Peeling force adjustable ceramic green sheet production method

Abstract

To provide a ceramic green sheet production method which can suitably control the peeling force of a peeling film of a ceramic green sheet formed on the peeling film to effectively suppress the peeling upon conveying or working the ceramic green sheet and can easily execute peeling when the ceramic green sheet is thereafter peeled from the peeling film with a low peeling force.SOLUTION: Provided is a ceramic green sheet production method which has the steps of: a) applying ceramic slurry on a ceramic green sheet production peeling film; b) forming the ceramic green sheet from the ceramic slurry applied in the step a); c) irradiating a face opposite to the face formed with the ceramic green sheet in the ceramic green sheet production peeling film with ultraviolet rays; and d) peeling the ceramic green sheet formed in the step b) from the ceramic green sheet production peeling film.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a ceramic green sheet, and more specifically, to a method for producing a ceramic green sheet that can appropriately control the releasability of a ceramic green sheet formed on a release film from the release film, effectively suppressing peeling during transportation and processing of the ceramic green sheet, and can subsequently be easily peeled off from the release film with a low peeling force. [Background technology]

[0002] In the manufacture of sheet-like ceramic members, a manufacturing method has been widely used that includes the steps of applying a ceramic slurry onto a release film, drying the slurry to form a ceramic green sheet, processing the formed ceramic green sheet as necessary, and then peeling the ceramic green sheet from the release film. Various release films have been proposed for use in such manufacturing methods to produce ceramic green sheets. For example, there has been proposed a band-shaped flexible support having one side used as a ceramic paint coating surface, the ceramic paint coating surface having an area that has been subjected to a release treatment and an area that has not been subjected to the release treatment (see Patent Document 1), and a release film characterized in that a band-shaped printed layer is laminated on at least one side of a polyester film, and the printed layer is covered with a release layer (see Patent Document 2).

[0003] In the above-mentioned method for producing a ceramic green sheet, from the viewpoint of appropriately peeling off the ceramic green sheet, it is preferable that the release film for producing the ceramic green sheet has excellent peelability (light release). On the other hand, when the ceramic green sheet is transported or processed before peeling, it is necessary to suppress lifting or peeling of the ceramic green sheet, and from that viewpoint, it is preferable that the release film requires a large force for peeling (heavy release). [Prior art documents] [Patent documents]

[0004] [Patent Document 2] Japanese Patent Application Publication No. 8-130152 [Patent Document 2] Japanese Patent Application Publication No. 10-230576 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above technical background, the present invention aims to provide a method for producing a ceramic green sheet, which appropriately controls the releasability of a ceramic green sheet formed on a release film from the release film, effectively suppresses peeling during transportation and processing of the ceramic green sheet, and subsequently enables the ceramic green sheet to be easily peeled off from the release film with a low peeling force. [Means for solving the problem]

[0006] As a result of extensive research, the inventors have discovered that by providing a specific ultraviolet irradiation step between the step of forming a ceramic green sheet on a release film for producing a ceramic green sheet and the step of peeling the formed ceramic green sheet from the release film, it is possible to make the peel force appropriate before and after ultraviolet irradiation, respectively, thereby solving the above-mentioned problems, and have thus completed the present invention. That is, the present invention provides: [1] a) applying a ceramic slurry onto a release film for producing a ceramic green sheet; b) forming a ceramic green sheet from the ceramic slurry applied in the a) step; c) irradiating the surface of the release film for producing a ceramic green sheet opposite to the surface on which the ceramic green sheet is formed with ultraviolet light; and d) peeling the ceramic green sheet formed in the step b) from the release film for producing the ceramic green sheet; The present invention relates to a method for producing a ceramic green sheet, comprising the steps of:

[0007] Below, [2] to [9] are each a preferred aspect or embodiment of the present invention. [2] The method for producing a ceramic green sheet according to [1], wherein a peel force P2 (mN / 50 mm) when peeling the ceramic green sheet from the release film for producing the ceramic green sheet after the step c) is smaller than a peel force P1 (mN / 50 mm) when peeling the ceramic green sheet from the release film for producing the ceramic green sheet after the step b) and before the step c). [3] The method for producing a ceramic green sheet according to [2], wherein a ratio P2 / P1 of the peel force P2 (mN / 50 mm) to the peel force P1 (mN / 50 mm) is 0.80 or less. [4] The release film for producing a ceramic green sheet has a base material and a release agent layer provided on at least one side of the base material, The release agent layer contains an addition reaction type silicone composition. The method for producing a ceramic green sheet according to any one of [1] to [3]. [5] The addition reaction type silicone composition is (A) a linear organopolysiloxane having two or more alkenyl groups in each molecule, (B) a cyclic siloxane having 2 to 4 alkenyl groups per molecule; (C) an organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in each molecule, and (D) a catalytic amount of a platinum group metal catalyst; The method for producing a ceramic green sheet according to [4], [6] The method for producing a ceramic green sheet according to any one of [1] to [5], further comprising a step of performing electrode printing, half-cutting, and / or punching after the step b) and before the step c). [7] A method for producing a ceramic product, comprising the step of producing a ceramic green sheet by the method for producing a ceramic green sheet according to any one of [1] to [6]. [8] The method for producing a ceramic product according to [7], further comprising a step of firing the ceramic green sheet. [9] The method for producing a ceramic product according to [7] or [8], wherein the ceramic product is a multilayer ceramic capacitor or a multilayer ceramic substrate. Effect of the Invention

