KR20230143567A - Release film, method of producing release film and laminate - Google Patents

Abstract

Provided is a release film capable of producing a ceramic green sheet with suppressed defects without generating concave defects on the release surface, a method for manufacturing the release film, or a laminate including the release film.
Crosslinking a composition comprising a polyester substrate and a release layer disposed on the polyester substrate, wherein the release layer contains a block isocyanate having a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester resin. A release film comprising a crosslinked product, a method for producing the release film, and a laminate containing the release film.

Description

Release film, method for producing release film, and laminate {RELEASE FILM, METHOD OF PRODUCING RELEASE FILM AND LAMINATE}

This disclosure relates to a release film, a method of producing the release film, and a laminate.

As the performance and miniaturization of electronic devices increase, the electronic components used in the electronic devices are also required to have higher performance and miniaturization. Among electronic components, for example, the number of multilayer ceramic capacitors mounted on a substrate is increasing, and there is a strong demand for miniaturization.

In the manufacture of a multilayer ceramic capacitor, a process of applying a ceramic slurry on a release layer of a release film and drying it to form a ceramic green sheet is generally included.

Patent Document 1 is characterized by having, on at least one side of the polyester film, an application layer formed from a coating solution containing a crosslinking agent and a mold release agent and containing 30% by weight or less of polymers other than these as a proportion of non-volatile components. Laminated polyester films are described.

Japanese Patent Publication No. 2016-030378

In a release film comprising a base material and a release layer disposed on the base material, minute concave-shaped defects (hereinafter also referred to as concave-shaped defects) appear on the peeling surface, which is the application surface of the ceramic slurry. This may occur, and defects on the peeling surface may be transferred, resulting in minute defects occurring in the ceramic green sheet.

The present disclosure has been made in consideration of such circumstances, and the problem to be solved by one embodiment of the present disclosure is to manufacture a ceramic green sheet in which concave defects do not occur on the peeling surface and micro defects are suppressed. A release film is provided.

The problem to be solved by another embodiment of the present disclosure is to provide a laminate including the release film.

Additionally, a problem to be solved by another embodiment of the present disclosure is to provide a method for producing a release film that can produce a ceramic green sheet with suppressed defects without generating concave defects on the release surface.

Means for solving the above problems include the following embodiments.

<1> Includes a polyester base material and a release layer,

A release film, wherein the release layer contains a crosslinked product formed by crosslinking a composition containing a block isocyanate having a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester resin.

<2> The block isocyanate is on the lower temperature side than the dissociation temperature of the DSC curve obtained by differential scanning calorimetry, and the temperature at which it exhibits a heat value of 1/3 of the heat value at the dissociation temperature is 80°C. The release film according to <1>, which is a compound having the above properties.

<3> The peeling film according to <1> or <2>, wherein the blocking agent in the blocked isocyanate is an oxime compound, a pyrazole compound, an acid amide compound, or a lactam compound.

<4> The release film according to any one of <1> to <3>, wherein the composition contains a silicone compound.

<5> Comprising a polyester base material and a release layer,

A release film in which the release layer contains a crosslinked product of an isocyanate and a non-polyester resin, and a compound containing a residue derived from an oxime compound, a pyrazole compound, an acid amide compound, or a lactam compound.

<6> The release film according to any one of <1> to <5>, which is for producing ceramic green sheets.

<7> The release film according to any one of <1> to <6>, wherein the polyester base material does not substantially contain particles.

<8> Among <1> to <7>, wherein the non-polyester resin is at least one type of resin selected from the group consisting of urethane resin, acrylic resin, polyvinyl alcohol resin, olefin resin, and silicone resin. The release film described in any one.

<9> The peeling film according to any one of <1> to <8>, wherein the peeling layer has a thickness of 0.001 μm to 0.2 μm.

<10> further includes a particle-containing layer,

The release film according to any one of <1> to <9>, comprising the release layer, the polyester substrate, and the particle-containing layer in this order.

<11> The release film according to <10>, wherein the particle-containing layer contains a non-polyester resin.

<12> The release film according to <10> or <11>, wherein the non-polyester resin is at least one resin selected from the group consisting of an acrylic resin, a urethane resin, and an olefin resin.

<13> A method for producing a release film comprising a polyester substrate and a release layer,

A method for producing a release film, comprising the step of forming a release layer using a composition for forming a release layer containing a block isocyanate having a dissociation temperature of more than 100°C and less than or equal to 220°C, and a non-polyester resin.

<14> The process of forming the release layer is a step of forming a release layer by applying the release layer forming composition to one side of an unstretched polyester film or a uniaxially stretched polyester film. Method for producing release film.

<15> A laminate comprising the release film according to any one of <1> to <12> and a layer containing ceramic.

According to one embodiment of the present disclosure, a release film is provided that prevents concave defects from occurring on the release surface and can produce a ceramic green sheet with suppressed defects.

According to another embodiment of the present disclosure, a laminate including the release film is provided.

Additionally, according to another embodiment of the present disclosure, a method for producing a release film is provided that can produce a ceramic green sheet with suppressed defects without generating concave defects on the release surface.

Hereinafter, the release film, the production method of the release film, and the laminate of the present disclosure will be described in detail. However, the present disclosure is by no means limited to the following embodiments, and may be implemented with appropriate changes within the scope of the purpose of the present disclosure.

In this specification, the numerical range indicated using “~” means a range that includes the numerical values written before and after “~” as the lower limit and upper limit. In the numerical range described stepwise in this specification, the upper limit or lower limit value described as a predetermined numerical range may be replaced with the upper limit or lower limit value of another numerical range described stepwise. In addition, in the numerical range described in this specification, the upper limit or lower limit described in the predetermined numerical range may be replaced with the value shown in the examples.

In this specification, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified, when multiple substances corresponding to each component exist in the composition.

In this specification, the term "process" includes not only independent processes but also cases where the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes.

In this specification, a combination of two or more preferred aspects is a more preferred aspect.

In this specification, the “longitudinal direction” means the elongated direction of the release film during production of the release film, and has the same meaning as the “conveyance direction” and “machine direction.”

In this specification, “width direction” means a direction perpendicular to the longitudinal direction. In this specification, “orthogonal” is not limited to strict orthogonal but includes approximately orthogonal. “Approximately perpendicular” means intersecting within the range of 90°±5°, preferably intersecting within the range of 90°±3°, and more preferably intersecting within the range of 90°±1°. do.

In addition, in this specification, "film width" means the distance between both ends in the width direction of a peeling film.

In this specification, weight average molecular weight (Mw) means a value measured by gel permeation chromatography (GPC). Additionally, in the case of a molecular weight of 1000 or less, the molecular weight is calculated based on the type and number of atoms constituting the compound.

Measurement by GPC uses HLC (registered trademark)-8020GPC (Tosoh Co., Ltd.) as a measuring device, and TSKgel (registered trademark) Super Multipore HZ-H (4.6 mmID × 15 cm, Tosoh Co., Ltd.) as a column. ) are used, and as an eluent, THF (tetrahydrofuran) is used. In addition, as measurement conditions, the sample concentration is 0.45 mass%, the flow rate is 0.35 ml/min, the sample injection amount is 10 μL, and the measurement temperature is 40°C, and the measurement is performed using an RI detector.

The calibration curve is "standard sample TSK standard, polystyrene" from Tosoh Co., Ltd.: "F-40", "F-20", "F-4", "F-1", "A-5000", "A- 2500", "A-1000", and "n-propylbenzene".

In this specification, when it is simply referred to as “the release film of the present disclosure” without any particular explanation, both the first embodiment and the second embodiment described later will be explained.

[Release film]

The release film of the first embodiment of the present disclosure includes a polyester base material and a release layer, and the release layer contains a block isocyanate having a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester resin. A release film comprising a crosslinked product formed by crosslinking the composition.

The release film of the second embodiment of the present disclosure includes a polyester base material and a release layer, and the release layer includes a crosslinked product of isocyanate and a non-polyester resin, an oxime compound, a pyrazole compound, and an acid. Contains compounds containing residues derived from amide compounds or lactam compounds.

In a release film containing a polyester base material and a release layer, minute concave defects (i.e., concave defects) may occur on the release surface. Although the cause of the occurrence of concave defects on the peeling surface is not clear, the present inventors estimate as follows.

In the manufacturing process of a release film containing a polyester base material and a release layer, in the case of stretching of the polyester base material, formation of the release layer, etc., the composition for obtaining the crosslinked product contained in the release layer is heated to about 100°C. There are cases. Therefore, if the composition for obtaining the crosslinked product contains a blocked isocyanate compound with a dissociation temperature of 100°C or lower, the blocking agent is detached by the heating, and the crosslinking reaction proceeds. If the polyester base material is stretched after heating, the area where the crosslinking reaction has progressed due to heating may not be able to keep up with the stretching, and cracks (i.e. cracks) may occur on the peeled surface. It is thought to be a factor in the concave shape defect. In fields where a high level of surface smoothness of the peeling surface is required, such as in the production of ceramic green sheets where microscopic defects affect condenser performance, concave defects occurring on the peeling surface may not be tolerated. For example, in the case of a release film for producing a ceramic green sheet, concave defects on the release surface are transferred and cause defects (mainly microconvex defects) in the ceramic green sheet being manufactured.

On the other hand, in the release film of the first embodiment of the present disclosure, the release layer includes a crosslinked product formed by crosslinking a composition containing a block isocyanate with a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester resin. do. This crosslinked product is obtained by desorbing the blocking agent of block isocyanate having a dissociation temperature of more than 100°C and 220°C or less and crosslinking with the non-polyester resin contained in the composition. In this way, by using a block isocyanate with a dissociation temperature of more than 100°C and 220°C or less and a non-polyester resin in the composition for obtaining the crosslinked product contained in the release layer, in the production process of the release film, such composition Even when heated to about 100°C, desorption of the blocking agent is suppressed, making it difficult for the crosslinking reaction to proceed. As a result, it is assumed that the occurrence of concave defects resulting from cracks occurring on the peeling surface as described above will be suppressed. And, it is assumed that defects in the ceramic green sheet can be suppressed by manufacturing a ceramic green sheet using the release film of the first embodiment of the present disclosure in which no concave defects occur on the peeling surface.

Moreover, in the release film of the second embodiment of the present disclosure, the release layer is derived from a crosslinked product of isocyanate and a non-polyester resin, and an oxime compound, a pyrazole compound, an acid amide compound, or a lactam compound. Contains a compound containing a moiety. The compound containing a residue derived from an oxime compound, pyrazole compound, acid amide compound, or lactam compound contained in the release layer coexists with a crosslinked product of isocyanate and non-polyester resin. , and from the structure of the residues contained in the molecule (i.e., residues derived from oxime compounds, residues derived from pyrazole compounds, residues derived from acid amide compounds, or residues derived from lactam compounds), all dissociation temperatures It is assumed that it is derived from block isocyanate whose temperature exceeds 100°C. That is, the release film of the second embodiment of the present disclosure determines that the release layer contains a crosslinked product formed by crosslinking a composition containing a non-polyester resin and a block isocyanate having a dissociation temperature of more than 100°C. do. For this reason, it is assumed that the release film of the second embodiment of the present disclosure can suppress the occurrence of concave defects on the release surface for the same reason as the release film of the first embodiment of the present disclosure. And, it is presumed that defects in the ceramic green sheet can be suppressed by manufacturing a ceramic green sheet using the release film of the second embodiment of the present disclosure in which minute concave-shaped defects do not occur on the peeling surface.

In contrast, Patent Document 1 describes the use of block isocyanate with a dissociation temperature of 100°C or lower, and does not describe block isocyanate protected with a blocking agent containing an oxime group, pyrazole group, or amide group. not.

<Polyester base material>

The release film of the present disclosure includes a polyester substrate.

A polyester substrate is a film-like object containing polyester resin as the main polymer component. Here, the “main polymer component” means the polymer with the highest content (mass) among all polymers contained in the film-like object.

