CN108349107B

CN108349107B - Release film for ceramic green sheet production process

Info

Publication number: CN108349107B
Application number: CN201680063814.7A
Authority: CN
Inventors: 佐藤庆一; 深谷知巳
Original assignee: Lintec Corp
Current assignee: Lintec Corp
Priority date: 2015-12-10
Filing date: 2016-11-29
Publication date: 2020-03-06
Anticipated expiration: 2036-11-29
Also published as: CN108349107A; SG11201804742SA; KR20180093918A; JP6646424B2; TWI701138B; MY186971A; PH12018501229A1; TW201725117A; JP2017105092A; WO2017098956A1

Abstract

The present invention provides a release film 1A for a ceramic green sheet manufacturing process, which is a release film 1A for a ceramic green sheet manufacturing process provided with a substrate 11 and a release agent layer 12 provided on one side of the substrate 11, wherein the release agent layer 12 is formed by curing a release agent composition containing a melamine resin and a polyorganosiloxane, and the modulus of elasticity of a coating film measured from the surface of the release agent layer 12 opposite to the substrate 11 is 3.5-7.0 GPa, as measured by a nanoindentation test. According to the release film 1A for a ceramic green sheet production process, migration of polyorganosiloxane from the release agent layer to the ceramic green sheet can be suppressed.

Description

Release film for ceramic green sheet production process

Technical Field

The present invention relates to a release film used in a process for producing a ceramic green sheet.

Background

Conventionally, in order to manufacture a laminated ceramic product such as a laminated ceramic capacitor or a multilayer ceramic substrate, ceramic green sheets are molded, and a plurality of the obtained ceramic green sheets are laminated and fired.

The ceramic green sheet is formed by applying a ceramic slurry containing a ceramic material such as barium titanate or titanium oxide to a release film. The release film is required to have the following releasability: the thin ceramic green sheet molded on the release film can be peeled from the release film with an appropriate peeling force without deformation, breakage, or the like. Further, when the ceramic slurry is applied and dried, the surface of the release film to which the ceramic slurry is applied (the surface in contact with the ceramic slurry and the ceramic green sheet; hereinafter, sometimes referred to as "release surface") is required to have smoothness so as not to cause defects such as pinholes and thickness unevenness in the ceramic green sheet.

Examples of such release films are disclosed in patent documents 1 and 2. In the release film disclosed in patent document 1, a layer made of an ultraviolet curable resin is provided on a substrate, and a silicone resin layer formed by an addition reaction of an organopolysiloxane is provided thereon as a release agent layer. The release film disclosed in patent document 2 is produced by applying a coating liquid containing a (meth) acrylate component and a modified silicone oil modified with a (meth) acryloyl group and/or a vinyl group onto a substrate and curing the coating film, thereby forming a layer containing a cured product of the (meth) acrylate component on the substrate and forming a layer containing a polysiloxane polymer component thereon as a release agent layer.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5675246

Patent document 2: japanese patent No. 5423975

Disclosure of Invention

Technical problem to be solved by the invention

However, the silicone component in the release agent composition may be easily transferred to the surface of the ceramic green sheet which is in contact with the release agent layer. The surface after the transfer of the silicone gives slip, and the adhesion is lowered. When a ceramic green sheet is produced using such a release sheet in which a polysiloxane component is easily transferred and a laminated ceramic product is produced using the ceramic green sheet, when pressure is applied to the laminated ceramic green sheets, a shift in the plane direction may occur between the layers of the laminated ceramic product. If such a shift occurs, the positional accuracy of the electrodes and the like in the resulting laminated ceramic product is degraded, and the product performance of the laminated ceramic product cannot be obtained. Therefore, a release film which is less likely to transfer a silicone component to a ceramic green sheet has been desired.

However, the release films described in patent documents 1 and 2 cannot sufficiently suppress the transfer of the silicone component.

The present invention has been made in view of such circumstances, and an object thereof is to provide a release film for a ceramic green sheet production process, which can suppress migration of polyorganosiloxane from a release agent layer to a ceramic green sheet.

Means for solving the problems

In order to achieve the above object, the first aspect of the present invention provides a release film for a ceramic green sheet production process, comprising a substrate and a release agent layer provided on one side of the substrate, wherein the release agent layer is formed by curing a release agent composition containing a melamine resin and a polyorganosiloxane, and a modulus of elasticity of a coating film measured from a surface of the release agent layer opposite to the substrate by a nanoindentation test is 3.5 to 7.0GPa (invention 1).

In the invention (invention 1), the release agent layer is formed by using the release agent composition containing polyorganosiloxane, so that the surface free energy is appropriately low, and the release property when the release film is released from the ceramic green sheet is excellent. In addition, in the release agent layer, by sufficiently curing the melamine resin so that the modulus of elasticity of the coating film is in the above range, the polyorganosiloxane enclosed in the mesh structure is strongly bound, and migration of the polyorganosiloxane from the release agent layer to the ceramic green sheet can be suppressed.

In addition, in general, the "melamine resin" means a mixture containing a plurality of melamine compounds and/or nuclei obtained by condensation of the melamine compounds. In the present specification, the term "melamine resin" means the above mixture or an aggregate of 1 melamine compound. In the present specification, a cured product of the melamine resin is referred to as a "cured melamine product".

In the invention (invention 1), the polyorganosiloxane preferably has a mass average molecular weight of 500 to 20000 (invention 2).

In the above inventions (inventions 1 and 2), the content of the polyorganosiloxane in the release agent composition is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the melamine resin (invention 3).

In the above inventions (inventions 1 to 3), it is preferable that the melamine resin contained in the release agent composition contains methylated melamine and/or iminomethylolmelamine (invention 4).

In the above inventions (inventions 1 to 4), it is preferable that a resin layer (invention 5) is further provided between the base material and the release agent layer.

In the above invention (invention 5), the resin layer is preferably formed by curing a resin composition containing an active energy ray-curable component or a thermosetting component (invention 6).

In the above invention (invention 6), the active energy ray-curable component is preferably a multifunctional acrylate (invention 7).

In the above inventions (inventions 1 to 7), it is preferable that the release agent layer further includes a second resin layer (invention 8) provided on the opposite side of the base material from the release agent layer.

Drawings

Fig. 1 is a sectional view of a release film for a process of manufacturing a ceramic green sheet according to a first embodiment of the present invention.

