WO2024018993A1

WO2024018993A1 - Mold release film with antistatic layer

Info

Publication number: WO2024018993A1
Application number: PCT/JP2023/025924
Authority: WO
Inventors: 良太粂井; 由佳天野; 悠介柴田; 充晴中谷
Original assignee: 東洋紡株式会社
Priority date: 2022-07-19
Filing date: 2023-07-13
Publication date: 2024-01-25

Abstract

The present invention addresses the problem of providing an excellent mold release film for the production of a ceramic green sheet, the mold release film enabling the achievement of both reduction in electrostatic charge during unwinding and prevention of pinholes, local thickness variation and the like, even if a ceramic green sheet is thinned.　The present invention provides a mold release film with an antistatic layer, the mold release film comprising a base material, an antistatic layer that is provided on one surface of the base material with a first functional layer being interposed therebetween, and a mold release layer that is provided on the other surface side of the base material. With respect to this mold release film with an antistatic layer, the antistatic layer is formed of an antistatic layer-forming composition that contains an antistatic agent and a thermosetting binder resin; the antistatic agent contains a conductive polymer; and the side on which the antistatic layer is provided has a surface resistivity (logΩ/□) of 3 to 10.

Description

Release film with antistatic layer

The present invention relates to a release film for producing ceramic green sheets. More specifically, even when a resin sheet such as a ceramic green sheet is thinned, an antistatic layer can suppress the generation of pinholes, prevent local thickness variations, and reduce unwinding static electricity. Regarding a mold release film. In particular, it relates to a release film used in the production of ceramic green sheets.

Normally, in the manufacturing process of multilayer ceramic capacitors, a ceramic slurry or the like is molded onto a release film, once it is rolled, and then the process proceeds to the next step. In recent years, as ceramic green sheets have become thinner, not only the smoothness of the surface of the release layer, but also the back surface of the release film (the side opposite to the release layer), which comes into contact with the ceramic green sheet in a rolled state, has improved. The smoothness of the back surface of the film is also attracting attention.

On the other hand, a release film with a high surface smoothness tends to cause blocking when wound up into a roll, which tends to cause problems such as charging when the roll is unrolled. In order to prevent such problems, it is known to add an antistatic function to the release film by containing an antistatic agent or the like.

For example, Patent Documents 1 and 2 disclose a technique in which an antistatic layer is provided on the release layer side to provide an antistatic function.

Further, Patent Document 3 discloses a technique for imparting an antistatic function to the back surface of the film.

Japanese Patent Application Publication No. 2012-224011 Japanese Patent Application Publication No. 2003-251756 Japanese Patent Application Publication No. 02-073833 (Japanese Patent Publication No. 7-68388)

In the antistatic release film disclosed in Patent Document 1, the components contained in the antistatic layer may aggregate, resulting in deterioration of the surface smoothness of the release layer, and the effect of the antistatic layer may inhibit curing. This may lead to deterioration of mold performance.

Similarly, in the antistatic film shown in Patent Document 2, an antistatic agent is added to the release layer, which may lead to deterioration of the release performance.

In the antistatic release film shown in Patent Document 3, in order to impart antistatic properties to the release film, an alkyl ammonium salt or the like is applied to the base material of the release film by inline coating during base material film formation. Those with an antistatic layer have been used. By providing an antistatic layer on the back side, there is no negative effect on the surface of the mold release layer, but since the surface of the antistatic layer is difficult to slip, the antistatic layer may fall off due to contact with guide rolls, etc. during ceramic green sheet molding. This could easily cause foreign matter to be generated.

Furthermore, in recent years, demand for release films for manufacturing multilayer ceramic capacitors has been increasing in countries around the world, which may result in longer product transportation times. During long-term storage in a roll state, stress is applied to the film, causing the antistatic layer to fall off, resulting in deterioration of antistatic properties and slipperiness.

The present invention has been made against the background of the problems of the prior art. That is, the object of the present invention is to provide a highly smooth mold release surface and back surface, to have good releasability, antistatic properties, easy sliding properties, and adhesion, and to have excellent antistatic properties and easy slipping properties even after long-term storage. An object of the present invention is to provide a release film having an antistatic layer that does not easily fall off even when rubbed.

The present invention can exhibit the following aspects.

[1] A base material, an antistatic layer provided on one surface of the base material via a first functional layer, and a release layer provided on the other surface side of the base material. ,
The antistatic layer is a layer formed from an antistatic layer forming composition containing an antistatic agent and a thermosetting binder resin,
The antistatic agent includes a conductive polymer,
A release film with an antistatic layer having a surface resistivity (logΩ/□) of 3 or more and 10 or less on the side where the antistatic layer is provided.

[2] The base material does not substantially contain inorganic particles,
The first functional layer is a slip coating layer,
The slip coating layer includes particles,
The release film with an antistatic layer according to [1], wherein the antistatic layer is provided on one surface of a base material via the easy-sliding coating layer.

[3] The release film with an antistatic layer according to [1] or [2], wherein the conductive polymer is a polythiophene-based conductive polymer.

[4] The antistatic layer-equipped mold release according to any one of [1] to [3], wherein the thermosetting binder resin contains at least one selected from acrylamide resin, melamine resin, polycarbodiimide resin, and oxazoline resin. film.

[5] In the antistatic layer, when the total solid content of the conductive polymer and thermosetting binder resin is 100% by mass, the content of the thermosetting binder resin is 40% by weight or more and 95% by weight. The release film with an antistatic layer according to any one of [1] to [4] below.

[6] The antistatic layer has a surface roughness Sa of 1 nm or more and 25 nm or less, and a maximum peak height P of 60 nm or more and 500 nm or less [1] to [5] The release film with an antistatic layer according to any one of the above.

[7] In the release layer, the surface roughness Sa of the surface opposite to the base material is 0.1 nm or more and 5 nm or less, and the maximum peak height P is 1 nm or more and 50 nm or less [1] to [6] ] The release film with an antistatic layer according to any one of the above.

[8] After storing the release film roll in an environment of 40°C and 50% humidity or less for 30 days, the amount of charge when rewinding at 100 m/min is more than -2 kV and less than +2 kV [1] to [7] The release film with an antistatic layer according to any one of the above.

According to the present invention, even when the ceramic green sheet is made thin, it is possible to suppress the occurrence of pinholes, prevent local thickness variations, etc., and reduce unwinding charging. A release film with an antistatic layer suitable for manufacturing green sheets is provided.

Hereinafter, the present invention will be explained in detail.

The release film with an antistatic layer of the present invention comprises a base material, an antistatic layer provided on one surface of the base material via a first functional layer, and a release film provided on the other surface of the base material. and a release layer,
The antistatic layer is a layer formed from an antistatic layer forming composition containing an antistatic agent and a thermosetting binder resin,
The antistatic agent contains a conductive polymer,
This is a release film with an antistatic layer that has a surface resistivity (logΩ/□) of 3 or more and 10 or less on the side where the antistatic layer is provided.

In one embodiment, the release film with an antistatic layer of the present invention is a release film with an antistatic layer for producing a ceramic green sheet. (Hereinafter, it may simply be referred to as a release film with an antistatic layer).

With the release film with an antistatic layer of the present invention, deterioration of the surface smoothness of the release layer can be suppressed, and inhibition of hardening of the release layer due to the influence of the antistatic layer can also be suppressed. Therefore, the present invention can exhibit excellent mold release performance while having antistatic properties.

Furthermore, since the mold release layer of the present invention does not contain an antistatic agent, the mold release layer can exhibit high smoothness, hardness, and mold release properties without deteriorating mold release performance.

Furthermore, in the present invention, the surface of the antistatic layer can exhibit slipperiness. Furthermore, the present invention can prevent the antistatic layer from falling off, which may occur due to contact with guide rolls or the like during ceramic green sheet molding. Therefore, the generation of foreign matter during molding of the ceramic green sheet can also be suppressed.

In addition, the present invention is suitable for long-term storage and transportation in a roll state, for example, when transporting a release film from Japan to overseas, and for example, suppresses the antistatic layer from falling off from the film during transport. can.

(Base material)
The film preferably used as a base material in the present invention is a film composed of a polyester resin, and a polyester film mainly containing at least one selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate is preferable. . Alternatively, the film may be made of a polyester in which a third component monomer is copolymerized as part of the dicarboxylic acid component or diol component of the polyester as described above. Among these polyester films, polyethylene terephthalate film is most preferred from the viewpoint of balance between physical properties and cost.

Further, the polyester film described above may be a single layer or a multilayer. Further, each of these layers may contain various additives in the polyester resin as needed, as long as the desired effects of the present invention are achieved. Examples of additives include antioxidants, light stabilizers, antigelation agents, organic wetting agents, antistatic agents, and ultraviolet absorbers.

The polyethylene terephthalate film that is the base material in the present invention does not substantially contain particles with a particle size of 1.0 μm or more. When the base material has a multilayer structure, the layer forming the surface in contact with the release layer does not substantially contain particles with a particle size of 1.0 μm or more. Hereinafter, regardless of whether the base material has a single-layer structure or a multi-layer structure, it is desirable that the layer forming the surface in contact with the release layer exhibits the following aspects.

Further, particles having a particle size of less than 1.0 μm and 1 nm or more may be present in the base material. Because the base material does not substantially contain particles with a particle size of 1.0 μm or more, such as inorganic particles, the mold release layer can exhibit high smoothness and mold release properties, and can be applied to resin sheets such as green sheets in the base material. It is possible to reduce the occurrence of defects caused by transfer of the particle shape.

In one embodiment, the base material does not contain particles with a particle size of less than 1.0 μm, so that it is possible to more effectively suppress problems caused by transfer of the particle shape in the base material to the resin sheet.

In one embodiment, the base material of the present invention, for example, a polyethylene terephthalate film, is preferably a film that does not substantially contain inorganic particles. Thereby, it is possible to more effectively suppress the transfer of the particle shape in the base material to the resin sheet and the occurrence of defects.

For example, a base material that does not substantially contain particles with a particle size of less than 1.0 μm is preferably also substantially free of particles with a particle size of 1.0 μm or more.

Here, in the present invention, "contains substantially no particles" means, for example, in the case of inorganic particles less than 1.0 μm, the amount of inorganic elements determined by fluorescent X-ray analysis is 50 ppm or less, preferably 10 ppm. Hereinafter, it most preferably means a content that is below the detection limit. Even if particles are not actively added to the film, contaminants derived from foreign substances or dirt attached to the raw resin or the line or equipment in the film manufacturing process are peeled off and mixed into the film. This is because there is. Further, "substantially not containing particles with a particle size of 1.0 μm or more" means that particles with a particle size of 1.0 μm or more are not included.

(Antistatic layer)
The release film with an antistatic layer of the present invention has an antistatic layer provided on one surface of a base material via a first functional layer. By laminating the antistatic layer, it is possible to suppress the adhesion of foreign matter, and furthermore, it is possible to suppress peeling defects due to electrostatic force. As will be described later, by providing the antistatic layer through the first functional layer, the adhesion between the antistatic layer and the base material can be improved, and the effect of suppressing the antistatic layer from falling off can also be improved. Furthermore, the antistatic layer of the present invention also has slipperiness.

.

The antistatic layer is a layer formed from an antistatic layer forming composition containing an antistatic agent and a thermosetting binder resin. In one embodiment, the composition for forming an antistatic layer is a layer obtained by curing a composition containing a conductive polymer and a thermosetting binder resin. Such a composition may simply be referred to as an antistatic layer forming composition.

The means for laminating the antistatic layer is not particularly limited, and known methods such as coating, vacuum deposition, and bonding can be used. For example, it is preferable to apply a coating liquid containing an antistatic agent from the viewpoint of shortening the manufacturing process and stable film formation.

