JP2022144248A - Release film for ceramic green sheet manufacturing process - Google Patents

Abstract

To provide a release film for a ceramic green sheet manufacturing process, which allows a ceramic green sheet to be easily released.SOLUTION: There is provided a release film 1 for a ceramic green sheet manufacturing process, the film including a substrate 11 and a release agent layer 12 provided on one side of the substrate 11. An elastic deformation work rate is 45% or more, an elastic displacement amount is 1.90 μm or less, and a plastic displacement amount is 1.12 μm or less in a load displacement curve measured when a load of 20 mN is applied to the release agent layer 12 side of the release film 1 for a ceramic green sheet manufacturing process, using a microsurface hardness tester.SELECTED DRAWING: Figure 1

Description

The present invention relates to a release film used in the process of manufacturing ceramic green sheets.

2. Description of the Related Art Conventionally, in order to manufacture laminated ceramic products such as laminated ceramic capacitors and multilayer ceramic substrates, ceramic green sheets are formed, and a plurality of the obtained ceramic green sheets are laminated and fired.

A ceramic green sheet is formed by coating a release film with a ceramic slurry containing a ceramic material such as barium titanate or titanium oxide. The release film is required to have releasability such that the release film can be separated from the thin ceramic green sheet formed on the release film with an appropriate release force without cracking, breaking, or the like.

As the release film, a film-like substrate is usually subjected to a release treatment with a release agent to form a release agent layer (Patent Documents 1 and 2).

JP 2020-49803 Patent No. 6610810

In recent years, there has been a demand for precision and miniaturization of multilayer ceramic products, and thinning of molded ceramic green sheets is also progressing. As the film becomes thinner, it becomes more difficult to separate the ceramic green sheet from the release film. Therefore, there is a demand for a release film from which the ceramic green sheet can be released more easily.

By the way, the inventors of the present invention have found that when the molded ceramic green sheet is cut on the release film, the edge of the ceramic green sheet (hereinafter referred to as the "cut part") is formed by cutting the ceramic green sheet by the cutting blade. There is.) is in a state of floating from the release film. In particular, the inventors found that such "floating" can be effectively used as a starting point for peeling the ceramic green sheet.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a release film for a ceramic green sheet manufacturing process that allows the ceramic green sheet to be easily released.

In order to achieve the above object, firstly, the present invention provides a release film for a ceramic green sheet manufacturing process, comprising a substrate and a release agent layer provided on one side of the substrate, wherein the ceramic green In the load-displacement curve measured when a load of 20 mN is applied to the release agent layer side of the release film for sheet manufacturing process using a microsurface hardness tester, the elastic deformation work rate is 45% or more, and the elastic Provided is a release film for a ceramic green sheet manufacturing process, characterized by having a displacement of 1.90 μm or less and a plastic displacement of 1.12 μm or less (Invention 1).

In the above invention (invention 1), the substrate preferably contains a filler (invention 2).

In the above invention (invention 2), the filler is preferably a hydroxyapatite-based filler (invention 3).

In the above inventions (Inventions 2 and 3), the substrate comprises a first resin layer containing the filler, and a second resin layer laminated on one side of the first resin layer and containing no filler. (Invention 4).

In the above inventions (inventions 1 to 4), the surface of the release agent layer opposite to the substrate preferably has an arithmetic mean roughness (Ra) of 1 nm or more and 20 nm or less (invention 5).

In the above inventions (inventions 1 to 5), the maximum protrusion height (Rp) on the surface of the release agent layer opposite to the substrate is preferably 10 nm or more and 200 nm or less (invention 6).

In the above inventions (Inventions 1 to 6), the thickness of the release agent layer is preferably 10 nm or more and 1000 nm or less (Invention 7).

In the above inventions (Inventions 1 to 7), the thickness of the base material is preferably 10 μm or more and 100 μm or less (Invention 8).

In the release film for the ceramic green sheet manufacturing process according to the present invention, when the ceramic green sheet is cut on the release film, the cut portion is likely to float. The float can be effectively used as a trigger for peeling off the ceramic green sheet. Therefore, the release film for the ceramic green sheet manufacturing process according to the present invention can easily release the ceramic green sheets.

1 is a cross-sectional view of a release film for a ceramic green sheet manufacturing process according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view schematically showing a state in which a ceramic green sheet is cut on a release film for a ceramic green sheet manufacturing process according to one embodiment of the present invention. FIG. 2 is an enlarged schematic cross-sectional view showing a state in which a ceramic green sheet is cut on a release film for a ceramic green sheet manufacturing process according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an enlarged state of cutting a ceramic green sheet on a conventional release film for a ceramic green sheet manufacturing process. FIG. 4 is a diagram schematically showing a load-displacement curve;

Embodiments of the present invention will be described below.
FIG. 1 is a cross-sectional view of an example of a release film for a ceramic green sheet manufacturing process according to this embodiment. As shown in the figure, a release film for a ceramic green sheet manufacturing process (hereinafter sometimes simply referred to as "release film") 1 according to the present embodiment includes a substrate 11 and a and a release agent layer 12 . Moreover, the release film 1 according to this embodiment may further include an intermediate layer between the substrate 11 and the release agent layer 12 .