Fig. 2 is a sectional view of a release film for a process of manufacturing a ceramic green sheet according to a second embodiment of the present invention.

Fig. 3 is a sectional view of a release film for a process of manufacturing a ceramic green sheet according to a third embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described.

[ Release film for ceramic Green sheet production Process ]

As shown in fig. 1, the release film 1A for the ceramic green sheet production process according to the first embodiment (hereinafter, may be simply referred to as "release film 1A") includes a substrate 11 and a release agent layer 12.

As shown in fig. 2, the release film 1B for the ceramic green sheet production process according to the second embodiment (hereinafter, may be simply referred to as "release film 1B") includes a substrate 11, a resin layer 13 laminated on one surface (upper surface in fig. 2) of the substrate 11, and a release agent layer 12 laminated on the surface of the resin layer 13 opposite to the substrate 11.

As shown in fig. 3, a release film 1C for a ceramic green sheet production process according to a third embodiment (hereinafter, may be simply referred to as "release film 1C") includes a substrate 11, a resin layer 13 laminated on one surface (upper surface in fig. 3) of the substrate 11, a release agent layer 12 laminated on a surface of the resin layer 13 opposite to the substrate 11, and a second resin layer 14 laminated on the other surface (lower surface in fig. 3) of the substrate 11.

In the

release films

1A, 1B, and 1C, the release agent layer 12 is formed of a release agent composition containing a melamine resin and a polyorganosiloxane. Further, the modulus of elasticity of the coating film measured from the surface of the release agent layer 12 opposite to the resin layer 13 is 3.5 to 7.0GPa, as measured by a nanoindentation test.

In the

release films

1A, 1B, and 1C, since the release agent layer 12 is formed using a release agent composition containing polyorganosiloxane, the surface free energy of the release surface of the release agent layer 12 has a moderately low value. Further, the

release films

1A, 1B, and 1C have the above-described coating film elastic modulus. Thus, the peeling force when peeling the

release films

1A, 1B, and 1C from the ceramic green sheets molded on the peeling surfaces of the

release films

1A, 1B, and 1C is appropriately low, and excellent peeling properties can be exhibited.

Further, in the

release films

1A, 1B, and 1C, the polyorganosiloxane is confined in the mesh-like structure formed by curing the melamine resin. Here, by sufficiently curing the melamine resin so that the elastic modulus of the coating film is within the above range, the polyorganosiloxane enclosed in the mesh-like structure is strongly bound, and free movement of the polyorganosiloxane in the cured melamine resin is restricted. Therefore, when the ceramic green sheets are molded on the release surfaces of the

release films

1A, 1B, and 1C, the polyorganosiloxane can be inhibited from migrating from the release agent layer 12 to the ceramic green sheets. Thus, when the ceramic green sheets molded by using the

release films

1A, 1B, and 1C are laminated, the adhesion force between the ceramic green sheets is improved, and the occurrence of misalignment between the ceramic green sheets or between the electrode printing surface and the surface of the ceramic green sheet in contact therewith can be suppressed in the production of the laminated ceramic product.

In the

release films

1A, 1B, and 1C, the release agent layer 12 is formed of a release agent composition containing a melamine resin. Therefore, it is possible to avoid the surface free energy of the release agent layer 12 becoming too low compared to the case where the release agent layer is formed using only polyorganosiloxane. In addition, unlike the active energy ray-curable resin in which the surface layer is insufficiently cured due to oxygen inhibition, the melamine resin is cured by heat curing, and therefore, in the release agent layer 12, not only the elastic modulus of the entire coating film is improved, but also the elastic modulus in the inner layer and the surface layer is sufficiently improved. This makes it possible to sufficiently fix the polyorganosiloxane present in the vicinity of the surface layer of the release agent layer 12. Further, the melamine resin has high affinity with a resin contained in the resin layer 13 described later. Therefore, in the release films 1B and 1C provided with the resin layer 13, the adhesion between the release agent layer 12 and the resin layer 13 is excellent, and the release agent layer 12 can be inhibited from peeling off from the resin layer 13.

1. Release agent layer

(1) Melamine resin

The melamine resin contained in the stripping agent composition contains a melamine compound represented by the following general formula (a) or a polynuclear body formed by condensation of 2 or more melamine compounds.

[ chemical formula 1]

In the formula (a), X represents-H, -CH₂-OH, or-CH₂-O-R. These groups constitute reactive groups of the condensation reaction of the above-mentioned melamine compounds with each other. Specifically, the-NH group formed by the reaction of X being H can be in the-N-CH₂-OH group and-N-CH₂-condensation reactions between the R groups. Furthermore, by making X be-CH₂-N-CH formed by-OH₂-OH group, and by making X a-CH₂-N-CH formed by-O-R₂-O-R group, capable of being simultaneously at-NHRadical, -N-CH₂-OH group and-N-CH₂A condensation reaction between the-O-R groups.

In the above-mentioned-CH₂In the-O-R group, R represents an alkyl group having 1 to 8 carbon atoms. The number of carbon atoms is preferably 1 to 6, and particularly preferably 1 to 3. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and an octyl group, and a methyl group is particularly preferable.

The above-mentioned X's may be the same or different. The above-mentioned R may be the same or different.

Melamine compounds generally exist in the following classes: all X is-CH₂-all ether type of O-R; at least 1X is-CH₂Imino-hydroxymethyl type with-OH and at least 1X being H; at least 1X is-CH₂-OH and in the absence of X, which is H; and at least 1X is H and is absent-CH₂-OH of the imino type of X. As the melamine compound contained in the melamine resin, methylated melamine (all ether type in which R is methyl), iminomethylolmelamine (imino-methylol type), methylolmelamine (methylol type), butylated melamine (all ether type in which R is butyl), and the like are preferably used. Further, from the viewpoint of being easily dissolved in an organic solvent and easily cured at a low temperature, it is preferable to use methylated melamine or iminomethylolmelamine. In particular, iminomethylolmelamine is preferably used from the viewpoint of further improving the reaction rate without the need for a reaction for removing a protective group.

The melamine resin may contain 2 to 50, in addition 2 to 30, particularly 2 to 10, and further 2 to 5 condensed polynuclear bodies of the compound represented by the formula (a).