The antistatic layer of the present invention is a layer formed from an antistatic layer forming composition containing an antistatic agent and a thermosetting binder resin, and the antistatic agent contains a conductive polymer.

(conductive polymer)
The conductive polymer in the present invention is a polymer capable of imparting antistatic properties, and may be a polymer utilizing ionic conduction such as a cationic compound, a π-electron conjugated conductive polymer, or the like. From the viewpoint of antistatic properties under low humidity, it is preferable to use a π-electron conjugated conductive polymer. In addition, π-electron conjugated conductive polymers can maintain a high level of antistatic performance without depending on moisture in the air, so they have good antistatic performance in various environments where the film is used. preferable.

Furthermore, an antistatic agent can be used in combination as long as the effects of the conductive polymer according to the present invention are not impaired. The antistatic agent may be a polymer using ionic conduction such as a cationic compound, a π-electron conjugated conductive polymer, other than the conductive polymer in the present invention, a surfactant, a silicon oxide compound, etc. , a conductive metal compound, etc. can be used.

Examples of π-electron conjugated conductive polymers include aniline polymers containing aniline or its derivatives as a constitutional unit, pyrrole polymers containing pyrrole or its derivatives as a constitutional unit, and acetylene polymers containing acetylene or its derivatives as a constitutional unit. Examples include polymers, thiophene-based polymers containing thiophene or its derivatives as a constitutional unit, and the like. In order to obtain high transparency, it is preferable that the π-electron conjugated conductive polymer does not have a nitrogen atom, and in particular, thiophene-based polymers containing thiophene or its derivatives as a constituent unit have a disadvantage in terms of transparency. It is preferable because Preferably, the conductive polymer is a polythiophene-based conductive polymer, and polyalkylenedioxythiophene is particularly suitable. Examples of polyalkylene dioxythiophene include polyethylene dioxythiophene, polypropylene dioxythiophene, poly(ethylene/propylene) dioxythiophene, and the like.

In order to improve the antistatic properties of thiophene-based polymers containing thiophene or its derivatives as a constituent unit, a doping agent may be added, for example, per 100 parts by mass of the polymer containing thiophene or its derivatives as a constituent unit. It can be blended from 0.1 parts by mass to 500 parts by mass. When the amount is too large, electron transfer becomes difficult, resulting in a problem of deterioration of antistatic performance.On the other hand, when it is small, there is a problem of deterioration of dispersibility in solvents. Examples of the doping agent include LiCl, R _1-30 COOLi (R _1-30 : saturated hydrocarbon group having 1 to 30 carbon atoms), R _1-30 SO ₃ Li, R _1-30 COONa, R _1-30 _SO3Na , _R1-30COOK , _R1-30SO3K , _{tetraethylammonium} , _I2 , _BF3Na , _BF4Na , _HClO4 , _CF3SO3H , _FeCl3 _, tetracyanoquinoline (TCNQ) , Na ₂ B ₁₀ Cl ₁₀ , phthalocyanine, porphyrin, glutamic acid, alkyl sulfonate, polystyrene sulfonate Na (K, Li) salt, styrene/styrene sulfonate Na (K, Li) salt copolymer, polystyrene sulfonate anion , styrene sulfonic acid/styrene sulfonic acid anion copolymer, and the like.

In one embodiment, the antistatic agent may include a conductive polymer, and the antistatic agent may be a conductive polymer. In the present invention, the antistatic agent contained in the antistatic layer, such as a conductive polymer, is contained in an amount of 5% by mass or more when the total solid content of the antistatic agent and thermosetting binder resin is 100% by mass. It is preferably contained in an amount of 10% by mass or more, and more preferably in an amount of 10% by mass or more.

In addition, in the case of using a π-electron conjugated conductive polymer as an antistatic agent, when using the above-mentioned doping agent, the content of the π-electron conjugated conductive polymer specified in the present application in the antistatic layer includes: This refers to the total amount of the conductive polymer and the doping agent. By including the antistatic agent in such an amount, good antistatic properties can be imparted. Further, by adding such an amount, a large number of minute irregularities derived from the antistatic agent are formed, the pressure applied to the particles derived from the antistatic agent is dispersed, and the dropping of the antistatic agent can be suppressed, which is preferable.

In the present invention, the antistatic agent, such as a conductive polymer, contained in the antistatic layer is preferably 60% by mass or less, more preferably 50% by mass, based on 100% by mass of the total solid content in the antistatic layer. It is as follows. In addition, in the case of using a π-electron conjugated conductive polymer as an antistatic agent, when using the above-mentioned doping agent, the content of the π-electron conjugated conductive polymer specified in the present application in the antistatic layer includes: This refers to the total amount of the conductive polymer and the doping agent.

Containing the antistatic agent in such an amount is preferable because it does not cause interaction with the thermosetting binder resin, makes coarse aggregation of particles derived from the antistatic agent less likely to occur, and prevents the antistatic layer from falling off.

For example, when the total solid content of the antistatic agent and thermosetting binder resin is 100% by mass, the antistatic agent is contained in an amount of 5% by mass or more and 60% by mass or less, and 10% by mass or more and 50% by mass or less. It may be.

In one aspect, the antistatic agent is contained in an amount of 10% by mass or more and less than 50% by mass, and is contained in an amount of 10% by mass or more and less than 45% by mass. When the content of the antistatic agent is less than 50% by mass, the maximum protrusion height P (also referred to as maximum peak height P) of the antistatic layer can be lowered, and furthermore, the powder falling off of the antistatic layer can be suppressed. .

(Thermosetting binder resin)
In the present invention, an antistatic layer is provided on one surface of a base material via a first functional layer. Improving the adhesion between the base material, the first functional layer, and the antistatic layer results in improved adhesion between the antistatic layer and the base material. By improving the adhesion, it is possible to prevent the antistatic layer from falling off, which may occur due to contact with a guide roll or the like during ceramic green sheet molding, for example. Therefore, the generation of foreign matter during molding of the ceramic green sheet can also be suppressed.

In addition, it is suitable for long-term storage, for example in a roll state, and can suppress the antistatic layer from falling off from the film.

In this manner, the present invention can provide a release film having an antistatic layer that does not easily fall off even in response to external factors such as rubbing.

In the present invention, in order to bring the antistatic layer into close contact with the base material, the antistatic layer is preferably formed from a composition containing a thermosetting binder resin. Containing a thermosetting binder resin is preferable because durability is improved and deterioration in antistatic performance is suppressed even when processed under high temperature and high humidity conditions. Specific thermosetting binder resins include acrylamide, melamine, carbodiimide, and oxazoline binders.

In one embodiment, the thermosetting binder resin includes at least one selected from acrylamide resin, melamine resin, polycarbodiimide resin, and oxazoline resin.

From the viewpoint of sufficient self-crosslinking, melamine-based materials are preferred. In addition to the thermosetting binder resins described above, urea-based, epoxy-based, isocyanate-based, polycarbodiimide-based, and aziridine-based resins may be used in combination without any particular problem. Further, in order to promote the crosslinking reaction, a catalyst or the like may be used as appropriate.

In the present invention, it is desirable that the first functional layer contains the components described below. Thus, in the present invention, the functions of each layer can be fully exhibited by selecting the components described in this specification according to the function of each layer. Furthermore, to provide a release film having antistatic properties, slipperiness, and adhesion, and having an antistatic layer that has excellent antistatic properties and slipperiness even after long-term storage, and does not easily fall off even when rubbed. Can be done.

Examples of the melamine-based thermosetting binder resin used in the present invention include full ether type melamine resin, methylol type melamine resin, imino type melamine resin, and imino-methylol type melamine resin.

Although there are no particular limitations on the type of melamine resin used, full ether type melamine resins are most preferred from the viewpoint of curability of the coating film.

The thermosetting binder resin contained in the antistatic layer of the present invention has a content of 40% by mass when the total solid content of the conductive polymer and the thermosetting binder resin is 100% by mass. It is at least 95% by weight.

The thermosetting binder resin preferably accounts for 50% by mass or more based on 100% by mass of the total solid content in the antistatic layer. If it is 40% by mass or more, a strong coating film with a higher crosslinking density can be obtained, and the adhesion with the easy-to-slip coating layer and solvent resistance are favorable, so it is preferable. Furthermore, if it is 50% by mass or more, it is preferable because it will result in a stronger coating film and will also have better antistatic performance and slipperiness over time.

The thermosetting binder resin is preferably contained in an amount of 95% by mass or less, and may be 90% by mass or less, based on 100% by mass of the total solid content in the antistatic layer. A content of 95% by mass or less is preferable because it can be used without affecting antistatic performance.

A surfactant may be used in the antistatic layer in the present invention to improve the appearance. Examples of surfactants include nonionic surfactants such as acetylene glycol, polyoxyethylene octylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, and fluoroalkyl carboxylic acids, perfluoroalkyl carboxylic acids, and perfluoroalkyl carboxylic acids. Fluorine surfactants such as fluoroalkylbenzenesulfonic acid, perfluoroalkyl quaternary ammonium, perfluoroalkyl polyoxyethylene ethanol, and silicone surfactants can be used.

In addition to the above, the antistatic layer may contain a lubricant, a pigment, an ultraviolet absorber, a silane coupling agent, etc., as necessary, as long as the purpose of the present invention is not impaired.

The thickness of the antistatic layer of the present invention is preferably 0.005 μm or more and 1 μm or less. More preferably, it is 0.01 μm or more and 0.5 μm or less, and still more preferably 0.01 μm or more and 0.2 μm or less. It is preferable that the thickness of the antistatic layer is 0.005 μm or more because an antistatic effect can be obtained. On the other hand, a thickness of 1 μm or less is preferable because less coloring occurs and transparency increases.　

The surface resistivity of the antistatic layer of the present invention is 10 [logΩ/□] or less. More preferably, it is 9 [logΩ/□] or less, and still more preferably 8 [logΩ/□] or less. For example, it may be 6.0 [logΩ/□] or less. By setting the surface resistivity to 10 [logΩ/□] or less, charging of the film can be suppressed, and adhesion of foreign matter during the process can be prevented. Furthermore, it is preferable to set the resistance to 9 [logΩ/□] or less, or 8 [logΩ/□] or less, since it is possible to reduce product defects due to charging during the production of ceramic green sheets.

Further, the lower limit of the surface resistivity of the antistatic film does not need to be particularly determined, but it is preferably 3.0 [logΩ/□] or more. It is preferable that the surface resistivity of the antistatic film is 3.0 [logΩ/□] or more because the antistatic agent can be used without being transferred to the ceramic green sheet.

In one embodiment, the surface resistivity of the antistatic film is 3.2 [logΩ/□] or more, and may be, for example, 3.5 [logΩ/□] or more.

For example, the surface resistivity of the antistatic film is 3.0 [logΩ/□] or more and 8 [logΩ/□] or less.

In the present invention, the method for forming the antistatic layer is not particularly limited. A method is used in which the first functional layer is developed by coating or the like, the solvent and the like are removed by drying, and then heated and cured. At this time, the drying temperature during solvent drying and thermosetting is preferably 180°C or lower, more preferably 150°C or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 180° C. or lower, the flatness of the film is maintained, and there is little risk of causing thickness unevenness of the ceramic green sheet, which is preferable. It is particularly preferable that the temperature is 150° C. or lower, since the film can be processed without impairing its flatness, and the possibility of causing thickness unevenness of the ceramic green sheet is further reduced.