In the release film 1 according to the present embodiment, the elastic deformation work rate is measured in the load-displacement curve measured when a load of 20 mN is applied to the release agent layer 12 side of the release film 1 using a microsurface hardness tester. 45% or more, the amount of elastic displacement is 1.90 μm or less, and the amount of plastic displacement is 1.12 μm or less.

The release film 1 according to the present embodiment, which satisfies these physical properties, can effectively float at the cut portion of the ceramic green sheet when the molded ceramic green sheet is cut on the release film 1. FIG. 2 schematically shows how such cutting is performed. As shown in the figure, cutting is performed using a cutting blade 4 in a state in which the laminated body of the molded ceramic green sheet 2 and the release film 1 is placed on a support base 3 . At this time, the cutting blade 4 is inserted from the side of the ceramic green sheet 2 and pushed down until a part of the release film 1 is cut. Thereby, the ceramic green sheets 2 are completely divided. When the release film 1 according to the present embodiment is used, the edge of the ceramic green sheet 2 is locally separated from the release film 1 at the position (cutting portion) where the cutting blade 4 enters, resulting in a "float 5". easily occur. The float 5 can be effectively used as a starting point for separating the ceramic green sheet 2 and the release film 1 after cutting. That is, only the release film 1 can be easily gripped at the position of the float 5, and the ceramic green sheet 2 and the release film 1 can be separated satisfactorily without imposing an unintentional load on the ceramic green sheet 2. It becomes possible to

As described above, the reason why the release film 1 according to the present embodiment is likely to cause the float 5 is considered as follows. However, it is not limited to the following reasons, and the possibility that there are complex reasons with other events or completely different reasons is not denied.

FIG. 3 schematically shows how the ceramic green sheet 2 is cut in the release film 1 according to this embodiment. In particular, FIG. 3 is an enlarged view of the cut portion. In the release film 1 according to the present embodiment, by satisfying the physical properties described above, it becomes difficult for the ceramic green sheet 2 to follow the release film 1 when the cutting blade 4 is pushed in as shown in FIG. . As a result, the edges produced by cutting the ceramic green sheet 2 are well separated from the release film 1, and a float 5 is produced. Furthermore, as shown in FIG. 3B, when the cutting blade 4 is pulled back, the release film 1 according to the present embodiment is vigorously restored, thereby separating the end portion of the ceramic green sheet 2 from the release film 1. (the distance indicated by "h" in the figure; hereinafter sometimes referred to as the "height" of the float 5) becomes greater. As a result, in the release film 1 according to the present embodiment, a large float 5 is generated, and the ceramic green sheet 2 can be released satisfactorily.

On the other hand, FIG. 4 schematically shows how the ceramic green sheet 2 is cut in the conventional release film 1'. In particular, FIG. 4 is an enlarged view of the cut portion. In the conventional release film 1 ′, the ceramic green sheet 2 follows the release film 1 when the cutting blade 4 is pushed in as shown in FIG. 4( a ). As a result, the edges of the ceramic green sheet 2 produced by cutting remain substantially in close contact with the release film 1, and good floats 5 do not occur. Furthermore, as shown in FIG. 4B, when the cutting blade 4 is pulled back, the restoration of the conventional release film 1' becomes insufficient, and the distance between the edge of the ceramic green sheet 2 and the release film 1' ( In the figure, the distance indicated by "h'") is not sufficiently large. As a result, it becomes difficult to separate the ceramic green sheet 2 with the conventional release film 1'.

In the release film 1 according to the present embodiment, the elastic deformation work rate (hereinafter referred to as It is sometimes simply referred to as "elastic deformation work rate") is 45% or more, preferably 48% or more, and more preferably 50% or more. When the lower limit of the elastic deformation work rate is within the above range, the release film 1 can be easily restored even if it is deformed by the force applied when cutting the ceramic green sheet. As a result, when the ceramic green sheet 2 is cut, the float 5 is likely to occur in the cut portion of the ceramic green sheet 2, and as a result, the peelability is further improved.

In addition, the release film 1 according to the present embodiment preferably has an elastic deformation work rate of 55% or less, particularly preferably 53% or less, and further preferably 52% or less. When the upper limit of the elastic deformation work rate is within the above range, wear of the cutting blade 4 can be easily suppressed. A method for calculating the elastic deformation power is as shown in the test examples described later.

In the release film 1 according to the present embodiment, the elastic displacement amount in the load-displacement curve measured when a load of 20 mN is applied to the release agent layer 12 of the release film 1 using a microsurface hardness tester (hereinafter simply referred to as may be referred to as “elastic displacement amount”) is 1.90 μm or less. When the upper limit of the elastic displacement is in the above range, the brittleness of the release film 1 is suppressed, and the tensile strength of the release film cut by cutting is maintained, thereby improving the workability of the ceramic green sheet 2. become good.

