and 0.15 part of polyoxyethylene oleyl ether (trade name: Emulgen 404) (S 1 component) by adding 0.15 part of a nonionic surfactant. Obtained. The solid content concentration of the coating was 6.0% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows.

Main agent: 84. 1% by mass

Cross-linking agent: 8.4% by mass

Silane coupling agent: 5.0% by mass

Surfactant: 2.5% by mass

[Unstretched polyester film forming process]

The polyethylene terephthalate composition obtained above was dried at 170 for 5 hours until the water content of the polyethylene terephthalate composition was 0.05% by mass or less. Subsequently, the dried polyethylene terephthalate composition was supplied to the extruder, melted at a melting temperature of 280 to 300, and filtered with high precision using a steel wire filter with an average opening of 11 im. By extruding the molten sheet into a molten sheet and quenching the molten sheet with a cooling drum by electrostatic contact method, a thickness of 45 An unstretched polyester film of 0 m was obtained.

[Primary stretching process]

Using the obtained unstretched polyester film, a uniaxially stretched polyester film in the longitudinal direction was obtained in the same manner as in Example 1.

[Inline coating process]

Next, a polyester film having a coating film is applied to the obtained longitudinally uniaxially stretched polyester film by applying the coating agent prepared above so that the thickness of the release layer in the obtained release film is 40 nm. Got. The coating was applied to the surface that did not contact the cooling drum in the unstretched polyester film forming process.

[Secondary stretching process]

Subsequently, the polyester film having the obtained coating film was supplied to stainless steel, and a biaxially stretched polyester film was obtained in the same manner as in Example 1.

[Heat setting process]

The obtained biaxially stretched polyester film was cut in the same manner as in Example 1 to obtain a release film having a total thickness of 31 1 m. Various measurements and evaluations were performed using the obtained release film. The results are shown in Table 2.

Example 4

A release film was obtained in the same manner as in Example 3 except that the conditions in each step were as follows. Table 2 shows the results of various measurements and evaluations using the obtained release film.

[Preparation of paint]

As a surfactant, instead of polyoxyethylene glycol ether, 0.06 part nonionic silicone surfactant polyoxyethylene methylpolysiloxane copolymer (manufactured by Nippon Emulsion Co., Ltd.) Name: E MA LEXSS-5 0 5 1) (S 2 component) was used. The solid content concentration of the coating material was 6.0% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows. Main agent: 85.4% by mass

Cross-linking agent: 8.5% by mass

Silane power pulling agent: 5.1% by mass

Surfactant: 1.0% by mass

[Secondary stretching process]

The transverse draw ratio was 4.5 times.

[Heat setting process]

The amount of relaxation in the relaxation treatment was 4.0%.

Example 5

A release film was obtained in the same manner as in Example 4 except that the conditions in each step were as follows. Table 2 shows the results of various measurements and evaluations using the obtained release film.

[Preparation of paint]

0.15 part nonionic silicone surfactant polyoxyethylene / methylpolysiloxane copolymer (manufactured by Nippon Emulsion Co., Ltd., trade name: EMALEX SS-5051) (S 2 component) ) Was used. The solid content concentration of the coating was 6.0% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows.

Main agent: 84. 1% by mass

Cross-linking agent: 8.4% by mass

Silane power pulling agent: 5.0% by mass

Surfactant: 2.5% by mass

Example 6

[Preparation of paint]

As the surfactant, 0.3 part of a nonionic silicone surfactant Lioxyethylene methylpolysiloxane copolymer (Nippon Emulsion Co., Ltd.)

Trade name: EMALEX SS-5051) (S 2 component) was used. The solid content of the coating was 6.2% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows.

Main agent: 82.0% by mass

Crosslinking agent: 8.2% by mass

Silane power pulling agent: 4.9% by mass

Surfactant: 4.9% by mass

Example 7

[Preparation of paint]

As a surfactant, 0.6 part of a nonionic silicone surfactant, polyoxyethylene.'methylpolysiloxane copolymer (manufactured by Nippon Emulsion Co., Ltd., trade name: EMALEX SS-5051) (S Two components) were used. The solid content concentration of the coating was 6.5% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows.

Main agent: 78. 1% by mass

Cross-linking agent: 7.8% by mass

Silane power pulling agent: 4.7% by mass

Surfactant: 9.4% by mass

Comparative Example 4

[Preparation of paint]

No surfactant was used. The solid content concentration of the coating was 5.9% by mass. . In addition, the solid content ratio of each component in the release layer 100% by mass obtained from this coating composition is as follows.