[0008] The method for producing a ceramic green sheet of the present invention has remarkable technical effects of great practical value, such as appropriately controlling the peel force of a ceramic green sheet formed on a release film for producing a ceramic green sheet from the release film, and realizing both heavy peeling during transportation and processing of the ceramic green sheet and light peeling thereafter when peeling the ceramic green sheet from the release film, which was impossible or difficult to achieve with conventional techniques, and can be particularly suitably used in the production of various ceramic products. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram showing one embodiment of the method for producing a ceramic green sheet of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention relates to a) applying a ceramic slurry onto a release film for producing a ceramic green sheet; b) forming a ceramic green sheet from the ceramic slurry applied in the a) step; c) irradiating the surface of the release film for producing a ceramic green sheet opposite to the surface on which the ceramic green sheet is formed with ultraviolet light; and d) peeling the ceramic green sheet formed in the step b) from the release film for producing the ceramic green sheet; The method for producing a ceramic green sheet includes the steps of: That is, the method for producing a ceramic green sheet of the present invention is sufficient as long as it includes each of the above steps a) to d), and may or may not include other steps. Therefore, the production method of the present invention may consist of only the above steps a) to d), or may include other steps such as electrode printing, half-cutting, and punching in addition to the above steps a) to d). Each of the above steps will now be described.

[0011] a) Coating process In step a) of the method for producing a ceramic green sheet of the present invention, for example, a technique that has been conventionally used in this technical field for applying a ceramic slurry onto a release film for producing a ceramic green sheet can be appropriately used, and for example, the following technique can be used.

[0012] Ceramic Slurry The ceramic slurry used in step a) is not particularly limited, and for example, any ceramic slurry that has been conventionally used in the present technical field for producing ceramic green sheets can be used as appropriate. The ceramic slurry preferably contains ceramic particles and a solvent, and the ceramic particles are preferably dispersed in the solvent.

[0013] As the ceramic particles, inorganic compound particles capable of forming ceramics by sintering can be used. Examples of inorganic compounds include oxides, nitrides, oxynitrides, borides, etc. of metals or semimetals. More specific examples of inorganic compounds include perovskite compounds such as barium titanate (BaTiO3), calcium titanate (CaTiO3), strontium titanate (SrTiO3), calcium zirconate (CaZrO3), strontium zirconate (SrZrO3), etc. When these inorganic compounds are used as the main component of the ceramic particles, they may contain Mn, Mg, Si, Co, Ni, rare earth elements, etc. as a minor component with a content less than that of the main component.

[0014] The particle size of the ceramic particles is usually 50 nm or more and 2000 nm or less, preferably 50 nm or more and 700 nm or less, and more preferably 100 nm or more and 500 nm or less.

[0015] The solvent may be an organic solvent or an inorganic solvent such as an aqueous solvent, but is preferably an organic solvent from the viewpoint of ease of solvent removal when forming a ceramic green sheet in step b) described later. As the organic solvent, toluene, ethanol, hexane, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, butanol, xylene, or a mixed solvent thereof can be preferably used, and a mixed solvent of toluene and ethanol, or a mixed solvent of toluene and isopropyl alcohol can be particularly preferably used. The boiling point of the solvent is not particularly limited, but is preferably from 60 to 130°C, and particularly preferably from 70 to 130°C.

[0016] From the viewpoint of ease of handling of the ceramic green sheets, the ceramic slurry preferably contains a binder in addition to ceramic particles and a solvent. As the binder, various binders conventionally used in the present technical field for producing ceramic green sheets can be appropriately used, for example, polyvinyl butyral, urethane resin, polyvinyl acetate resin, acrylic resin, cellulose resin, etc. Among them, polyvinyl butyral, acrylic, etc. can be particularly preferably used. The amount of binder used is not particularly limited, but is preferably 3 to 20 parts by mass, and particularly preferably 5 to 10 parts by mass, per 100 parts by mass of ceramic particles.

[0017] The ceramic slurry may contain, in addition to the above-mentioned ceramic particles, solvent, and optional binder, other components such as a plasticizer, a surfactant, a dispersion stabilizer, and an antistatic agent. Suitable plasticizers include dibutyl phthalate, fatty acid esters, and the like.

[0018] The ceramic particles and organic solvent described above, and other components such as a binder and a plasticizer, if desired, are mixed with stirring to produce a ceramic slurry. The method of stirring and mixing is not particularly limited, and any method and device conventionally used in the present technical field for producing ceramic slurries can be used as appropriate, but for example, stirring and mixing can be performed using a ball mill. By using a ball mill, the particle size of the ceramic particles can be adjusted at the same time.

[0019] There is no particular restriction on the content of ceramic particles in the ceramic slurry, and it may be appropriately set depending on the method of application to the release film and the drying conditions when forming the ceramic green sheet, but it is usually 70 to 95 mass %, and preferably 80 to 95 mass %. The viscosity of the ceramic slurry is not particularly limited and may be appropriately set depending on the method of application to the release film, but the viscosity measured with a Brookfield viscometer is preferably 2.0 to 1000.0 mPa s, and particularly preferably 10.0 to 300.0 mPa s.

[0020] The release film for producing a ceramic green sheet used in the method for producing a ceramic green sheet of the present invention is not particularly limited, and for example, any release film that has been conventionally used in the production of ceramic green sheets in this technical field can be used as appropriate. Therefore, the configuration of the release film for producing a ceramic green sheet is not particularly limited, but it is preferable that the release film has a substrate and a release agent layer provided on at least one of the substrates. The release film in this embodiment may be composed of only the substrate and the release agent layer, or may have other layers such as an antistatic layer, a filling layer, etc. in addition to the substrate and the release agent layer.