The release film 1 according to the present embodiment preferably has an elastic displacement amount of 1.50 μm or more, particularly preferably 1.70 μm or more, further preferably 1.80 μm or more. When the lower limit of the elastic displacement is within the above range, the release film 1 has a sufficient restoring distance immediately after being cut, and the height of the float 5 of the ceramic green sheet tends to be large.

In the release film 1 according to the present embodiment, the plastic displacement amount (hereinafter simply referred to as is 1.12 μm or less, preferably 1.10 μm or less, and more preferably 1.08 μm or less. When the upper limit of the amount of plastic displacement is within the above range, the edges of the ceramic green sheet 2 are less likely to follow the cutting blade 4 and be pushed into the release film 1 . As a result, the float 5 is likely to occur at the cut portion of the ceramic green sheet 2 when cutting the ceramic green sheet, and as a result, the peelability is further improved.

In addition, the release film 1 according to the present embodiment preferably has a plastic displacement amount of 1.00 μm or more, particularly preferably 1.02 μm or more, further preferably 1.04 μm or more. When the lower limit of the amount of plastic displacement is within the above range, it becomes easier to increase the height of the float 5 .

1. Physical Properties of Release Film for Ceramic Green Sheet Manufacturing Process In the release film 1 according to the present embodiment, the surface of the release agent layer 12 opposite to the substrate 11 has an arithmetic mean roughness (Ra) of 20 nm or less. is preferably 15 nm or less, and more preferably 10 nm or less. As ceramic green sheets become thinner, the surface of the release agent layer 12 of the release film 1 is required to have higher smoothness. A uniform ceramic green sheet can be formed by setting the upper limit of the arithmetic mean roughness within the above range. Although the lower limit of the arithmetic mean roughness (Ra) is not particularly limited, it is preferably 1 nm or more, particularly preferably 1.5 nm or more, and further preferably 2 nm or more. In addition, the method for measuring the arithmetic mean roughness (Ra) is as shown in the test examples described later.

In the release film 1 according to the present embodiment, the maximum protrusion height (Rp) on the surface of the release agent layer 12 opposite to the base material 11 is preferably 200 nm or less, particularly preferably 150 nm or less. , and more preferably 100 nm or less. Highly laminated and highly integrated multi-layer ceramic capacitors (MLCCs) require ceramic green sheets with a thickness of 1.0 μm or less. When the upper limit of the maximum projection height is within the above range, even if the ceramic green sheet is a thin film, it becomes easy to suppress the occurrence of pinholes during manufacturing. Although the lower limit of the maximum projection height (Rp) is not particularly limited, it is preferably 10 nm or more, particularly preferably 20 nm or more, and further preferably 30 nm or more. The method for measuring the maximum protrusion height (Rp) is as shown in the test examples described later.

The peel force required for peeling the release film 1 from the ceramic green sheet formed on the release surface of the release film 1 according to the present embodiment can be set as appropriate, but should be 100 mN / 40 mm or less. is preferred, particularly preferably 50 mN/40 mm or less, more preferably 30 mN/40 mm or less. When the upper limit of the peel force is within the above range, more excellent peelability can be exhibited. In addition, the lower limit of the peel force is preferably a peel force that does not cause unintended peeling from the molded ceramic green sheet, for example, it is preferably 5 mN/40 mm or more, particularly 10 mN/40 mm or more. is preferably In addition, the method for measuring the peel force is as shown in the test examples described later.

The height of the float 5 of the ceramic green sheet at the cutting portion (the height indicated by "h" in FIG. 3(b)) is preferably 1.0 μm or more, particularly 1.5 μm or more. It is preferably 2.0 μm or more, more preferably 2.0 μm or more. The height of the float 5 is preferably 10 μm or less, particularly preferably 8 μm or less, and more preferably 5 μm or less.

2. Substrate The substrate 11 of the release film 1 according to the present embodiment is particularly limited as long as it satisfies the conditions regarding the load displacement curve described above when the release film 1 is configured and the release agent layer 12 can be laminated. not a thing Materials for the substrate 11 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; Resin; Propylene-based copolymer such as ethylene-polypropylene random copolymer; Ethylene-(meth)acrylic acid copolymer, ethylene-methyl (meth)acrylate copolymer, other ethylene-(meth)acrylate esters Ethylene-based copolymers such as copolymers; Ethylene-vinyl acetate copolymers; Polyvinyl chloride, polyvinyl chloride-based resins such as vinyl chloride copolymers; (meth) acrylic acid ester copolymers; polystyrene; polycarbonate; fluorine resin, and the like. In addition, a material obtained by cross-linking these or an ionomer thereof may be used as a material. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same is true for other similar terms. Among the above-mentioned materials, it is preferable to use a polyester-based resin from the viewpoint that it is easy to satisfy the conditions related to the load-displacement curve described above, and it is particularly preferable to use polyethylene terephthalate, and biaxially stretched polyethylene terephthalate is used. is preferred.