(First functional layer)
The first functional layer is provided between the substrate and the antistatic layer. In particular, it is provided to improve the adhesion between the base material and the antistatic layer. Moreover, the first functional layer can contribute to solving problems in the antistatic layer. For example, the conventional antistatic layer has a problem in that the antistatic layer easily falls off due to contact with a guide roll or the like during ceramic green sheet molding because its surface is difficult to slip. Further, there is a problem in that foreign matter may be generated due to this. The first functional layer in the present invention can contribute to solving the above-mentioned problems that conventional antistatic layers have.

As described above, the first functional layer in the present invention is preferably a layer that can improve the adhesion between the base material and the antistatic layer and provide slipperiness to the antistatic layer. The first functional layer that performs this function is referred to as a slip coating layer in the present invention.

(Easy slip coating layer)
The antistatic release film of the present invention preferably has an easily coated layer on one surface of the polyester base film as described above. That is, the antistatic layer is provided on one surface of the base material via the slippery coating layer.

By providing the easy-sliding coating layer, not only the transportability of the film is improved, but also the adhesion between the base material and the antistatic layer is improved.

It is preferable that the easy-sliding coating layer contains at least a binder resin and particles.

(Binder resin in slip coating layer)
It is preferable that the binder resin constituting the easily coated layer in the present invention includes an acrylic resin. The acrylic resin preferably has a hydroxyl group and a carboxyl group in its molecule. It is more preferable that the structural unit having a hydroxyl group is contained in an amount of 20 to 90 mol% based on 100 mol% of the total structural units. It is preferable that the content of the structural unit having a hydroxyl group is 20 mol % or more, since the water solubility of the acrylic resin can be maintained at an appropriate level. On the other hand, when the amount is 90 mol% or less, the hydroxyl groups of the acrylic resin and the particles contained in the easy-sliding coating layer do not significantly interact with each other, and the particles are uniformly dispersed, which is preferable.

In order to introduce hydroxyl groups into acrylic resin, monomers having hydroxy groups such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, etc. It is preferable to use a ring-opening adduct of γ-butyrolactone or ε-caprolactone to meth)acrylate as a copolymerization component. Among these, 2-hydroxyethyl (meth)acrylate is preferred in that it does not inhibit water solubility. Note that two or more of these may be used in combination. Needless to say, the acrylic resin referred to in the present invention includes methacrylic resin.

The hydroxyl value of the acrylic resin is preferably 10 mgKOH/g or more, more preferably 20 mgKOH/g or more, even more preferably 30 mgKOH/g or more. If the hydroxyl value of the acrylic resin is 10 mgKOH/g or more, the water solubility of the acrylic resin will be good, which is preferable. It is also preferable because it increases the number of reaction points with the thermosetting binder resin in the antistatic layer, making it possible to more firmly fix the antistatic layer to the base material.

The hydroxyl value of the acrylic resin is preferably 250 mgKOH/g or less, more preferably 230 mgKOH/g or less, even more preferably 200 mgKOH/g or less. When the hydroxyl value of the acrylic resin is 250 mgKOH/g or less, the hydroxyl groups of the acrylic resin and the particles contained in the easy-slip coating layer do not interact excessively, and the particles are uniformly dispersed, which is preferable.

The acrylic resin used in the present invention preferably has a carboxyl group in addition to a hydroxyl group. By having a carboxyl group, it becomes possible to form a crosslinked structure with a crosslinking agent and easily impart water solubility. Examples include monomers containing a carboxy group such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid, and monomers containing an acid anhydride group such as maleic anhydride and itaconic anhydride.

The monomer having a carboxyl group is preferably 4 mol% or more, more preferably 10 mol% or more, based on 100 mol% of the total constituent units of the acrylic resin. When the content is 4 mol % or more, it becomes easy to form a crosslinked structure in the slip coating layer and to impart water solubility, which is preferable. The monomer having a carboxyl group is preferably at most 65 mol%, more preferably at most 50 mol%. When it is 65 mol % or less, the Tg of the resulting coating film will not be too high compared to the preferred range described below, and film forming properties and stretching suitability in in-line coating will be good, which is preferable.

In order to develop good water solubility, it is preferable to neutralize carboxyl groups introduced into the acrylic resin by copolymerization of acrylic acid or methacrylic acid. Basic neutralizing agents include amine compounds such as ammonia, trimethylamine, triethylamine, and dimethylaminoethanol, and inorganic basic substances such as potassium hydroxide and sodium hydroxide. For ease of application and ease of formation of a crosslinked structure, it is preferable to use an amine compound as a neutralizing agent. Among these, ammonia is most preferred since particle aggregation does not occur. Further, the neutralization rate is preferably 30 mol% to 95 mol%, more preferably 40 mol% to 90 mol%. When the neutralization rate is 30 mol% or more, the water solubility of the acrylic resin is sufficient, the acrylic resin can be easily dissolved when preparing a coating solution, and there is no risk of whitening of the coating surface after drying. preferable. On the other hand, it is preferable that the neutralization rate is 95 mol % or less because the water solubility is not too high and it is easy to mix alcohol and the like in preparing the coating liquid.

The acid value of the acrylic resin is preferably 40 mgKOH/g or more, more preferably 50 mgKOH/g or more, still more preferably 60 mgKOH/g or more. If the acid value of the acrylic resin is 40 mgKOH/g or more, the number of crosslinking points with the oxazoline crosslinking agent or the carbodiimide crosslinking agent increases, so that a strong coating film with higher crosslinking density can be obtained, which is preferable.

The acid value of the acrylic resin is preferably 400 mgKOH/g or less, more preferably 350 mgKOH/g or less, even more preferably 300 mgKOH/g or less. When the acid value of the acrylic resin is 400 mgKOH/g or less, the carboxyl groups of the acrylic resin and the particles contained in the easy-sliding coating layer do not significantly interact with each other, and the particles are uniformly dispersed, which is preferable. It is preferable that the particles have good dispersibility because coarse protrusions will not occur on the easily coated surface and pinholes will not occur in the ceramic sheet.

The glass transition temperature (Tg) of the acrylic resin is preferably 50°C or higher, more preferably 55°C or higher, and still more preferably 60°C or higher. It is preferable that the glass transition temperature of the acrylic resin is 50° C. or higher because the hardness of the slip coating layer becomes appropriately high.

The glass transition temperature (Tg) of the acrylic resin is preferably 110°C or lower, more preferably 105°C or lower, even more preferably 100°C or lower. It is preferable that the glass transition temperature of the acrylic resin is 110° C. or lower because the coating film can be uniformly stretched without cracking in the stretching step after applying the easy-sliding coating layer.

As the Tg adjusting monomer copolymerized to bring the Tg within the above range, (meth)acrylic monomers and non-acrylic vinyl monomers can be used. Specific examples of (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and n-amyl (meth)acrylate. Acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, Examples include (meth)acrylic acid alkyl esters such as stearyl (meth)acrylate; nitrogen-containing acrylic monomers such as (meth)acrylamide, diacetone acrylamide, n-methylolacrylamide, and (meth)acrylonitrile; vinyl methacrylate; These can be used alone or in combination of two or more.

Examples of non-acrylic vinyl monomers include styrene monomers such as styrene, α-methylstyrene, vinyltoluene (a mixture of m-methylstyrene and p-methylstyrene), and chlorostyrene; vinyl acetate, vinyl propionate, and vinyl butyrate. , vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl pivalate, vinyl octylate, vinyl monochloroacetate, divinyl adipate, Examples include vinyl esters such as vinyl crotonate, vinyl sorbate, vinyl benzoate, and vinyl cinnamate; and halogenated vinyl monomers such as vinyl chloride and vinylidene chloride; one type or two or more types can be used.

As for the monomer for Tg adjustment, it is preferable to determine the appropriate amounts of the hydroxyl group-containing monomer and the carboxyl group-containing monomer, and then use the remainder as the remaining amount. The Tg of the copolymer is determined by the following Fox formula.

W _n : Mass fraction of each monomer (mass%)
Tg _n : Tg (K) of homopolymer of each monomer

It is preferable that a component that lowers the surface free energy, such as a long-chain alkyl group, be introduced as a monomer copolymerized for Tg adjustment. As the acrylic resin into which a long-chain alkyl group has been introduced, an acrylic resin having an alkyl group having about 8 to 20 carbon atoms in the side chain of the acrylic resin is preferable. Further, a copolymer which is a polymer having (meth)acrylic acid ester as the main repeating unit and which contains a long chain alkyl group having 8 to 20 carbon atoms in the transesterified portion can also be suitably used.

The monomer having a long chain alkyl group in the monomer copolymerized for Tg adjustment is preferably 50 mol% or less, more preferably 40 mol% or less, based on 100 mol% of the total constituent units of the acrylic resin. If it is 50 mol% or less, the Tg of the resulting coating film will not be too low compared to the preferred range, and the hardness of the coating film can be maintained at a high level, which is preferable. In the present invention, as long as the Tg can be maintained within a suitable range, the monomer having a long-chain alkyl group may be used in an amount of 0 mol%, but if it is 5 mol% or more, the effect of adjusting the Tg of the acrylic resin is is clear, which is preferable.

The acrylic resin used in the present invention can be obtained by known radical polymerization. Emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, etc. can all be employed. From the point of view of ease of handling, solution polymerization is preferred. Examples of water-soluble organic solvents that can be used in solution polymerization include ethylene glycol n-butyl ether, isopropanol, ethanol, n-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3-oxolane, methyl sorosolve, and ethyl sorosolve. , ethyl carbitol, butyl carbitol, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and the like. These may be used in combination with water.

The polymerization initiator may be any known compound that generates radicals, but preferably is a water-soluble azo polymerization initiator such as 2,2-azobis-2-methyl-N-2-hydroxyethylpropionamide. The polymerization temperature, time, etc. are selected as appropriate.

The weight average molecular weight (Mw) of the acrylic resin is preferably about 10,000 to 200,000. A more preferred range is 20,000 to 150,000. When Mw is 10,000 or more, there is no fear of thermal decomposition within the tenter, which is preferable. When Mw is 200,000 or less, the viscosity of the coating liquid does not increase significantly and the coating properties are good, which is preferable.

As the binder for the slip coating layer in the present invention, other binder resins may be used in combination with the acrylic resin. Examples of other binder resins include polyester resins, urethane resins, polyvinyl resins (such as polyvinyl alcohol), polyalkylene glycols, polyalkylene imines, methylcellulose, hydroxycellulose, and starches.

The content of the acrylic resin in the easily coated layer is preferably 20% by mass or more and 95% by mass or less based on the total solid content. More preferably, it is 30% by mass or more and 90% by mass or less. If it is 20% by mass or more, the carboxyl group as a crosslinking component will not decrease too much and the crosslinking density will not become low, which is preferable. If it is 95% by mass or less, the amount of the crosslinking agent to be crosslinked will not become too small and the crosslinking density will not become low, which is preferable.

(Crosslinking agent)
In the present invention, in order to form a crosslinked structure in the easy-slip coating layer, it is preferable that the easy-slip coating layer contains at least one crosslinking agent selected from oxazoline-based crosslinking agents and carbodiimide-based crosslinking agents. By containing an oxazoline-based crosslinking agent or a carbodiimide-based crosslinking agent, the adhesion to the PET base material is improved, and the coating strength of the slippery layer is improved by promoting crosslinking with the carboxyl group of the acrylic resin. can be done. Furthermore, by selecting a crosslinking agent that reacts with carboxyl groups, the hydroxyl groups in the acrylic resin can remain, and the remaining hydroxyl groups react with the thermosetting binder in the antistatic layer, resulting in stronger adhesion. can be granted. Further, other crosslinking agents may be used in combination, and specific examples of crosslinking agents that can be used in combination include urea-based, epoxy-based, melamine-based, isocyanate-based, and silanol-based. Further, in order to promote the crosslinking reaction, a catalyst or the like may be used as appropriate.