Main ingredient: 86. 2% by mass'

Cross-linking agent: 8.6% by mass

Silane coupling agent: 5.2% by mass

Surfactant: 0% by mass

[Primary stretching process]

The longitudinal draw ratio was 3.0 times.

Comparative Example 5

A release film was obtained in the same manner as in Comparative Example 4 except that the conditions in the following steps were as follows. Table 2 shows the results of various measurements and evaluations using the obtained release film.

[Primary stretching process]

The longitudinal draw ratio was 4.8 times.

[Secondary stretching process]

The transverse draw ratio was 3.0 times.

Comparative Example 6

A biaxially stretched polyester film having no release layer was obtained in the same manner as in Example 3 except that the coating agent was not applied.

Next, an addition polymerization type silicone resin composition (manufactured by Toshiba Silicone Co., Ltd., trade name: TPR-6721) in a toluene solution (solid content concentration: 3% by mass), Pt catalyst (manufactured by Toshiba Silicone Co., Ltd.) Product name: CM 670) was added so as to be 1 part by mass with respect to 100 parts by mass of the solid content of the addition polymerization type silicone resin composition to prepare a release agent coating liquid. This release agent coating liquid does not contain a surfactant. Subsequently, the roll of the biaxially stretched polyester film without the release layer obtained above is unwound and unrolled biaxially. In the center of the polyester film in the width direction, apply the release agent coating solution prepared above to a coating amount (wet) of 6 g / m ² Using an air levitation conveying dryer with a space of 38 cm between the lower and upper air flow outlets, conveying tension: 2, OOO kPa, drying temperature: 16 0:, drying time: 16 seconds Then, a release layer was formed by drying with a mold, and a release film having a weight after drying and curing of the release layer of 0.2 gZm ² was obtained. Table 2 shows the results of various measurements and evaluations using the obtained release film. The release agent coating solution was applied to the surface that was not in contact with the cooling drum in the unstretched polyester film forming process.

Table 2

Table 2 (continued)

00

Example 8

[Production of polyester]

In the same manner as in Example 1, a polyethylene terephthalate composition having an intrinsic viscosity of 0.65 (35: in orthoclonal phenol) was obtained.

[Preparation of paint]

A coating agent was obtained in the same manner as in Example 3. The solid content concentration of the coating material was 6.0% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows.

Main agent: 8 4.1% by mass

Crosslinking agent: 8.4% by mass

Silane power pulling agent: 5.0% by mass

Surfactant: 2.5% by mass

[Unstretched polyester film forming process]

Using the polyethylene terephthalate composition obtained above, an unstretched polyester film having a thickness of 4500 / m was obtained in the same manner as in Example 3.

[Primary stretching process]

[Inline coating process]

[Secondary stretching process]

Subsequently, the polyester film having the obtained coating film was supplied to stainless steel, and a biaxially stretched polyester film was obtained in the same manner as in Example 1. [Heat setting process]

A release film having a total thickness of 31 m was obtained in the same manner as in Example 1 except for the obtained biaxially stretched polyester film. Table 3 shows the results of various measurements and evaluations using the obtained release film as the release film before slitting.

[Slit process]

The winding conditions are as follows: initial tension 4 7 N m, tension taper ratio 60% (—constant), nip pressure 15 ON / m, nip pressure taper ratio 100%, speed 1 8 O mZ, 4 A release film roll having a width of 5 O mm and a length of 2,00 m was obtained. Table 3 shows the results of various measurements and evaluations on the obtained release film roll.

Further, sampling was performed at a position of 50 Om from the surface layer of the obtained release film roll to obtain a release film. Table 3 shows the results of various measurements and evaluations using the release film obtained here as the release film after slitting.

Example 9

A release film before slitting, a release film roll, and a release film after slitting were obtained in the same manner as in Example 8 except that the conditions in each step were as follows. Table 3 shows the results of various measurements and evaluations using these.

[Preparation of paint]

No surfactant was used. The solid content of the coating was 5.9% by mass. Further, the solid content ratio of each component in 100% by mass of the release layer obtained from this coating agent is as follows.