The substrate 11 may be a film made of one of the materials described above, or may be a film made of a plurality of materials described above. Furthermore, the substrate 11 may be a laminated film formed by laminating a plurality of such films. In this laminated film, the materials constituting each layer may be of the same type or of different types.

In addition, from the viewpoint that the substrate 11 easily satisfies the conditions regarding the load-displacement curve described above, it is preferable that the substrate 11 contains a filler, and in particular, it is preferable that the filler is added to the resin described above. The filler is not particularly limited as long as it enables the achievement of the conditions regarding the load-displacement curve described above, and may be an inorganic filler or an organic filler. In particular, the filler is preferably an inorganic filler, and examples thereof include fillers such as silica, hydroxyapatite, titanium oxide, calcium carbonate, kaolin, and aluminum oxide. Among these, hydroxyapatite-based fillers are preferred. These fillers may be used individually by 1 type, and may use 2 or more types together.

The average particle diameter of the filler is preferably 100 nm or more, particularly preferably 200 nm or more, and more preferably 300 nm or more. The average particle size of the filler is preferably 2000 nm or less, particularly preferably 1800 nm or less, and more preferably 1500 nm or less. When the average particle diameter of the filler is within the above range, the obtained release film 1 easily satisfies the conditions regarding the load-displacement curve described above.

When the base material 11 contains a filler (when the base material 11 contains a filler over its entirety; excluding the case where the first resin layer described later is provided), the content of the filler in the base material 11 is , preferably 0.5% by mass or more, and particularly preferably 0.6% by mass or more. Moreover, the content of the filler is preferably 1.5% by mass or less, and particularly preferably 1.4% by mass or less. When the content of the filler is within the above range, the obtained release film 1 easily satisfies the conditions regarding the load-displacement curve described above.

Further, the base material 11 includes at least a layer containing a filler (first resin layer) and a layer (second resin layer) that is laminated on one side of the first resin layer and does not contain a filler. It is also preferable to be By including the first resin layer and the second resin layer in this manner, the release film 1 composed of the base material 11 can more easily satisfy the conditions regarding the load-displacement curve described above. Each of the first resin layer and the second resin layer may have only one layer in the base material 11, or may have two or more layers. A typical example is the substrate 11 in which a first resin layer, a second resin layer, and a first resin layer are laminated in this order.

The method for manufacturing the base material 11 is not particularly limited as long as the conditions regarding the load-displacement curve described above can be satisfied, and for example, it can be manufactured by a general method. For example, the base material 11 can be obtained by molding the resin described above into a film by a melt extrusion molding method, a calendering method, or the like.

Further, in the case of manufacturing the substrate 11 containing the above filler (the substrate 11 without the second resin layer), the filler is added to the above resin, and the film is formed in the same manner as described above. The substrate 11 can be obtained by molding.

The manufacturing method of the substrate 11 including the first resin layer and the second resin layer is also not particularly limited. For example, when extruding the resin described above, the filler is supplied to the surface of the resin layer immediately after being molded into a film, and the filler is unevenly distributed only on the surface layer of the resin layer, thereby obtaining the base material 11. be able to. In this case, the first resin layer is formed as the surface layer in which the filler exists, and the second resin layer is formed as the central layer in which the filler does not exist. As another manufacturing method, first, a filler-added resin (first resin layer resin) and a filler-free resin (second resin layer resin) are prepared, and then these are mixed together. The substrate 11 can also be obtained by co-extrusion molding. Alternatively, the base material 11 may be obtained by laminating the obtained layers after individually molding these resins into films.

For the purpose of improving adhesion to the release agent layer 12 provided on the surface of the base material 11, one or both sides of the base material 11 may optionally be subjected to a surface treatment such as an oxidation method or roughening method, or a primer treatment. can be done. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. A thermal spraying method and the like can be mentioned. These surface treatment methods are appropriately selected according to the type of the base material 11, but in general, the corona discharge treatment method is preferably used in terms of effect and operability.

The breaking stress in the width direction of the substrate 11 (the direction orthogonal to the flow direction of the substrate 11 during manufacture; hereinafter sometimes referred to as the “TD direction”) is preferably 200 MPa or more, particularly 220 MPa or more. and more preferably 240 MPa or more. Moreover, the breaking stress in the width direction of the substrate 11 is preferably 340 MPa or less, particularly preferably 320 MPa or less, further preferably 320 MPa or less. When the breaking stress of the base material 11 is within the above range, the strength required in each step is sufficiently maintained, the crystallinity of the resin increases, and the release film 1 easily achieves a large elastic deformation work rate. Become. The details of the method for measuring the breaking stress are as described in Examples described later.