The polyester base material may contain one type of individual polyester resin, or may contain two or more types of polyester resin.

[polyester resin]

Polyester resin is a polymer that has an ester bond in its main chain. Polyester resin is usually formed by polycondensing a dicarboxylic acid compound and a diol compound, which will be described later.

In the present disclosure, “main chain” refers to the relatively longest bond chain among the molecules of the polymer compound constituting the resin.

The polyester resin is not particularly limited, and known polyester resins can be used. Polyester resins include, for example, polyethylene terephthalate (PET), polyethylene-2,6-naphthalate (PEN), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), and copolymers thereof. Among them, at least one selected from the group consisting of PET, PEN, and copolymers thereof is preferable, and PET is more preferable.

The intrinsic viscosity of the polyester resin is preferably 0.50 dl/g or more and less than 0.80 dl/g, and more preferably 0.55 dl/g or more and less than 0.70 dl/g.

The melting point (Tm) of the polyester resin is preferably 220°C to 270°C, and more preferably 245°C to 265°C.

The glass transition temperature (Tg) of the polyester resin is preferably 65°C to 90°C, and more preferably 70°C to 85°C.

The manufacturing method of the polyester resin is not particularly limited, and known methods can be used. For example, a polyester resin can be produced by polycondensing at least one dicarboxylic acid compound and at least one diol compound in the presence of a catalyst.

Hereinafter, the materials used for manufacturing polyester and manufacturing conditions will be described.

(Dicarboxylic acid compound)

Examples of dicarboxylic acid compounds include dicarboxylic acids such as aliphatic dicarboxylic acid compounds, alicyclic dicarboxylic acid compounds, and aromatic dicarboxylic acid compounds, and dicarboxylic acid esters such as methyl ester compounds and ethyl ester compounds of these dicarboxylic acids. I can hear it. Among them, aromatic dicarboxylic acid or methyl aromatic dicarboxylate is preferable.

Examples of aliphatic dicarboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosanedioic acid, pimelic acid, azelaic acid, Examples include methylmalonic acid and ethylmalonic acid.

Examples of alicyclic dicarboxylic acid compounds include adamantane dicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, and decalindadicarboxylic acid.

As aromatic dicarboxylic acid compounds, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4 , 4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylindicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid, and 9,9'-bis. (4-carboxyphenyl)fluorenic acid and their methyl ester forms.

Among them, terephthalic acid or 2,6-naphthalenedicarboxylic acid is preferable, and terephthalic acid is more preferable.

Only one type of dicarboxylic acid compound may be used, or two or more types may be used in combination. When using terephthalic acid as a dicarboxylic acid compound, terephthalic acid may be used alone, or may be used in combination with other aromatic dicarboxylic acids such as isophthalic acid, or aliphatic dicarboxylic acids.

(diol compound)

Examples of diol compounds include aliphatic diol compounds, alicyclic diol compounds, and aromatic diol compounds, and among them, aliphatic diol compounds are preferable.

Examples of aliphatic diol compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and 1,2-butanediol. , 1,3-butanediol, and neopentyl glycol, with ethylene glycol being preferred.

Examples of alicyclic diol compounds include cyclohexanedimethanol, spiroglycol, and isosorbide.

Examples of aromatic diol compounds include bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, and 9,9'-bis(4-hydroxyphenyl)fluorene. .

As for the diol compound, only one type may be used, or two or more types may be used together.

(catalyst)

The catalyst used in the production of polyester resin is not particularly limited, and known catalysts that can be used in the synthesis of polyester resin can be used.

Catalysts include, for example, alkali metal compounds (e.g., potassium compounds, sodium compounds), alkaline earth metal compounds (e.g., calcium compounds, magnesium compounds), zinc compounds, lead compounds, manganese compounds, and cobalt compounds. , aluminum compounds, antimony compounds, titanium compounds, germanium compounds, and phosphorus compounds. Among them, titanium compounds are preferable from the viewpoint of catalytic activity and cost.

Only one type of catalyst may be used, or two or more types may be used together. As the catalyst, at least one selected from potassium compounds, sodium compounds, calcium compounds, magnesium compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium compounds, and germanium compounds. It is preferable to use a metal catalyst and a phosphorus compound together, and it is more preferable to use a titanium compound and a phosphorus compound together.

As the titanium compound, an organic chelate titanium complex is preferable. The organic chelate titanium complex is a titanium compound that has an organic acid as a ligand.

Examples of organic acids include citric acid, lactic acid, trimellitic acid, and malic acid.

As the titanium compound, the titanium compounds described in [0049] to [0053] of Japanese Patent Publication No. 5575671 can also be used, and the contents of the above publication are incorporated herein by reference.

(End sealant)

In the production of polyester resin, an end capping agent may be used as needed. By using an end cap agent, a structure derived from the end cap agent is introduced into the ends of the polyester resin.

The end capping agent is not limited and any known end capping agent can be used. Examples of end capping agents include oxazoline-based compounds, carbodiimide-based compounds, and epoxy-based compounds.

As an end capping agent, the contents described in [0055] to [0064] of Japanese Patent Application Laid-Open No. 2014-189002 can also be referred to, and the contents of the above publication are incorporated herein by reference.

(manufacturing conditions)

The reaction temperature when producing the polyester resin is not limited and can be set appropriately depending on the raw materials. The reaction temperature is preferably 260°C to 300°C, and more preferably 275°C to 285°C.

The pressure when manufacturing the polyester resin is not limited and can be set appropriately depending on the raw materials. The pressure is preferably 1.33×10 ^-3 to 1.33×10 ^-5 MPa, and more preferably 6.67×10 ^-4 to 6.67×10 ^-5 MPa.

As a polyester resin production (e.g., synthetic method), the method described in [0033] to [0070] of Japanese Patent Publication No. 5575671 can also be used, and the content of the above publication is incorporated herein by reference.

[Content of each ingredient]

The content of the polyester resin in the polyester substrate is preferably 85% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more, with respect to the total mass of the polymer in the polyester substrate, 98% by mass or more is particularly preferable.

The upper limit of the content of the polyester resin is not particularly limited and can be appropriately set, for example, in the range of 100% by mass or less with respect to the total mass of the polymer in the polyester base material.

When the polyester base material contains polyethylene terephthalate, the content of polyethylene terephthalate is preferably 90% by mass to 100% by mass, and 95% by mass to 100% by mass, relative to the total mass of the polyester resin in the polyester base material. is more preferable, 98 to 100 mass% is more preferable, and 100 mass% is especially preferable.

The polyester base material may contain components other than the polyester resin (for example, catalyst, unreacted raw material components, particles, water, etc.).

From the viewpoint of improving the smoothness of the release film, it is preferable that the polyester base material does not substantially contain particles. Examples of particles include particles included in the particle-containing layer described later.

In this specification, "does not substantially contain particles" means that when elements derived from particles are quantitatively analyzed for a polyester substrate by fluorescence X-ray analysis, the particle content is 50% relative to the total mass of the polyester substrate. It is defined as being less than or equal to ppm by mass, preferably less than or equal to 10 ppm by mass, and more preferably less than or equal to the detection limit. This means that without actively adding particles to the polyester substrate, contamination components derived from foreign substances, raw material resin, or contamination attached to the lines or equipment during the manufacturing process of the polyester substrate are peeled off and the polyester substrate is removed. This is because there are cases where it gets mixed up.

[Properties of polyester base]

(Orientation)

The polyester base material is preferably a biaxially oriented polyester base material.

“Biaxial orientation” means the property of having molecular orientation in the biaxial direction. Molecular orientation is measured using a microwave transmission type molecular orientation meter (for example, MOA-6004, manufactured by Oji Keisoku Kiki Co., Ltd.). The angle formed by the biaxial directions is preferably within the range of 90°±5°, more preferably within the range of 90°±3°, and more preferably within the range of 90°±1°. The biaxially oriented polyester base material in the release film of the present disclosure preferably has molecular orientation in the longitudinal direction and the width direction. The biaxially oriented polyester base material can be manufactured by a method described later (specifically, a stretching process).

(density)

The density of the polyester base material is preferably 1.39 g/cm ³ to 1.41 g/cm ³ , more preferably 1.395 g/cm ³ to 1.405 g/cm ³ , and 1.398 g/cm ³ to 1.400 g/cm ³ . It is more desirable.

The density of the polyester base material can be measured using an electronic hydrometer (product name "SD-200L", manufactured by Alpha Mirage).

(thickness)

The thickness of the polyester base material is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 40 μm or less, since peelability can be controlled. The lower limit of the thickness is not particularly limited, but since strength is improved and processability is improved, 3 μm or more is preferable, 10 μm or more is more preferable, and 20 μm or more is still more preferable.

The thickness of the polyester substrate was determined by making a section with a cross section perpendicular to the main surface of the release film and using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It is taken as the arithmetic mean value of the thickness of the five sections of the above section, which is measured using .

<Peel layer>

The peeling layer is provided to enable peeling of the peeling film.

When a release film is used to produce a ceramic green sheet, the ceramic green sheet is formed on the release surface, which is the surface opposite to the polyester substrate of the release layer. That is, a ceramic green sheet is provided on the peeling surface of the peeling film so that peeling is possible.

In addition, the release layer may be provided directly on the surface of the polyester substrate or may be provided on the polyester substrate through another layer, but it is preferable to provide it directly on the surface of the polyester substrate because of its superior smoothness. .

The release layer contains a crosslinked product formed by crosslinking a composition containing a block isocyanate with a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester resin. Hereinafter, block isocyanates with a dissociation temperature of more than 100°C and 220°C or less are also referred to as “specific block isocyanates,” and block isocyanates with a dissociation temperature of more than 100°C and 220°C or less and non-polyester resins. The composition it contains is also called “composition for forming a peeling layer.”

Among them, the release layer is preferably formed by crosslinking a composition containing a block isocyanate with a dissociation temperature of more than 100°C and not more than 220°C and a non-polyester resin.

[Specific block isocyanate]

Specific block isocyanates have a dissociation temperature of more than 100°C and less than 220°C. Certain block isocyanates are compounds used as crosslinking agents. By using a specific block isocyanate, it is possible to suppress the occurrence of concave defects on the peeling surface.

In this specification, the dissociation temperature of blocked isocyanate means "the deprotection reaction of blocked isocyanate in the DSC curve obtained by differential scanning calorimetry (DSC) (i.e., the blocking agent is isocyanate It means the temperature of the endothermic peak according to the reaction of desorption from the cyanate group. In addition, examples of the differential scanning calorimeter used for differential scanning calorimetry include, but are not limited to, model number DSC6200 manufactured by Seiko Instruments Co., Ltd.

The dissociation temperature of the specific block isocyanate is preferably 110°C or higher, more preferably 120°C or higher, from the viewpoint of producing a ceramic green sheet with suppressed defects without generating concave defects on the peeling surface. 130°C or higher is more preferable.

Moreover, the dissociation temperature of the specific block isocyanate is preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 160°C or lower from the viewpoint of ease of production of the crosslinked product contained in the release layer.

Specific block isocyanates are on the lower temperature side than the dissociation temperature of the DSC curve obtained by differential scanning calorimetry, and exhibit a heat value that is 1/3 of the heat value at the dissociation temperature (hereinafter also referred to as temperature X). It is preferable that it is a compound whose temperature is 80°C or higher. A specific block isocyanate having such physical properties means that the blocking agent is difficult to desorb at a temperature lower than the dissociation temperature. In addition, when the temperature I am separated. Therefore, by using a compound at which the temperature It can be suppressed. Additionally, as a result, a ceramic green sheet with suppressed defects can be manufactured.

The specific block isocyanate is a compound in which the isocyanate group of polyisocyanate is protected (i.e., blocked) with a blocking agent, and there is no particular limitation as long as the dissociation temperature is in the range of more than 100°C and less than 220°C. Additionally, the dissociation temperature of a specific blocked isocyanate is mainly determined depending on the type of blocking agent.