[0021] Base material The substrate constituting the release film for producing ceramic green sheets of this embodiment is not particularly limited, and any substrate may be appropriately selected from those conventionally known as substrates in the technical field. Examples of such substrates include films made of plastics such as polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, polycarbonate, and ethylene-vinyl acetate copolymers, and may be a single layer or a multilayer of two or more layers of the same or different types. Among these, polyester films are preferred, polyethylene terephthalate films are particularly preferred, and biaxially stretched polyethylene terephthalate films are even more preferred. Polyethylene terephthalate films are less likely to generate dust during processing, use, etc., and therefore can effectively prevent ceramic slurry coating defects caused by dust, etc.

[0022] In order to properly perform the ultraviolet irradiation in step d) described below, the substrate film is preferably a transparent film, and is preferably substantially light-transmitting at least in the ultraviolet region. More specifically, the light transmittance of the substrate film at a wavelength of 380 to 780 nm is preferably 80% or more, and particularly preferably 85% or more.

[0023] In addition, this substrate may be subjected to a surface treatment such as an oxidation method or a primer treatment for the purpose of improving adhesion to a release agent layer preferably provided on at least one surface of the substrate. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment. These surface treatment methods are appropriately selected depending on the type of substrate film, but generally, corona discharge treatment is preferably used in terms of effectiveness and operability. There is no particular restriction on the thickness of the substrate, which may be appropriately set based on mechanical strength and ease of handling during production and use, but is usually 10 to 300 μm, preferably 12 to 200 μm, and particularly preferably 15 to 125 μm.

[0024] The arithmetic mean roughness (Ra) of the surface of the substrate on the release agent layer side is preferably from 0.1 to 70 nm, and more preferably from 1 to 60 nm. The arithmetic mean roughness (Ra) of the surface of the substrate on the release agent layer side is preferably 0.1 to 70 nm in terms of handling of the substrate, suppression of poor electrical continuity, etc. In addition, substrates having a surface arithmetic mean roughness (Ra) of 1 to 70 nm are relatively easy and inexpensive to obtain, and are therefore also preferable in terms of availability and production costs of the release film for producing the ceramic green sheet of this embodiment.

[0025] The arithmetic mean roughness (Ra) of the surface of the substrate opposite to the release agent layer side is preferably from 5 to 70 nm, and particularly preferably from 10 to 60 nm. When the arithmetic mean roughness (Ra) of the surface of the substrate opposite the release agent layer is equal to or greater than the above lower limit, blocking during winding of the release film for producing a ceramic green sheet of this embodiment can be effectively suppressed, while when the arithmetic mean roughness (Ra) is equal to or less than the above upper limit, it becomes easy to smooth the surface of the release agent layer.

[0026] Release agent layer There are no particular limitations on the material of the release agent layer constituting the release film for producing ceramic green sheets in this embodiment, and any material can be used as long as it does not contradict the object of the present invention, particularly the appropriate control of the releasability of the ceramic green sheet from the release film.

[0027] Addition reaction type silicone composition From the viewpoint of appropriately controlling the releasability of the ceramic green sheet from the release film, it is preferable for the composition to contain an addition reaction type silicone composition, and more specifically, it is preferable for the composition to contain an addition reaction type silicone composition containing the following components (A) to (D). (A) A linear organopolysiloxane having two or more alkenyl groups in one molecule. (B) Cyclic siloxane having 2 to 4 alkenyl groups per molecule (C) Organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule. (D) a catalytic amount of a platinum group metal catalyst

[0028] (A) A linear organopolysiloxane having two or more alkenyl groups in one molecule. The (A) linear organopolysiloxane having two or more alkenyl groups per molecule that constitutes the above-mentioned addition reaction silicone composition preferably has an absolute viscosity at 25°C of 0.04 Pa s or more, as measured using a rotational viscometer. As described above, the component (A) has at least two alkenyl groups in one molecule, and a preferred specific example thereof is one having a structure represented by the following general formula (1). [ka] (In the formula, R 1 is an alkenyl group, R 2 represents a monovalent organic group or a hydroxyl group that does not contain an aliphatic unsaturated bond, and X 1 is expressed by the following formula (2): [ka] It is a group represented by the following formula: a3, b3, c3, d3, and e3 are preferably selected from positive numbers that satisfy the requirement that the viscosity of the organopolysiloxane of component (A) at 25°C be 0.04 Pa s or more and that the viscosity of a 30% by mass toluene solution at 25°C be 70 Pa s or less, and b3, c3, d3, and e3 may be 0. α and β are integers of 0 or 1 to 3.

[0029] R 1 is preferably an alkenyl group having 2 to 6 carbon atoms, such as a vinyl group, an allyl group, or a butenyl group; R 2 is preferably a monovalent organic group having 1 to 20 carbon atoms, particularly preferably 1 to 8 carbon atoms, selected from alkyl groups having 1 to 12 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or a butyl group; a cycloalkyl group having 4 to 20 carbon atoms, such as a cyclohexyl group; an aryl group having 6 to 20 carbon atoms, such as a phenyl group or a tolyl group; or substituted monovalent hydrocarbon groups, such as a chloromethyl group, a trifluoropropyl group, or a cyanoethyl group, in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups have been substituted with halogen atoms, cyano groups, or the like; further, alkoxy groups having 1 to 12 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, or a methoxyethoxy group; a hydroxyl group; and monovalent hydrocarbon groups containing an epoxy group having 2 to 20 carbon atoms, for example, a glycidyl group, a glycidyloxy group, or an epoxycyclohexyl group-substituted alkyl group, but which does not contain an aliphatic unsaturated bond. R 1 is preferably a vinyl group from an industrial standpoint, and R 2 In view of production and properties, it is preferable that at least 80 mol % of the alkyl group be methyl groups.

[0030] The number of alkenyl groups per molecule of the organopolysiloxane of component (A) is two or more, and the content per 100 g of organopolysiloxane is preferably 0.001 to 0.3 mol. 1 It is preferable that a3, b3, c3, d3, and e3 are selected so that the number of alkenyl groups per molecule, c3+b3×(e3+β)+2α, is in the range of 2 to 2,500.