In the release agent composition for forming the release agent layer 12, the mass average molecular weight of the melamine resin is preferably 120 to 10000, particularly preferably 200 to 5000, and further preferably 1000 to 4000. By setting the mass average molecular weight to 120 or more, the melamine resin can be stably crosslinked, and a smoother release surface can be formed. On the other hand, when the mass average molecular weight is 10000 or less, the viscosity of the release agent composition can be suppressed from becoming too high, and the coating property when the release agent composition is coated on the substrate 11 can be improved. The mass average molecular weight in the present specification is a value in terms of standard polystyrene measured by a Gel Permeation Chromatography (GPC) method.

(2) Polyorganosiloxane

As the polyorganosiloxane contained in the release agent composition, a polymer of a silicon-containing compound represented by the following general formula (b) can be used.

In the formula (b), m is an integer of 1 or more. In the formula (b), R¹～R⁸Preferably an alkyl group or an aryl group, and particularly preferably an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, and octyl, and examples of the aryl group having 6 to 8 carbon atoms include phenyl and methylphenyl, with methyl being particularly preferred.

R¹～R⁸May be the same or different. Further, there are a plurality of R¹And R²When R is¹And R²The repeating units may be the same or different.

The polyorganosiloxane contained in the release agent composition preferably has an organic group at a terminal or a side chain. That is, R in the formula (b) is preferable¹～R⁸At least 1 of which is an organic group. In the present specification, the "organic group" refers to a group not containing the above-mentioned alkyl group and aryl group. Examples of such an organic group include those having a repeating structure such as polyether, polyester, and polyurethane. In such an organic group, an atom at one end of each of polyether, polyester, polyurethane, and the like is bonded to a silicon atom at the end or in the chain of polyorganosiloxane.

Further, it is preferable that the polyorganosiloxane contains a functional group capable of undergoing a crosslinking reaction. Capable of carrying out a crosslinking reactionThe functional group (b) may be directly bonded to a silicon atom of the polyorganosiloxane, or may be bonded to the polyorganosiloxane via the above-mentioned organic group. That is, R in the formula (b) is preferable¹～R⁸At least 1 of them is a functional group capable of crosslinking or an organic group having a functional group capable of crosslinking. Examples of the crosslinkable functional group directly bonded to the silicon atom include an alkenyl group, a hydrogen group (hydrosilyl group), a hydroxyl group (hydroxysilyl group), and the like; examples of the functional group bonded to the polyorganosiloxane via an organic group include a hydroxyl group, a carboxyl group, a glycidyl group, and a (meth) acryloyl group. Among these functional groups, a hydroxyl group directly bonded to a silicon atom (hydroxysilane group) or a hydroxyl group via an organic group is particularly preferable. In the present specification, "(meth) acryloyl" refers to both acryloyl and methacryloyl. The same holds true for other similar terms.

When the release agent layer 12 is formed by curing a release agent composition containing a polyorganosiloxane having a hydroxyl group, the melamine resin and the polyorganosiloxane are chemically bonded via the hydroxyl group, and the polyorganosiloxane is fixed by the melamine cured product. Thus, free movement of the polyorganosiloxane in the release agent layer 12 is effectively restricted, and migration of the polyorganosiloxane from the release agent layer 12 to the ceramic green sheet can be effectively suppressed. As a result, when the ceramic green sheets are stacked, the occurrence of surface direction misalignment between the ceramic green sheets or between the electrode printing surface and the surface of the ceramic green sheet in contact therewith can be effectively suppressed, and the positional accuracy of the electrode and the like can be improved.

The polyorganosiloxane has a mass average molecular weight of preferably 500 to 20000, particularly preferably 1000 to 10000, and further preferably 3000 to 8000. By setting the mass-average molecular weight of the polyorganosiloxane to 500 or more, the surface free energy of the release surface of the release agent layer 12 is appropriately reduced, and the release force at the time of releasing the

release films

1A, 1B, 1C from the ceramic green sheet can be effectively reduced. When the mass average molecular weight of the polyorganosiloxane is 20000 or less, the viscosity of the release agent composition can be suppressed from becoming too high, and the release agent composition can be easily applied.

The content of the polyorganosiloxane in the release agent composition is preferably 0.1 to 30 parts by mass, particularly preferably 0.3 to 25 parts by mass, and further preferably 0.5 to 20 parts by mass, based on 100 parts by mass of the melamine resin. When the content of the polyorganosiloxane in the release agent composition is 0.1 part by mass or more, the surface free energy of the release surface of the release agent layer 12 is sufficiently reduced, and an appropriate release force can be achieved. On the other hand, when the content of the polyorganosiloxane in the release agent composition is 30 parts by mass or less, the mobility of the polyorganosiloxane can be suppressed. This can prevent excessive reduction in the surface free energy of the release agent composition, and can suppress rejection (damping) that occurs when a coating liquid of the release agent composition is applied to the resin layer 13, and thus the

release films

1A, 1B, and 1C can be favorably produced.

(3) Other ingredients

Preferably, the stripper composition further comprises an acid catalyst. As examples of the acid catalyst, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphorous acid, p-toluenesulfonic acid and the like are preferable, and p-toluenesulfonic acid is particularly preferable. By adding an acid catalyst to the release agent composition, the condensation reaction of the melamine resin proceeds efficiently.

The content of the acid catalyst in the stripping agent composition is preferably 0.1 to 30 parts by mass, particularly preferably 0.5 to 20 parts by mass, and further preferably 1 to 15 parts by mass, relative to 100 parts by mass of the melamine resin.

In addition to the above components, the release agent composition may contain a crosslinking agent, a reaction inhibitor, and the like.

(4) Thickness of Release agent layer

The thickness of the release agent layer 12 is preferably 5 to 2000 nm. In particular, in the release sheet 1A comprising the base material 11 and the release agent layer 12, the thickness of the release agent layer 12 is preferably 100 to 2000nm, particularly preferably 150 to 1000nm, and further preferably 200 to 600 nm. In addition, in the release sheet 1B or the release sheet 1C further including the resin layer 13 between the substrate 11 and the release agent layer 12, the thickness of the release agent layer 12 is preferably 5 to 300nm, particularly preferably 10 to 250nm, and further preferably 15 to 200 nm. When the thickness of the release agent layer 12 is 5nm or more, the function as the release agent layer 12 can be effectively exhibited. Further, the generation of warpage can be suppressed by setting the thickness of the release agent layer 12 to 2000nm or less.