The breaking elongation of the base material 11 in the width direction (TD direction) is preferably 80% or more, particularly preferably 85% or more, further preferably 90% or more. The breaking elongation in the width direction of the substrate 11 is preferably 120% or less, particularly preferably 110% or less, and further preferably 105% or less. When the elongation at break of the substrate 11 is within the above range, the release film 1 is less likely to be plastically deformed, and the release film 1 is less likely to be cut by the cutting blade 4, so that the ceramic green sheet 2 can be cut more easily. become good. The details of the method for measuring the elongation at break are as described in Examples below.

The thickness of the base material 11 is preferably 10 μm or more, particularly preferably 15 μm or more, further preferably 20 μm or more. Also, the thickness of the base material 11 is preferably 100 μm or less, particularly preferably 50 μm or less, and further preferably 38 μm or less. When the thickness of the base material 11 is within the above range, the obtained release film 1 easily satisfies the conditions regarding the load-displacement curve described above.

3. Release Agent Layer The release agent constituting the release agent layer 12 is not particularly limited as long as it satisfies the above-described load-displacement curve conditions when the release film 1 is formed. For example, silicone release agents, fluorine release agents, acrylic release agents, alkyd release agents, long-chain alkyl group release agents, thermoplastic resin release agents, and the like can be used. Among them, it is preferable to use a silicone-based release agent as the release agent that constitutes the release agent layer 12 . These release agents may be used singly or in combination of two or more.

Any of an addition reaction type, a condensation reaction type, an ultraviolet curing type, an electron beam curing type, and the like may be used as the silicone release agent. Among these, addition-reactive silicone-based release agents are particularly preferred because of their high reactivity and excellent productivity, small changes in release force over time, and excellent effects such as no curing shrinkage.

Addition reaction type silicone-based release agents include, for example, release agent compositions containing a main agent comprising an alkenyl group-containing polyorganosiloxane compound and a catalyst that accelerates the addition reaction. The release agent composition may further contain a cross-linking agent.

Polydimethylsiloxane, dimethylsiloxane-methylphenylsiloxane copolymer, and the like are used as the main skeleton of the polyorganosiloxane compound that constitutes the main agent and the cross-linking agent, for example. The alkenyl group used in the polyorganosiloxane of the main agent includes alkenyl groups having 2 to 10 carbon atoms such as vinyl group, allyl group, propenyl group and hexenyl group. The position of the alkenyl group in the polyorganosiloxane may be at the molecular terminal or at the side chain. Polyorganosiloxane as the main agent preferably has two or more alkenyl groups per molecule.

The weight-average molecular weight of polyorganosiloxane as the main agent is preferably 50,000 or more, particularly preferably 100,000 or more, further preferably 150,000 or more. Also, the weight average molecular weight is preferably 1,000,000 or less, particularly preferably 800,000 or less, further preferably 600,000 or less. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

When the weight average molecular weight of the polyorganosiloxane is within the above range, excellent coatability can be easily achieved. In addition, since the weight average molecular weight of the polyorganosiloxane is 50,000 or more, it is possible to prevent the coating viscosity of the release agent composition from becoming too low, suppress the occurrence of cissing, and provide a uniform surface condition of the release agent. It becomes easy to obtain the layer 12. Furthermore, since the weight average molecular weight of the polyorganosiloxane is 1,000,000 or less, it is possible to effectively suppress the increase in the coating viscosity of the release agent composition, and to ensure good solubility in the diluent solvent. can do.

Specific examples of the polyorganosiloxane used for the cross-linking agent include a dimethylhydrogensiloxy group-blocked dimethylsiloxane-methylhydrogensiloxane copolymer and a trimethylsiloxy group-blocked dimethylsiloxane-methylhydrogensiloxane copolymer. , trimethylsiloxy group end-blocked methylhydrogenpolysiloxane, poly(hydrogensilsesquioxane), and the like.

The catalyst is not particularly limited as long as it can cure the release agent composition. Specific examples include fine particle platinum, fine particle platinum adsorbed on a carbon powder carrier, chloroplatinic acid , alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, and platinum-based compounds such as palladium and rhodium. The content of the catalyst is preferably about 1 ppm or more and 1000 ppm or less with respect to the total amount of components other than the catalyst.

Furthermore, the addition reaction type silicone release agent may contain addition reaction inhibitors, release modifiers, adhesion improvers and the like, if desired. In addition to the release agent, antistatic agents, dyes, pigments, and other additives may also be used as materials for the release agent layer 12 .

The thickness of the release agent layer 12 is preferably 10 nm or more, particularly preferably 15 nm or more, further preferably 20 nm or more. The thickness of the release agent layer 12 is preferably 1000 nm or less, particularly preferably 800 nm or less, and more preferably 500 nm or less. When the thickness of the release agent layer 12 is within the above range, the resulting release film 1 easily satisfies the conditions regarding the load-displacement curve described above.