Main agent: 8 6.2% by mass

Cross-linking agent: 8.6% by mass

Silane pulling agent: 5.2% by mass

Surfactant: 0% by mass

[Secondary stretching process]

The transverse draw ratio was 4.5 times. -

[Heat setting process]

The amount of relaxation in the relaxation treatment was 4.0%. Example 10

A release film before slitting, a release film roll, and a release film after slitting were obtained in the same manner as in Example 9 except that the conditions in each step were as follows. Table 3 shows the results of various measurements and evaluations using these.

[Preparation of paint]

As a surfactant, 0.06 part of a nonionic silicone surfactant polyoxyethylene / methylpolysiloxane copolymer (manufactured by Nippon Emulsion Co., Ltd., trade name: EMALEX S S-50 δ 1) ( S 2 component) was used. The solid content concentration of the coating material was 6.0% by mass. Moreover, the solid content ratio of each component in the release layer 100% by mass obtained from this coating agent is as follows.

Main agent: 85.4% by mass

Cross-linking agent: 8.5% by mass

Silane power pulling agent: 5.1% by mass

Surfactant: 1.0% by mass

Example 1 1

A release film before the slit, a release film roll, and a release film after the slit were obtained in the same manner as in Example 10 except that the conditions in each step were as follows. Table 3 shows the results of various measurements and evaluations using these.

[Preparation of paint]

The amount of surfactant (S 2 component) added was 0.15 parts. The solid content concentration of the coating was 6.0% by mass. In addition, the solid content ratio of each component in the release layer 100% by mass obtained from this coating agent is as follows.

Main agent: 84. 1% by mass

Cross-linking agent: 8.4% by mass

Silane coupling agent: 5.0% by mass

Surfactant: 2.5% by mass

[Slit process]

Table 3 shows the winding conditions in the slitting process. Example 1 2 to: I 5

A release film before slitting, a release film roll, and a release film after slitting were obtained in the same manner as in Example 11 except that the winding conditions in the slitting process were as shown in Table 3. Table 3 shows the results of various measurements and evaluations using these.

Example 1 6

A release film before slitting, a release film roll, and a release film after slitting were obtained in the same manner as in Example 10, except that the conditions in each step were as follows. Table 3 shows the results of various measurements and evaluations using these.

[Preparation of paint]

The amount of surfactant (S 2 component) added was 0.3 parts. The solid content concentration of the coating material was 6.2% by mass. Further, the solid content ratio of each component in the release layer (100% by mass) obtained from the coating composition is as follows.

Main agent: 82.0% by mass

Cross-linking agent: 8.2% by mass

Silane power pulling agent: 4.9% by mass

Surfactant: 4.9% by mass

Example 1 7

[Preparation of paint]

The amount of surfactant (S 2 component) added was 0.6 parts. The solid content concentration of the coating material was 6.5% by mass. Further, the solid content ratio of each component in the release layer (100% by mass) obtained from the coating composition is as follows.

Main agent: 7 8. 1% by mass

Cross-linking agent: 7.8% by mass

Silane power pulling agent: 4.7% by mass Surfactant: 9.4% by mass

Comparative Example 7

[Primary stretching process]

The longitudinal draw ratio was 3.0 times.

Comparative Example 8

[Primary stretching process]

The longitudinal draw ratio was 4.8 times.

[Secondary stretching process]

The transverse draw ratio was 3.0 times.

Comparative Example 9

A biaxially stretched polyester film having no release layer was obtained in the same manner as in Example 8 except that the coating agent was not applied.

-Next, a Pt catalyst (manufactured by Toshiba Silicone Co., Ltd., trade name) was added to a toluene solution (solid content concentration: 3% by mass) of an addition polymerization type silicone resin composition (Toshiba Silicone Co., Ltd., trade name: TPR-6672). CM 670) was added at 1 part by mass with respect to 100 parts by mass of the solid content of the addition polymerization type silicone resin composition to prepare a release agent coating solution. This release agent coating liquid does not contain a surfactant.

Subsequently, the roll of the biaxially stretched polyester film having no release layer obtained above was unwound, and the release agent prepared above was placed in the center in the width direction of the unrolled biaxially stretched polyester film. Apply the agent coating solution to a coating amount (wet) of 6 gZm ^2, and use an air levitation transport dryer with a space of 38 cm between the lower and upper air flow outlets. , OOO kPa, Drying temperature: 16 Ot: Drying time: A release layer was formed by drying in 16 seconds, and a release film having a weight after drying and curing of the release layer of 0.2 g Zm ² was obtained. Table 3 shows the results of various measurements and evaluations using the release film obtained here as the release film before slitting. The release agent coating solution was applied to the surface that did not contact the cooling drum in the unstretched polyester film forming step.