[0031] The main skeleton structure of the organopolysiloxane of component (A) is straight-chain, however, those containing branched-chain structures, such as those represented by the cases where b3 is not 0, are also included in the term straight-chain here.

[0032] (B) Cyclic siloxane having 2 to 4 alkenyl groups per molecule (B) a cyclic siloxane having from 2 to 4 alkenyl groups per molecule which constitutes the above-mentioned addition reaction silicone composition is presumed to function preferably as a coupling agent, connecting the above-mentioned substrate with the above-mentioned component (A) and the non-adhesive cured coating formed from component (C) described below.

[0033] The component (B) is not particularly limited as long as it is a cyclic siloxane having 2 to 4 alkenyl groups in one molecule, but the following component (B') is particularly preferably used.

[0034] Component (B') is easy to produce, and is advantageous in terms of availability and cost. In addition, it is the same silicone compound as component (A), and can be stably dissolved or dispersed in the addition reaction type silicone composition, which is advantageous in terms of production and storage of the composition. Component (B') is preferably a low molecular weight siloxane with a low degree of polymerization, with an absolute viscosity of less than 0.04 Pa·s at 25°C measured using a rotational viscometer, and a high alkenyl content of 0.3 to 2.0 mol / 100g, preferably 0.3 to 1.3 mol / 100g, and particularly 0.4 mol / 100g or more. In addition, two siloxane units in which a substituent containing an alkenyl group is bonded to a silicon atom are arranged close to each other, thereby increasing the organicity of the surroundings and facilitating the approach of the alkenyl group to the substrate, thereby favoring the reaction and interaction due to the radical reaction. There is no particular lower limit to the absolute viscosity, but it is preferably 0.1 mPa·s.

[0035] Component (B') is a cyclic siloxane having a structure in which two siloxane units in which a substituent containing an alkenyl group is bonded to a silicon atom are bonded directly or via three or less intervening siloxane units in which the substituent is not bonded to a silicon atom.

[0036] In this case, the component (B') is preferably one represented by the following composition formula (3) having a structure represented by the following general formula (4). [M] m1 [M A ] m2 [D] d1 [D A ] d2 [T] t1 [T A ] t2 [Q] q1 - (3) [ka] (In the formula, R 3 represents a substituent containing an alkenyl group having 2 to 10 carbon atoms. A is R 4 or a siloxane residue selected to satisfy formula (3) bonded via an oxygen atom, where two A's bonded to one silicon atom are -O(SiR 4 2O) y - to form a ring structure. 4 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, x is an integer of 0 to 3, and y is an integer selected so as to satisfy the average degree of polymerization of 2 to 50 of the organopolysiloxane of formula (3). M, M A , D, D A , T, T A Q is a siloxane unit of the formula: 1 / 2 indicates that the adjacent siloxane unit is bonded via an oxygen atom. [ka] m1, m2, d1, d2, t1, t2, and q1 are numbers that satisfy the following equations. t1+t2+2×q1≦m1+m2≦2+t1+t2+2×q1 0≦d1+d2≦48, 0≦t1+t2≦30, 0≦q1≦20 0.25≦(m2+d2+t2) / (m1+m2+d1+d2+t1+t2+q1)≦1)

[0037] Also, R 3 Examples of the substituent containing an alkenyl group include alkenyl groups such as vinyl and allyl groups, and (meth)acryloyloxy-substituted alkyl groups such as acryloyloxypropyl and methacryloyloxypropyl groups. R 4 Examples of the monovalent organic group include linear, branched or cyclic alkyl groups such as methyl, ethyl, propyl and hexyl groups, aryl groups such as phenyl and tolyl groups, aralkyl groups such as benzyl groups, unsubstituted monovalent hydrocarbon groups such as alkenyl groups such as vinyl and allyl groups, groups in which some or all of the hydrogen atoms of these unsubstituted monovalent hydrocarbon groups have been substituted with halogen atoms, and groups in which the hydrogen atoms of the above alkyl groups have been substituted with (meth)acryloyloxy groups, for example (meth)acryloyloxypropyl groups. Thus, R 4 is R 3 may be also possible.

[0038] A is R 4 or a siloxane residue selected to satisfy formula (3) bonded via an oxygen atom, such as a methyl group, an ethyl group, a propyl group, a vinyl group, an allyl group, a (meth)acryloxypropyl group, a -OSi(CH3)2(CH=CH2) group, a -O-Si(CH3)3 group, a -O-Si(CH3)2(C6H5) group, a methoxy group, an ethoxy group, a propoxy group, etc. In addition, when two A's bonded to one silicon atom are -O(SiR 4 2O) y - to form a ring structure, specifically, [ka] may be also possible.

[0039] The average degree of polymerization of the component (B') is preferably from 2 to 50, and particularly preferably from 2 to 40. This average degree of polymerization is a polystyrene-equivalent value measured by gel permeation chromatography (GPC). It is preferable that y is selected so as to satisfy the above average degree of polymerization, and it is particularly preferable that y is an integer of 0 to 10, and particularly preferably 1 to 8.

[0040] As is clear from the above formula (4), the organosiloxane of the component (B') has two -SiR 3 A-group is -O-(SiO) x It is preferable that the structure has two -SiR groups each having an alkenyl group bonded to a silicon atom, and the two -SiR groups each having an alkenyl group bonded to a silicon atom are bonded to each other through -(x=0 to 3, particularly 0 or 1). 3 Since the A-groups are close to each other, if A is an alkenyl group, they are naturally close to each other. However, even if A is an alkyl group such as a methyl group or an aryl group such as a phenyl group, the -SiR 3 A- are adjacent to each other, and x, which indicates the degree of this proximity, is preferably 3 at the maximum, and more preferably 0 or 1.