(block system)

Blocking agents for specific block isocyanates include, for example, phenol compounds, alcohol compounds, oxime compounds, mercaptan compounds, lactam compounds, amine compounds, acid amide compounds, pyrazole compounds, triazole compounds, and, Bisulfite compounds can be mentioned.

Examples of phenolic compounds include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, Examples include 3,4-xylenol, 3,5-xylenol, and ethylphenol.

Examples of alcohol compounds include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, propylene glycol monomethyl ether, ethylene glycol, and benzyl alcohol. You can.

Examples of oxime compounds include acetoxime, methyl ethyl ketone oxime, acetaldoxime, formaldoxime, diacetylmonoxime, and cyclohexane oxime. Among them, acetoxime and methyl ethyl ketone oxime are preferable from the viewpoint of ease of synthesis and adjustment of dissociation temperature.

Examples of mercaptan compounds include butyl mercaptan and dodecyl mercaptan.

Examples of lactam compounds include ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam. Among them, ε-caprolactam is preferable from the viewpoint of ease of synthesis and adjusting the dissociation temperature.

Examples of amine compounds include diphenylaniline, aniline, and ethyleneimine.

Examples of acid amide compounds include acetanilide and acetic acid amide.

As pyrazole compounds, methylpyrazole (for example, 2-methylpyrazole, 3-methylpyrazole, 4-methylpyrazole), dimethylpyrazole (for example, 2,4-dimethylpyrazole, 2,5-dimethylpyrazole, 3,4-dimethylpyrazole, 3,5-dimethylpyrazole), 4-nitro-3,5-dimethylpyrazole, and 4-bromo-3 , 5-dimethylpyrazole. Among them, methylpyrazole and dimethylpyrazole are preferable from the viewpoint of ease of synthesis and adjusting the dissociation temperature.

Examples of triazole compounds include 1,2,4-triazole.

Among them, the blocking agent in a specific block isocyanate is an oxime compound, a lactam compound, an acid amide compound, or a pyrazole compound from the viewpoint of keeping the dissociation temperature of the block isocyanate from 100°C to 220°C. It is desirable.

(polyisocyanate)

Examples of the polyisocyanate whose isocyanate group is protected by a blocking agent include adduct (also referred to as adduct form) obtained by adding 3 moles of diisocyanate to 1 mole of trimethylolpropane, 3 Biuret obtained by reacting 1 mole of water with 1 mole of diisocyanate (also called biuret body), or isocyanurate obtained by polymerizing 3 moles of diisocyanate (also called isocyanurate body) ) and polyisocyanate having a form of polyisocyanate.

Polyisocyanate whose isocyanate group is protected by a blocking agent also includes polyisocyanate obtained by reacting polyol (e.g., polyester polyol, polyether polyol, low molecular weight polyol). Urethane polyisocyanate may be used.

Examples of diisocyanate include aromatic diisocyanate, aliphatic diisocyanate, and alicyclic isocyanate. Ceramic green sheet with suppressed defects without generating concave defects on the peeling surface. From the viewpoint of manufacturing, aliphatic diisocyanate is preferable, and hexamethylene diisocyanate is especially preferable.

Examples of aromatic diisocyanate, which is an example of diisocyanate, include 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-Diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, tetraalkyl diphenyl methane diisocyanate, dialkyl diphenyl methane diisocyanate Cyanate, 1,3-phenylene diisocyanate, polymeric diphenylmethane diisocyanate, tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate) anate), 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 1,5-naphthylene diisocyanate, and naphthalene diisocyanate can be mentioned.

Examples of aliphatic diisocyanate, which is an example of diisocyanate, include hexamethylene diisocyanate, trimethylene diisocyanate, and trimethylhexamethylene diisocyanate (2,2, 4- or 2,4,4-trimethylhexamethylene diisocyanate), lysine diisocyanate, xylylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate Cyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, and 1,5-pentamethylene diiso Examples include cyanate.

Examples of alicyclic isocyanates, which are examples of diisocyanate, include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, and cyclohexane diiso. Cyanate (1,3- or 1,4-cyclohexanediisocyanate), 3-isocyanatemethyl-3,5,5-trimethylcyclohexylisocyanate, methylcyclohexane Diisocyanate (-2,4- or -2,6-methylcyclohexane diisocyanate), and norbornene diisocyanate are included.

Among them, the isocyanurate form of hexamethylene diisocyanate, hexamethylene diisocyanate, from the viewpoint of ease of availability, ease of synthesis, and production of ceramic green sheets with suppressed defects without generating concave defects on the peeling surface. The biuret form of cyanate and the adduct form of hexamethylene diisocyanate are preferred.

Specific examples of specific blocked isocyanates include compounds in which the isocyanate group of the isocyanurate form of hexamethylene diisocyanate is blocked with an oxime compound, a lactam compound, an acid amide compound, or a pyrazole compound, and hexamethylene diisocyanate. A compound in which the isocyanate group of the biuret form of methylene diisocyanate is blocked with an oxime compound, lactam compound, acid amide compound, or pyrazole compound, and the isocyanate group of the adduct form of hexamethylene diisocyanate. Compounds in which the nate group is blocked with an oxime compound, a lactam compound, an acid amide compound, or a pyrazole compound can be mentioned.

As the specific block isocyanate, a commercially available product may be used.

Examples of commercially available products include 2554, 2507, and BI-301 of the Coronate series manufactured by Tosoh Corporation, and SBN-70D, SBN-70P, MF-B60B, 17B-60P, and TPA of the Duranate series manufactured by Asahi Kasei Corporation. -B80E, E402-B80B, B-830, B-815N, B-820NSU, B-842N, B-846N, B870N, B874N, B882N of the Takenate series manufactured by Mitsui Chemicals Co., Ltd., etc.

Among the compositions for forming a release layer, only one type of specific block isocyanate may be used, and two or more types may be used.

In the composition for forming a release layer, the content of specific block isocyanate may be 1% by mass to 90% by mass, and is preferably 5% by mass to 35% by mass, based on the total solid content of the composition for forming a release layer. , In particular, from the viewpoint of excellent peelability and from the viewpoint of producing a ceramic green sheet with suppressed defects without generating concave defects on the peeling surface, it is more preferable that it is 10% by mass to 25% by mass. Here, the total solid content means the total mass excluding the solvent contained in the composition for forming a peeling layer.

In the composition for forming a release layer, the content ratio of the specific block isocyanate to the non-polyester resin is preferably 0.01 to 1, and since solvent resistance is excellent, it is more preferable to be 0.1 to 1.

[Non-polyester resin]

The composition for forming a release layer contains a non-polyester resin.

Non-polyester resin means resin other than polyester resin. Specifically, non-polyester resins include urethane resin, olefin resin, fluorine resin, alkaline resin, acrylic resin, polyester resin, polyvinyl alcohol resin, melamine resin, epoxy resin, phenol resin, and styrene butadiene. At least one selected from the group consisting of copolymers and silicone resins is preferred.

As the non-polyester resin, a non-polyester resin having a functional group (hereinafter also referred to as functional group R) that can be crosslinked with an isocyanate group is preferable. If the composition for forming a release layer contains a non-polyester resin having a functional group R, a crosslinked product is obtained through a crosslinking reaction with a specific block isocyanate, and solvent resistance is improved.

Examples of the functional group R that the non-polyester resin has include a hydroxy group, a carboxy group, an amino group, a thiol group, and an amide group. Among them, from the viewpoint of ease of availability and crosslinkability with specific block isocyanate, it is preferable that the functional group R is a hydroxy group or a carboxy group.

From the viewpoint of suppressing defects in the ceramic green sheet, the non-polyester resin is preferably at least one selected from the group consisting of urethane resin, acrylic resin, polyvinyl alcohol resin, olefin resin, and silicone resin. . Among them, the non-polyester resin is selected from the group consisting of a urethane resin having a functional group R, an acrylic resin having a functional group R, a polyvinyl alcohol resin, an olefin resin having a functional group R, and a silicone resin having a functional group R. It is preferable that there is at least one type.

The urethane resin is not particularly limited as long as it is a polymer having a urethane bond in the main chain, and known urethane resins such as the reaction product of polyisocyanate and polyol can be used.

As described above, the urethane resin is preferably a urethane resin having a functional group R, and is more preferably a urethane resin having a carboxyl group.

Urethane resin can improve solvent resistance by adjusting the crosslinking reaction with the oxazoline compound, for example, by adjusting the structure and flexibility of the polyol and polyisocyanate as raw materials. From the point of superior solvent resistance, it is preferable that the urethane resin contains a polyester structure.

Commercially available products of urethane resin include, for example, Hydran (registered trademark) AP-20, AP-40N and AP-201 (manufactured by DIC Corporation), Takelac (registered trademark) W-605, W -5030 and W-5920 (above, manufactured by Mitsui Chemicals Co., Ltd.), Super Flex (registered trademark) 210 and 130, and Elastron (registered trademark) H-3-DF, E-37, and H-15 (Above, Daiichi High School Seiyaku Co., Ltd. product).

The acrylic resin is a resin containing a structural unit derived from (meth)acrylate, and may be copolymerized with a vinyl monomer such as styrene.

The acrylic resin is preferably an acrylic resin having a functional group R as described above.

The acrylic resin is not particularly limited, but preferably contains a structural unit derived from (meth)acrylate having an alkyl group of 1 to 12 carbon atoms, and a unit derived from (meth)acrylate having an alkyl group of 1 to 8 carbon atoms. It is more preferable to include structural units.

The acrylic resin may have an acid-modifying component. The acrylic resin may contain a structural unit derived from (meth)acrylic acid as an acid-modified component. By including a structural unit derived from (meth)acrylic acid, a carboxy group as a functional group R is introduced into the acrylic resin. Additionally, (meth)acrylic acid may form an acid anhydride or may be neutralized with at least one selected from alkali metals, organic amines, and ammonia.

The acid value of the acrylic resin is preferably 30 mgKOH/g or less, and more preferably 20 mgKOH/g or less. The lower limit of the acid value is not particularly limited and is, for example, 0 mgKOH/g, but in terms of application as an aqueous dispersion, 2 mgKOH/g or more is preferable. By setting the acid value of the acrylic resin within the above range and/or including a structural unit derived from (meth)acrylate having an alkyl group of 1 to 12 carbon atoms, the resin can be made difficult to be compatible with polyester resin. By making it difficult for the polyester base to be compatible with the polyester resin, impurities such as oligomers contained in the polyester base can be suppressed from precipitating in the peeling layer, and as a result, defects in the ceramic green sheet can be further suppressed. there is.

Polyvinyl alcohol resin is a resin containing structural units derived from vinyl alcohol in the main chain, and has a hydroxy group as the functional group R. The polyvinyl alcohol resin may have a group other than a hydroxy group, for example, a carboxy group, as the functional group R.

The polyvinyl alcohol resin may be copolymerized with vinyl acetate or the like in addition to vinyl alcohol. Monomers that may be copolymerized with vinyl alcohol include vinyl acetate and vinyl butyral.

The polyvinyl alcohol resin may be partially saponified or completely saponified. Specifically, the saponification degree of the polyvinyl alcohol resin is preferably 80 to 100, and more preferably 90 to 100.

The olefin resin may be a resin containing a structural unit derived from olefin in the main chain. By having a structural unit derived from olefin in the main chain, the crosslinking reaction with the oxazoline compound can be adjusted and solvent resistance can be improved.

The olefin resin is preferably an olefin resin having a functional group R as described above.

The olefin is not particularly limited, but alkenes having 2 to 6 carbon atoms are preferable, ethylene, propylene, or hexene are more preferable, and ethylene is still more preferable.

The structural unit derived from the olefin contained in the polyolefin is preferably 50 mol to 99 mol%, and more preferably 60 mol to 98 mol%, relative to all structural units of the polyolefin.

As the olefin resin, acid-modified olefin resin is preferable and carboxy-modified olefin resin is preferable. Examples of the acid-modified olefin resin include copolymers obtained by modifying the above-mentioned olefin resin with an acid-modifying component such as an unsaturated carboxylic acid or its anhydride.