4. Intermediate Layer In the release film 1 according to the present embodiment, an intermediate layer may be provided between the substrate 11 and the release agent layer 12 from the viewpoint of easily satisfying the conditions regarding the load-displacement curve described above. Materials for the intermediate layer include, but are not limited to, ultraviolet curable resins, melamine resins, epoxy resins, alkyd resins, urea resins, and the like.

When the release film 1 has an intermediate layer, the intermediate layer preferably has a thickness of 10 μm or more, particularly preferably 15 μm or more, and further preferably 20 μm or more. Also, the thickness of the intermediate layer is preferably 1000 μm or less, particularly preferably 800 μm or less, further preferably 500 μm or less. When the thickness of the intermediate layer is within the above range, the obtained release film 1 easily satisfies the conditions regarding the load-displacement curve described above.

5. Manufacturing method of release film for ceramic green sheet manufacturing process The release film 1 according to the present embodiment is, for example, coated on one surface of the substrate 11 with a coating liquid containing a release agent composition and optionally an organic solvent. After that, it is dried and cured to form the release agent layer 12 . Examples of the coating method that can be used include gravure coating, bar coating, spray coating, spin coating, knife coating, roll coating, and die coating.

The organic solvent is not particularly limited, and various solvents can be used. Examples include hydrocarbon compounds such as toluene, hexane and heptane, as well as acetone, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone and mixtures thereof.

The coating film obtained by coating the release agent composition as described above is preferably heat-cured. In this case, the heating temperature is preferably 90° C. or more and 140° C. or less, and the heating time is preferably about 10 seconds or more and 120 seconds or less. Moreover, curing of the release agent composition may be accelerated by irradiation with ultraviolet rays as necessary.

When the release film 1 according to the present embodiment has an intermediate layer, the intermediate layer is formed on one side of the substrate 11 using a general method according to the material of the intermediate layer. be able to. After that, the release film 1 can be obtained by forming the release agent layer 12 on the surface of the intermediate layer opposite to the substrate 11 by the method described above.

6. Usage of Release Film for Ceramic Green Sheet Manufacturing Process The release film 1 according to the present embodiment can be used to manufacture a ceramic green sheet. Specifically, a ceramic green sheet is obtained by applying a ceramic slurry containing a ceramic material such as barium titanate or titanium oxide to the release surface of the release agent layer 12 and then drying the ceramic slurry. can be done. Coating can be performed using, for example, a slot die coating method, a doctor blade method, or the like.

Examples of binder components contained in the ceramic slurry include butyral-based resins and acrylic-based resins. Examples of solvents contained in the ceramic slurry include organic solvents and aqueous solvents.

After molding the ceramic green sheets, the ceramic green sheets can be cut on the release film 1 . This cutting can be performed by a general method. Following the cutting, the release film 1 is released from the ceramic green sheet.

Since the release film 1 according to the present embodiment satisfies the above-described load displacement curve conditions, the float 5 is likely to occur at the cut portion of the ceramic green sheet 2 during cutting. When peeling the release film 1 from the ceramic green sheet 2, the float 5 can be used as a starting point. Therefore, according to the release film 1 according to this embodiment, the ceramic green sheet 2 can be easily released.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, another layer such as an antistatic layer may be provided on the surface of the substrate 11 opposite to the release agent layer 12 or between the substrate 11 and the release agent layer 12 .

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Preparation of base material]
The following base materials A to G were prepared. Among these substrates, substrates A to F were obtained by forming films by changing the amount and type of filler added to polyethylene terephthalate.
<Base material A>
Main material: polyethylene terephthalate, filler: hydroxyapatite, thickness: 31 μm, breaking stress (MD direction): 237 MPa, breaking stress (TD direction): 287 MPa, breaking elongation (MD direction): 152%, breaking elongation (TD direction): 100%
<Base material B>
Main material: polyethylene terephthalate, filler: hydroxyapatite, thickness: 31 μm, breaking stress (MD direction): 237 MPa, breaking stress (TD direction): 287 MPa, breaking elongation (MD direction): 152%, breaking elongation (TD direction): 100%
<Base material C>
Main material: polyethylene terephthalate, filler: hydroxyapatite, thickness: 31 μm, breaking stress (MD direction): 235 MPa, breaking stress (TD direction): 281 MPa, breaking elongation (MD direction): 145%, breaking elongation (TD direction): 97%
<Base material D>
Main material: polyethylene terephthalate, filler: silica, thickness: 31 μm, breaking stress (MD direction): 232 MPa, breaking stress (TD direction): 285 MPa, breaking elongation (MD direction): 129%, breaking elongation (TD direction) ): 84%
<Base material E>
Main material: polyethylene terephthalate, filler: silica, thickness: 31 μm, breaking stress (MD direction): 239 MPa, breaking stress (TD direction): 282 MPa, breaking elongation (MD direction): 145%, breaking elongation (TD direction) ): 102%
<Base material F>
Main material: polyethylene terephthalate, filler: silica, thickness: 31 μm, breaking stress (MD direction): 233 MPa, breaking stress (TD direction): 280 MPa, breaking elongation (MD direction): 140%, breaking elongation (TD direction) ): 99%

