Release film, film laminate, and methods for manufacturing these.

Abstract

To provide a novel release film that has an excellent light-level releasing property and is easy to peel off from a silicone adhesive layer, and can reduce an amount of fluorinated silicone used, and a film laminate using the release film.SOLUTION: There is provided a mold release film having a mold release layer formed by curing a mold release layer composition containing: a (A) curable silicone having a fluorine substituent; a (B) curable silicone having no fluorine substituent; and a (D) curing catalyst, on at least one surface side of a substrate film, wherein in a concentration distribution of fluorine atoms in a thickness direction within the mold release layer, fluorine atoms are unevenly distributed on a surface of the mold release layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a release film, a film laminate using the same, a method for manufacturing the same, and a method for using the same. [Background technology]

[0002] In recent years, the number of automobiles equipped with liquid crystal displays (LCDs) has increased. In such automotive applications, the panels are often exposed to high and low temperatures for extended periods, requiring adhesives that bond the panel components together with high levels of weather resistance and heat resistance. Silicone-based adhesives are attracting attention as a suitable solution.

[0003] Silicone adhesives have excellent heat resistance, chemical resistance, and transparency, and exhibit adhesive strength even to materials that are difficult to adhere to with general adhesives, such as silicone rubber, fluororesin, and metals, and also have excellent re-adhesion properties. Silicone adhesives are typically used in the form of tape (film) with the adhesive layer intact. They are usually stored with one or both sides covered with a release film before use, and the release film is peeled off before use.

[0004] For this type of application, silicone release films, which are made by coating a base film with a silicone release agent, are frequently used as release films. However, when such silicone release films are coated with silicone adhesives, the similar chemical structures of the release agent and the adhesive tend to cause strong adhesion between the adhesive and the release film, making them difficult to peel off. Therefore, to lower the peeling force value against silicone adhesives (making them easier to peel), methods such as introducing fluorine into the silicone release agent have been employed. For example, Patent Document 1 proposes a fluorinated silicone material having a fluorine substituent to exhibit peelability against silicone adhesives. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-201035 [Overview of the project] [Problems that the invention aims to solve]

[0006] Silicones having fluorine substituents (also referred to as "fluorinated silicones"), as disclosed in Patent Document 1, are highly chemically stable and low-toxicity substances. However, because fluorinated silicones are expensive, there is a need to reduce their usage. Furthermore, since release films coated with fluorinated silicone release agents are difficult to recycle, reducing the amount of fluorinated silicone used has also been desirable from this perspective. In addition, the durability of the release layer has sometimes been a problem.

[0007] Therefore, the present invention relates to a silicone release film formed using fluorinated silicone, and aims to provide a new release film and a film laminate using the release film that have easy release properties from the silicone adhesive layer and can reduce the amount of fluorinated silicone used. Furthermore, the present invention aims to provide a new release film and a film laminate using the release film that can improve the durability of the release layer. [Means for solving the problem]

[0008] The present invention proposes a first release film having a release layer on at least one side of a base film, which is formed by curing a release layer composition comprising (A) a curable silicone having a fluorine substituent, (B) a curable silicone not containing a fluorine substituent, and (D) a curing catalyst, characterized in that, in the concentration distribution of fluorine atoms in the thickness direction within the release layer, fluorine atoms are unevenly distributed on the surface of the release layer, and the fluorine atom concentration on the surface of the release layer is 39.0% or more.

[0009] The present invention also provides a second release film having a release layer on at least one side of a base film, which is formed by curing a release layer composition comprising (A) a curable silicone having a fluorine substituent, (B) a curable silicone without a fluorine substituent, and (D) a curing catalyst. The concentration distribution of fluorine atoms in the thickness direction within the release layer is measured using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam) at a constant sputtering rate. The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) is divided equally into 9 parts based on the total sputtering time to determine the 1st measurement point (sputtering time 0), the 2nd measurement point, ..., the 10th measurement point. We propose a release film characterized in that the fluorine atom concentration (atom%) at the second to tenth measurement points is 80.0% or less of the fluorine atom concentration (atom%) at the first measurement point (sputtering time 0), that is, 80.0% or less of the fluorine atom concentration (atom%) at the first measurement point (sputtering time 0) when it is set to 100.0%.

[0010] The present invention also provides a third release film comprising a release layer on at least one side of a base film, which is formed by curing a release layer composition comprising (A) a curable silicone having a fluorine substituent, (B) a curable silicone without a fluorine substituent, and (D) a curing catalyst. The concentration distribution of fluorine atoms in the thickness direction within the release layer is measured using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam) under a constant sputtering rate. The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) is divided equally into 9 parts based on the total sputtering time to determine the 1st measurement point (sputtering time 0), the 2nd measurement point, ..., the 10th measurement point. We propose a release film characterized in that the average fluorine atom concentration (atom%) at the 6th to 10th measurement points is higher than 2.2% of the fluorine atom concentration (atom%) at the 1st measurement point (sputtering time 0), that is, higher than 2.2% of the fluorine atom concentration (atom%) at the 1st measurement point (sputtering time 0), which is set to 100.0%.