[0041] Specific examples of organosiloxanes having the structure of formula (3) above include linear or branched organopolysiloxanes of the following formulas (5) and (6). [ka] (In the formula, R 3 , R 4 is as above. Y is expressed by the following formula (5a) [ka] In formula (5a), R 3 , R 4 is as above. Y 1 is expressed by the following formula (5b): [ka] In formula (5b), R 3 , R 4 is as stated above. a2, b2, ay, and by are integers of 0 to 48, preferably 0 to 45, and more preferably 0 to 40; c2 and cy are integers of 0 to 30, preferably 0 to 25, and more preferably 0 to 20; d2 and dy are integers of 0 to 20, preferably 0 to 18, and more preferably 0 to 15.

[0042] Formulas (5), (5a), and (5b) each show a random structure, but R 3 Two siloxane units in which a substituent containing an alkenyl group is bonded to a silicon atom are directly or 3 is bonded with three or less intervening siloxane units that are not bonded to silicon atoms.) [ka] (In the formula, R 3 , R 4 is as above. Z is expressed by the following formula (6a) [ka] In formula (6a), R 3 , R 4 is as above. Z 1 is expressed by the following formula (6b): [ka] In formula (6b), R 3 , R 4 is as stated above. a2, b2, ay, and by are integers of 0 to 48, preferably 0 to 45, and more preferably 0 to 40; c2 and cy are integers of 0 to 30, preferably 0 to 25, and more preferably 0 to 20; d2 and dy are integers of 0 to 20, preferably 0 to 18, and more preferably 0 to 15.

[0043] Formulas (6), (6a), and (6b) each show a random structure, while R 3Two siloxane units in which a substituent containing an alkenyl group is bonded to a silicon atom are directly or 3 is bonded with three or less intervening siloxane units that are not bonded to silicon atoms.)

[0044] A more specific structure of the component (B') is, for example, the following formula: [ka] (wherein x is as defined above), [ka] It is also possible to use an organopolysiloxane having a branched structure in which the main skeleton is formed by trifunctional or tetrafunctional siloxane units represented by the following formula:

[0045] Here, examples of the siloxane residue B in the above-mentioned branched structure organopolysiloxane include the following. [ka] (However, R 20 is R 4 or R 3 R 0 is -O-(SiR 4 R 20 ) y6 -SiR 4 2R 20 where y is as above. y1+y2+y6=y, where y1 and y6 are integers of 0 or more, and y2 is integers of 1 or more. y3+y4=y, where y3 and y4 are integers of 0 or more. y5=y.

[0046] More specifically, the following can be mentioned: [ka]

[0047] It is also preferable to use an organopolysiloxane having a cyclic structure represented by the following general formula (7) as component (B'). [ka] (In the formula, R 3 , R 4 is as above. R 5 represents a substituent having an OH group or a SiH group as a functional group, or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms and no aliphatic unsaturated bonds, a1 is 0 or 1, b1 is an integer from 1 to 6, c1 is an integer from 0 to 5, and a1+b1+c1 is an integer of 2 or more.

[0048] In the above formula, R 5 Examples of the substituent having an OH group or a SiH group as a functional group include a hydroxyl group and a hydrogen atom bonded to a silicon atom, as well as -CH2CH2CH2-O-CH2CH2-OH. R 5 The monovalent hydrocarbon group of R does not include an alkenyl group. 4 Examples of the above-mentioned examples are the same as those given above.

[0049] A specific example of (B') that is industrially desirable is a compound represented by the formula (7) above, R 3 is a vinyl group, R 4 is a methyl group, R 5 is a hydrogen atom, a1=0 to 1, b1=1 to 4, and c1=0 to 1. More preferably, a1=0, b1=2 to 4, and c1=0.

[0050] In many cases, it is advantageous for the molecular weight of the (B) components, including the (B') component, to be small, but if the molecular weight is too small, there is a concern that when the composition is applied to a substrate and heated, it will evaporate too quickly and be removed from the composition without reacting. Therefore, it is desirable to have a molecular weight that gives the (B) component a boiling point of 80°C or higher. Using ultraviolet light irradiation to prevent the temperature from becoming too high is effective in reducing this effect.

[0051] The amount of component (B) is not particularly limited, but is preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 9 parts by mass, per 100 parts by mass of component (A). If the amount of component (B) is 0.1 part by mass or more, a substantial effect of addition can be realized, and if it is 10 parts by mass, there is no risk of reducing curability.

[0052] (C) Organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane (C) having at least three hydrogen atoms bonded to silicon atoms per molecule that constitutes the above-mentioned addition reaction type silicone composition is preferably one represented by the following average composition formula (8). R 2 f H g SiO (4-f-g) / 2 (8) (In the formula, R 2 As shown above, f is 0 to 3, g is 0 to 3, and f+g is a positive number from 1 to 3.)

[0053] The molecular structure may be linear, branched, or cyclic. There are no substantial limitations on the absolute viscosity at 25°C measured using a rotational viscometer, and it may be in the range of several mPa·s to tens of thousands of mPa·s. Specific examples of component (C) include the following organohydrogenpolysiloxanes.

[0054] [ka] (In the above formula, Me is a methyl group, h, l, and n are each 3 to 500, m, p, and s are each 1 to 500, and i, j, k, o, q, r, t, u, v, and w are each 0 to 500.)

[0055] The amount of organohydrogenpolysiloxane of component (C) blended is preferably such that the number of moles of SiH groups contained therein is 1 to 10 times the total number of moles of alkenyl groups contained in component (A). Since the number of moles of SiH groups contained in component (C) is equal to or greater than the total number of moles of alkenyl groups contained in component (A), curability is sufficient, whereas since it is 10 times or less, the effect does not saturate and heavy peeling can be suppressed.