As a crosslinking agent having an oxazoline group, for example, a polymerizable unsaturated monomer having an oxazoline group may be used together with other polymerizable unsaturated monomers as necessary by conventionally known methods (for example, solution polymerization, emulsion polymerization, etc.). Examples include polymers having oxazoline groups obtained by copolymerizing with.

Examples of the polymerizable unsaturated monomer having an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-vinyl-2-oxazoline. Examples include isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These may be used alone or in combination of two or more.

Examples of other polymerizable unsaturated monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate. Alkyl or cycloalkyl esters of (meth)acrylic acid having 1 to 24 carbon atoms such as acrylate, lauryl (meth)acrylate, and isobornyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, etc. Hydroxyalkyl esters having 2 to 8 carbon atoms of (meth)acrylic acid; Vinyl aromatic compounds such as styrene and vinyltoluene; (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, dimethylaminoethyl (meth)acrylate, Examples include adducts of glycidyl (meth)acrylate and amines; polyethylene glycol (meth)acrylate; N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate, (meth)acrylonitrile, and the like. These may be used alone or in combination of two or more.

Other polymerizable unsaturated monomers are hydrophilic monomers from the viewpoint of improving compatibility with other resins, wettability, crosslinking reaction efficiency, etc. by using the obtained crosslinking agent having an oxazoline group as a water-soluble crosslinking agent. Preferably, it is a body. Examples of hydrophilic monomers include monomers having a polyethylene glycol chain such as 2-hydroxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and monoester compounds of (meth)acrylic acid and polyethylene glycol; Examples include aminoethyl (meth)acrylate and its salts, (meth)acrylamide, N-methylol (meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, (meth)acrylonitrile, sodium styrene sulfonate, and the like. Among these, monomers having polyethylene glycol chains, such as methoxypolyethylene glycol (meth)acrylate and monoester compounds of (meth)acrylic acid and polyethylene glycol, which are highly soluble in water, are preferred.

The crosslinking agent having an oxazoline group preferably has an oxazoline group content of 3.0 to 9.0 mmol/g. More preferably, it is within the range of 4.0 to 8.0 mmol/g. If it is within the range of 4.0 to 8.0 mmol/g, it is preferable because an appropriate crosslinked structure can be formed.

Examples of carbodiimide crosslinking agents include monocarbodiimide compounds and polycarbodiimide compounds. Examples of monocarbodiimide compounds include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide, and the like. . As the polycarbodiimide compound, those produced by conventionally known methods can be used. For example, it can be produced by synthesizing isocyanate-terminated polycarbodiimide through a condensation reaction of diisocyanate with removal of carbon dioxide.

Examples of diisocyanates that are raw materials for synthesizing polycarbodiimide compounds include isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and 4,4-diphenylmethane diisocyanate. , 4-dicyclohexylmethane diisocyanate, alicyclic diisocyanates such as 1,3-bis(isocyanatemethyl)cyclohexane, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate. From the viewpoint of yellowing, aromatic aliphatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates are preferred.

Furthermore, the above diisocyanate may be used by controlling the molecule to an appropriate degree of polymerization using a compound that reacts with the terminal isocyanate, such as monoisocyanate. Examples of the monoisocyanate for controlling the degree of polymerization by blocking the terminals of polycarbodiimide include phenyl isocyanate, tolylene isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate, and the like. In addition, compounds having an OH group, -NH2 group, COOH group, or SO3H group can be used as the terminal capping agent.

The condensation reaction of diisocyanate accompanied by decarbonization proceeds in the presence of a carbodiimidization catalyst. Examples of the catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-2 -phospholene-1-oxide and phospholene oxides such as 3-phospholene isomers thereof, and 3-methyl-1-phenyl-2-phospholene-1-oxide is preferred from the viewpoint of reactivity. Note that the amount of the catalyst used can be a catalytic amount.

It is desirable that the above-mentioned mono- or polycarbodiimide compounds be kept in a uniformly dispersed state when blended into water-based paints. It is preferable to add a hydrophilic segment to the molecular structure of the compound and blend it into the paint in the form of a self-emulsion or self-dissolution.

The carbodiimide crosslinking agent used in the present invention may be water-dispersible or water-soluble. Water-soluble resins are preferred because they have good compatibility with other water-soluble resins and improve the crosslinking reaction efficiency of the easily coated layer. In order to make a carbodiimide compound water-soluble, it is necessary to synthesize isocyanate-terminated polycarbodiimide by a condensation reaction involving removal of carbon dioxide from isocyanate, and then add a hydrophilic moiety having a functional group that is reactive with an isocyanate group. It can be manufactured by

Hydrophilic moieties include (1) quaternary ammonium salts of dialkylamino alcohols and quaternary ammonium salts of dialkylaminoalkylamines, (2) alkyl sulfonates having at least one reactive hydroxyl group, and (3) Examples include poly(ethylene oxide) end-capped with an alkoxy group, a mixture of poly(ethylene oxide) and poly(propylene oxide), and the like. When the above hydrophilic moiety is introduced into the carbodiimide compound, it becomes (1) cationic, (2) anionic, and (3) nonionic. Among these, nonionic resins that are compatible with other water-soluble resins are preferred, regardless of their ionicity.

The content of the crosslinking agent in the easily coated layer is preferably 5% by mass or more and 80% by mass or less based on the total solid content. More preferably, it is 10% by mass or more and 70% by mass or less. If it is 5% by mass or more, it is preferable because the crosslinking density of the resin in the coating layer does not decrease. If it is 80% by mass or less, the amount of carboxyl groups in the acrylic resin to be crosslinked will not become too small and the crosslinking density will not become low, which is preferable.

(Particles in the slippery coating layer)
The easy-sliding coating layer preferably contains lubricant particles in order to impart slipperiness to the surface. Particles may be inorganic particles or organic particles, and are not particularly limited, but include (1) silica, kaolinite, talc, light calcium carbonate, heavy calcium carbonate, zeolite, alumina, Barium sulfate, carbon black, zinc oxide, zinc sulfate, zinc carbonate, zirconium oxide, titanium dioxide, satin white, aluminum silicate, diatomaceous earth, calcium silicate, aluminum hydroxide, hydrated halloysite, calcium carbonate, magnesium carbonate, calcium phosphate, hydroxide Inorganic particles such as magnesium and barium sulfate, (2) Acrylic or methacrylic, vinyl chloride, vinyl acetate, nylon, styrene/acrylic, styrene/butadiene, polystyrene/acrylic, polystyrene/isoprene, polystyrene/ Examples of organic particles include isoprene-based, methyl methacrylate/butyl methacrylate-based, melamine-based, polycarbonate-based, urea-based, epoxy-based, urethane-based, phenol-based, diallylphthalate-based, and polyester-based organic particles.

It is particularly preferable to use organic particles in order to prevent the particles from falling off from the slip coating layer. The use of organic particles is preferable because it strengthens the interaction with the binder and crosslinking agent component of the slip coating layer, making it easier to prevent falling off. Among the organic particles, acrylic resin particles and/or methacrylic resin particles, which have a similar chemical structure to the acrylic resin present in the easy-slip coating layer, are particularly preferred in terms of preventing the particles from falling off the easy-slip coating layer. .

The average particle diameter of the particles is preferably 10 nm or more, more preferably 20 nm or more, and still more preferably 30 nm or more. It is preferable that the average particle diameter of the particles is 10 nm or more because it is difficult to aggregate and ensures slipperiness.

The average particle diameter of the particles is preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 600 nm or less. When the average particle diameter of the particles is 1000 nm or less, transparency is maintained and the particles do not fall off, which is preferable.

Furthermore, for example, it is possible to use a mixture of small particles with an average particle size of about 10 to 270 nm and large particles with an average particle size of about 300 to 1000 nm. It is preferable to reduce the average length (RSm) of the roughness curve element while keeping P) small to achieve both slipperiness and smoothness, and particularly preferably small particles of 30 nm or more and 250 nm or less and average particles. The method is to use large particles with a diameter of 350 to 600 nm. When using a mixture of small particles and large particles, it is preferable that the mass content of the small particles is greater than the mass content of the large particles with respect to the entire solid content of the coating layer.

The method for measuring the average particle size of particles is to observe the particles in the cross section of the processed film using a transmission electron microscope or scanning electron microscope, observe 100 non-agglomerated particles, and use the average value to determine the average particle size. This was done using the method of determining the diameter.

The shape of the particles is not particularly limited as long as the object of the present invention is met, and spherical particles and irregularly shaped non-spherical particles can be used. The particle diameter of irregularly shaped particles can be calculated as a circular equivalent diameter. The equivalent circle diameter is a value obtained by dividing the area of the observed particle by π, calculating the square root, and doubling the square root.

The ratio of particles to the total solid content of the easily coated layer is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. It is preferable that the ratio of particles to the total solid content of the easy-slip coating layer is 50% by mass or less, since transparency is maintained and particles do not noticeably fall off from the easy-slip coating layer.

The ratio of the particles to the total solid content of the easily coated layer is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more. It is preferable that the ratio of particles to the total solid content of the easy-slip coating layer is 1% by mass or more because slipperiness can be ensured.

As a method for measuring the content of particles contained in the easy-slip coating layer, for example, when the easy-slip coating layer contains an organic component resin and inorganic particles, the following method can be used. First, the easy-sliding coating layer provided on the processed film is extracted from the processed film using a solvent or the like and dried to solidify, thereby removing the easy-sliding coating layer. Next, only the inorganic components can be obtained by applying heat to the obtained slip coating layer and burning and distilling off the organic components contained in the slip coating layer. By measuring the weight of the obtained inorganic component and the easy-slip coating layer before combustion and distillation, the mass % of particles contained in the easy-slip coating layer can be determined. At this time, accurate measurement can be achieved by using a commercially available differential thermal/thermogravimetric simultaneous measuring device. In addition, the ratio of the above-mentioned particles in the total solid content of the easy-sliding coating layer means the ratio of the total amount of the plurality of types when there are multiple types of particles.

(Additives in slip coating layer)
In order to impart other functionality to the easy-sliding coating layer, various additives may be included within a range that does not impair the coating appearance. Examples of the additives include fluorescent dyes, optical brighteners, plasticizers, ultraviolet absorbers, pigment dispersants, foam inhibitors, antifoaming agents, and preservatives.

The easy-sliding coating layer can also contain a surfactant for the purpose of improving leveling properties during coating and defoaming the coating liquid. The surfactant may be cationic, anionic, or nonionic, but silicone, acetylene glycol, or fluorine surfactants are preferred. It is preferable that these surfactants be contained in the coating layer within a range that does not cause abnormalities in the coating appearance if added in excess.

As a coating method, both the so-called in-line coating method, in which the coating is applied at the same time as the polyester base film is formed, and the so-called offline coating method, in which the polyester base film is coated with a separate coater after the film is formed, can be applied, but the in-line coating method is more efficient and preferable.

Any known method can be used to apply the coating liquid to a polyethylene terephthalate (hereinafter sometimes abbreviated as PET) film. For example, reverse roll coating method, gravure coating method, kiss coating method, die coater method, roll brushing method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method, curtain coating method, etc. Can be mentioned. These methods may be used alone or in combination.

In the present invention, a method for providing an easy-slip coating layer on a polyester film includes a method of coating a polyester film with a coating liquid containing a solvent, particles, and resin and drying the coating solution. Examples of the solvent include organic solvents such as toluene, water, or a mixture of water and a water-soluble organic solvent, but from the viewpoint of environmental issues, water alone or a so-called aqueous solvent, which is a mixture of water and a water-soluble organic solvent, is preferable. solvents are preferred.