2. Base material

The base material 11 of the

release films

1A, 1B, 1C is not particularly limited as long as the resin layer 13 can be laminated. Examples of the substrate 11 include polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polypropylene and polymethylpentene; the film made of plastic such as polycarbonate or polyvinyl acetate may be a single layer or may be a multilayer of 2 or more layers of the same or different types. Among them, a polyester film is preferable, a polyethylene terephthalate film is particularly preferable, and a biaxially stretched polyethylene terephthalate film is further preferable. Since the polyethylene terephthalate film is less likely to generate dust during processing, use, and the like, for example, poor application of ceramic slurry due to dust and the like can be effectively prevented. Further, by subjecting the polyethylene terephthalate film to antistatic treatment, it is possible to prevent ignition due to static electricity when applying ceramic slurry using an organic solvent, or to improve the effect of preventing poor application.

In the substrate 11, one or both surfaces may be subjected to surface treatment by an oxidation method, an embossing method, or the like, or primer treatment as necessary for the purpose of improving adhesion to the release agent layer 12 or the resin layer 13 provided on the surface thereof. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet type), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment, and examples of the texturing method include sand blast treatment and thermal spray coating. These surface treatment methods may be appropriately selected according to the type of the substrate film, but in general, corona discharge treatment methods are preferably used in view of effects and workability.

The thickness of the substrate 11 is usually 10 to 300 μm, preferably 15 to 200 μm, and particularly preferably 20 to 125 μm.

3. Resin layer

The release film according to the present embodiment may include a resin layer 13 between the substrate 11 and the release agent layer 12. Fig. 2 and 3 each show release films 1B and 1C provided with a resin layer 13. In the release films 1B and 1C, the resin layer 13 provided between the substrate 11 and the release agent layer 12 absorbs the unevenness of the surface of the substrate 11 on the resin layer 13 side. This provides the resin layer 13 with a high smoothness on the surface opposite to the substrate 11. Further, by providing the release agent layer 12 on the surface of the resin layer 13, the smoothness of the release surface of the release agent layer 12 becomes excellent.

The resin forming the resin layer 13 is not particularly limited as long as smoothness can be imparted to the release surface without impairing the effects of the present invention. The resin forming the resin layer 13 is preferably a resin with which the release films 1B and 1C easily achieve a film elastic modulus of 3.5 to 7.0 GPa. Particularly, the resin layer 13 is preferably formed of a resin composition containing a curable component. The curable component may be an active energy ray-curable component or a thermosetting component.

(1) Active energy ray-curable component

The active energy ray-curable component is not particularly limited as long as it is a component that is cured by irradiation with an active energy ray without impairing the effects of the present invention, and may be any of a monomer, an oligomer, or a polymer, or a mixture thereof. In particular, as the active energy ray-curable component, a component constituting an acrylic resin is preferably used, and a multifunctional acrylate is particularly preferably used

Examples of the polyfunctional acrylate include bifunctional types such as 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate hydroxytrimethylacetate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, di (acryloyloxyethyl) isocyanurate, and allylated cyclohexyl di (meth) acrylate; trifunctional types such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, tris (acryloyloxyethyl) isocyanurate, and e-caprolactone-modified tris- (2- (meth) acryloyloxyethyl) isocyanurate; tetrafunctional types such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; pentafunctional types such as propionic acid-modified dipentaerythritol penta (meth) acrylate; hexafunctional types such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate. These can be used alone in 1 kind, also can be combined with more than 2 kinds. The multifunctional acrylate preferably has 3 to 15 functional groups, and particularly preferably 3 to 6 functional groups, from the viewpoint of easily forming a crosslinked structure and easily setting the coating elastic modulus of the release films 1B and 1C to a value described later. Among the above multifunctional acrylates, pentaerythritol triacrylate or dipentaerythritol hexaacrylate is preferably used in view of effectively absorbing unevenness on the surface of the substrate and achieving excellent smoothness on the release surface.

When the resin layer 13 is formed from a resin composition containing an active energy ray-curable component, the resin composition preferably further contains a photopolymerization initiator. By containing the photopolymerization initiator, the active energy ray-curable component can be cured efficiently, and the polymerization curing time and the irradiation dose of the active energy ray can be reduced.

When a polyfunctional acrylate is used as the active energy ray-curable component, α -aminoalkylphenones are preferably used from the viewpoint of accelerating the polymerization reaction and improving the curability, α -aminoalkylphenones include, for example, 2-methyl-1 [4- (methylthio) phenyl ] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-dimethylamino-2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, and α -aminoalkylphenones are preferably contained in the resin composition in an amount of 1 to 20 parts by mass, particularly preferably 3 to 15 parts by mass, and further preferably 5 to 10 parts by mass, based on 100 parts by mass of the polyfunctional acrylate.

(2) Thermosetting component

The thermosetting component is not particularly limited as long as it is a component that is cured by heating without impairing the effects of the present invention. Particularly, as the thermosetting component, melamine resin, alkyd resin, epoxy resin, phenol resin, urea resin, polyester resin, urethane resin, polyimide resin, and benzo

An oxazine (benzoxazine) resin or an acrylic resin, and a melamine resin is particularly preferably used. By using the melamine resin, the adhesion between the resin layer 13 and the release agent layer 12 is improved, and peeling of the release agent layer 12 from the resin layer 13 can be effectively suppressed. Further, by using the melamine resin, the modulus of elasticity of the coating film of the release films 1B and 1C is improved, and the releasability when the release films 1B and 1C are peeled from the ceramic green sheet is improved.

The melamine resin used for forming the resin layer 13 is not particularly limited, but the same type of melamine resin as that used for forming the release agent layer 12 is preferably used. At this time, the melamine resins between the resin layer 13 and the release agent layer 12 exhibit high affinity with each other, whereby high adhesion can be obtained between the resin layer 13 and the release agent layer 12, and peeling of the release agent layer 12 can be further effectively suppressed.

(3) Other ingredients

In addition to the above components, the resin composition may contain a crosslinking agent, a reaction inhibitor, an antistatic agent, an adhesion improver, and the like.

(4) Thickness of resin layer

The thickness of the resin layer 13 is preferably 100 to 3000nm, particularly preferably 300 to 2000nm, and further preferably 500 to 1000 nm. By setting the thickness of the resin layer 13 to 100nm or more, unevenness on the surface of the substrate 11 can be effectively absorbed, and excellent smoothness of the release surface can be achieved. Further, by setting the thickness of the resin layer 13 to 3000nm or less, the occurrence of warpage in the release films 1B and 1C can be effectively suppressed.