[0056] (D)Platinum group metal catalyst As the platinum group metal catalyst (D) constituting the above-mentioned addition reaction type silicone composition, any of the conventionally known catalysts can be used, such as platinum black, chloroplatinic acid, chloroplatinic acid-olefin complex, chloroplatinic acid-alcohol coordination compound, rhodium, and rhodium-olefin complex. The amount of (D) platinum group metal catalyst (addition reaction catalyst) added is a catalytic amount, and it is preferable to mix 5 to 1,000 ppm (mass ratio) of platinum or rhodium based on the combined mass of components (A), (B), and (C) in order to form a sufficient cured coating, but this amount can be increased or decreased as appropriate depending on the reactivity of the components or the desired curing rate.

[0057] It is preferable to add (E) an organic solvent to the above-mentioned addition reaction type silicone composition when applying it. This makes it possible to improve the stability of the treatment bath and the applicability to various substrates, and to adjust the coating amount and viscosity. Specific examples of the (E) organic solvent that can uniformly dissolve the addition reaction type silicone composition include toluene, xylene, ethyl acetate, acetone, methyl ethyl ketone, and hexane. A mixed solvent of toluene / hexane / methyl ethyl ketone can be particularly preferably used. When the (E) organic solvent is added, the amount added is preferably 100 to 9,900 parts by mass per 100 parts by mass of the (A) component. Furthermore, component (E) is an optional component. If component (E) is not included, the viscosity of components (A), (B), (C), and (D) can be adjusted to obtain appropriate coatability for the coating device being used.

[0058] The above-mentioned addition reaction type silicone composition can be easily produced by uniformly mixing the above-mentioned components (A), (B), (C), and (D), and optionally (E), but in order to ensure a sufficient pot life, it is preferable to add and mix component (D) immediately before coating. Also, when an organic solvent for component (E) is used, it is preferable to uniformly dissolve components (A) and (B) in component (E) and then mix components (C) and (D).

[0059] The release agent layer may contain components other than the above-described addition reaction type silicone composition, provided that such components do not contradict the object of this embodiment. For example, the release agent layer may appropriately contain silicone compounds other than the components (A) to (C) of the above-described addition reaction type silicone composition, and / or catalysts, epoxy compounds, acrylic compounds, leveling agents, radical generators, photosensitizers, antistatic agents, etc.

[0060] The release agent layer can be formed by applying a raw material for the release agent layer, preferably a curable composition such as the above-mentioned addition reaction type silicone composition, to at least one surface of the substrate, and then drying or curing the applied composition by irradiation with active energy rays such as light. The coating method is not particularly limited, and for example, gravure coating, bar coating, spray coating, spin coating, knife coating, roll coating, die coating, etc. can be used.

[0061] The drying temperature is preferably 70 to 120° C., particularly preferably 90 to 100° C. The drying time is preferably 5 to 60 seconds, particularly preferably 10 to 20 seconds. After drying, curing may be performed. As the active energy ray, ultraviolet rays, electron beams, etc. are usually used. The irradiation amount of the active energy ray varies depending on the type of energy ray. For example, in the case of ultraviolet rays, the light amount is 100 to 1000 mJ / cm. 2 is preferable, and particularly 150 to 300 mJ / cm 2 In the case of electron beams, the dose is preferably about 0.1 to 50 kGy.

[0062] The thickness of the release agent layer is preferably 0.05 to 2 μm, and particularly preferably 0.2 to 1.5 μm. A thickness of 0.05 μm or more is preferable from the viewpoint of smoothness of the surface of the release agent layer and suppression of pinholes and thickness unevenness of the ceramic green sheet. A thickness of 2 μm or less is preferable from the viewpoint of suppression of curling due to cure shrinkage of the release agent layer. It is also preferable from the viewpoint of suppression of blocking and charging.

[0063] Other layers The release film for producing a ceramic green sheet used in the present invention may have layers other than the above-mentioned substrate and release agent layer, such as a protective layer, an adhesive layer, an antistatic layer, etc. The substrate and the release agent layer may be laminated directly to each other, or may be laminated via another layer such as an adhesive layer.

[0064] Ceramic slurry application In step a), the method of applying the slurry can be appropriately selected depending on the type and thickness of the ceramic green sheet to be formed in step b). For example, an applicator, on-roll die coater, reduced pressure die coater, off-roll die coater, slit coater, curtain coater, lift coater, knife coater, cast coater, reverse roll coater, blade coater, screen printing method, etc. can be appropriately used.

[0065] The coating speed is preferably 50 to 500 m / min. The coating thickness is not particularly limited, but is preferably 5.0 to 20.0 times, and more preferably 5.0 to 10.0 times, the thickness of the ceramic green sheet formed in step b) and more preferably 0.5 to 10 μm and more preferably 1.0 to 8.0 μm.

[0066] b) green sheet formation process; In step b), the solvent is removed from the ceramic slurry applied in step a) by drying or the like, thereby forming a ceramic green sheet on the release film. The temperature and time for drying in step b) are not particularly limited, but drying can be performed usually at 60 to 100° C., preferably 70 to 100° C., for usually 30 to 300 seconds, preferably 30 to 120 seconds.

[0067] By setting the drying time in step b) to 30 seconds or more, the particles in the sheet can be arranged uniformly and densely by the time drying is completed, thereby reducing voids in the green sheet. By setting the drying time in step b) to 120 seconds or less, the production efficiency in the manufacturing process of the ceramic green sheet can be improved.