Commercially available products of olefin resin include, for example, the Zaixen (registered trademark) series such as Zaixen AC, A, L, NC, and N (manufactured by Sumitomo Seika Co., Ltd.), Chemipearl S100, S120, S200, S300, and S650. and Chemipearl (registered trademark) series such as SA100 (manufactured by Mitsui Chemicals Co., Ltd.), Hi-Tech (registered trademark) series such as Hi-Tech S3121 and S3148K (manufactured by Toho Chemicals Co., Ltd.), Arobase SE-1013, SE -Arobase (registered trademark) series such as 1010, SB-1200, SD-1200, DA-1010 and DB-4010 (manufactured by Unichika Co., Ltd.), Harden AP-2, NZ-1004 and NZ-1005 ( Examples include Toyobo Co., Ltd.), and Sepoljeon G315 and VA407 (Sumitomo Seika Co., Ltd.).

Additionally, acid-modified olefin resins described in [0022] to [0034] of Japanese Patent Application Laid-Open No. 2014-076632 can also be preferably used.

Silicone resin refers to a silicone compound with a weight average molecular weight of 1000 or more, which has a silicone structure (main chain composed of polysiloxane bonds) in the molecule.

The silicone resin is preferably a compound having a dimethylsiloxane structure. In addition, the silicone resin may be an organic-inorganic composite resin in which an inorganic component made of polysiloxane and an organic component are complexed, and in this case, it is preferable to include a structural unit having a functional group R and a structural unit having dimethylsiloxane. It is more preferable to include a structural unit having a carboxyl group and a structural unit having dimethylsiloxane. Additionally, the silicone resin is preferably a compound in which a functional group R is introduced into at least one of the terminal and side chains of the main chain formed of polysiloxane bonds.

When using a silicone resin as a non-polyester resin, the silicone resin can serve both as a non-polyester resin and a silicone compound.

Among the compositions for forming a release layer, only one type of non-polyester resin may be used, and two or more types may be used.

In the composition for forming a release layer, the content of the non-polyester resin may be 10% by mass to 99% by mass, and is preferably 25% by mass to 80% by mass, based on the total solid content of the composition for forming a release layer. From the viewpoint of excellent properties and from the viewpoint of producing a ceramic green sheet with suppressed defects without generating concave defects on the peeling surface, it is preferably 30% by mass to 65% by mass.

In addition, in the composition for forming a release layer, the content ratio of the specific block isocyanate to the non-polyester resin may be 0.01 to 1, from the viewpoint of excellent release properties, and from the viewpoint of generating minute concave defects on the release surface. From the viewpoint of manufacturing a ceramic green sheet with suppressed defects, it is preferably 0.1 to 0.5.

[Silicone compound]

The composition for forming a release layer preferably contains a silicone compound. If a silicone compound is contained, the peeling layer has excellent peelability.

The silicone compound is not particularly limited as long as it is a compound having a siloxane bond in the molecule. The silicone compound is preferably a compound having a dimethylsiloxane structure because of its superior peelability. The silicone compound may be a low molecule or an oligomer, and is preferably an oligomer.

The molecular weight of the silicone compound is preferably 150 or more, more preferably 350 or more, and still more preferably 650 or more. The upper limit of the molecular weight of the silicone compound is less than 1000.

Among them, a crosslinkable silicone compound is preferable as the silicone compound because it has superior solvent resistance. The component that the silicone compound crosslinks may be a specific block isocyanate or a component included in the composition for forming another peeling layer. Additionally, it is preferable that the crosslinkable site is introduced into at least one of the terminal and side chains of the silicone compound.

Examples of silicone compounds include polydimethylsiloxane and hydrodienesiloxane, which have a vinyl group introduced into at least one of the terminal and side chains. These silicone compounds have superior solvent resistance because a crosslinked product is obtained by reacting using a platinum catalyst.

Moreover, examples of the silicone compound include polydimethylsiloxane having a hydroxyl group at the terminal, and polydimethylsiloxane having a hydrogen atom at the terminal. These silicone compounds have superior solvent resistance because a crosslinked product is obtained by carrying out a condensation reaction using an organic tin catalyst.

Additionally, the silicone compound may be a silicone compound that can be crosslinked by the action of ultraviolet rays or electron beams. Examples of silicone compounds that can be crosslinked by the action of ultraviolet rays or electron beams include silicone compounds capable of radical polymerization and silicone compounds having an epoxy group. More specifically, acrylate-modified polydimethylsiloxane, and glycidoxy-modified polydimethylsiloxane.

Among them, the silicone compound is more preferably a silicone compound having a functional group capable of crosslinking with an isocyanate group from the viewpoint of crosslinking with a specific block isocyanate. More specifically, it is more preferable that the silicone compound has a functional group capable of crosslinking an isocyanate group on at least one of the terminal and side chains of the silicone compound.

Examples of the functional group that can be crosslinked with the isocyanate group of the silicone compound include the same functional group R as that of the non-polyester resin. Among them, from the viewpoint of ease of availability and crosslinkability with specific block isocyanate, it is preferable that the functional group R of the silicone compound is a hydroxy group or a carboxy group. That is, the silicone compound is preferably a silicone compound having a hydroxyl group and a silicone compound having a carboxyl group.

Among the compositions for forming a peeling layer, only one type of silicone compound may be used, and two or more types may be used.

In the composition for forming a release layer, the content of the silicone compound is preferably 1% by mass to 90% by mass with respect to the total solid content of the composition for forming a release layer, and is more preferably 5% by mass or more from the viewpoint of peelability. .

[Desirable conditions]

In the release film of the present disclosure, it is preferable that the composition for forming a release layer satisfies at least one of the conditions (1) to (3) shown below.

(1) Contains a specific block isocyanate and a non-polyester resin having a functional group R other than the silicone resin, and further contains a silicone compound.

(2) It contains a specific block isocyanate and a non-polyester resin, and the non-polyester resin is a silicone resin having a functional group R.

(3) Contains a specific block isocyanate and a non-polyester resin having a functional group R other than the silicone resin, and further contains a silicone resin.

In the case of conditions (1) and (3), the specific block isocyanate reacts with at least a non-polyester resin having a functional group R other than the silicone resin, and a crosslinked product is obtained. Moreover, the peelability of the peeling layer is achieved by the silicone compound or silicone resin. In addition, in the case of condition (1), the silicone compound and silicone resin do not need to have the functional group R, but it is preferable that they have the functional group R from the viewpoint of solvent resistance.

In the case of condition (2), the specific block isocyanate reacts with the silicone resin having at least the functional group R, and a crosslinked product is obtained. Moreover, in the case of condition (2), the composition for forming a peeling layer may further contain a silicone compound. The silicone compound at this time does not need to have a functional group R, but it is preferable to have a functional group R from the viewpoint of solvent resistance.

[additive]

The composition for forming a peeling layer may contain additives in addition to the above components. Additives include surfactants, light and heavy peeling additives for adjusting the peeling force, adhesion improvers, antistatic agents, and catalysts for promoting the crosslinking reaction.

From the viewpoint of improving the smoothness of the release layer, it is preferable that the composition for forming the release layer contains a surfactant.

The surfactant is not particularly limited and includes silicone-based surfactants, fluorine-based surfactants, and hydrocarbon-based surfactants. Among them, it is preferable that the surfactant is a hydrocarbon-based surfactant.

The silicone-based surfactant is not particularly limited as long as it is a surfactant that has a silicon-containing group as a hydrophobic group, and examples include polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. .

Commercially available silicone surfactants include, for example, BYK (registered trademark) -306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, and BYK. -349 (above, manufactured by BYK), and KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643 , KF-6020,

The fluorine-based surfactant is not particularly limited as long as it is a surfactant that has a fluorine-containing group as a hydrophobic group, and examples include perfluorooctanesulfonic acid and perfluorocarboxylic acid.

Commercially available products of fluorine-based surfactants include, for example, Megapak (registered trademark) F-114, F-410, F-440, F-447, F-553, and F-556 (above, manufactured by DIC Co., Ltd.) ), and Surfron (registered trademark) S-211, S-221, S-231, S-233, S-241, S-242, S-243, S-420, S-661, S-651, and S-386 (manufactured by AGC Semi Chemical Co., Ltd.).

In addition, as a fluorine-based surfactant, from the viewpoint of improving environmental compatibility, compounds having a linear perfluoroalkyl group with 7 or more carbon atoms, such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), can be replaced. It is preferred to use a surfactant derived from the material.

Examples of hydrocarbon-based surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants.

Examples of anionic surfactants include alkyl sulfate, alkylbenzenesulfonate, alkyl phosphate, and fatty acid salt.

Nonionic surfactants include, for example, polyalkylene glycol mono or dialkyl ether, polyalkylene glycol mono or dialkyl ester, and polyalkylene glycol monoalkyl ester/monoalkyl ether. You can.

Examples of cationic surfactants include primary to tertiary alkylamine salts and quaternary ammonium compounds.

Examples of amphoteric surfactants include surfactants that have both an anionic moiety and a cationic moiety in the molecule.

Commercially available anionic surfactants include, for example, Rapizol (registered trademark) A-90, A-80, BW-30, B-90, and C-70 (manufactured by Nichiyu Co., Ltd.); NIKKOL (registered trademark) OTP-100 (above, manufactured by Nikko Chemical Co., Ltd.), KOHACOOL (registered trademark) ON, L-40, and Phosphanol (registered trademark) 702 (above, Toho Kagaku Kogyo Co., Ltd.) ), Byulite (registered trademark) A-5000, and SSS (above, manufactured by Sanyo Kasei Kogyo Co., Ltd.).

Commercially available nonionic surfactants include, for example, Naroacti (registered trademark) CL-95, HN-100 (product name: Sanyo Kasei Kogyo Co., Ltd.), Lisorex BW400 (product name: Kokyu Alcohol Kogyo Co., Ltd.) ), EMALEX (registered trademark) ET-2020 (above, manufactured by Nippon Emulsion Co., Ltd.), and Surfinol (registered trademark) 104E, 420, 440, 465, and Dynol (registered trademark) 604, 607. (Above, manufactured by Nisshin Kagaku Kogyo Co., Ltd.).

Among hydrocarbon-based surfactants, anionic surfactants and/or nonionic surfactants are preferable, and anionic surfactants are more preferable.

The anionic hydrocarbon-based surfactant preferably has a plurality of hydrophobic end groups because smoothness is further improved. The hydrophobic end group may be a part of the hydrocarbon group possessed by the hydrocarbon-based surfactant. For example, a hydrocarbon-based surfactant having a hydrocarbon group having a branched chain structure at the end has a plurality of hydrophobic end groups.

Examples of anionic hydrocarbon-based surfactants having a plurality of hydrophobic end groups include di-2-ethylhexyl sodium sulfosuccinate (having four hydrophobic end groups) and di-2-ethyloctyl sodium sulfosuccinate (having four hydrophobic end groups). has 4), and branched alkylbenzenesulfonate (has 2 hydrophobic terminal groups).

One type of surfactant may be used, or two or more types may be used in combination.

When the composition for forming a peeling layer contains a surfactant, the content of the surfactant is preferably 0.1% by mass to 10% by mass with respect to the total solid content of the composition for forming a peeling layer, from the viewpoint of further improving the smoothness of the peeling layer. , 0.1 mass% to 5 mass% is more preferable, and 0.5 mass% to 2 mass% is more preferable.

Additionally, the composition for forming a release layer may contain a crosslinking agent other than the specific block isocyanate as an additive.

Other crosslinking agents are not particularly limited and known ones can be used.

Other crosslinking agents include, for example, melamine compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, and oxazoline compounds.

For details on the melamine compound, epoxy compound, and isocyanate compound, the descriptions [0081] to [0083] of Japanese Patent Application Laid-Open No. 2015-163457 can be referred to.

As a carbodiimide compound, the description of [0038] to [0040] in Japanese Patent Application Publication No. 2017-087421 can be referred to.