4. Second resin layer

In the release film 1C, a second resin layer 14 is provided on the surface of the substrate 11 opposite to the resin layer 13 (hereinafter, may be referred to as "substrate back surface"). Since the second resin layer 14 absorbs the irregularities present on the back surface of the substrate, the surface of the second resin layer 14 opposite to the substrate 11 has higher smoothness than the smoothness of the back surface of the substrate. Further, when the release film 1C on which the ceramic green sheet is formed is wound into a roll, the ceramic green sheet comes into contact with the surface of the second resin layer 14 having high smoothness, and thus a ceramic green sheet having higher smoothness can be provided. Further, the presence of the second resin layer 14 cancels out the curing shrinkage of the resin layer 13 and/or the release agent layer 12 from the curing shrinkage of the second resin layer 14, and thus the occurrence of warpage in the release film 1C can be suppressed.

The resin used to form the second resin layer 14 is not particularly limited. As the resin used for the second resin layer 14, the above-described resin used for forming the resin layer 13 can be used. In the release film 1C, the resin layer 13 and the second resin layer 14 may be formed of the same resin or different resins. However, from the viewpoint of suppressing warpage, it is preferable that the resin layer 13 and the second resin layer 14 are formed of the same resin.

The thickness of the second resin layer 14 may be set in the same manner as the resin layer 13. However, from the viewpoint of effectively suppressing the occurrence of warpage, the ratio of the thickness of the second resin layer 14 to the total thickness of the resin layer 13 and the release agent layer 12 is preferably 0.2 to 2, particularly preferably 0.7 to 1.5, and more preferably 0.8 to 1.2.

5. Physical Properties of Release film for ceramic Green sheet production Process

The

release films

1A, 1B, and 1C have a film elastic modulus of 3.5 to 7.0GPa, preferably 4.0 to 6.5GPa, and particularly preferably 4.5 to 6.3GPa, measured from the surface of the release agent layer 12 opposite to the resin layer 13 by a nanoindentation test. By setting the coating elastic modulus of the

release films

1A, 1B, and 1C to 3.5GPa or more, good releasability can be effectively achieved when the

release films

1A, 1B, and 1C are peeled from the ceramic green sheets. Further, by setting the coating elastic modulus of the

release films

1A, 1B, and 1C to 7.0GPa or less, the

release films

1A, 1B, and 1C can be easily wound.

The measurement of the elastic modulus of the coating film in the present specification was performed by a nanoindentation test. Specifically, the

release films

1A, 1B, and 1C cut to a size of 10mm × 10mm were fixed to a glass plate adhered to an aluminum base with a two-liquid epoxy adhesive. In this case, the

release films

1A and 1B are fixed to the glass plate by applying a two-component epoxy adhesive to the surface of the substrate 11 opposite to the release agent layer 12. On the other hand, in the release film 1C, a two-component epoxy adhesive was applied to the surface of the second resin layer 14 opposite to the substrate 11, and this surface was fixed to a glass plate. Subsequently, the elastic modulus of the coating was measured from the surface of the release agent layer 12 opposite to the base material 11 using a micro hardness evaluation device ("Nano index SA 2" manufactured by MTS corporation in the test example).

The peeling force required for peeling the

release films

1A, 1B, and 1C from the ceramic green sheets formed on the peeling surfaces of the

release films

1A, 1B, and 1C can be appropriately set, but is preferably 5 to 100mN/40mm, particularly preferably 7 to 50mN/40mm, and further preferably 10 to 30mN/40 mm. The release agent layer 12 is formed by using a release agent composition containing polyorganosiloxane for the

release films

1A, 1B, 1C, and the release force of 5 to 100mN/40mm can be appropriately set because the

release films

1A, 1B, 1C have appropriate elasticity.

When the ceramic green sheet is molded using the

release films

1A, 1B, and 1C, the polyorganosiloxane can be inhibited from migrating from the release agent layer 12 to the ceramic green sheet. Thus, when the ceramic green sheets are peeled from the

release films

1A, 1B, and 1C after the ceramic green sheets are molded on the release surfaces of the

release films

1A, 1B, and 1C, the amount of polyorganosiloxane migration on the surfaces of the ceramic green sheets in contact with the release surfaces is reduced. Specifically, when the ceramic green sheets are molded using the

release films

1A, 1B, and 1C, the silicon atom ratio measured on the surfaces of the ceramic green sheets in contact with the release surfaces is preferably less than 1.0 atom%, particularly preferably less than 0.5 atom%, and more preferably 0.3 atom% or less. The silicon atom ratio can be calculated by the following formula based on the amounts (XPS count) of silicon atoms (Si), carbon atoms (C), and oxygen atoms (O) measured by X-ray photoelectron spectroscopy (XPS), for example.

Silicon atom ratio (atomic%) [ (Si element amount)/{ (C element amount) + (O element amount) + (Si element amount) } x 100

The ceramic green sheet for measurement may be appropriately selected from those in which silicon is not detected by XPS (that is, silicon compounds are not contained), and the silicon atom ratio may be used as an evaluation criterion for the migration amount of polyorganosiloxane in the release agent layer 12.

The maximum protrusion height Rp of the release surfaces of the

release films

1A, 1B, and 1C is preferably 5 to 800nm, more preferably 10 to 400nm, and still more preferably 20 to 200 nm. In particular, in the release films 1B and 1C provided with the resin layer 13, the maximum protrusion height Rp of the release surface is preferably 5 to 300nm, more preferably 10 to 150nm, and still more preferably 20 to 75 nm. By setting the maximum protrusion height Rp of the release surface to the above range, the ceramic green sheets formed using the

release films

1A, 1B, and 1C exhibit excellent smoothness, and a laminated ceramic product exhibiting excellent performance can be manufactured. In particular, the release films 1B and 1C can form ceramic green sheets having more excellent smoothness because the maximum protrusion height Rp is set to a very small value as described above by providing the resin layer 13. The method of measuring the maximum protrusion height Rp of the release surface is shown in test examples described later.

6. Method for producing release film for ceramic green sheet production process

In the production of the release film 1A, a coating liquid containing a release agent composition and, if necessary, an organic solvent is applied to one surface of the substrate 11, and then the coating film is dried and cured to form the release agent layer 12. Thus, a release film 1A was obtained.