[Slit process]

With the winding conditions in the slitting process as shown in Table 3, a release film tool and a release film after slitting were obtained. Table 3 shows the results of various measurements and evaluations using these.

Reference example 1

A release film before slitting, a release film roll, and a release film after slitting were obtained in the same manner as in Example 11 except that the scraping conditions in the slitting process were as shown in Table 3. Table 3 shows the results of various measurements and evaluations using these.

Table 3

Table 3 (continued)

Table 3 (continued)

Table 3 (continued)

Example 1 8

[Production of polyester]

[Preparation of paint]

Main agent: 8 4.1% by mass

Crosslinking agent: 8.4% by mass

Silane coupling agent: 5.0% by mass

Surfactant: 2.5% by mass

[Unstretched polyester film forming process]

The polyethylene terephthalate composition obtained above was dried at 170 for 5 hours until the water content of the polyethylene terephthalate composition was 0.05% by mass or less. Subsequently, the dried polyethylene terephthalate composition is fed to an extruder, melted at a melting temperature of 28 to 300, and high using a steel wire filter with an average opening of 11 / m. After precision filtration, the sheet was extruded from a die to form a molten sheet, and the molten sheet was contacted and rapidly cooled to a cooling drum by an electrostatic contact method to obtain an unstretched polyester film having a thickness of about 4880 m.

[Primary stretching process]

The obtained unstretched polyester film was preheated at 75, and then stretched 3.8 times in the longitudinal direction at a film temperature of 105 between low-speed and high-speed rolls, and then rapidly cooled. A longitudinally uniaxially stretched polyester film was obtained.

[Inline coating process]

Next, a polyester film having a coating film is applied to the obtained longitudinally uniaxially stretched polyester film by applying the coating agent prepared above so that the thickness of the release layer in the obtained release film is 40 nm. Got. Application of paint Was applied to the surface that did not contact the cooling drum in the unstretched polyester film forming process.

[Secondary stretching process]

Subsequently, a polyester film having the obtained coating film was supplied to stainless steel, and a biaxially stretched polyester film was obtained in the same manner as in Example 1.

[Heat setting process]

The obtained biaxially stretched polyester film was cut in the same manner as in Example 1 to obtain a release film having a total thickness of 31 xm. Various measurements and evaluations were performed using the obtained release film. The results are shown in Table 4.

Example 19

A release film having a total thickness of 31 / m was obtained in the same manner as in Example 18 except that the conditions in each step were as follows. Various measurements and evaluations were performed using the obtained release film. The results are shown in Table 4. '

[Coating adjustment]

As a surfactant, 0.06 part of a nonionic silicone surfactant polyoxyethylene / methylpolysiloxane copolymer (manufactured by Nippon Emulsion Co., Ltd., trade name) instead of polyoxyethylene glycol ether EMALEX S S-5051) (S 2 component) was used. The solid content concentration of the coating was 6.0% by mass. Moreover, the solid content ratio of each component in the release layer 100% by mass obtained from this coating agent is as follows.

Main agent: 84. 1% by mass

Cross-linking agent: 8.4% by mass

Silane power pulling agent: 5.0% by mass

Surfactant: 2.5% by mass

[—Next stretching process]

The longitudinal draw ratio was 4.0 times.

[Heat setting process]

The amount of relaxation in the relaxation treatment was 4.0%. Table 4

Measurement / Evaluation Item Unit Example 18 Example 19

Type ― S1 S2 Surfactant contained in the release layer

Content Mass% 2.5 5 5 Longitudinal direction Magnification 3. 8 4.0 0 Stretch ratio Width direction Double 4 1 4.1

Surface magnification 15. 6 16. 4 Film thickness-μm 31 31

Load 0.3 MPa% 1 0.33 -0.35 Longitudinal elongation (s _MD ) Load 1. OMPa% -0.26 -0.29

Load 2.5 MPa% -0. 12 -0. 15 Elongation rate in the width direction (s _TD ) Load 0. 01 MPa% -0. 38 —0. 37 Longitudinal thermal elongation rate (HS _MD ) No load% -0 23 -0. 25 Thermal elongation in the width direction (HS _TD ) No load% -0. 40 -0. 39 One Ho _TD ―%