For carbodiimide compounds and isocyanate compounds, the descriptions in [0074] to [0075] of International Publication No. 2018/034294 can be referred to.

For oxazoline compounds, the descriptions of [0111] to [0117] in Japanese Patent Application Laid-Open No. 2013-058746 and [0038] to [0048] in Japanese Patent Application Laid-Open No. 2015-160434 can be referred to.

As another crosslinking agent, the descriptions [0082] to [0084] of International Publication No. 2017/169844 can be referred to.

When the composition for forming a release layer contains another crosslinking agent, the content of the other crosslinking agent is preferably 0% by mass to 30% by mass with respect to the total solid content of the composition for forming a release layer.

[Content of each ingredient]

The content of the crosslinked product (specifically, the crosslinked product of isocyanate and non-polyester resin) in the release layer is preferably 50% by mass or more, and 70% by mass or more, relative to the total mass of the release layer. It is more preferable, and 90% by mass or more is more preferable.

The upper limit of the content of the crosslinked product can be appropriately set to less than 100% by mass with respect to the total mass of the peeling layer.

In the peeling layer, a compound containing a residue derived from the blocking agent of the blocked isocyanate (for example, a compound containing a residue derived from an oxime compound, pyrazole compound, acid amide compound, or lactam compound) remains. do.

The content of the compound containing a residue derived from the blocking agent of the blocked isocyanate in the release layer is preferably 0.0001% by mass to 1% by mass, and 0.0001% by mass to 0.5% by mass, based on the total mass of the release layer. It is more preferable that it is mass %.

(Compounds containing residues derived from blocking agents)

The compound containing a residue derived from a blocking agent is often at least one selected from compounds corresponding to the blocking agent of blocked isocyanate, its derivatives, and its decomposition products.

Specifically, the compound containing a residue derived from an oxime compound is often at least one selected from oxime compounds, their derivatives, and decomposition products, and the compound containing a residue derived from a pyrazole compound is pyrazole. It is often at least one selected from a compound, its derivative, and its decomposition product, and the compound containing a residue derived from an acid amide compound is often at least one selected from an acid amide compound, its derivative, and its decomposition product. , the compound containing a residue derived from a lactam compound is often at least one selected from lactam compounds, their derivatives, and their decomposition products.

[Properties of peeling layer]

(thickness)

The thickness of the peeling layer can be set according to the purpose of use and is not particularly limited, but is preferably 0.001 μm to 0.2 μm, and is preferably 0.01 μm to 0.2 μm in that the peel performance and peeling surface smoothness are well balanced. It is more preferable, and 0.03 μm to 0.1 μm is more preferable.

The thickness of the peeling layer is measured by producing a section with a cross-section perpendicular to the main surface of the peeling film and using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). This is taken as the arithmetic mean value of the thickness of the five sections of the above section.

<Particle-containing layer>

The release film of the present disclosure preferably further includes a particle-containing layer, and more preferably includes a release layer, a polyester substrate, and a particle-containing layer in this order.

The particle-containing layer refers to a layer containing particles.

If the release film is provided with a particle-containing layer, the transportability of the release film can be improved. Specifically, in the release film, the winding quality can be improved (blocking is suppressed), the occurrence of scratches and defects during conveyance can be suppressed, and conveyance wrinkles during high-speed conveyance can be reduced.

The particle-containing layer may be provided directly on the surface of the polyester substrate or may be provided on the surface of the polyester substrate through another layer, but it is preferable to provide it directly on the surface of the polyester substrate because of better adhesion.

Additionally, the particle-containing layer preferably contains particles and a binder, and may further contain additives.

Hereinafter, particles, binders, and additives will be described.

(particle)

The average particle diameter of the particles contained in the particle-containing layer is not particularly limited, and is preferably 10 nm to 2 μm, more preferably 30 nm to 1.5 μm, and 30 nm because of better transportability and ability to suppress transfer traces. ~500nm is more preferred.

In addition, in view of superior transportability and the ability to suppress transfer traces, the average particle diameter of the particles contained in the particle-containing layer is 10 nm to 200 nm (more preferably 30 nm to 130 nm), and the thickness of the particle-containing layer is 1 nm to 1 nm. It is preferably 200 nm (more preferably 10 nm to 100 nm), and the average particle diameter of the particles is preferably larger than the thickness of the particle-containing layer.

As the particles contained in the particle-containing layer, one type may be used alone, or two or more types of particles may be used.

When the particle-containing layer contains two or more types of particles with different particle diameters, the particle-containing layer preferably contains at least one type of particle whose average particle diameter is within the above range, and the two or more types of particles with different particle diameters all have an average particle diameter of It is more preferable that the particles fall within the above range.

Examples of particles contained in the particle-containing layer include organic particles and inorganic particles. Among them, when manufacturing a ceramic green sheet, organic particles are preferable from the viewpoint of suppressing the defect rate of the ceramic capacitor manufactured using the obtained ceramic green sheet.

As organic particles, resin particles are preferable. Resins constituting the resin particles include, for example, acrylic resins such as polymethyl methacrylate resin (PMMA), polyester resins, silicone resins, styrene resins, and styrene-acrylic resins. The resin particles may have a crosslinked structure. Examples of resin particles having a crosslinked structure include divinylbenzene crosslinked particles.

In addition, in this disclosure, an acrylic resin means a resin containing a structural unit derived from acrylate or methacrylate.

Examples of inorganic particles include silica particles (also referred to as silicon dioxide particles), titania particles (also referred to as titanium oxide particles), calcium carbonate, barium sulfate, and alumina particles (also referred to as aluminum oxide particles). Among them, the inorganic particles are preferably silica particles from the viewpoint of further improving haze and durability.

The shape of the particles is not particularly limited, and examples include fine particles, spherical shapes, cubic shapes, spindle shapes, scale shapes, aggregated shapes, and irregular shapes. An agglomerated phase means a state in which primary particles are aggregated. The shape of the particles in the agglomerated phase is not limited, but spherical or indeterminate shapes are preferred.

As the aggregated particles, fumed silica particles are preferable. Available commercial products include, for example, the Aerosil series manufactured by Nippon Aerosil Co., Ltd.

As non-agglomerated particles, colloidal silica particles are preferred. Available commercial products include, for example, the Snotex (registered trademark) series manufactured by Nissan Chemical Co., Ltd.

The particle content in the particle-containing layer is preferably 0.1% by mass to 30% by mass, and 1% by mass to 25% by mass, relative to the total mass of the particle-containing layer, from the viewpoint of transportability and suppressing transfer traces. % is more preferable, and 1% by mass to 15% by mass is more preferable.

Moreover, the content of the particles is preferably 0.0001 mass% to 0.01 mass%, and more preferably 0.0005 mass% to 0.005 mass%, relative to the total mass of the peeling film.

(Non-polyester resin (binder))

The particle-containing layer preferably contains a non-polyester resin. The non-polyester resin contained in the particle-containing layer has a function as a binder.

Non-polyester resin means resin other than polyester resin. Specifically, the non-polyester resin is preferably at least one selected from the group consisting of acrylic resin, urethane resin, olefin resin, polyvinyl alcohol resin, and acrylonitrile butadiene resin. In view of its superior effect, it is preferable that it is at least one type of resin selected from the group consisting of acrylic resin, urethane resin, and olefin resin.

Here, the solubility parameters (SP values) of non-polyester resins (particularly acrylic resins, urethane resins, and olefin resins) and polyester resins are different. That is, since the compatibility between acrylic resin, urethane resin, and olefin resin and polyester resin is insufficient, it becomes difficult for impurities such as oligomers to precipitate from the polyester substrate via the particle-containing layer onto the conveyance surface. It is assumed that this makes it difficult for protrusions resulting from impurities contained in the polyester base material to occur on the conveyance surface.

Non-polyester resins such as the above-described acrylic resins, urethane resins, and olefin resins are not particularly limited, and known resins can be used.

The non-polyester resin is preferably an acid-modified resin, that is, an acid group-containing resin.

Additionally, the particle-containing layer may contain polyester resin.

The acrylic resin has the same meaning as the acrylic resin mentioned as an example of the non-polyester resin contained in the composition for forming the release layer, and the preferred embodiments are also the same.

The olefin resin has the same meaning as the olefin resin mentioned as an example of the non-polyester resin contained in the composition for forming the release layer, and the preferred embodiments are also the same.

By having a structural unit derived from olefin in the main chain, the olefin resin can be made into a resin that is difficult to miscible with polyester resin, and impurities such as oligomers contained in the polyester base material are suppressed from precipitation in the particle-containing layer, making ceramic Defects in the green sheet can be suppressed.

The urethane resin has the same meaning as the urethane resin mentioned as an example of the non-polyester resin contained in the composition for forming a peeling layer, and the preferred embodiment is also the same.

Since it is easy to form a film by application, the urethane resin is preferably a urethane resin having an acidic group, or a form containing urethane resin and a dispersant. Examples of acidic groups include carboxyl groups.

Urethane resin can be made into a resin that is difficult to compatible with polyester resin, for example, by adjusting the structure and hydrophobicity (hydrophilicity) of the raw materials polyol and isocyanate, and is included in the polyester base material. Precipitation of impurities such as oligomers in the particle-containing layer is suppressed, and defects in the ceramic green sheet can be suppressed. Since defect suppression can be further improved, it is preferable that the urethane resin contains a polyester structure.

The non-polyester resin contained in the particle-containing layer may have a crosslinked structure. That is, the particle-containing layer may be a crosslinked membrane.

In order to form a non-polyester resin having a crosslinked structure, a method of forming a particle-containing layer using a composition for forming a particle-containing layer containing a crosslinking agent can be used, as will be described later.

The particle-containing layer may contain one type of binder alone, or may contain two or more types of binders. Moreover, the particle-containing layer may contain one type of non-polyester resin alone, or may contain two or more types of non-polyester resin.

The content of the binder (preferably non-polyester resin) is preferably 30% by mass to 99.8% by mass, and more preferably 50% by mass to 99.5% by mass, relative to the total mass of the particle-containing layer, from the viewpoint of suppressing defects. do.

(additive)

The particle-containing layer may contain additives other than the above particles and binder.

Additives contained in the particle-containing layer include, for example, surfactants, waxes, antioxidants, ultraviolet absorbers, colorants, reinforcing agents, plasticizers, antistatic agents, flame retardants, rust inhibitors, and anti-fungal agents.

The particle-containing layer preferably contains a surfactant because the smoothness of areas other than the areas where projections formed by particles exist on the transport surface are improved.

The surfactant is not particularly limited, but the same surfactants as those listed as examples of the surfactant contained in the composition for forming the peeling layer can be used.

One type of surfactant may be used, or two or more types may be used in combination.

When the particle-containing layer contains a surfactant, the content of the surfactant is preferably 0.1% by mass to 10% by mass relative to the total mass of the particle-containing layer, and is 0.1% by mass to 5% by mass because surface smoothness is superior. is more preferable, and 0.5 mass% to 2 mass% is more preferable.

There are no particular restrictions on the wax, and it may be a natural wax or a synthetic wax. Natural waxes include carnauba wax, candelilla wax, beeswax, montan wax, paraffin wax, and petroleum wax. In addition, the lubricant described in [0087] of International Publication No. 2017/169844 can also be used.

The wax content is preferably 0% by mass to 10% by mass with respect to the total mass of the particle-containing layer.

[Properties of particle-containing layer]

(thickness)

For example, when the particle-containing layer is formed by applying a composition containing particles and a non-polyester resin onto one side of a polyester film, the thickness of the particle-containing layer is often 1 μm or less.

Additionally, when a polyester film on which a particle-containing layer is laminated is formed by co-extrusion, the thickness of the particle-containing layer is often 1 μm to 10 μm.

The thickness of the particle-containing layer is preferably 1 nm to 3 μm, and when manufacturing by coating, from the viewpoint of manufacturing suitability and haze reduction, 1 nm to 500 nm is preferable, 1 nm to 250 nm is more preferable, and 10 nm to 100 nm is preferable. It is more preferable, and 20 nm to 100 nm is particularly preferable.