Although the solid content concentration of the easy-sliding coating liquid depends on the type of binder resin and the type of solvent, it is preferably 0.5% by mass or more, and more preferably 1% by mass or more. The solid content concentration of the coating liquid is preferably 35% by mass or less, more preferably 20% by mass or less.

The drying temperature after coating also depends on the type of binder resin, the type of solvent, the presence or absence of a crosslinking agent, the solid content concentration, etc., but is preferably 70°C or higher and preferably 250°C or lower.

(Manufacture of polyester film)
In the present invention, the polyester film serving as the base film can be manufactured according to a general polyester film manufacturing method. For example, a polyester resin is melted, unoriented polyester extruded into a sheet, stretched in the longitudinal direction using a speed difference between rolls at a temperature higher than the glass transition temperature, and then stretched in the transverse direction with a tenter. One example is a method of applying heat treatment. Another method is to carry out biaxial stretching simultaneously in the longitudinal and lateral directions within a tenter.

In the present invention, the polyester film serving as the base film may be a uniaxially stretched film or a biaxially stretched film, but it is preferably a biaxially stretched film.

The thickness of the polyester film base material is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm or more. A thickness of 5 μm or more is preferable because the film is less likely to wrinkle during transportation.

The thickness of the polyester film base material is preferably 50 μm or less, more preferably 45 μm or less, and still more preferably 40 μm or less. It is preferable that the thickness is 40 μm or less because the cost per unit area decreases.

In the case of in-line coating, it may be applied to an unstretched film before stretching in the longitudinal direction, or it may be applied to a uniaxially stretched film after stretching in the longitudinal direction and before stretching in the lateral direction. When coating is performed before stretching in the longitudinal direction, it is preferable to provide a drying step before stretching with rolls. When coating a uniaxially stretched film before being stretched in the lateral direction, the film heating process in the tenter can also serve as a drying process, so it is not necessarily necessary to provide a separate drying process. The same applies to the case of simultaneous biaxial stretching.

The thickness of the easily coated layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, even more preferably 0.02 μm or more, and particularly preferably 0.03 μm or more. It is preferable that the thickness of the coating layer is 0.001 μm or more because the film forming properties of the coating film are maintained and a uniform coating film can be obtained.

The thickness of the easily coated layer is preferably 2 μm or less, more preferably 1 μm or less, even more preferably 0.8 μm or less, and particularly preferably 0.5 μm or less. It is preferable that the thickness of the coating layer is 2 μm or less, since there is no fear that blocking will occur.

A ceramic green sheet that is coated and molded onto a release layer, which will be described later, is wound up into a roll together with a release film after being coated and molded. At this time, the ceramic green sheet is wound up with the back surface of the release film in contact with the surface thereof. In order to prevent defects from occurring on the surface of the ceramic green sheet, the outermost surface of the release film (the outermost surface of the entire release layer that is not in contact with the polyester film) needs to be appropriately flat.

The area surface average roughness (Sa) of the surface opposite to the base material of the release layer is 0.1 nm or more and 5 nm or less, for example, 0.2 nm or more and 4.5 nm or less.

The maximum protrusion height (P) is preferably 1 nm or more and 50 nm or less, for example, 1 nm or more and 40 nm or less.

In the antistatic layer, the area surface average roughness (Sa) of the surface opposite to the base material is 1 nm or more and 25 nm or less, and the maximum protrusion height (P) is 60 nm or more and 500 nm or less. It is preferable that the average roughness (Sa) and maximum protrusion height (P) are within such ranges, since the easily coated surface does not become too smooth and can maintain appropriate slipperiness. Furthermore, the smooth coated surface does not become too rough and defects in the ceramic green sheet due to protrusions do not occur, which is preferable. In one embodiment, the area surface average roughness (Sa) is 1 nm or more and 20 nm or less, and the maximum protrusion height (P) is 60 nm or more and 300 nm or less.

In the antistatic layer, the average surface roughness (Sa) of the surface opposite to the base material and the maximum protrusion height (P) are both the surface roughness of the region of the surface opposite to the base material in the release layer. It is desirable that the average roughness (Sa) be larger than the value of the maximum protrusion height (P). Such a relationship between the antistatic layer and the release layer makes it suitable for long-term storage and transportation in a roll state, and it is possible to suppress the antistatic layer from falling off from the film.

(Release layer)
The release layer is provided on a side of the base material that is different from the antistatic layer.

The resin constituting the release layer in the present invention is not particularly limited, and silicone resins, fluororesins, alkyd resins, various waxes, aliphatic olefins, etc. can be used, and each resin may be used alone or in combination of two or more types. You can also do that.

As the release layer in the present invention, for example, silicone resin refers to a resin having a silicone structure in the molecule, and examples thereof include curable silicone, silicone graft resin, and modified silicone resin such as alkyl-modified resin. From these viewpoints, it is preferable to use a reactive cured silicone resin. As the reactive cured silicone resin, addition reaction type, condensation reaction type, ultraviolet ray or electron beam curing type, etc. can be used. More preferably, a low-temperature curing addition reaction type that can be processed at low temperatures and an ultraviolet or electron beam curing type are preferred. By using these materials, processing can be performed at low temperatures when coating a polyester film. Therefore, there is less heat damage to the polyester film during processing, a polyester film with high flatness can be obtained, and defects such as pinholes can be reduced even when manufacturing ultra-thin ceramic green sheets with a thickness of 0.2 to 2.0 μm. Can be done.

Examples of addition reaction type silicone resins include those that are cured by reacting polydimethylsiloxane into which a vinyl group has been introduced into the terminal or side chain with hydrogen siloxane using a platinum catalyst. At this time, it is more preferable to use a resin that can be cured within 30 seconds at 120° C., as this allows processing at low temperatures. Examples include low-temperature addition-curing types manufactured by Dow Corning Toray (LTC1006L, LTC1056L, LTC300B, LTC303E, LTC310, LTC314, LTC350G, LTC450A, LTC371G, LTC750A, LTC755, LTC760A, etc.) and thermal UV-curing types (LTC 851, BY24 -510, BY24-561, BY24-562, etc.), Shin-Etsu Chemical's solvent addition + UV curing type (X62-5040, X62-5065, X62-5072T, KS5508, etc.), dual cure curing type (X62-2835, X62 -2834, X62-1980, etc.).

Examples of condensation reaction silicone resins include those that create a three-dimensional crosslinked structure by condensing polydimethylsiloxane having an OH group at the end and polydimethylsiloxane having an H group at the end using an organotin catalyst. Can be mentioned.

Examples of UV-curable silicone resins include those that use the same radical reaction as normal silicone rubber crosslinking as the most basic type, those that are photocured by introducing unsaturated groups, and those that are cured by photocuring by introducing unsaturated groups, and those that are made by decomposing onium salts with UV rays. Examples include those that generate a strong acid and use this to cleave the epoxy groups to effect crosslinking, and those that effect crosslinking by addition reaction of thiol to vinylsiloxane. Moreover, an electron beam can also be used instead of the ultraviolet rays. Electron beams have more energy than ultraviolet rays, and it is possible to carry out a crosslinking reaction using radicals without using an initiator as in the case of ultraviolet curing. Examples of resins used include UV-curable silicones manufactured by Shin-Etsu Chemical (X62-7028A/B, X62-7052, X62-7205, X62-7622, X62-7629, X62-7660, etc.), Momentive Performance UV curing silicone manufactured by Materials Co., Ltd. (TPR6502, TPR6501, TPR6500, UV9300, UV9315, XS56-A2982, UV9430, etc.), UV curing silicone manufactured by Arakawa Chemical Co., Ltd. (Silico Lease UV POLY200, POLY215, POLY201, KF-UV2) 65AM etc. ).

As the above-mentioned ultraviolet curable silicone resin, acrylate-modified or glycidoxy-modified polydimethylsiloxane can also be used. Good mold release performance can also be achieved by mixing these modified polydimethylsiloxanes with polyfunctional acrylate resins, epoxy resins, etc. and using them in the presence of an initiator.

Examples of other resins that may be used include stearyl-modified, lauryl-modified alkyd resins and acrylic resins, and alkyd resins and acrylic resins obtained by reaction with methylated melamine.

Examples of the amino alkyd resin obtained by the reaction of methylated melamine include Tesfine 303, Tesfine 305, and Tesfine 314 manufactured by Hitachi Chemical. Examples of the aminoacrylic resin obtained by the reaction of methylated melamine include Tesfine 322 manufactured by Hitachi Chemical.

When the above resins are used in the release layer in the present invention, they may be used alone or in a mixture of two or more types. Further, in order to adjust the release force, it is also possible to mix additives such as light release additives and heavy release additives.

The release coating layer in the present invention can contain particles with a particle size of 1 μm or less, but from the viewpoint of pinhole generation, it is preferable not to substantially contain particles that form protrusions.

Additives such as adhesion improvers and antistatic agents may be added to the release layer in the present invention. Furthermore, in order to improve the adhesion to the base material, it is also preferable to subject the surface of the polyester film to pretreatment such as anchor coating, corona treatment, plasma treatment, atmospheric pressure plasma treatment, etc. before providing the release coating layer.

In the present invention, the thickness of the release layer may be set depending on the purpose of use and is not particularly limited, but is preferably within a range where the thickness of the release coating layer after curing is 0.005 to 2.0 μm. Good. It is preferable that the thickness of the release coating layer is 0.005 μm or more because the release performance is maintained. Further, it is preferable that the thickness of the release coating layer is 2.0 μm or less, since the curing time will not be too long and there is no risk of uneven thickness of the ceramic green sheet due to deterioration of the flatness of the release film. Furthermore, since the curing time is not too long, there is no risk of the resin constituting the release coating layer coagulating, and there is no risk of forming protrusions, which is preferable because pinhole defects in the ceramic green sheet are less likely to occur.

The outer surface of the film on which the release layer is formed (the release coating layer surface of the entire coated film that is not in contact with the polyester film) is flat in order to prevent defects from occurring in the ceramic green sheet that is coated and molded on top of it. It is desirable that the area surface average roughness (Sa) is 5 nm or less and the maximum protrusion height (P) is 30 nm or less. More preferably, the area surface average roughness is 5 nm or less and the maximum protrusion height is 20 nm or less. If the area surface roughness is 5 nm or less and the maximum protrusion height is 30 nm or less, defects such as pinholes will not occur during the formation of the ceramic green sheet, and the yield will be good, which is preferable. Although it can be said that the smaller the area surface average roughness (Sa) is, the more preferable it is, but it may be 0.1 nm or more, or 0.3 nm or more. It can be said that the smaller the maximum protrusion height (P) is, the more preferable it is, but it may be 1 nm or more, or 3 nm or more.

In the present invention, the method of forming the mold release layer is not particularly limited, and a coating liquid in which a mold release resin is dissolved or dispersed is spread by coating on one side of a polyester film as a base material, and a solvent etc. After removing by drying, heat drying, heat curing, or ultraviolet curing is used. At this time, the drying temperature during solvent drying and thermosetting is preferably 180°C or lower, more preferably 150°C or lower, and most preferably 120°C or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less. When the temperature is 180° C. or lower, the flatness of the film is maintained, and there is little risk of causing thickness unevenness of the ceramic green sheet, which is preferable. It is particularly preferable that the temperature is 120° C. or lower, since the film can be processed without impairing its flatness, and the possibility of causing thickness unevenness of the ceramic green sheet is further reduced.