In addition, in the production of the release film 1B, a coating liquid containing a resin composition and, if necessary, an organic solvent is applied to one surface of the substrate 11, and then the coating film is dried and cured to form the resin layer 13. Further, a coating liquid containing a release agent composition and, if necessary, an organic solvent is applied to the surface of the resin layer 13 opposite to the substrate 11, and then the release agent composition is cured by drying and heating to form the release agent layer 12. Thus, a release film 1B was obtained.

In addition, in the production of the release film 1C, a coating liquid containing a resin composition for the resin layer 13 and, if necessary, an organic solvent is applied to one surface of the substrate 11, and then the coating film is dried and cured to form the resin layer 13. Further, after a coating liquid containing a resin composition for the second resin layer 14 and an organic solvent as needed is applied to the other surface of the substrate 11, the coating film is dried and cured to form the second resin layer 14. Next, a coating liquid containing a release agent composition and, if necessary, an organic solvent is applied to the surface of the resin layer 13 opposite to the substrate 11, and then the release agent composition is cured by drying and heating to form the release agent layer 12. Thus, a release film 1C was obtained. The second resin layer 14 may be formed before the resin layer 13, or may be formed after the release agent layer 12.

In the above method, when the resin composition contains an active energy ray-curable component, a coating film formed from the resin composition is cured by irradiation with an active energy ray. As the active energy ray, for example, an active energy ray having an energy quantum among electromagnetic waves or charged particle beams, specifically, ultraviolet rays or electron beams can be used. Ultraviolet rays which are easy to handle are particularly preferable. The ultraviolet ray irradiation may be carried out by using a high-pressure mercury lamp, a xenon lamp or the like, and the irradiation amount of the ultraviolet ray is preferably 50 to 1000mW/cm in terms of illuminance²Left and right. In addition, the light quantity is preferably 50 to 10000mJ/cm²More preferably 80 to 5000mJ/cm²Particularly preferably 200 to 2000mJ/cm². On the other hand, the electron beam irradiation may be performed by using an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad. The irradiation of the coating film with active energy rays may be performed in an inert gas atmosphere such as nitrogen.

When the resin composition contains a thermosetting component, a coating film formed from the resin composition is cured by heating. The heating temperature is preferably 90 to 140 ℃, and particularly preferably 110 to 130 ℃. The heating time is preferably about 10 to 120 seconds, and particularly preferably about 50 to 70 seconds.

In the above-described method, as a coating method of the coating liquid, for example, a gravure coating method, a bar coating method, a spray coating method (spray coating method), a spin coating method (spin coating method), a knife coating method (knife coating method), a roll coating method, a die coating method (die coating method), or the like can be used.

The organic solvent is not particularly limited, and various organic solvents can be used. For example, isopropyl alcohol, isobutyl alcohol, acetone, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and a mixture thereof, including hydrocarbon compounds such as toluene, hexane, and heptane, can be used.

7. Method for using release film for ceramic green sheet production process

For manufacturing the ceramic green sheet,

release films

1A, 1B, 1C may be used. Specifically, a ceramic slurry containing a ceramic material such as barium titanate or titanium oxide is applied to the release surface of the release agent layer 12, and then the ceramic slurry is dried to obtain a ceramic green sheet. The coating may be performed by, for example, a slit die coating method, a doctor blade method, or the like.

Examples of the binder component contained in the ceramic slurry include butyral resin, acrylic resin, and the like. Examples of the solvent contained in the ceramic slurry include an organic solvent and a water-based solvent.

The

release films

1A, 1B, and 1C can exhibit excellent releasability by forming the release agent layer 12 using a release agent composition containing polyorganosiloxane and by giving the

release films

1A, 1B, and 1C appropriate elasticity. Further, in the release agent layer 12, since the polyorganosiloxane is confined in the mesh-like structure formed by curing the melamine resin, the free movement of the polyorganosiloxane is restricted, and therefore, the polyorganosiloxane can be suppressed from migrating from the release agent layer 12 to the ceramic green sheet. Thus, when the molded ceramic green sheets are stacked, the bonding force between the ceramic green sheets is improved, and the occurrence of misalignment between the ceramic green sheets can be suppressed. In the release films 1B and 1C including the resin layer 13, the resin layer 13 absorbs the irregularities on the surface of the substrate 11, and thus the release surface of the release agent layer 12 can have excellent smoothness. Further, by forming the release agent layer 12 from a release agent composition containing a melamine resin, the adhesion between the release agent layer 12 and the resin layer 13 becomes excellent, and therefore, the release agent layer 12 can be prevented from peeling off from the resin layer 13.

The embodiments described above are described for easy understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

For example, other layers such as an antistatic layer may be provided between the substrate 11 and the release agent layer 12 of the release film 1A, between the substrate 11 and the resin layer 13 of the release films 1B and 1C, between the resin layer 13 and the release agent layer 12, or between the substrate 11 and the second resin layer 14 of the release film 1C.

Examples

The present invention will be described more specifically with reference to examples and the like, but the scope of the present invention is not limited to these examples and the like.

[ example 1]

(1) Formation of resin layer

A coating liquid of a resin composition having a solid content of 15 mass% was obtained by mixing 100 parts by mass of pentaerythritol triacrylate (SHIN-NAKAMURA CHEMICAL CO., LTD., trade name: A-TMM-3L) (the amount in terms of solid content; the same applies hereinafter) as an active energy ray-curable component and 10 parts by mass of 2-methyl-1 [4- (methylthio) phenyl ] -2-morpholinopropan-1-one (IRGACURE 907, a α -aminoalkylphenone compound, manufactured by BASF Corp.) as a photopolymerization initiator with toluene as a solvent.

The obtained coating solution of the resin composition was uniformly applied using a Meyer rod #6A biaxially stretched polyethylene terephthalate film (thickness: 31 μm) as a substrate had an arithmetic average roughness Ra of 10nm and a maximum protrusion height Rp of 80nm on the surface. Then, the coating film was dried at 80 ℃ for 60 seconds, and irradiated with ultraviolet rays (illuminance: 150 mW/cm) using an electrodeless lamp under a nitrogen atmosphere (oxygen concentration of 1% or less)²Light amount: about 350mJ/cm²) The resin composition was cured to obtain a laminate in which a resin layer having a thickness of 500nm was laminated on a substrate.