The thickness of the particle-containing layer is the thickness of the five points of the section, which is measured by producing a section with a cross section perpendicular to the main surface of the release film and using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It is taken as the arithmetic average.

<Properties of peeling film>

[thickness]

The thickness of the release film is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 40 μm or less because of excellent peelability. Moreover, the thickness of the release film is preferably 3 μm or more, more preferably 10 μm or more, and still more preferably 20 μm or more, since strength is improved and processability is improved.

The thickness of the peeling film is assumed to be measured using a continuous stylus type thickness meter. Specifically, it is performed at five arbitrary locations where the positions of the peeling film are different. The arithmetic mean value of the obtained five measured values is taken as the thickness of the peeling film.

[Method for producing release film]

The manufacturing method of the release film of this disclosure is demonstrated.

The method for producing the release film of the present disclosure is not particularly limited as long as the release film described above is obtained, and known methods can be used.

For example, the method for producing a release film of the present disclosure is a method for producing a release film including a polyester base material and a release layer, a block isocyanate having a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester It includes a step of forming a peeling layer using a composition for forming a peeling layer containing a resin.

Among them, since the release film can be produced with good productivity, a preferred method for producing the release film is:

An extrusion molding process for forming an unstretched polyester film by extrusion molding,

A first stretching step of stretching an unstretched polyester film in one of the conveyance direction and the width direction to form a uniaxially stretched polyester film, and stretching the uniaxially stretched polyester film in the other of the conveyance direction and the width direction. A second stretching step to form a biaxially stretched polyester film is performed stepwise or simultaneously,

A release layer that forms a release layer by applying a release layer forming composition to one side of the polyester film between the extrusion molding process and the stretching process, between the first stretching process and the second stretching process, or after the stretching process. A manufacturing method including a forming process can be mentioned.

By the above manufacturing method, a release film comprising a polyester substrate and a release layer disposed on the polyester substrate is obtained. That is, the polyester base material in the release film is preferably obtained by stretching an unstretched polyester film in the conveyance direction and the width direction, respectively.

In addition, the method for producing a release film of the present disclosure forms a particle-containing layer on the other side of the polyester film between the extrusion molding process and the stretching process, between the first stretching process and the second stretching process, or after the stretching process. A particle-containing layer forming step of applying the composition to form a particle-containing layer may be further included.

By the above manufacturing method, a polyester substrate, a release layer disposed on one side of the polyester substrate, and a particle-containing layer disposed on the side opposite to the side on which the polyester substrate release layer is disposed. A release film comprising

Hereinafter, each step in a preferred embodiment of the manufacturing method of the present disclosure will be described. In addition, the manufacturing method of the present disclosure is not limited to one preferred embodiment, and the following steps can be appropriately omitted.

[Extrusion molding process]

The extrusion molding process is a process of forming an unstretched polyester film by extrusion molding.

More specifically, it is a process of extruding a molten resin containing a raw polyester resin into a film form to form an unstretched polyester film. The polyester resin as a raw material has the same meaning as the polyester resin described in the item [Polyester resin] above.

In addition, in order to produce a polyester film that does not substantially contain particles, it is preferable to use polyester pellets that do not contain particles during extrusion molding.

The extrusion molding method is a method of molding a raw material resin into a desired shape by, for example, extruding a molten body of the raw material resin using an extruder.

The molten body extruded from the extrusion die is cooled and molded into a film shape. For example, the molten body can be molded into a film by contacting the molten body with a casting roll and cooling and solidifying the molten body on the casting roll. When cooling the molten body, it is desirable to further blow wind (preferably cold wind) to the molten body.

[Stretching process]

The stretching process is a first stretching process in which an unstretched polyester film is stretched in either the transport direction or the width direction to form a uniaxially stretched polyester film, and a uniaxially stretched polyester film is stretched in either the transport direction or the width direction. The second stretching step of stretching in the other direction to form a biaxially stretched polyester film is a step of performing it step by step or simultaneously.

One of the first stretching process and the second stretching process is a longitudinal stretching process for stretching the polyester film in the conveyance direction (hereinafter also referred to as “vertical stretching”), and the other of the first stretching process and the second stretching process is , This is a transverse stretching process in which a polyester film is stretched in the width direction (hereinafter also referred to as “transverse stretching”). During stretching, polyester polymers are aligned in each direction.

The stretching process may be simultaneous biaxial stretching in which longitudinal stretching and transverse stretching are performed simultaneously, or may be sequential biaxial stretching in which longitudinal stretching and transverse stretching are performed separately in stages. As a mode of sequential biaxial stretching, for example, a mode in which vertical stretching and transverse stretching are performed in that order; A mode in which vertical stretching, horizontal stretching, and vertical stretching are performed in that order; And, an aspect in which the stretching is carried out in the order of vertical stretching, longitudinal stretching, and transverse stretching can be mentioned. Among them, the sequential biaxial stretching is preferably carried out in the order of vertical stretching and transverse stretching.

Hereinafter, a mode in which longitudinal stretching and transverse stretching are performed in that order will be described, but the manufacturing method is not limited to that mode.

The draw ratio in the longitudinal stretching process is set appropriately, but is preferably 2.0 to 5.0 times, more preferably 2.5 to 4.0 times, and further preferably 2.8 to 4.0 times.

The stretching speed in the longitudinal stretching process is preferably 800%/sec to 1500%/sec, more preferably 1000%/sec to 1400%/sec, and more preferably 1200%/sec to 1400%/sec. Here, the "stretching speed" refers to the value expressed as a percentage divided by the length Δd in the conveyance direction of the polyester film stretched for 1 second in the longitudinal stretching process by the length d0 in the conveyance direction of the polyester film before stretching. am.

In the longitudinal stretching process, it is preferable to heat the unstretched polyester film. This is because vertical stretching becomes easier through heating.

In the transverse stretching process, it is preferable to preheat the uniaxially stretched polyester film before transverse stretching. By preheating the uniaxially stretched polyester substrate, the uniaxially stretched polyester substrate can be easily horizontally stretched.

The stretch ratio (transverse stretch ratio) in the width direction of the uniaxially stretched polyester film in the transverse stretching process is not particularly limited, but is preferably larger than the stretch ratio in the longitudinal stretching process.

The draw ratio in the transverse stretching process is preferably 3.0 times to 6.0 times, more preferably 3.5 times to 5.0 times, and further preferably 3.5 times to 4.5 times.

The stretching speed in the transverse stretching process is preferably 8%/sec to 45%/sec, more preferably 10%/sec to 30%/sec, and more preferably 15%/sec to 20%/sec.

[Particle-containing layer formation process]

The particle-containing layer forming process is a process of forming a particle-containing layer by applying a composition for forming a particle-containing layer to one side of a polyester film.

The particle-containing layer forming process is performed, for example, between the extrusion molding process and the first stretching process, between the first stretching process and the second stretching process, or after the stretching process. Among them, the particle-containing layer forming step is preferably performed between the first stretching step and the second stretching step.

The particle-containing layer disposed on one side of the polyester substrate through the particle-containing layer forming step has the same meaning as the layer described in the above particle-containing layer section.

Hereinafter, the mode of applying the composition for forming a particle-containing layer will be described.

First, the composition for forming the particle-containing layer will be described.

The composition for forming a particle-containing layer can be prepared by mixing the components described in the particle-containing layer section above and a solvent.

Examples of solvents include water and alcohol.

The composition for forming a particle-containing layer may contain one type of solvent alone, or may contain two or more types of solvents.

The content of the solvent is preferably 80% by mass to 99.5% by mass, and more preferably 90% by mass to 99% by mass, relative to the total mass of the composition for forming the particle-containing layer.

That is, in the composition for forming a particle-containing layer, the total content of components (solid content) other than the solvent is preferably 0.5% by mass to 20% by mass, and 1% by mass to 10% by mass, based on the total mass of the composition for forming a particle-containing layer. % is more preferable.

For each component other than the solvent in the composition for forming a particle-containing layer, the content of each component relative to the total mass of the solid content of the composition for forming a particle-containing layer is the same as the preferable content of each component relative to the total mass of the particle-containing layer described above. It is desirable to adjust the content of each component in the composition for forming a particle-containing layer so that

Additionally, the composition for forming the particle-containing layer may contain a crosslinking agent.

Examples of the crosslinking agent include the specific block isocyanate described above and the other crosslinking agents described above.

The content of the crosslinking agent is preferably 0% by mass to 50% by mass with respect to the total mass of the particle-containing layer.

The mass ratio of the crosslinking agent to the binder in the composition for forming a particle-containing layer is preferably 2% by mass to 50% by mass.

The method of applying the composition for forming the particle-containing layer is not particularly limited, and known methods can be used. Examples of the application method include spray coating, slit coating, roll coating, blade coating, spin coating, bar coating, and dip coating.

The heating temperature in forming the particle-containing layer is preferably 180°C or lower, more preferably 150°C or lower, and still more preferably 120°C or lower. The lower limit is not particularly limited and may be 60°C or higher.

Additionally, in order to improve the adhesion between the polyester film and the particle-containing layer, pretreatment such as anchor coat, corona treatment, and plasma treatment may be performed on the surface of the polyester film before providing the particle-containing layer.

[Peel layer formation process]

The peeling layer forming process is a process of forming a peeling layer by applying a peeling layer forming composition to one side of the polyester film.

The release layer forming process is performed between the extrusion molding process and the first stretching process, between the first stretching process and the second stretching process, or after the stretching process.

Among them, from the viewpoint of adhesion between the release layer and the polyester substrate, it is preferable that the release layer forming step is performed between the extrusion molding step and the first stretching step, or between the first stretching step and the second stretching step.

That is, it is preferable that the release layer forming step is a step of forming a release layer by applying a release layer forming composition to one side of an unstretched polyester film or a uniaxially stretched polyester film.

When the release layer forming process is performed after the stretching process, it is preferably performed after the cooling process described later, and it is more preferable that it is performed after the winding process and the trimming process described later.

The release layer formed on one side of the polyester film through the release layer forming process has the same meaning as the layer described in the section on the release layer.

First, the composition for forming a peeling layer will be described.

The composition for forming a release layer preferably contains the components described in the section for the release layer above and a solvent.

Examples of solvents include water, alcohol, ether, ketone, and aromatic hydrocarbons.

The composition for forming a peeling layer may contain one type of solvent alone, or may contain two or more types of solvents.

The content of the solvent is preferably 80% by mass to 99.5% by mass, and more preferably 90% by mass to 99% by mass, with respect to the total mass of the composition for forming a peeling layer.

That is, in the composition for forming a release layer, the total content of components (solid content) other than the solvent is preferably 0.5% by mass to 20% by mass, and 1% by mass to 10% by mass, relative to the total mass of the composition for forming a release layer. % is more preferable.

For each component other than the solvent in the composition for forming a release layer, the content of each component relative to the total mass of solids in the composition for forming a release layer is the same as the preferable content of each component relative to the total mass of the release layer described above. It is preferable to adjust the content of each component in the composition for forming a peeling layer so that it becomes stable.

The method of applying the composition for forming a release layer is not particularly limited, and known methods can be used. Specific examples of the application method are as described in the particle-containing layer forming process.

The heating temperature in forming the peeling layer is preferably 180°C or lower, more preferably 150°C or lower, and still more preferably 120°C or lower. The lower limit is not particularly limited and may be 60°C or higher.

Additionally, in order to improve the adhesion between the polyester film and the release layer, pretreatment such as anchor coat, corona treatment, and plasma treatment may be performed on the surface of the polyester film before providing the release layer.

[Heat setting process]

The method for producing a release film of the present disclosure may include a heat setting step as a heat treatment for the polyester film obtained in the stretching step after the stretching step.

In the heat setting process, the polyester film obtained through the stretching process can be heated and heat set. By crystallizing the polyester resin through heat setting, shrinkage of the polyester substrate can be suppressed.