In the present invention, the surface tension of the coating liquid when applying the composition forming the mold release layer is not particularly limited, but is preferably 30 mN/m or less. By controlling the surface tension as described above, it is possible to improve the applicability after coating and reduce the unevenness of the coating film surface after drying.

In the present invention, a solvent having a boiling point of 90° C. or higher is preferably added to the coating liquid when applying the composition forming the mold release layer, although it is not particularly limited. By adding a solvent with a boiling point of 90°C or higher, bumping during drying can be prevented, the coating film can be leveled, and the smoothness of the coating film surface after drying can be improved. The amount added is preferably about 10 to 80% by mass based on the entire coating liquid.

Any known coating method can be used to apply the composition forming the release layer, such as roll coating methods such as gravure coating method and reverse coating method, bar coating method such as wire bar coating method, die coating method, etc. Conventionally known methods such as a spray coating method and an air knife coating method can be used.

The amount of charge when the release film with an antistatic layer of the present invention is wound into a roll, the release film roll is stored at 40°C and a humidity of 50% or less for 30 days, and then rewound at 100 m/min is - More than 2kV and less than +2kV. In one embodiment, the amount of charge is −1.5 kV or more and +1.5 kV or less, for example, −1.0 kV or more and +1.0 kV or less.

In one embodiment, the amount of charge is −0.5 kV or more and +0.5 kV or less.

When the amount of charge is within this range, it is possible to suppress the inclusion of foreign matter during the production of the ceramic green sheet, and it is possible to reduce product defects due to charge.

(Ceramic green sheet and ceramic capacitor)
Generally, a multilayer ceramic capacitor has a rectangular parallelepiped ceramic body. Inside the ceramic body, first internal electrodes and second internal electrodes are provided alternately along the thickness direction. The first internal electrode is exposed on the first end surface of the ceramic body. A first external electrode is provided on the first end surface. The first internal electrode is electrically connected to the first external electrode at the first end surface. The second internal electrode is exposed on the second end surface of the ceramic body. A second external electrode is provided on the second end surface. The second internal electrode is electrically connected to the second external electrode at the second end surface.

The release film for producing ceramic green sheets of the present invention is used to produce such multilayer ceramic capacitors. For example, it is manufactured as follows. First, using the release film of the present invention as a carrier film, a ceramic slurry for forming a ceramic body is applied and dried. A conductive layer for forming the first or second internal electrode is printed on the coated and dried ceramic green sheet. A ceramic green sheet, a ceramic green sheet printed with a conductive layer for forming the first internal electrode, and a ceramic green sheet printed with a conductive layer for forming the second internal electrode are laminated as appropriate and pressed. By this, a mother laminate is obtained. The mother laminate is divided into multiple parts to produce raw ceramic bodies. A ceramic body is obtained by firing a raw ceramic body. Thereafter, the multilayer ceramic capacitor can be completed by forming the first and second external electrodes.

Next, the present invention will be explained in detail using Examples and Comparative Examples, but the present invention is of course not limited to the following Examples. Moreover, the evaluation method used in the present invention is as follows.

[NMR measurement]
The ratio of the copolymer components introduced into the acrylic polyol was determined by nuclear magnetic resonance spectroscopy ( ^1H -N
MR, ¹³ C-NMR: Varian Unity 400, manufactured by Agilent). The measurement was performed by removing the solvent in the synthesized acrylic polyol using a vacuum drier, and then dissolving the dried product in deuterated chloroform. From the obtained NMR spectrum, peaks of chemical shift δ (ppm) assigned to each group site were identified. The integrated intensity of each peak obtained was determined, and the composition ratio (mol%) of the copolymer component introduced into the acrylic polyol was confirmed from the number of hydrogens at each group site and the integrated intensity.

[Check Tg]
The Tg of the acrylic polyol was determined from the composition ratio of the copolymer components determined by the above NMR measurement and the Fox equation described above.

(1) Surface characteristics of coated film These are values measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100). For the area surface average roughness (Sa) and the average length of the roughness curve element (RSm), the average value of five measurements was used, and for the maximum protrusion height (P), the maximum value of the five measurements was used.

(Measurement condition)
・Measurement mode: WAVE mode ・Objective lens: 50x ・0.5×Tube lens ・Measurement area 187×139μm (Sa, P measurement)
(4) Powdery resistance of antistatic layer A release film for green sheet production (3 cm (film width direction) x 20 cm (film longitudinal direction)) was placed in a friction fastness tester (manufactured by Daiei Kagaku Seiki Seisakusho, RT-200). was attached with the antistatic layer facing upward, and aluminum foil (thickness: 80 μm, arithmetic mean surface roughness: 0.03 μm) was used at the contact area between the load head (2 cm x 2 cm, 200 g) and the sample film, and the distance was 10 cm. was made to make 10 reciprocations at a speed of 2 seconds per reciprocation. The obtained film was placed on a black mount and visually checked to see if powder had fallen off.

◎: Powder falling cannot be confirmed on the black mount.

○: A slight amount of powder can be observed on a part of the black mount.

△: Slight powder fall can be observed on the black mount overall.

×: Powder fall-off can be observed throughout on the black mount.

(5) Measurement of surface resistivity The surface resistivity of the surface of the antistatic film of the present invention is determined by measuring the surface resistivity of the surface of the antistatic layer using a surface resistance meter after controlling the humidity for 24 hours at a temperature of 23°C and a humidity of 55%. (Work Surface Tester ST-3 manufactured by Simco Japan Co., Ltd.) and evaluated using the following criteria.

◎: Surface resistivity is 3 or more and 6 or less [logΩ/□]
○: Surface resistivity is more than 6 and less than 10 [logΩ/□]
△: Surface resistivity is more than 10 and less than 12 [logΩ/□]
×: Surface resistivity is more than 12 [logΩ/□] or more
(5) Solvent Resistance Evaluation Method A The surface of the antistatic layer was wiped back and forth 10 times using a Kimwipe impregnated with a solvent (toluene). In addition, changes in appearance after the above treatment were evaluated using the following criteria.

〇: Almost no change △: Change ×: Change so much that the antistatic layer is stained (6) Solvent resistance evaluation Method B: The surface of the antistatic layer is coated with a Kimwipe impregnated with a solvent (ethanol). I wiped it back and forth 10 times. In addition, changes in appearance after the above treatment were evaluated using the following criteria.

〇: Almost no change △: Change ×: Change so much that the antistatic layer is stained (7) Peel force measurement of ceramic green sheet Next, use an applicator on the release surface of the obtained release film sample to remove The slurry was applied to a thickness of 2.0 μm, dried at 60° C. for 1 minute, and a ceramic green sheet was molded onto the release film. The obtained mold release film with ceramic green sheet was neutralized using a static eliminator (manufactured by Keyence Corporation, SJ-F020), and then tested using a peel tester (manufactured by Kyowa Interface Science Co., Ltd., VPA-3, load cell load 0.1N). The film was peeled off at a peeling angle of 90°, a peeling temperature of 25° C., and a peeling speed of 10 m/min. For the direction of peeling, stick a double-sided adhesive tape (manufactured by Nitto Denko Corporation, No. 535A) on the SUS plate attached to the peel tester, and attach the release film side to the double-sided tape on top of it. was fixed and peeled off by pulling the ceramic green sheet side. Among the measured values obtained, the average value of the peeling force over a peeling distance of 20 mm to 70 mm was calculated, and this value was taken as the peeling force. The measurement was carried out five times in total, and the average value of the peeling force was used for evaluation. Judgment was made based on the obtained peel force values based on the following criteria.

◎: 0.4 mN/mm or more, 0.6 mN/mm or less ○: More than 0.6 mN/mm, 0.8 mN/mm or less △: More than 0.8 mN/mm, 1.0 mN/mm or less ×: 0 Less than .4 mN/mm or greater than 1.0 mN/mm, or the ceramic green sheet breaks during measurement (8) Pinhole and thickness variation evaluation of ceramic green sheet Antistatic release obtained in each example and each comparative example The mold film was rolled up into a roll having a width of 400 mm and a length of 5000 m to obtain an antistatic release film. This antistatic release film roll was stored in an environment of 40° C. and humidity of 50% or less for 30 days, and then the antistatic film was used for evaluation.

A slurry composition I consisting of the following materials was stirred and mixed for 10 minutes, and dispersed for 10 minutes with zirconia beads having a diameter of 0.5 mm using a bead mill to obtain a primary dispersion. Thereafter, slurry composition II consisting of the following materials was added to the primary dispersion at a ratio of (slurry composition I): (slurry composition II) = 3.4:1.0, and a diameter of 0. Secondary dispersion was performed for 10 minutes using .5 mm zirconia beads to obtain a ceramic slurry.

(Slurry composition I)
Toluene 22.3 parts by mass Ethanol 18.3 parts by mass Barium titanate (average particle size 100 nm) 57.5 parts by mass Homogenol L-18 (manufactured by Kao Corporation) 1.9 parts by mass (Slurry Composition II)
Toluene 39.6 parts by mass Ethanol 39.6 parts by mass Dioctyl phthalate 3.3 parts by mass Polyvinyl butyral (Sekisui Chemical Co., Ltd. S-LEC BM-S) 16.3 parts by mass
1-Ethyl-3-methylimidazolium ethyl sulfate 0.5 parts by mass Apply to the release surface of the antistatic release film sample using an applicator so that the dried slurry has a thickness of 0.5 μm and heat at 90°C. After drying for 1 minute, the slurry surface and the smoothing coating layer surface were overlapped, and after applying a load of 1 kg/cm ² for 10 minutes, the release film was peeled off to obtain a ceramic green sheet.

Light was applied from the opposite side of the ceramic slurry coated surface to the central region of the obtained ceramic green sheet in the film width direction within a 25 cm ² area, and the occurrence of pinholes that were visible through the light was observed. Judging visually.

◎: No pinholes, particularly good thickness variation. ○: No pinholes, no particular problem with thickness variation. △: Very few pinholes, slightly visible thickness variation.

×: There are some pinholes, and the thickness variation is slightly noticeable.

(9) Charging of unwinding release film roll The antistatic release film obtained in each example and each comparative example was rolled up into a roll having a width of 400 mm and a length of 5000 m to obtain an antistatic release film roll. . After storing this antistatic release film roll for 30 days in an environment of 40° C. and 50% humidity or less, the amount of charge when rewinding at 100 m/min was measured using “KSD-0103” manufactured by Kasuga Denki Co., Ltd. The amount of charge was measured at every 500 M of unwinding length at a position 100 mm immediately after unwinding, and the average value was calculated.