[0068] By setting the drying temperature in step b) to 70°C or higher, substantially no solvent remains in the ceramic green sheet, and it is possible to prevent voids from occurring in the ceramic during the firing step. Also, by setting the drying temperature to 100°C or lower, it is possible to prevent swelling or dents on the surface of the green sheet caused by rapid evaporation of the solvent. Also, it is possible to have multiple drying zones and change the temperature for each drying zone.

[0069] The ceramic green sheet formed in step b) may be a single layer or a multilayer. In the case of a multilayer, the multilayer structure may be formed only of a plurality of ceramic green sheets, or may include other layers such as electrodes. To form a multi-layer ceramic green sheet in step b), the ceramic slurry may be applied multiple times in step a), during which other layers such as electrodes may be formed.

[0070] c) Ultraviolet irradiation process In step c), the surface of the release film for producing a ceramic green sheet opposite to the surface on which the ceramic green sheet is formed is irradiated with ultraviolet light. By irradiating with ultraviolet light in step c), the releasability of the ceramic green sheet formed on the release film can be improved. That is, the peel force P2 (mN / 50 mm) when the ceramic green sheet is peeled off from the release film after step c) can be made smaller than the peel force P1 (mN / 50 mm) when the ceramic green sheet is peeled off from the release film after step b) and before step c).

[0071] The ratio P2 / P1 of the peeling force P2 (mN / 50 mm) to the peeling force P1 (mN / 50 mm) is preferably 0.80 or less, more preferably 0.7 or less, and particularly preferably 0.6 or less. For practical purposes, it is preferable that the peel force P1 (mN / 50 mm) before irradiation is defined as heavy peel force, and the peel force P2 (mN / 50 mm) after irradiation is defined as light peel force.

[0072] In the present invention, by irradiating with ultraviolet light in step c), the releasability of the ceramic green sheet formed on the release film can be appropriately controlled, and peeling can be effectively suppressed during transportation and processing of the ceramic green sheet, allowing for stable transportation and processing. Furthermore, when the ceramic green sheet is subsequently peeled off from the release film, it can be easily peeled off with a low peeling force, and damage and deformation of the ceramic green sheet can be effectively suppressed.

[0073] The mechanism by which the releasability of the ceramic green sheet can be appropriately controlled by irradiating ultraviolet light onto the side of the release film for producing a ceramic green sheet opposite the side on which the ceramic green sheet is formed in step c) is not entirely clear, but it is presumed to be somehow related to the fact that ultraviolet light irradiation can cause changes in the structure of the interface between the release film for producing a ceramic green sheet and the ceramic green sheet.

[0074] The amount of ultraviolet light irradiation in step c) is not particularly limited, but is preferably 100 to 1000 mW / cm 2 It is preferable to irradiate with 150 to 300 mW / cm 2It is particularly preferable to irradiate with an integrated dose of 100 to 500 mJ / cm. 2 is preferably 100 to 300 mJ / cm 2 It is particularly preferred that: The wavelength of the ultraviolet light is not particularly limited, but is preferably 250 to 440 nm, and particularly preferably 300 to 400 nm. The ultraviolet irradiation in step c) can be carried out by a conventionally known ultraviolet irradiation device, and a high-pressure mercury lamp, a metal halide lamp, a fusion lamp, an LED lamp, etc. can be appropriately used.

[0075] d) Peeling process In step d), the ceramic green sheet formed in step b) is peeled off from the release film for producing the ceramic green sheet. The peeling method in step d) is not particularly limited and may be appropriately selected depending on the material and properties of the ceramic green sheet and the subsequent steps. For example, the ceramic green sheet can be peeled off by heating or by deforming the release film after cutting only the ceramic green sheet on the release film. In the present invention, since the peeling force in step d) is low (light peeling), damage to the ceramic green sheets is effectively reduced. The peeling force in the peeling step is preferably from 10 to 300 (mN / 50 mm), and particularly preferably from 15 to 200 (mN / 50 mm).

[0076] Electrode printing process, half-cut process, punching process The method for producing a ceramic green sheet of the present invention may further include, in addition to the above steps a) to d), a step of performing electrode printing, half-cutting and / or punching after step b) and before step c). In this embodiment, since the peel force P1 after step b) and before step c) is relatively high (heavy peeling), peeling, floating, etc. of the green sheet from the release film is effectively suppressed when performing electrode printing, half cutting, and / or punching, and electrode printing, half cutting, and / or punching can be performed stably and with high precision. The peeling force P1 after step b) and before step c) is preferably 15 to 400 (mN / 50 mm), and particularly preferably 50 to 200 (mN / 50 mm).

[0077] By firing the ceramic green sheet obtained by the manufacturing method of the present invention, various ceramic products can be manufactured. According to the above embodiment having an electrode printing step after step b) and before step c), after electrode printing, a multilayer ceramic capacitor or a multilayer ceramic substrate can be manufactured through steps c) (ultraviolet light irradiation), d) (peeling), lamination and pressure bonding, cutting and separation, firing, and external electrode formation. EXAMPLES

[0078] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. It is not something that is done.

[0079] Preparation of release film for ceramic green sheet production Silicone release agent X-62-1980, which contains (A) a linear organopolysiloxane having two or more alkenyl groups per molecule, (B) a cyclic siloxane having from two to four alkenyl groups per molecule, and (C) an organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms per molecule, (D) a silicone catalyst CAT-PL-50T containing a catalytic amount of a platinum group metal catalyst, and a silicone reaction inhibitor CAT-PLR-2 (all manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed in a mass ratio of 100:1:3 and diluted with a mixed solvent of toluene / hexane / methyl ethyl ketone = 4 / 6 / 3 to form a 1.2% diluted solution. A 38 μm-thick polyethylene terephthalate film (CE900) manufactured by KOLON was used as the substrate, and the above-mentioned diluted solution was applied onto the substrate using a Mayer bar No. 4 (9.14 μm). After drying at 95° C. for 20 seconds, the substrate was aged at 40° C. for 3 days to produce a release film for producing ceramic green sheets consisting of the substrate and a release agent layer.