The surface temperature (heat setting temperature) of the polyester film in the heat setting process is not particularly limited, but is preferably less than 240°C, more preferably 235°C or less, and still more preferably 230°C or less. The lower limit is not particularly limited, but is preferably 190°C or higher, more preferably 200°C or higher, and even more preferably 210°C or higher.

The heating time in the heat setting process is preferably 5 seconds to 50 seconds, more preferably 5 seconds to 30 seconds, and still more preferably 5 seconds to 10 seconds.

[Thermal relaxation process]

The method for producing a release film of the present disclosure may include a heat relaxation step after the heat setting step.

In the heat relaxation process, it is preferable to heat relax the polyester film heat-set by the heat-setting process by heating it at a lower temperature than the heat-setting process. Residual distortion of polyester film can be alleviated through thermal relaxation.

The surface temperature (thermal relaxation temperature) of the polyester film in the heat relaxation process is preferably 5°C or more lower than the heat setting temperature, more preferably 15°C or more lower, and 25°C or more lower. Preferred, and a temperature lower than 30° C. is particularly preferred. That is, the thermal relaxation temperature is preferably 235°C or lower, more preferably 225°C or lower, more preferably 210°C or lower, and especially preferably 200°C or lower.

The lower limit of the thermal relaxation temperature is preferably 100°C or higher, more preferably 110°C or higher, and still more preferably 120°C or higher.

[Cooling process]

The method for producing a release film of the present disclosure may include a cooling step of cooling the heat-relaxed polyester film.

The cooling rate of the polyester film in the cooling process is preferably more than 2000°C/min but less than 4000°C/min, more preferably 2000°C/min to 3500°C/min, and more than 2200°C/min but less than 3000°C/min. is more preferable, and 2300°C/min to 2800°C/min is particularly preferable.

In the cooling process, it is also desirable to include a process for expanding the heat-relaxed polyester film in the width direction (expansion process).

The expansion rate of the polyester film in the width direction by the expansion process, that is, the ratio of the polyester film width at the end of the cooling process to the polyester film width before the start of the cooling process, is preferably 0% or more. And, 0.001% or more is more preferable, and 0.01% or more is more preferable.

The upper limit of the expansion rate is not particularly limited, but is preferably 1.3% or less, more preferably 1.2% or less, and still more preferably 1.0% or less.

[Winding process]

The manufacturing method of the release film of this disclosure may have a winding process of obtaining a roll-shaped polyester film by winding up the polyester film obtained through the said process.

[Trimming process]

The manufacturing method of the present disclosure includes a trimming step of continuously cutting the polyester film along the conveyance direction and cutting off at least one end in the width direction of the polyester film before performing the winding step. You can do it.

[Other conditions]

The conveyance speed of the polyester film in each process other than the vertical stretching process of the production method of the release film of the present disclosure is not particularly limited, but in the transverse stretching process, heat setting process, heat relaxation process, and cooling process. , in terms of productivity and quality, 50 m/min to 200 m/min is preferable, and 80 m/min to 150 m/min is more preferable.

In addition, in the production method of the release film of the present disclosure, the method of forming the particle-containing layer by applying the composition for forming the particle-containing layer in the particle-containing layer forming step has been described. However, the method of forming the particle-containing layer is not limited to the above embodiment, Known methods can be used. For example, a method of forming an unstretched polyester film in which a particle-containing layer is laminated by co-extrusion molding is included.

In particular, the method for producing the release film of the present disclosure,

A vertical stretching step of stretching the unstretched polyester film in the conveyance direction,

A step of forming a particle-containing layer by applying a composition for forming a particle-containing layer to one side of the uniaxially stretched polyester film obtained in the longitudinal stretching process;

A step of forming a release layer by applying a release layer forming composition to the other side of the uniaxially stretched polyester film obtained in the longitudinal stretching step;

It is preferable to include a transverse stretching step of stretching the uniaxially stretched polyester film having the particle-containing layer and the peeling layer in the width direction while heating.

[Use of release film]

The release film of the present disclosure is preferably a release film (carrier film) used in the production of ceramic green sheets. The ceramic green sheet manufactured using the above release film can be suitably used in the manufacture of ceramic capacitors, which require multilayering of internal electrodes in accordance with miniaturization and increase in capacity.

In addition, the release film of the present disclosure includes a protective film for dry film resist, a film for forming sheets such as decorative layers and resin sheets, a release film for process manufacturing such as a semiconductor manufacturing process, a release film for a polarizing plate manufacturing process, and, It can also be used as a separator for adhesive films for labels, medical and office supplies, etc.

[Laminate]

The laminate of the present disclosure includes the release film of the present disclosure and a layer containing ceramic.

The details of the release film are as above.

The layer containing ceramic may be provided directly on the surface of the release film or may be provided on the release film through another layer, but it is preferable to provide it directly on the surface of the release film because of its superior smoothness.

The ceramic contained in the ceramic-containing layer is not particularly limited as long as it is a ceramic contained in the ceramic green sheet, and examples include ferroelectric materials such as barium titanate, and paraelectric materials such as titanium oxide and calcium titanate. Examples include electromagnetic material.

The layer containing ceramic preferably includes a binder. The binder is not particularly limited as long as it is a binder contained in the ceramic green sheet, and examples include polyvinyl butyral.

The laminate of the present disclosure can be manufactured, for example, by applying a ceramic slurry containing ceramic and a solvent onto the peeling surface of the peeling film, and drying the solvent contained in the ceramic slurry. Examples of solvents include ethanol and toluene.

The method for applying the ceramic slurry is not particularly limited, and for example, known methods such as the reverse roll method can be applied.

Additionally, a ceramic green sheet is obtained by peeling the release film from the laminate of the present disclosure. That is, the layer containing ceramic powder in the laminate of the present disclosure becomes a ceramic green sheet.

Example

The present disclosure will be described in more detail below with reference to examples. The materials, usage amounts, ratios, processing details, and processing procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present disclosure. Accordingly, the scope of the present disclosure is not limited to the specific examples shown below.

<Synthesis of block isocyanate>

-Synthesis Example 1-

A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen spray pipe, and dropping funnel was placed in a nitrogen atmosphere, 600 parts by mass of HDI (hexamethylene diisocyanate) was introduced, and while stirring, The temperature was maintained at 70°C. Tetramethylammonium capreate was added as an isocyanurate catalyst, and when the yield reached 40%, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporation can to obtain polyisocyanate (HDI trimer, isocyanurate form of HDI). The isocyanate group concentration of the obtained polyisocyanate was 23.0%, the number average molecular weight was 670, the average number of isocyanate groups was 3.3, and the unreacted HDI concentration was 0.2 mass%.

Using the same apparatus as above, 100 parts by mass of the obtained polyisocyanate and 50 parts by mass of dipropylene glycol monomethyl ether were introduced under a nitrogen atmosphere, and mixed at 50°C until a uniform solution was obtained. After that, 52.7 parts by mass of methoxypolyethylene glycol (number average molecular weight: 680, hydroxyl value of resin content: 82 mgKOH/g) was added, the temperature was raised to 120°C, and the temperature was maintained for 2 hours. After that, the reaction liquid was brought to 70°C, and then 40.2 parts by mass of methyl ethyl ketone oxime was added. After 1 hour, it was confirmed that there was no absorption of isocyanate groups by measuring the infrared spectrum of this reaction solution, and a solution containing aqueous block isocyanate A was obtained. This solution was adjusted with methanol so that the concentration of aqueous block isocyanate A was 10% by mass.

-Synthesis Examples 2, 3-

Except that methyl ethyl ketone oxime was changed to the blocking agent shown in Table 1, the same operation was performed as in Synthesis Example 1 to obtain blocked isocyanates B to C.

<Example 1>

(Extrusion molding process)

Pellets of polyethylene terephthalate were produced using the titanium compound described in Japanese Patent Publication No. 5575671 (citric acid chelated titanium complex, VERTEC AC-420, manufactured by Johnson-Mathy Corporation) as a polymerization catalyst. The obtained pellets were dried until the water content was 50 ppm or less, and then placed into the hopper of a twin-screw kneading extruder. Next, it was melted at 280°C and extruded. The molten body (melt) was passed through a filter (hole diameter 3 μm) and then extruded from a die into a cooling drum at 25°C to obtain a film made of unstretched polyethylene terephthalate (unstretched film). Additionally, the extruded molten body (melt) was brought into close contact with the cooling drum by the electrostatic application method.

(Vertical stretching process)

A uniaxially stretched polyester film was produced by stretching the unstretched film in the longitudinal direction (conveyance direction) under conditions of 90°C and 3.4 times.

(Particle-containing layer formation process, peeling layer formation process)

Composition A1 for forming a particle-containing layer shown below was applied to one side of the polyester film uniaxially stretched in the longitudinal direction using a bar coater. The composition L1 for forming a release layer shown below was applied using a bar coater to the surface of the uniaxially stretched polyester film opposite to the surface on which the particle-containing layer was applied. The formed coating film was dried with hot air at 100°C to form a particle-containing layer and a peeling layer. That is, composition A1 for forming a particle-containing layer and composition L1 for forming a release layer were in-line coated on a uniaxially stretched polyester film. At this time, the application amounts of composition A1 for forming a particle-containing layer and composition L1 for forming a peeling layer were adjusted so that the thickness of the particle-containing layer after transverse stretching described later was 40 nm and the thickness of the peeling layer was 100 nm.

The polyester film that has undergone the longitudinal stretching process, the particle-containing layer forming process, and the peeling layer forming process is stretched in the width direction using a tenter under the conditions of a stretching temperature of 120°C, a stretching ratio of 4.2 times, and a stretching speed of 50%/sec. , biaxially stretched polyester film was produced. Next, it was heat-set at a temperature of 227°C for 6 seconds and further thermally relaxed by 4% at 190°C. After that, it was cooled at a rate of 2500°C/min, both ends of the film were trimmed, extrusion processing (knurling) was performed, and then the film was wound at a tension of 40 kg/m. The thickness of the obtained peeling film was 31 μm, the width was 1.5 m, and the winding length was 7000 m.

[Preparation of composition A1 for forming particle-containing layer]

· Crosslinked PMMA particles (Eposta (registered trademark) MX050W, manufactured by Nippon Shokubai Co., Ltd., average particle diameter 70 nm, solid content concentration 10% by mass aqueous dispersion)... 8 parts by mass

·Urethane resin B (product name “Hydran (registered trademark) AP-40N”, manufactured by DIC Corporation, aqueous dispersion with solids concentration adjusted to 25% by mass)… 157 parts by mass

・Surfactant B (product name "Rapisol (registered trademark) A-90", di-2-ethylhexyl sodium sulfosuccinate, manufactured by Nichiyu Co., Ltd., solid content concentration 1 mass% water dilution)... 56 parts by mass

·water… 779 parts by mass

[Preparation of composition L1 for forming a release layer]

· Solution containing aqueous block isocyanate A (dissociation temperature 120°C, solid concentration 10% by mass)... 60 parts by mass

・Silicon compound: Silicone compound A (product name "X-22-3701E", manufactured by Shin-Etsu Chemical Co., Ltd., silicone compound having a carboxyl group, solid content concentration 10% by mass diluted in water)... 96 parts by mass

・Non-polyester resin: Urethane resin A (product name "Super Flex (registered trademark) 210", manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ester-based urethane aqueous dispersion, solids concentration of 35% by mass with water) (adjusted to 25% by mass)... 96 parts by mass

・Surfactant A (product name "Naroacti (registered trademark) CL-95", manufactured by Sanyo Kasei Kogyo Co., Ltd., nonionic surfactant, solid content concentration 1% by mass aqueous solution)... 20 parts by mass

・Surfactant B (product name "Rapisol (registered trademark) A-90", di-2-ethylhexyl sodium sulfosuccinate, manufactured by Nichiyu Co., Ltd., solid content concentration 1 mass% water dilution)... 20 parts by mass

·Distilled water… 708 parts by mass

<Example 2 to Example 15, Comparative Example 1>

Regarding the solid content contained in the composition for forming a release layer, the type and content (% by mass) of each component were changed to those shown in Table 1, and the type of resin contained in the composition for forming a particle-containing layer was changed to those shown in Table 1. Except this, a release film was produced in the same manner as in Example 1.