[0011] The present invention also proposes a method for producing a release film, characterized by mixing (A) a curable silicone having a fluorine substituent, (C) a silicone crosslinking agent, and (D) a curing catalyst, then stirring and / or allowing it to stand (in the present invention, this process is also referred to as "pretreatment"), then mixing it with (B) a curable silicone without a fluorine substituent to prepare a release layer composition, and applying this release layer composition to at least one side of a base film. [Effects of the Invention]

[0012] The first and second release films proposed by the present invention relate to a release layer formed using fluorinated silicone, and by ensuring that the concentration distribution of fluorine atoms in the thickness direction within the release layer is such that fluorine is unevenly distributed on the surface of the release layer, the films have easy release properties relative to the silicone adhesive layer, while reducing the amount of fluorinated silicone used. Furthermore, the third release film proposed by the present invention relates to a release layer formed using fluorinated silicone, and by ensuring that fluorine is present inside the release layer, the durability of the release layer can be improved. Furthermore, the method for manufacturing a release film proposed in the present invention makes it possible to suitably manufacture such a release film. [Brief explanation of the drawing]

[0013] [Figure 1] This graph shows the atomic concentration distributions of carbon (C), oxygen (O), silicon (Si), and fluorine (F) obtained from XPS (X-ray photoelectron spectroscopy) in Example 1 (vertical axis: atomic concentration (atom%), horizontal axis: sputtering time (min)). [Figure 2] This graph shows the atomic concentration distributions of carbon (C), oxygen (O), silicon (Si), and fluorine (F) obtained in Example 2 using XPS (X-ray photoelectron spectroscopy), with the vertical axis representing the atomic concentration (atom%) and the horizontal axis representing the sputtering time (min). [Figure 3]As measurement data of XPS (X-ray photoelectron spectroscopy) obtained in Example 5, it is a graph showing the atomic concentration distributions of carbon (C), oxygen (O), silicon (Si), and fluorine (F) (vertical axis: each atomic concentration (atom%), horizontal axis: sputtering time (min)). [Figure 4] As measurement data of XPS (X-ray photoelectron spectroscopy) obtained in Comparative Example 1, it is a graph showing the atomic concentration distributions of carbon (C), oxygen (O), silicon (Si), and fluorine (F) (vertical axis: each atomic concentration (atom%), horizontal axis: sputtering time (min)). <000009X>As measurement data of XPS (X-ray photoelectron spectroscopy) obtained in Comparative Example 2, it is a graph showing the atomic concentration distributions of carbon (C), oxygen (O), silicon (Si), and fluorine (F) (vertical axis: each atomic concentration (atom%), horizontal axis: sputtering time (min)). [Figure 6] As measurement data of XPS (X-ray photoelectron spectroscopy) obtained in Comparative Example 3, it is a graph showing the atomic concentration distributions of carbon (C), oxygen (O), silicon (Si), and fluorine (F) (vertical axis: each atomic concentration (atom%), horizontal axis: sputtering time (min)).

Mode for Carrying Out the Invention

[0014] Next, the present invention will be described based on the embodiments. However, the present invention is not limited to the embodiments described below.

[0015] <<This Release Film>> A release film (referred to as "this release film") according to an example of an embodiment of the present invention includes a release layer composition (referred to as "this release layer composition") containing (A) a cured silicone having a fluorine substituent (also referred to as "fluorinated cured silicone"), (B) a cured silicone not containing a fluorine substituent (also referred to as "non-fluorinated cured silicone"), and (D) a curing catalyst on one side or both sides of a base film (referred to as "this base film"), and optionally further containing (C) a silicone crosslinking agent, and is provided with a release layer (referred to as "this release layer") formed by curing the composition.

[0016] <Main release layer> The release layer is a layer formed by the curing of the release layer composition, and it is preferable that the fluorine atoms are unevenly distributed on the surface of the release layer in the thickness direction of the release layer. This uneven distribution of fluorine on the surface of the release layer makes it possible to achieve excellent easy peelability, allowing for easy removal from the silicone adhesive layer, and also reduces the amount of fluorinated silicone used.

[0017] In this release layer, the concentration distribution (ratio) of fluorine (F) atoms in the thickness direction within the release layer is measured using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam) at a constant sputtering rate. The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) is divided equally into 9 points based on the total sputtering time to determine the 1st measurement point (sputtering time 0), the 2nd measurement point, ..., the 10th measurement point. At the 1st measurement point (sputtering time 0), i.e., the fluorine atom concentration (atom%) on the surface of the release layer (also referred to as atomic concentration%) is preferably 39.0% or higher, more preferably 39.5% or higher, and more preferably 40.0% or higher. On the other hand, there is no upper limit, but generally it is 60.0% or lower, and more preferably 50.0% or lower.