[0080] Ceramic Slurry Preparation Barium titanate (BT-01, manufactured by Sakai Chemical Industry Co., Ltd.), polyvinyl butyral (S-LEC BH-S, manufactured by Sekisui Chemical Co., Ltd.), dibutyl phthalate, toluene, and ethanol were mixed in a mass ratio of 100:8:2:50:50 to prepare a ceramic slurry as the raw material for the ceramic green sheets.

[0081] Comparative Example 1 The ceramic slurry prepared above was applied to the release agent layer side of the release film for producing a ceramic green sheet prepared above with an applicator to a thickness of 50 μm, and dried at 70° C. for 2 minutes to form a ceramic green sheet with a thickness of 8 μm.

[0082] Measurement of peel strength of green sheet To evaluate the peelability of the green sheet, the peel strength was measured as follows. The release film and the ceramic green sheet formed on it were cut into strips of 50 mm x 200 mm, and the green sheet was peeled off from the release film at an angle of 180° using a Tensilon (A&D Co., Ltd.: RTG-1210) to measure the peel strength.

[0083] When an attempt was made to peel off the formed ceramic green sheet according to the above evaluation method, the ceramic green sheet broke and the peel force could not be measured. When a peeling test was performed using a similar sample, the ceramic green sheet also broke, but it could be peeled off with a peeling force of 300 mN / 50 mm before the breakage. Furthermore, when a peeling test was performed using a similar sample, the ceramic green sheet also broke, but it could be peeled off with a peeling force of 310 mN / 50 mm before the breakage.

[0084] Example 1 After the formation of the ceramic green sheet, a ceramic green sheet was formed and the peel strength was evaluated in the same manner as in Comparative Example 1, except that ultraviolet light was irradiated from the side of the release film opposite to the side on which the ceramic green sheet was formed, using a high-pressure mercury lamp, before the evaluation of the peel strength of the green sheet. The ultraviolet light irradiation was 242 mW / cm 2 So, total 200mJ / cm 2 went. The green sheet peel force was 165 mN / 50 mm. I was able to let go.

[0085] Example 2 The UV irradiation conditions were 209mW / cm 2 So, the total is 204mJ / cm 2 A ceramic green sheet was formed in the same manner as in Example 1, except for changing the above, and the peel strength was evaluated. The green sheet peel force was 180 mN / 50 mm.

[0086] The peel strength in Examples 1 and 2 was about half that of Comparative Example 1, and the peel strength could be significantly reduced by irradiation with ultraviolet light. [Industrial Applicability]

[0087] The release film for producing a ceramic green sheet of the present invention appropriately controls the peel force of the ceramic green sheet from the release film, and achieves both heavy peeling during transportation and processing of the ceramic green sheet and light peeling when the ceramic green sheet is subsequently peeled from the release film at a high level that exceeds the limits of conventional technology. Since it can be suitably used in the production of various ceramic products, it has high applicability in various fields of industry, including the electrical and electronics industry, electronic parts industry, machinery industry, and automotive industry. [Explanation of symbols]

[0088] 1: Release film for ceramic green sheet manufacturing 2: Ceramic slurry 3: Application roller 4: Drying 5: UV exposure 6: Winding roller

Claims

1. a) A step of applying a ceramic slurry onto a release film for manufacturing a ceramic green sheet; b) A step of forming a ceramic green sheet from the ceramic slurry applied in the step a); c) A step of irradiating ultraviolet rays onto the surface of the release film for manufacturing the ceramic green sheet opposite to the surface on which the ceramic green sheet is formed; and d) A step of peeling the ceramic green sheet formed in the step b) from the release film for manufacturing the ceramic green sheet. A method for manufacturing a ceramic green sheet, comprising the above steps.

2. The peeling force P ２ (mN / 50 mm) when peeling the ceramic green sheet from the peeling film for manufacturing the ceramic green sheet after the step c) is １ smaller than the peeling force P (mN / 50 mm) when peeling the ceramic green sheet from the peeling film for manufacturing the ceramic green sheet before the step c) after the step b), and the method for manufacturing a ceramic green sheet according to claim 1.

3. The peeling force P ２ (mN / 50 mm) and the peeling force P １ (mN / 50 mm), and the ratio P ２ / P １ is 0.80 or less. The method for producing a ceramic green sheet according to claim 2.

4. The release film for manufacturing the ceramic green sheet has a base material and a release agent layer provided on at least one of the base materials, The release agent layer contains an addition reaction type silicone composition. The method for manufacturing a ceramic green sheet according to any one of Claims 1 to 3.

5. The addition reaction type silicone composition is (A) A linear organopolysiloxane having two or more alkenyl groups in one molecule; (B) A cyclic siloxane having two or more and four or less alkenyl groups in one molecule; (C) An organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms in one molecule; and (D) A catalytic amount of a platinum group metal-based catalyst. The method for manufacturing a ceramic green sheet according to Claim 4, containing the above components.

6. The method for manufacturing a ceramic green sheet according to any one of Claims 1 to 3 further includes a step of performing electrode printing, half-cutting, and / or punching before the step c) after the step b).

7. A method for manufacturing a ceramic product, comprising a step of manufacturing a ceramic green sheet by the method for manufacturing a ceramic green sheet according to any one of Claims 1 to 3.

8. The method for manufacturing a ceramic product according to Claim 7, further comprising a step of firing the ceramic green sheet.

9. The method for manufacturing a ceramic product according to Claim 7, wherein the ceramic product is a multilayer ceramic capacitor or a multilayer ceramic substrate.

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