◎: More than -0.5kV and less than 0.5kV ○: More than 0.5kV and less than 1kV, or more than -1kV and less than -0.5kV
△: 1kV or more, less than 5kV, or more than -5kV, -1kV or less
×: -5kV or less, 5kV or more (preparation of polyethylene terephthalate pellets (PET(I)))
As the esterification reactor, a continuous esterification reactor consisting of a three-stage complete mixing tank having a stirrer, a partial condenser, a raw material inlet, and a product outlet was used. TPA (terephthalic acid) is set at 2 tons/hour, EG (ethylene glycol) is set at 2 moles per 1 mole of TPA, antimony trioxide is set at an amount such that Sb atoms are 160 ppm relative to the produced PET, and these slurries are converted into esters. The mixture was continuously supplied to the first esterification reactor of the esterification reactor and reacted at 255°C for an average residence time of 4 hours at normal pressure. Next, the reaction product in the first esterification reactor is continuously taken out of the system and supplied to the second esterification reactor, and the reaction product is distilled from the first esterification reactor into the second esterification reactor. In addition, an EG solution containing magnesium acetate tetrahydrate in an amount such that Mg atoms are 65 ppm relative to the produced PET, and 40 ppm P atoms relative to the produced PET is supplied. An EG solution containing an amount of TMPA (trimethyl phosphate) was added, and the mixture was reacted at 260°C for an average residence time of 1 hour at normal pressure. Next, the reaction product of the second esterification reactor was continuously taken out of the system and supplied to the third esterification reactor, and was heated to 39 MPa (400 kg/cm ² ) using a high-pressure disperser (manufactured by Nippon Seiki Co., Ltd.). Average particles made of 0.2% by mass of porous colloidal silica with an average particle diameter of 0.9 μm that has been subjected to dispersion treatment at a pressure of 5 times on average and 1% by mass of ammonium salt of polyacrylic acid per calcium carbonate. While adding 0.4% by mass of synthetic calcium carbonate having a diameter of 0.6 μm as a 10% EG slurry, the mixture was reacted at 260° C. for an average residence time of 0.5 hours at normal pressure. The esterification reaction product produced in the third esterification reactor was continuously fed to a three-stage continuous polycondensation reactor to perform polycondensation, and stainless steel fibers with a 95% cut diameter of 20 μm were sintered. After filtering with a filter, ultrafiltration was performed and extruded into water, and after cooling, it was cut into chips to obtain PET chips with an intrinsic viscosity of 0.60 dl/g (hereinafter abbreviated as PET (I)). . The lubricant content in the PET chip was 0.6% by mass.

(Preparation of polyethylene terephthalate pellets (PET(II)))
On the other hand, in the production of the above PET chip, a PET chip with an intrinsic viscosity of 0.62 dl/g containing no particles of calcium carbonate, silica, etc. was obtained (hereinafter abbreviated as PET (II)).

(Manufacture of laminated film X)
After drying, these PET chips were melted at 285°C, melted at 290°C by a separate melt extruder extruder, and filtered with sintered stainless steel fibers with a 95% cut diameter of 15 μm and a filter with a 95% cut diameter of 15 μm. Two stages of filtration are performed using a filter made of sintered stainless steel particles of 15 μm, and they are merged in the feed block, and PET (I) becomes the anti-release side layer and PET (I) becomes the release side layer. The unstretched material was laminated as shown, extruded (casting) into a sheet at a speed of 45 m/min, electrostatically adhered and cooled on a casting drum at 30°C using the electrostatic adhesion method, and unstretched with an intrinsic viscosity of 0.59 dl/g. A polyethylene terephthalate sheet was obtained. The layer ratio was adjusted by calculating the discharge amount of each extruder so that anti-release surface side layer/mold release surface side layer = 60%/40%. Next, this unstretched sheet was heated with an infrared heater, and then stretched 3.5 times in the machine direction at a roll temperature of 80° C. using a speed difference between the rolls. Thereafter, it was introduced into a tenter and stretched 4.2 times in the transverse direction at 140°C. Then, heat treatment was performed at 210° C. in a heat fixing zone. Thereafter, a 2.3% relaxation treatment was performed at 170° C. in the transverse direction to obtain a biaxially stretched polyethylene terephthalate film X having a thickness of 31 μm. The Sa of the release side layer of the obtained film X was 23 nm, and the Sa of the anti-release side layer was 21 nm.

(Manufacture of laminated film Y)
After drying, these PET chips were melted at 285°C, melted at 290°C by a separate melt extruder extruder, and filtered with sintered stainless steel fibers with a 95% cut diameter of 15 μm and a filter with a 95% cut diameter of 15 μm. Two stages of filtration are performed using a filter made of sintered stainless steel particles of 15 μm, and they are merged in the feed block, with PET (I) forming the anti-release side layer and PET (II) forming the release side layer. The unstretched material was laminated as shown, extruded (casting) into a sheet at a speed of 45 m/min, electrostatically adhered and cooled on a casting drum at 30°C using the electrostatic adhesion method, and unstretched with an intrinsic viscosity of 0.59 dl/g. A polyethylene terephthalate sheet was obtained. The layer ratio was adjusted by calculating the discharge amount of each extruder so that anti-release surface side layer/mold release surface side layer = 60%/40%. Next, this unstretched sheet was heated with an infrared heater, and then stretched 3.5 times in the machine direction at a roll temperature of 80° C. using a speed difference between the rolls. Thereafter, it was introduced into a tenter and stretched 4.2 times in the transverse direction at 140°C. Then, heat treatment was performed at 210° C. in a heat fixing zone. Thereafter, a 2.3% relaxation treatment was performed at 170° C. in the transverse direction to obtain a biaxially stretched polyethylene terephthalate film Y having a thickness of 31 μm. The Sa of the release side layer of the obtained film Y was 2 nm, and the Sa of the anti-release side layer was 26 nm.

(Manufacture of acrylic polyol A)
In a four-neck flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen blowing tube, 231 parts by mass of methyl methacrylate (MMA), 130 parts by mass of stearyl methacrylate (SMA), and 100 parts by mass of hydroxyethyl methacrylate (HEMA). , 33 parts by mass of methacrylic acid (MAA) and 1153 parts by mass of isopropyl alcohol (IPA) were charged, and the temperature inside the flask was raised to 80° C. while stirring. Stirring was performed for 3 hours while maintaining the inside of the flask at 80° C., and then 0.5 parts by mass of 2,2-azobis-2-methyl-N-2-hydroxyethylpropionamide was added to the flask. After purging the inside of the flask with nitrogen while raising the temperature to 120°C, the mixture was stirred at 120°C for 2 hours.
Next, a vacuum operation of 1.5 kPa was performed at 120° C. to remove unreacted raw materials and solvent, and an acrylic polyol was obtained. The inside of the flask was returned to atmospheric pressure and cooled to room temperature, and 1976 parts by mass of an IPA aqueous solution (water content 50% by mass) was added and mixed. Thereafter, ammonia was added using a dropping funnel while stirring, and the acrylic polyol was neutralized until the pH of the solution was in the range of 5.5 to 7.5. I got an A. Acrylic polyol A had a Tg of 88°C, an acid value of 87 mgKOH/g, and a hydroxyl value of 100 mgKOH/g.

(Production of oxazoline crosslinking agent B)
460.6 parts of isopropyl alcohol was charged into a flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, and the mixture was heated to 80° C. while slowly flowing nitrogen gas. A monomer mixture prepared in advance consisting of 126 parts of methyl methacrylate, 210 parts of 2-isopropenyl-2-oxazoline and 84 parts of methoxypolyethylene glycol acrylate, and 2,2'-azobis which is a polymerization initiator are added thereto. An initiator solution consisting of 21 parts of (2-methylbutyronitrile) ("ABN-E" manufactured by Nippon Hydrazine Kogyo Co., Ltd.) and 189 parts of isopropyl alcohol was added dropwise from a dropping funnel over a period of 2 hours to react. After the completion of the reaction, the reaction was continued for 5 hours. During the reaction, nitrogen gas was kept flowing to maintain the temperature inside the flask at 80±1°C. Thereafter, the reaction solution was cooled to obtain a resin (B) having an oxazoline group with a solid content concentration of 25%. The amount of oxazoline groups of the obtained resin (B) having oxazoline groups was 4.3 mmol/g, and the number average molecular weight measured by GPC (gel permeation chromatography) was 20,000.

(Acrylic particles C-1)
Acrylic particle water dispersion (manufactured by Nippon Shokubai, trade name MX100W, average particle size 150 nm, solid content concentration 10% by mass)
(Acrylic particles C-2)
Acrylic particle water dispersion (manufactured by Nippon Shokubai, trade name MX300W, average particle size 450 nm, solid content concentration 10% by mass)
(Adjustment of easy-slip coating liquid)
A slippery coating liquid having the following composition was prepared.

(Easy slip coating liquid)
Water 39.62 parts by mass Isopropyl alcohol 35.00 parts by mass Acrylic polyol resin A (solids concentration 20% by mass) 16.57 parts by mass Oxazoline crosslinking agent B (solids concentration 25% by mass) 5.68 parts by mass Acrylic particles C-1 2.37 parts by mass (average particle size 150 nm, solid content concentration 10% by mass)
Acrylic particles C-2 0.47 parts by mass (average particle size 450 nm, solid content concentration 10% by mass)
Surfactant D (silicone type, solid content concentration 10% by mass) 0.30 parts by mass (mold release agent solution)
100 parts by mass of heat/UV curable silicone resin (LTC851 manufactured by Toray Dow Corning) and 2 parts by mass of a platinum catalyst (SRX212 manufactured by Toray Dow Corning) as a curing catalyst were mixed into toluene/methyl ethyl ketone/heptane (=7:7). :6) A mold release agent solution having a solid content of 2% by mass was prepared by diluting with a solution.

(Example 1)
(Manufacture of laminated film Z)
As a film raw material polymer, PET resin pellets (PET (II)) having an intrinsic viscosity (solvent: phenol/tetrachloroethane = 60/40) of 0.62 dl/g and containing substantially no particles were used at a pressure of 133 Pa. It was dried at 135° C. for 6 hours under reduced pressure. Thereafter, it was fed into an extruder, melted and extruded at about 280°C into a sheet, and rapidly cooled and tightly solidified on a rotating cooling metal roll whose surface temperature was kept at 20°C to obtain an unstretched PET sheet.

This unstretched PET sheet was heated to 100°C with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group with a difference in circumferential speed to obtain a uniaxially stretched PET film.

Next, the easy-slip coating liquid was applied to one side of the PET film using a bar coater, and then dried at 80°C for 15 seconds. The coating amount after final stretching and drying was adjusted to 0.1 μm. Subsequently, with a tenter, the film was stretched 4.0 times in the width direction at 150°C, and while the length of the film in the width direction was fixed, it was heated at 230°C for 0.5 seconds, and further at 230°C for 10 seconds. % relaxation treatment in the width direction was performed to obtain a polyester film Z with an easy-sliding coating layer having a thickness of 31 μm. The Sa of the release side layer of the obtained film Z was 1 nm, and the Sa of the anti-release side layer was 6 nm.　　

(Formation of release coating layer)
A release agent solution was applied to the surface opposite to the surface on which the easy-slip coating layer of the polyester film with an easy-slip coating layer was formed using a reverse gravure coater so that the thickness after drying was 0.01 μm, and then After drying with hot air at 120°C for 30 seconds, UV irradiation (300 mJ/cm2) was immediately performed using an electrodeless lamp (H bulb manufactured by Heraeus Co., Ltd.) to form a release coating layer and obtain a release film. .

(Formation of antistatic layer)
The following composition 1 for forming an antistatic layer was applied to the surface of the release film on which the easily coated layer was formed to a thickness of 0.05 μm after drying using a reverse gravure coater, and then It was dried and cured with hot air at ℃ for 30 seconds to obtain an antistatic release film. A configuration in which an antistatic layer is thus formed on the surface opposite to the mold release layer via another layer is referred to as Configuration 1.

(Antistatic layer forming composition 1)
Water 42.24 parts by mass Isopropyl alcohol 42.24 parts by mass Antistatic agent E-1 (polythiophene-based conductive polymer, solid content concentration 1.20% by mass)
11.67 parts by mass Thermosetting binder resin F-1
(Made by Nippon Carbide Co., Ltd., melamine resin, full ether type, solid content concentration 70% by mass)
0.80 parts by mass Conductive additive G-1 (NMP) 3.00 parts by mass Surfactant H-1 (manufactured by Nissin Chemical Co., Ltd., Dynor 604, solid content concentration 100% by mass)
0.06 parts by mass After being wound up as a release roll, the unwinding charge is low when it is unwound again for ceramic sheet coating, and the adhesion of environmental foreign matter can be suppressed, ensuring quality without reducing the yield of ceramic capacitors. We were able to create a good ceramic capacitor.