The details of each component listed in Table 1 are as follows.

In addition, the crosslinking agent is block isocyanate A to C obtained in the above-mentioned synthesis 1 to 3.

(silicon compound)

Silicone compound A: Silicone compound having a carboxyl group (product name “X-22-3701E”, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Other cross-linking agents)

・Oxazoline: Oxazoline cross-linking agent (product name “Epocross (registered trademark) WS-700”, manufactured by Nippon Shokubai Co., Ltd.)

・Carbodiimide: Carbodiimide crosslinking agent (product name “Carbodilight V-02-L2”, manufactured by Nisshinbo Chemical Co., Ltd.)

(profit)

・Urethane Resin A: Product name “Super Flex (registered trademark) 210”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

・Urethane resin B: Product name “Hydran (registered trademark) AP-40N”, manufactured by DIC Co., Ltd.

· Urethane resin C: isophorone diisocyanate: terephthalic acid: isophthalic acid: ethylene glycol: diethylene glycol: dimethylolpropanoic acid = 12:19:18:21:25:5 ( polyester-based urethane resin formed by mol%)

Acrylic resin: A copolymer formed by polymerizing methyl methacrylate, styrene, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, and acrylic acid at a mass ratio of 59:8:26:5:2.

・Olefin resin: Product name “Jaixen (registered trademark) NC”, manufactured by Sumitomo Seika Co., Ltd.

・Polyester resin: Product name “Vironal (registered trademark) MD-1245”, manufactured by Toyobo Co., Ltd.

・PVA resin: Product name "Kurare Poval (registered trademark) PVA-117H", manufactured by Kurare Co., Ltd.

Silicone resin B: Acrylic silicone composite resin made of polysiloxane and acrylic resin (product name "Ceranate WSA-1070", manufactured by DIC Co., Ltd., solid content concentration 40% by mass)

· Long-chain alkyl compound: A compound containing a long-chain alkyl group synthesized according to the method described in [0082] of Japanese Patent Application Laid-Open No. 2014-151481.

(Surfactants)

・Surfactant A: Product name “Naroacti (registered trademark) CL-95”, manufactured by Sanyo Kasei Kogyo Co., Ltd.

・Surfactant B: Product name "Rapizol (registered trademark) A-90", manufactured by Nichiyu Co., Ltd.

Using the produced release film, evaluation was performed regarding minute concave defects on the release surface, peelability, solvent resistance, and defects in the ceramic green sheet. The evaluation method is as follows.

<Concave shape defect of peeling surface>

With respect to the peeling surface of the peeling film produced in the Examples and Comparative Examples, that is, the exposed surface of the peeling layer, the presence or absence and number of microscopic concave-shaped defects (i.e., cracks) were examined using an optical microscope at a magnification of 200 times. observed. The evaluation criteria are as follows.

A: No concave shape defects are visible at all.

B: 1 to 9 concave shape defects are visible.

C: 10 or more concave-shaped defects, or even if there are less than 10 concave-shaped defects, concave-shaped defects are visible on the entire observation surface.

<Peelability>

100 parts by mass of barium titanate powder (BaTiO ₃ ; manufactured by Sakai Chemical Industry Co., Ltd., product name "BT-03") as a ceramic powder, and polyvinylbutyral resin (product name "S-Lec (registered trademark) B·K) as a binder. 8 parts by mass of BM-2", manufactured by Sekisui Chemicals Co., Ltd., 4 parts by mass of dioctyl phthalate as a plasticizer (product name "dioctyl phthalate cica grade 1", manufactured by Kanto Chemicals Co., Ltd.), and 135 parts by mass of a mixed solution of toluene and ethanol (mass ratio 6:4) were mixed. A ceramic slurry was prepared by dispersing the mixed solution using a ball mill in the presence of zirconia beads and removing the beads from the obtained dispersion.

The release films produced in Examples and Comparative Examples were cut to a width of 250 mm and a length of 10 m. The cut release film was stored in an environment at room temperature and humidity (25°C, 50% RH) for one week. The prepared ceramic slurry was applied to the entire peeled surface of the peeled film after storage so that the film thickness after drying was 3 μm using a die coater. Afterwards, the obtained coating film was dried at 100°C for 2 minutes using a dryer. In this way, a release film with a ceramic green sheet was obtained.

A polyester adhesive tape (model number "No. 31B", manufactured by Nitto Denko Co., Ltd.) was attached to the surface of the ceramic green sheet in the release film with the ceramic green sheet. In that state, after standing at room temperature (25°C) for 24 hours, the release film with the ceramic green sheet was cut to a width of 20 mm to produce a test sample. The adhesive tape side of the test sample was fixed to the surface of the glass plate, and using an A & D. J. Tensilon universal testing machine, the peeling angle was 180° and the peeling speed was 100 mm/min, and the peeling film with the ceramic green sheet was peeled off. The peeling film was peeled, and the force required for peeling was measured. Peelability was evaluated based on the force required for peeling. The evaluation criteria are as follows.

A: The force required for peeling was 45 mN or less.

B: The force required for peeling was more than 45 mN and less than 100 mN.

C: The force required for peeling was over 100 mN.

<Solvent resistance>

For the release films produced in Examples and Comparative Examples, using a wess containing a mixed solution of methyl ethyl ketone and toluene (mass ratio 1:1), the surface of the release layer was subjected to a load of 1000 g/cm ² vertically 5 times. Polished horizontally 5 times. After that, the surface of the peeling layer was observed with the naked eye, and solvent resistance was evaluated based on the dissolution state of the peeling layer. The evaluation criteria are as follows.

A: The peeling layer is not dissolved at all.

B: The peeling layer was partially dissolved

C: The peeling layer was completely dissolved.

<Defect Evaluation 1>

A release film with a ceramic green sheet was obtained in the same manner as the method described in the evaluation of peelability, except that the application amount of the ceramic slurry was adjusted so that the film thickness after drying of the ceramic slurry was 1 μm. After being wound into a roll, a fluorescent lamp is illuminated from the release film side of the unwinding release film with ceramic green sheet, and an area of 1 m ² on the surface of the ceramic green sheet is observed with the naked eye to determine the presence of minute irregularities such as pinholes. The presence or absence of (hereinafter referred to as uneven defect) was confirmed. Based on the number of defects identified, the defects were evaluated. The evaluation criteria are as follows.

A: No uneven defects were confirmed on the ceramic green sheet.

B: 1 to 10 uneven defects were confirmed on the ceramic green sheet.

C: More than 11 uneven defects were confirmed on the ceramic green sheet.

<Defect Evaluation 2>

The peeling films obtained in each example and each comparative example were stored in a room temperature and humidity environment for 3 months. Using the release film after storage for 3 months, the release film with a ceramic green sheet was prepared in the same manner as the method described in the evaluation of peelability, except that the application amount of the ceramic slurry was adjusted so that the film thickness after drying of the ceramic slurry was 1 μm. got it The obtained release film with a ceramic green sheet was evaluated by the same method as defect evaluation 1. The evaluation criteria are as follows.

A: No uneven defects were confirmed on the ceramic green sheet.

B: 1 to 10 uneven defects were confirmed on the ceramic green sheet.

C: More than 11 uneven defects were confirmed on the ceramic green sheet.

The evaluation results are shown in Table 1. In Table 1, in the column of the release layer, the type and content (% by mass) of each component contained in the composition for forming the release layer are described. Content is the content of solid content of each component. In the particle-containing layer column, the type of resin contained in the composition for forming the particle-containing layer is described.

For silicone compounds and non-polyester resins, "Y" if it has a functional group capable of crosslinking with an isocyanate group, that is, a functional group R, and "Y" if it does not have a functional group capable of crosslinking an isocyanate group. “N” was written.

In the column of temperature Temperature was described.

[Table 1]

As for the peeling films of Examples 1 to 15, no concave defects were observed on the peeling surfaces, and no defects were observed in the produced ceramic green sheets.

In addition, it was confirmed that the release layer of the release film of Examples 1 to 15 contained a crosslinked product because no dissolution of the release layer was observed in the evaluation of solvent resistance. In addition, by applying pyrolysis gas chromatography/mass spectrometry (pyrolysis GC/MS) and Fourier transform infrared spectroscopy (FT-IR) to the peeling layers of the peeling films of Examples 1 to 15, Isocia The presence of a crosslinked product of nate and non-polyester resin was confirmed. In addition, gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) were applied to the release layers of the release films of Examples 1 to 15, and compared with the standard product. As a result, it was confirmed that the release layer contained a compound containing a residue derived from the blocking agent shown in Table 1.

On the other hand, in the release film of Comparative Example 1, a concave defect was observed on the release surface because the composition for forming the release layer contained a block isocyanate with a dissociation temperature of 100°C or lower. Additionally, in the laminate (release film with ceramic green sheet) using the release film of Comparative Example 1, uneven defects were confirmed on the surface of the ceramic green sheet.

Comparison of Examples 1, 12, and 13 showed that peelability was excellent when the content of the silicone compound was 5% by mass or more based on the total solid content of the composition for forming a peeling layer.

Comparison of Examples 1, 8, and 9 showed that the composition for forming a release layer had excellent solvent resistance when the content ratio of the specific block isocyanate to the non-polyester resin was 0.1 or more.

In Examples 8 and 15, it was found that since the particle-containing layer contained a non-polyester resin, the occurrence of uneven defects in defect evaluation 2 was suppressed compared to Example 14.

Claims (15)

Comprising a polyester base material and a release layer,
A release film, wherein the release layer contains a crosslinked product formed by crosslinking a composition containing a block isocyanate having a dissociation temperature of more than 100°C and 220°C or less, and a non-polyester resin. In claim 1,
The block isocyanate is on the lower temperature side than the dissociation temperature of the DSC curve obtained by differential scanning calorimetry, and the temperature at which it exhibits a heat value of 1/3 of the heat value at the dissociation temperature is 80°C or higher. A release film, which is a compound. In claim 1,
A release film wherein the blocking agent in the block isocyanate is an oxime compound, a pyrazole compound, an acid amide compound, or a lactam compound. In claim 1,
A release film, wherein the composition includes a silicone compound. Comprising a polyester base material and a release layer,
A release film in which the release layer contains a crosslinked product of an isocyanate and a non-polyester resin, and a compound containing a residue derived from an oxime compound, a pyrazole compound, an acid amide compound, or a lactam compound. In claim 1 or claim 5,
For manufacturing ceramic green sheets, release films. In claim 1 or claim 5,
A release film, wherein the polyester substrate is substantially particle-free. In claim 1 or claim 5,
A release film wherein the non-polyester resin is at least one type of resin selected from the group consisting of urethane resin, acrylic resin, polyvinyl alcohol resin, olefin resin, and silicone resin. In claim 1 or claim 5,
A release film wherein the release layer has a thickness of 0.001 μm to 0.2 μm. In claim 1 or claim 5,
Further comprising a particle-containing layer,
A release film comprising the release layer, the polyester substrate, and the particle-containing layer in this order. In claim 10,
A release film wherein the particle-containing layer contains a non-polyester resin. In claim 11,
A release film wherein the non-polyester resin is at least one type of resin selected from the group consisting of an acrylic resin, a urethane resin, and an olefin resin. A method for producing a release film comprising a polyester substrate and a release layer,
A method for producing a release film, comprising the step of forming a release layer using a composition for forming a release layer containing a block isocyanate having a dissociation temperature of more than 100°C and less than or equal to 220°C, and a non-polyester resin. In claim 13,
A method for producing a release film, wherein the step of forming the release layer is a step of forming the release layer by applying the release layer forming composition to one side of an unstretched polyester film or a uniaxially stretched polyester film. A laminate comprising the release film according to claim 1 or 5 and a layer containing ceramic.