(2) Formation of Release agent layer

A coating liquid of a release agent composition having a solid content of 2 mass% was obtained by mixing 100 parts by mass of an imino methylated melamine resin (NIPPON CARBIDEINDUSTRIES CO., INC., tradename: MX730, mass average molecular weight: 1508), 10 parts by mass of polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd., tradename: X-62-1387, mass average molecular weight: 2000), and 8 parts by mass of p-toluenesulfonic acid (POLYMER, Hitachi Chemical Co., Ltd., tradename: Drier900) as an acid catalyst with toluene as a solvent.

The obtained coating liquid of the release agent composition was uniformly applied to the surface of the laminate opposite to the substrate of the resin layer using a meyer bar # 6. Subsequently, the coating film was dried by heating at 120 ℃ for 60 seconds to cure the release agent composition, thereby forming a release agent layer having a thickness of 100nm on the laminate. By the above operation, a release film was obtained.

[ example 2]

A release film was produced in the same manner as in example 1 except that 100 parts by mass of an imino methylated melamine resin (NIPPON CARBIDENDUSTRIES CO., INC., tradename: MX730, mass average molecular weight: 1508) and 0.1 part by mass of a polydimethylsiloxane having a polyester-modified hydroxyl group (BYK-Chemie Japan, tradename: BYK-370, mass average molecular weight: 5000) and 8 parts by mass of a p-toluenesulfonic acid (Hitachi chemical PolyMER, tradename: Drier900) as an acid catalyst were mixed with toluene as a solvent to prepare a coating solution of a release agent composition having a solid content of 15% by mass, and a resin layer was formed by drying the coating film by heating at 120 ℃ for 60 seconds.

[ example 3]

A release film was obtained in the same manner as in example 1, except that the content of polydimethylsiloxane in the release agent composition was changed to 30 parts by mass.

[ example 4]

A release film was obtained in the same manner as in example 1, except that the content of polydimethylsiloxane in the release agent composition was changed to 40 parts by mass.

[ example 5]

A release film was obtained in the same manner as in example 1, except that 10 parts by mass of polydimethylsiloxane in the release agent composition was changed to 30 parts by mass of polydimethylsiloxane containing a polyester-modified hydroxyl group (product name: BYK-370, mass average molecular weight: 5000, manufactured by BYK-Chemie Japan).

Comparative example 1

A coating solution having a solid content of 15 mass% was obtained by mixing 100 parts by mass of pentaerythritol triacrylate (SHIN-NAKAMURA CHEMICAL CO., LTD., manufactured by A-TMM-3L.), 10 parts by mass of polydimethylsiloxane (SHIN-Etsu CHEMICAL Co., manufactured by Ltd., manufactured by SHIN-Etsu CHEMICAL Co., Ltd., manufactured by Ltd., commercial name X-62-1387, mass average molecular weight: 2000), and 10 parts by mass of 2-methyl-1 [4- (methylthio) phenyl ] -2-morpholinopropan-1-one (IRGACURE 907, α -aminoalkylphenones) as a photopolymerization initiator with toluene as a solvent.

The obtained coating liquid was uniformly applied to a surface of a biaxially stretched polyethylene terephthalate film (thickness: 31 μm) as a base material, the surface having an arithmetic average roughness Ra of 10nm and a maximum protrusion height Rp of 80nm, using a Meyer rod # 6. Then, the coating film was dried at 80 ℃ for 60 seconds, and irradiated with ultraviolet rays (illuminance: 150 mW/cm) using an electrodeless lamp under a nitrogen atmosphere (oxygen concentration of 1% or less)²Light amount: about 350mJ/cm²) The resin composition was cured to obtain a laminate in which a release agent layer having a thickness of 500nm was laminated on a base material.

Comparative example 2

A coating solution of a release agent composition having a solid content concentration of 1.5 mass% was prepared BY mixing 100 parts BY mass of an addition type silicone release agent (product name: CF-2172, mass average molecular weight: 300000, manufactured BY Dow Corning Toray Co., Ltd.) and 2 parts BY mass of a platinum catalyst (BY 24-835, manufactured BY Dow Corning Toray Co., Ltd.) using toluene as a solvent, and a release film was produced in the same manner as in example 1 except that the coating solution was used.

[ test example 1] (measurement of modulus of elasticity of coating film)

The release films obtained in examples and comparative examples were cut into a size of 10mm × 10mm, and then the back surface of the base material of the cut release film was fixed to a glass plate bonded to an aluminum base using a two-pack type epoxy adhesive. Then, using a micro hardness evaluation device (manufactured by MTS, Nano index SA2), the maximum indentation depth of the Indenter was 100nm, and the strain rate was 0.05sec^-1The nanoindentation test was performed under the conditions of a displacement amplitude of 2nm and a vibration frequency of 45Hz, and the modulus of elasticity of the coating film of the release film was measured. The results are shown in table 1.

[ test example 2] (evaluation of polyorganosiloxane migration)

An acrylic pressure-sensitive adhesive TAPE (product name: 31B TAPE) was attached to the release surface of the release agent layer of the release film stored at room temperature for 48 hours after the production in examples and comparative examples, and stored for 24 hours.

Subsequently, the adhesive tape was peeled from the release film, and the silicon atom ratio (at%) was calculated from the following formula based on the amounts (XPS count) of silicon atoms (Si), carbon atoms (C), and oxygen atoms (O) measured by X-ray photoelectron spectroscopy (XPS) on the surface of the adhesive tape in contact with the surface of the release agent layer.

As a measurement apparatus, ESCA 5600 manufactured by perkin elmer was used, and the measurement conditions were as follows.

An X-ray source: mg standard (15kv,400W)

Taking out the angle: 45 degree

Measuring time: 3 minutes

And (3) measuring elements: silicon atom (Si), carbon atom (C), oxygen atom (O)

Then, the polyorganosiloxane migration was evaluated based on the following criteria. The silicon atom ratio and the evaluation results are shown in table 1.