The above breaking stress and breaking elongation were measured using a tensile tester (manufactured by Orientec, product name "Tensilon") under an environment of 23 ° C. and 50% RH at a tensile speed of 200 mm / min. It is measured by

[Example 1]
As polyorganosiloxane, polyorganosiloxane having two or more vinyl groups at the terminal or side chain, and having no vinyl group is a methyl group (weight average molecular weight: 390,000, in 1 g of polyorganosiloxane Vinyl group amount: 0.25 mmol, solid content: 30 mass %) was dissolved in toluene to obtain an addition reaction type polyorganosiloxane solution with a solid content of 1.5 mass %. Next, 2 parts by mass of a platinum-based catalyst (manufactured by Dow Corning Toray Co., product name: SRX-212) is added to 100 parts by mass of the addition-reactive polyorganosiloxane solution and mixed to obtain a solid content of 1.5. A coating liquid of the release agent composition of mass % was obtained.

The obtained coating liquid of the release agent composition was uniformly applied to one side of the substrate A obtained in Production Example 1 using a bar coater. Then, it was dried by heating at 125° C. for 60 seconds to cure the release agent composition, thereby obtaining a release film for a ceramic green sheet manufacturing process in which a release agent layer having a thickness of 50 nm was laminated on a substrate.

[Examples 2-3, Comparative Examples 1-5]
A release film for the ceramic green sheet manufacturing process was obtained in the same manner as in Example 1, except that the type of substrate and the thickness of the release agent layer were changed as shown in Table 1.

[Test Example 1] (Measurement of Elastic Displacement, Plastic Displacement, and Elastic Deformation Work Rate Using a Microsurface Hardness Tester)
Using a micro surface hardness tester (manufactured by Shimadzu Corporation, product name: Dynamic Ultra Micro Hardness Tester W201S), the surface of the release agent layer side of the release film for the ceramic green sheet manufacturing process produced in Examples and Comparative Examples A load-displacement curve representing the relationship between the indentation depth displacement and the load was obtained.

FIG. 5 schematically shows the obtained load-displacement curves. In the load-displacement curve, the load (F) is plotted on the vertical axis and the indentation depth displacement (d) is plotted on the horizontal axis. As shown in the figure, when the load is increased from the time when no load is applied to the time when the maximum load is applied, the displacement from point P0 to point P1 (the amount of displacement at this time is defined as "d1") is as indicated by solid line A. Transition to. After that, when the load is removed, the transition is made along the solid line B from the point P1 to the point P2 (the amount of displacement at this time is defined as "d2"). Note that the point P3 is the intersection of the vertical line (broken line C) of the point P1 and the horizontal axis.

In the load-displacement curve, the amount of displacement d1 at the time of maximum load application (point P1) was defined as the amount of elastic displacement, and the amount of displacement d2 at the time of unloading (point P2) was defined as the amount of plastic displacement. In addition, the elastic deformation work rate is measured from the load-displacement curve, W _plast (plastic deformation work) as the area of the range surrounded by the solid line A, the solid line B and the horizontal axis, and the solid line B, the broken line C and the horizontal axis. _Deriving W _elast (elastic deformation work) as the area of the range that can be covered, and using the following formulas (1) and (2), the elastic deformation work rate (ηIT) was derived. Table 1 shows the results.
_Wtotal = _Wplast + _Welast (1)
ηIT=W _elast /W _total (2)

[Test Example 2] (Measurement of arithmetic mean roughness and maximum protrusion height of release agent layer)
A double-sided tape was attached to a glass plate, and the release films obtained in Examples and Comparative Examples were fixed to the glass plate via the double-sided tape so that the surface opposite to the surface to be measured was on the glass plate side. Arithmetic mean roughness (Ra; nm) and maximum protrusion height (Rp; nm) of the release surface and the back surface of the release film were measured with an optical interference surface profiler (manufactured by Veeco, product name: WYKO-1100). was used and observed at 50 magnifications in the PSI mode, and measurements were made based on the surface profile image obtained in the range of 91.2×119.8 μm. Table 1 shows the results.

[Test Example 3] (Evaluation of slurry coatability)
Barium titanate powder (BaTiO ₃ ; manufactured by Sakai Chemical Industry Co., Ltd., product name: BT-03) 100 parts by mass, polyvinyl butyral as a binder (manufactured by Sekisui Chemical Co., Ltd., product name: S-Lec B KBM-2) 8 parts by mass , and 4 parts by mass of dioctyl phthalate (manufactured by Kanto Kagaku Co., Ltd., product name: dioctyl phthalate 1st class) as a plasticizer, and 135 parts by mass of a toluene/ethanol mixed solvent (mass ratio 6/4). were mixed and dispersed to prepare a ceramic slurry.