Release film Longitudinal direction% 2. 9 1. 9

Thick spot

Characteristic Horizontal direction% 2. 5 2. 5

Release layer surface nm 452 454 Maximum height (Rmax)

Surface with no release layer nm 458 460 Release evaluation ― ― ◎ ◎ Release film ―

Peeling evaluation o 〇

Ceramic sheet ― ○ o Ceramic sheet evaluation Surface smoothness (Condition 2) ― ○ ○

(Practical property substitution evaluation) Thickness spots ― ◎ ◎

The invention's effect

The release film of the present invention has an appropriate dimensional change rate under the heating tension at the time of producing a ceramic sheet, and has an excellent heat shrinkage balance when the ceramic slurry is dried. That is, the performance required for a release film used in the production of a ceramic sheet is sufficiently satisfied. Therefore, when the release film of the present invention is used as a carrier film for producing a ceramic sheet, the thickness of the resulting ceramic sheet is excellent because the heat shrink balance of the carrier film is excellent not only in the conveying process but also in the drying process. Spots can be highly suppressed.

In addition, since the release film having a preferred embodiment in the present invention is excellent in surface smoothness, pinhole generation in the obtained ceramic sheet can be suppressed. Therefore, according to the release film having a preferred embodiment of the present invention, the productivity of the ceramic sheet and the ceramic capacitor can be improved.

Furthermore, the release film having a preferred embodiment of the present invention can highly suppress peeling charge generated in the step of unwinding the carrier film and the step of peeling the ceramic sheet from the carrier film. As a result, when the ceramic capacitor is manufactured using the ceramic sheet manufactured using the release film of the present invention, the displacement of the internal electrode of the obtained capacitor can be highly suppressed.

The film roll of the present invention can provide a release film having excellent flatness. When a ceramic capacitor is manufactured using a ceramic sheet manufactured using such a release film, a ceramic capacitor having a uniform capacity can be obtained.

Claims

The scope of the claims

1. a release film having a release layer on at least one surface of a polyester film,

When the tension is 0.2 MPa or more and 4.0 MPa or less in the longitudinal direction of the release film, the elongation ( _SMD ) in the longitudinal direction at 100 satisfies the following formula (1). The elongation rate (S _TD ) in the direction perpendicular to the longitudinal direction at 100 when a tension of 0.0 IMP a is applied in the direction perpendicular to the longitudinal direction of the material satisfies the following formula (2),

Release film satisfying the following formula (5): thermal elongation rate in the longitudinal direction (HS _MD ), thermal elongation rate in the direction perpendicular to the longitudinal direction (HS _TD ), and force.

0. 0961X—0. 45≤S _MD ≤0. 0961 X-0.25 (1) (In formula (1), X is the tension applied to the film unit area (MPa), and X is 0.2MPa. 4. Shows values below OMP a.)

—0. 6≤S _TD ≤- 0. 2 (2)

-0. 4≤HS _MD ≤-0. 1 (3)

—0. 6≤HS _TD ≤-0.

twenty four)

HS _MD > HS _TD (δ) 2. The maximum height (Rmax) measured with a contact-type three-dimensional surface roughness meter on the surface of the release layer is in the range of 100 nm to 600 nm. Release film.

3. Contact-type three-dimensional surface roughness tester on the surface of the release layer and the surface that does not have a release layer The release film according to claim 1 or 2, wherein the maximum height (Rma X) force measured in step 1 is 100 nm or more and 600 nm or less.

4. The release film according to any one of claims 1 to 3, wherein the release layer contains 0.5% by mass or more and 10% by mass or less surfactant with respect to the weight of the release layer.

5. The release film according to any one of claims 1 to 3, wherein the thickness unevenness in the vertical direction is 3.0% or less and the thickness unevenness in the horizontal direction is 3.0% or less.

6. The release film according to any one of claims 1 to 5, wherein the release layer is formed by applying a release layer forming composition to a polyester film stretched in one direction.

7. The release film according to any one of claims 1 to 6, which is used for producing ceramic sheets.

8. The release film according to claim 7, wherein the ceramic sheet is used for producing a ceramic capacitor.

9. A film roll obtained by winding the release film according to any one of claims 1 to 6 into a roll shape, wherein the roll surface layer has a Vickers hardness (Hv) of 0 or more and 45 or less. The