(Example 2)
The thermosetting binder resin in composition 1 for forming an antistatic layer used in Example 1 was replaced with thermosetting binder resin F-2 (manufactured by Nippon Carbide Co., Ltd., melamine resin, imino-methylol type, solid content concentration 70% by mass). An antistatic release film was obtained in the same manner as in Example 1, except that Composition 2 for forming an antistatic layer was used.

(Example 3)
Antistatic layer formation by changing the surfactant in composition 1 for forming an antistatic layer used in Example 1 to H-2 (manufactured by Nissin Chemical Co., Ltd., Surfynol SE-F, solid content concentration 81% by mass) An antistatic release film was obtained in the same manner as in Example 1, except that Composition 3 was used.

(Example 4)
An antistatic release film was obtained in the same manner as in Example 1, except that the antistatic layer forming composition 1 was changed to the following antistatic layer forming composition 4.

(Antistatic layer forming composition 4)
Water 45.10 parts by mass Isopropyl alcohol 45.10 parts by mass Antistatic agent E-1 (polythiophene-based conductive polymer, solid content concentration 1.20% by mass)
5.83 parts by mass Thermosetting binder resin F-1
(Made by Nippon Carbide Co., Ltd., melamine resin, full ether type, solid content concentration 70% by mass)
0.90 parts by mass Conductive additive G-1 (NMP) 3.00 parts by mass Surfactant H-1 (manufactured by Nissin Chemical Co., Ltd., Dynor 604, solid content concentration 100% by mass)
0.06 parts by mass (Example 5)
An antistatic release film was obtained in the same manner as in Example 1, except that the antistatic layer forming composition 1 was changed to the following antistatic layer forming composition 5.

(Antistatic layer forming composition 5)
Water 39.37 parts by mass Isopropyl alcohol 39.37 parts by mass Antistatic agent E-1 (polythiophene-based conductive polymer, solid content concentration 1.20% by mass)
17.50 parts by mass thermosetting binder resin F-1
(Made by Nippon Carbide Co., Ltd., melamine resin, full ether type, solid content concentration 70% by mass)
0.70 parts by mass Conductive additive G-1 (NMP) 3.00 parts by mass Surfactant H-1 (manufactured by Nissin Chemical Co., Ltd., Dynor 604, solid content concentration 100% by mass)
0.06 parts by mass (Example 6)
An antistatic release film was obtained in the same manner as in Example 1, except that the antistatic layer forming composition 1 was changed to the following antistatic layer forming composition 5.

(Antistatic layer forming composition 5)
Water 33.64 parts by mass Isopropyl alcohol 33.64 parts by mass Antistatic agent E-1 (polythiophene-based conductive polymer, solid content concentration 1.20% by mass)
29.17 parts by mass Thermosetting binder resin F-1
(Manufactured by Nippon Carbide Co., Ltd., melamine resin, full ether type, solid content concentration 70% by mass)
0.50 parts by mass Conductive additive G-1 (NMP) 3.00 parts by mass Surfactant H-1 (manufactured by Nissin Chemical Co., Ltd., Dynor 604, solid content concentration 100% by mass)
0.06 parts by mass (Example 7)
An antistatic release film was obtained in the same manner as in Example 1, except that the coating thickness was changed so that the thickness after drying was 0.10 μm.

(Example 8)
An antistatic release film was obtained in the same manner as in Example 1, except that the coating thickness was changed so that the thickness after drying was 0.15 μm.

(Example 9)
An antistatic release film was obtained in the same manner as in Example 1, except that the antistatic layer forming composition 1 was changed to the following antistatic layer forming composition 7.

(Antistatic layer forming composition 7)
Water 42.17 parts by mass Isopropyl alcohol 42.17 parts by mass Antistatic agent E-1 (polythiophene-based conductive polymer, solid content concentration 1.20% by mass)
11.67 parts by mass Thermosetting binder resin F-3
(Manufactured by Nisshinbo Chemical Co., Ltd., polycarbodiimide resin, solid content concentration 40% by mass)
0.93 parts by mass Conductive additive G-1 (NMP) 3.00 parts by mass Surfactant H-1 (manufactured by Nissin Chemical Co., Ltd., Dynor 604, solid content concentration 100% by mass)
0.06 parts by mass (Comparative Example 1)
An antistatic release film was obtained in the same manner as in Example 1, except that the antistatic layer forming composition 1 was changed to the following antistatic layer forming composition 8.

(Antistatic layer forming composition 8)
Water 19.30 parts by mass Isopropyl alcohol 19.30 parts by mass Antistatic agent E-1 (polythiophene-based conductive polymer, solid content concentration 1.20% by mass)
58.33 parts by mass Conductive additive G-1 (NMP) 3.00 parts by mass Surfactant H-1 (manufactured by Nissin Chemical Co., Ltd., Dynor 604, solid content concentration 100% by mass)
0.06 parts by mass (Comparative Example 2)
An antistatic release film was obtained in the same manner as in Example 1 except that the base material was changed to X.

(Comparative example 3)
An antistatic release film was obtained in the same manner as in Example 1 except that the base material was changed to Y.

(Comparative example 4)
An antistatic release film was obtained in the same manner as in Example 1, except that the base material was changed to Y and no antistatic layer was formed. A configuration in which no antistatic layer is formed as described above is referred to as configuration 2.

(Comparative example 5)
(Manufacture of polyester film)
As a film raw material polymer, PET resin pellets (PET (II)) having an intrinsic viscosity (solvent: phenol/tetrachloroethane = 60/40) of 0.62 dl/g and containing substantially no particles were used at a pressure of 133 Pa. It was dried at 135° C. for 6 hours under reduced pressure. Thereafter, it was fed into an extruder, melted and extruded at about 280°C into a sheet, and rapidly cooled and tightly solidified on a rotating cooling metal roll whose surface temperature was kept at 20°C to obtain an unstretched PET sheet.

(Formation of antistatic layer)
Apply the following antistatic layer forming composition 1 to the surface of the base material Z on which the easily coated layer is not formed (release layer surface) using a reverse gravure coater so that the thickness after drying is 0.05 μm. Then, it was dried and cured with hot air at 140° C. for 30 seconds to obtain an antistatic film.

(Formation of release coating layer)
A release agent solution was applied to the surface of the antistatic film on which the antistatic layer was formed using a reverse gravure coater so that the thickness after drying was 0.01 μm, and then dried with hot air at 120°C for 30 seconds. Immediately thereafter, UV irradiation (300 mJ/cm2) was performed using an electrodeless lamp (H bulb manufactured by Heraeus Co., Ltd.) to form a release coating layer and obtain an antistatic release film. In this way, a configuration in which an antistatic layer is provided on the side of the release layer of the base material Z and a release layer is provided on the antistatic layer is referred to as Configuration 3.

Table 1 shows the evaluation results for each example and comparative example.

Table 1 above shows the mass ratio of antistatic agent/thermosetting binder in the composition for forming an antistatic layer, and this indicates that the total solid content of the antistatic agent and thermosetting binder is 100% by mass. This is the mass ratio when

The embodiments and examples disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the present invention is indicated by the claims rather than the embodiments described above, and it is intended that equivalent meanings to the claims and all changes within the scope are included.

The object of the present invention is to have a highly smooth mold release surface and back surface, to have good peelability, antistatic property, easy sliding property, and adhesion, and to have excellent antistatic property and easy slipping property even after long-term storage, and to prevent rubbing. It is an object of the present invention to provide a release film having an antistatic layer that does not easily fall off even when the film is heated.

In Examples 1 to 9, the processed rolls are stored for a long time and when unwound again, the unwinding charge is low and environmental foreign matter is less likely to adhere, so high quality ceramic capacitors can be manufactured without reducing the yield of ceramic capacitors. was able to create. Furthermore, since the antistatic layer is provided through the first functional layer, good powder removal properties and solvent resistance are obtained.

On the other hand, in Comparative Example 1, since the thermosetting binder resin specified in the present invention was not used, the adhesion with the base material was poor, and even if an antistatic layer was provided through the first functional layer, the powder Poor removability and solvent resistance. Furthermore, when unwinding charging after long-term storage is measured, there is a concern that the yield may deteriorate due to adhesion of foreign matter. This is thought to be due to poor adhesion, which caused the film roll to repeat minute expansions and contractions during long-term storage, and the antistatic layer was scraped, resulting in poor unwinding charging. Furthermore, it is thought that the antistatic layer has an effect on the release layer, resulting in deterioration of surface roughness and deterioration of ceramic peel evaluation.

Further, in Comparative Examples 2 and 3, since the first functional layer was not provided, the adhesion to the base material was poor, and the powder removal property and solvent resistance were poor. Therefore, when unwinding and charging after long-term storage is measured, there is a concern that the yield will deteriorate due to adhesion of foreign matter.

Regarding Comparative Example 4, since no antistatic layer was provided, the unwinding charge after long-term storage becomes high, and there is a concern that the yield will deteriorate when producing a thin ceramic green sheet.

Regarding Comparative Example 5, since the antistatic agent was disposed between the base material and the release layer, it is thought that curing failure of the release layer occurred and the peel evaluation deteriorated.

According to the present invention, it has a highly smooth mold release surface and back surface, and has good releasability, antistatic property, easy slipping property, and adhesion, and has excellent antistatic property and easy slipping property even after long-term storage, and does not scratch. It becomes possible to provide a release film having an antistatic layer that does not easily fall off even when the film is heated. Furthermore, by using the release film for producing ceramic green sheets of the present invention, it is possible to obtain ultra-thin ceramic green sheets and to efficiently produce minute ceramic capacitors.

Claims

comprising a base material, an antistatic layer provided on one surface of the base material via a first functional layer, and a release layer provided on the other surface side of the base material,
The antistatic layer is a layer formed from an antistatic layer forming composition containing an antistatic agent and a thermosetting binder resin,
The antistatic agent includes a conductive polymer,
A release film with an antistatic layer having a surface resistivity (logΩ/□) of 3 or more and 10 or less on the side where the antistatic layer is provided.
The base material does not substantially contain inorganic particles,
The first functional layer is a slip coating layer,
The slip coating layer includes particles,
The antistatic layer is provided on one surface of the base material via the slip coating layer,
The release film with an antistatic layer according to claim 1.
The release film with an antistatic layer according to claim 1, wherein the conductive polymer is a polythiophene-based conductive polymer.
The release film with an antistatic layer according to claim 1, wherein the thermosetting binder resin contains at least one selected from acrylamide resin, melamine resin, polycarbodiimide resin, and oxazoline resin.
In the antistatic layer, when the total solid content of the antistatic agent and thermosetting binder resin is 100% by mass,
The release film with an antistatic layer according to claim 1, wherein the content of the thermosetting binder resin is 40% by weight or more and 95% by weight or less.
The antistatic layer according to claim 1, wherein the surface of the antistatic layer opposite to the base material has a surface roughness Sa of 1 nm or more and 25 nm or less, and a maximum protrusion height P of 60 nm or more and 500 nm or less. Comes with release film.
The antistatic device according to claim 1, wherein the release layer has a surface roughness Sa of 0.1 nm or more and 5 nm or less, and a maximum protrusion height P of 1 nm or more and 50 nm or less on the surface opposite to the base material. Layered release film.
The antistatic layer according to claim 1, wherein the release film roll is stored in an environment of 40° C. and 50% humidity or less for 30 days, and then the amount of charge when rewinding at 100 m/min is more than -2 kV and less than +2 kV. Release film.