◎ … the silicon atom ratio is less than 0.35 atom%

○ … the silicon atom ratio is 0.35 atom% or more and less than 0.5 atom%

△ … the silicon atom ratio is 0.5 atom% or more and less than 1.0 atom%

X … silicon atom ratio of 1.0 atomic% or more

[ test example 3] (evaluation of adhesion between layers constituting a Release film)

The surface of the resin layer on the side opposite to the base material (hereinafter, sometimes referred to as "resin layer surface") before the release agent layer was formed in examples 1 to 5 and comparative example 2 and the release surface of the release film obtained in examples and comparative example were rubbed with a finger 10 times, and it was visually judged whether or not turbidity (smear) or peeling (peeling-off) was generated under a fluorescent lamp. Then, the adhesiveness between the layers constituting the release film was evaluated based on the following evaluation criteria. The results are shown in table 1.

○ … neither generates turbidity nor drops when rubbing either the surface of the resin layer or the release surface, and has good adhesion

When at least one of the surface and the release surface of the resin layer was rubbed with x …, at least one of haze and peeling occurred, and adhesion was poor

[ test example 4] (measurement of peeling force)

To barium titanate (BaTiO)₃(ii) a SAKAI CHEMICAL INDUSTRY CO., LTD, trade name: BT-03), 100 parts by mass of polyvinyl butyral (SEKISUI CHEMICAL co., ltd., trade name: 8 parts by mass of S-LEC B.KBM-2), and dioctyl phthalate (manufactured by KANTO KAGAKU., trade name: dioctyl phthalate deer 1Grade) 1.4 parts by mass, 69 parts by mass of toluene and 46 parts by mass of ethanol were added, and the mixture was mixed and dispersed by using a ball mill to prepare a ceramic slurry.

The release films produced in examples and comparative examples, which were stored at room temperature for 48 hours, were uniformly coated with the ceramic slurry on the release surface of the release agent layer using an applicator, and then dried at 80 ℃ for 1 minute using a dryer. Thus, a ceramic green sheet having a thickness of 3 μm was obtained on the release film. Thus, a release film with a ceramic green sheet was produced.

The release film with the ceramic green sheet was left to stand at room temperature at 23 ℃ under an atmosphere of 50% relative humidity for 24 hours. Then, an acrylic pressure sensitive adhesive TAPE (product name: 31B TAPE) was attached to the surface of the ceramic green sheet opposite to the release film, and the ceramic green sheet was cut to a width of 20mm in this state. This was used as a measurement sample.

The adhesive tape side of the measurement sample was fixed on a flat plate, a release film was peeled from the ceramic green sheet at a peel angle of 180 ℃ and a peel speed of 100 mm/min using a tensile tester (manufactured by Shimadzu corporation, product name: AG-IS500N), and the force (peel force; mN/20mm) required for the peeling was measured. The results are shown in table 1.

[ test example 5] (measurement of surface roughness)

The release films obtained in examples and comparative examples were fixed to a glass plate via a double-sided tape so that the surface opposite to the release agent layer was on the glass plate side. The release surface of the release film was measured based on the range of 91.2X 119.8. mu.m in the obtained surface shape image by observing the maximum protrusion height (Rp; nm) at 50-magnification in PSI mode using an optical interference type surface shape observation apparatus (product name: WYKO-1100, manufactured by Bruker AXS Co.). The results are shown in table 1.

[ Table 1]

As is clear from table 1, the release film obtained in the examples can be peeled off from the ceramic green sheet with an appropriate peeling force. It was further found that the ratio of silicon atoms in the contact surface of the acrylic adhesive tape in contact with the release film obtained in the examples was relatively small. That is, it was found that the transfer of polyorganosiloxane from the release agent layer to the ceramic green sheet formed using the release film of example was effectively suppressed. Thus, it is expected that, when a laminated ceramic product is produced, the surface direction shift between the layers of the laminate of the ceramic green sheets, which is mainly caused by the migration of polyorganosiloxane, can be suppressed. Further, it was found that the release films obtained in examples had sufficiently high adhesion between the respective layers, and the release agent layer was not easily peeled off from the resin layer. Further, it was confirmed that the maximum protrusion height Rp of the release surface of the release film obtained in the example provided with the resin layer was relatively lower and smoothness was also more excellent than that of the release film of comparative example 1 not provided with the resin layer.

On the other hand, it was found that the ratio of silicon atoms in the contact surface of the acrylic pressure-sensitive adhesive tape in contact with the release film obtained in the comparative example was relatively large, and the migration of polyorganosiloxane to the ceramic green sheet formed using the release film could not be sufficiently suppressed. Further, it was found that the release film of comparative example 2 had low adhesion between the respective layers and was likely to cause peeling. Further, with respect to the release film of comparative example 1 having no resin layer, it was confirmed that the maximum protrusion height Rp of the release surface was higher and the smoothness was lower than those of the release films of examples.

Industrial applicability

The release film for the production process of a ceramic green sheet of the present invention is suitable for molding a ceramic green sheet having little migration of polyorganosiloxane.

Description of the reference numerals

1A, 1B, 1C … a release film for a ceramic green sheet production process; 11 … a substrate; 12 … a release agent layer; 13 … resin layer; 14 … second resin layer.

Claims

1. A release film for a ceramic green sheet production process, comprising a substrate and a release agent layer provided on one side of the substrate,

the release agent layer is formed by curing a release agent composition containing melamine resin and polysiloxane, the mass average molecular weight of the melamine resin is 1000-10000,

and a modulus of elasticity of the coating film measured from a surface of the release agent layer opposite to the base material by a nanoindentation test is 3.5 to 7.0 GPa.

2. The release film for use in the process of producing a ceramic green sheet according to claim 1, wherein the polyorganosiloxane has a mass-average molecular weight of 500 to 20000.

3. The release film for the production process of a ceramic green sheet according to claim 1, wherein the content of the polyorganosiloxane in the release agent composition is 0.1 to 30 parts by mass with respect to 100 parts by mass of a melamine resin.

4. The release film for the process of producing a ceramic green sheet according to claim 1, wherein the melamine resin contained in the release agent composition contains methylated melamine and/or iminomethylolmelamine.

5. The release film for the production process of a ceramic green sheet according to claim 1, further comprising a resin layer between the substrate and the release agent layer.

6. The release film for the process of producing a ceramic green sheet according to claim 5, wherein the resin layer is formed by curing a resin composition containing an active energy ray-curable component or a thermosetting component.

7. The release film for the process of producing a ceramic green sheet according to claim 6, wherein the active energy ray-curable component is a multifunctional acrylate.

8. The release film for the process of producing a ceramic green sheet according to claim 1, further comprising a second resin layer provided on the opposite side of the substrate from the release agent layer.