The ceramic slurry was applied to the surface of the release agent layer of the release film for the ceramic green sheet manufacturing process obtained in Examples and Comparative Examples using a die coater, and then dried at 80° C. for 1 minute. Thus, a ceramic green sheet having a thickness of 3 μm was formed on the release film to obtain a release film with the ceramic green sheet. This release film with a ceramic green sheet was illuminated with a fluorescent lamp from the release film side, and all surfaces of the formed ceramic green sheets were visually inspected to evaluate the slurry coatability according to the following criteria. Table 1 shows the results.
〇…There was no pinhole in the ceramic green sheet ×…There was a pinhole in the ceramic green sheet

[Test Example 4] (Measurement of peel strength against ceramic green sheet)
A release film with a ceramic green sheet produced by the same procedure as in Test Example 3 was allowed to stand for 24 hours in an atmosphere of room temperature of 23°C and humidity of 50%. Next, it was cut to a size of 100 mm in the machine direction and 40 mm in the width direction. This was used as a measurement sample. A 5 mm wide acrylic adhesive tape (manufactured by Nitto Denko, product name: 31B tape) was attached to one end of the short side of the ceramic green sheet surface of the measurement sample. The release film side of this measurement sample was fixed to a flat plate with double-sided tape, and the flat plate was placed horizontally on a peel tester (manufactured by Shimadzu Corporation, product name: AGS-20NX) so that the measurement sample faces upward. Then, the edge of the ceramic green sheet on the side to which the acrylic adhesive tape was attached was peeled off from the release film, and the edge was attached to a jig of a peel tester. In this state, the ceramic green sheet is pulled vertically upward (90° peeling) at a peeling speed of 200 mm/min, and the peeling film and the ceramic green sheet are peeled off. ) was measured. Table 1 shows the results.

[Test Example 5] (Evaluation of Sheet Lifting)
Using a texture analyzer (manufactured by Eiko Seiki Co., Ltd., product name: TA.XT.plus), a release film with a ceramic green sheet manufactured by the same procedure as in Test Example 3 was measured from the ceramic green sheet side with a Thomson blade under the following measurement conditions. was pushed in and a seat floating test was performed. Using a high-speed camera (manufactured by Keyence Corporation, product name: VW-5000), ceramic green sheet floating was evaluated according to the following evaluation criteria.
〔Measurement condition〕
・Blade material: Cemented carbide (FM10K)
・Blade angle: 42 degrees ・Blade tip width: 2 μm
・Pushing speed: 0.5mm/s
[Seat floating evaluation criteria]
Good: The float of the ceramic green sheet was 1.0 μm or more at the cutting portion when the blade was in contact with the base material.
x: The lift of the ceramic green sheet was less than 1.0 μm at the cut portion when the blade was in contact with the substrate.

In addition, the sample after the sheet floating test was observed with a digital microscope (manufactured by Keyence Corporation, product name: VHX-1000) through the release film, and the height of the sheet floating (indicated by "h" in FIG. 3(b) height) was measured. Table 1 shows the results.

As is clear from Table 1, the release films for the ceramic green sheet manufacturing process obtained in the examples were well lifted when the ceramic green sheets were cut.

The release film for the ceramic green sheet manufacturing process of the present invention is suitable for forming ceramic green sheets.

DESCRIPTION OF SYMBOLS 1... Release film 11... Base material 12... Release agent layer 2... Ceramic green sheet 3... Support stand 4... Cutting blade 5... Float

Claims (8)

A release film for a ceramic green sheet manufacturing process comprising a substrate and a release agent layer provided on one side of the substrate,
In the load displacement curve measured when a load of 20 mN is applied to the release agent layer side of the release film for the ceramic green sheet manufacturing process using a microsurface hardness tester, the elastic deformation work rate is 45% or more. 1. A release film for a ceramic green sheet manufacturing process, characterized by having an elastic displacement of 1.90 μm or less and a plastic displacement of 1.12 μm or less. 2. The release film according to claim 1, wherein the substrate contains a filler. 3. The release film according to claim 2, wherein the filler is a hydroxyapatite-based filler. 4. The base material comprises at least a first resin layer containing the filler, and a second resin layer laminated on one side of the first resin layer and containing no filler. 4. The release film for the ceramic green sheet manufacturing process according to any one of 2 or 3. The ceramic according to any one of claims 1 to 4, wherein the surface of the release agent layer opposite to the base has an arithmetic mean roughness (Ra) of 1 nm or more and 20 nm or less. Release film for green sheet manufacturing process. The ceramic according to any one of claims 1 to 5, wherein the maximum protrusion height (Rp) on the surface of the release agent layer opposite to the substrate is 10 nm or more and 200 nm or less. Release film for green sheet manufacturing process. The release film for a ceramic green sheet manufacturing process according to any one of claims 1 to 6, wherein the release agent layer has a thickness of 10 nm or more and 1000 nm or less. The release film for a ceramic green sheet manufacturing process according to any one of claims 1 to 7, wherein the thickness of the substrate is 10 µm or more and 100 µm or less.

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