[0018] Furthermore, the fluorine atom concentration (atom%) at the second to tenth measurement points of this release layer is preferably 80.0% or less of the fluorine atom concentration (atom%) at the first measurement point (sputtering time 0), with the fluorine atom concentration (atom%) at the first measurement point (sputtering time 0) being set to 100.0%. More preferably, it is 70.0% or less, of which 60.0% or less, of which 40.0% or less, and most preferably 30% or less. There is no particular lower limit. However, it is generally higher than 2.2%, and more preferably 3.0% or more, of which 4.0% or more, and most preferably 5.0% or more. Here, since the sputtering time correlates with the depth from the surface of the release layer, the sputtering time can be reinterpreted as an indicator of the depth from the surface of the release layer.

[0019] In order to ensure that fluorine is unevenly distributed on the surface of the release layer as described above, it is preferable to prepare the release layer composition by performing a "pre-treatment" as described later. However, the method is not limited to this.

[0020] Furthermore, it is preferable that the average fluorine atom concentration (atom%) at the 6th to 10th measurement points is 2.2% higher than the fluorine atom concentration (atom%) at the 1st measurement point (sputtering time 0), which is set to 100.0%, and more preferably 3.0% or higher, 4.0% or higher, and 5.0% or higher. However, taking into account the viewpoint of distributing more fluorine unevenly on the surface of the release layer, it is preferable that it be 30.0% or less, 20.0% or less, and 10.0% or less. By performing the "pre-treatment" described later, a greater amount of fluorine is distributed within the main release layer (closer to the substrate) compared to when no pre-reaction is performed. Although the detailed mechanism is not clear, it is presumed that the fluorine distributed is derived from intermediates (where one or more crosslinking agents are bonded to the fluorinated silicone resin, but the crosslinking reaction between the fluorinated silicone resins has not yet occurred) and by-products resulting from the "pre-treatment". In order to ensure that fluorine is unevenly distributed on the surface of the release layer while also containing a certain amount of fluorine within the release layer itself, it is preferable to perform the "pre-treatment" described later more thoroughly. However, the method is not limited to this.

[0021] As mentioned above, since the sputtering time correlates with the depth from the surface of the release layer, the above ratios may be determined using the depth from the surface of the release layer instead of the sputtering time. In this case, when measuring the fluorine atom concentration (atom%), if the distance between the surface of the release layer and the underlying layer, i.e., the base film, is not exactly nine sections due to variations in film thickness during sample preparation, the distance may be re-divided into nine sections using a different parameter, and the fluorine atom concentration (atom%) at the first to tenth measurement points may be calculated.

[0022] From the viewpoint of obtaining stable and desirable light peelability with respect to the silicone adhesive, the fluorine atom content in this release layer is preferably 500 ppm by mass or more, more preferably 1,000 ppm by mass or more, and more preferably 3,000 ppm by mass or more. On the other hand, from the viewpoint of reducing the amount of fluorinated silicone used and thus reducing the fluorine atom content, it is preferably 800,000 ppm by mass or less, more preferably 700,000 ppm by mass or less, more preferably 500,000 ppm by mass or less, and more preferably 300,000 ppm by mass or less.

[0023] <This release layer composition> This release layer composition comprises (A) a curable silicone having a fluorine substituent, (B) a curable silicone not having a fluorine substituent, and (D) a curing catalyst, and optionally further comprises (C) a silicone crosslinking agent.

[0024] ((A) Curable silicone having a fluorine substituent) Curable silicones having fluorine substituents can impart stable, easy-to-peel properties to silicone adhesives. Silicone is a polymer that has a siloxane bond (≡Si-O-Si≡) consisting of silicon and oxygen as its backbone, with organic groups mainly composed of methyl (-CH3) bonded to the silicon (Si). "Curing silicone" is a type of silicone that can be cured by cross-linking reaction through heating or light irradiation (ultraviolet light).

[0025] The term "fluorine substituent" refers to a substituent containing a fluorine atom. The substituents containing a fluorine atom (fluorine substituents) are not particularly limited as long as the substituent contains a fluorine atom. Specifically, examples include fluorine groups, trifluoromethyl groups, pentafluoroethyl groups, 2,2-trifluoroethyl groups, 1H,1H-heptafluorobutyl groups, 2H-hexafluoroisopropyl groups, perfluoro-t-butyl groups, and perfluorohexyl groups. However, the examples are not limited to these. Furthermore, as an example of a component having a fluorine substituent, we can mention resins that contain a fluorine substituent in the side chain portion of the resin skeleton.

[0026] Specific examples of curable silicones containing fluorine substituents include KP-911, X-70-201S, and X-41-3035 from Shin-Etsu Chemical Co., Ltd.; and FS1265-300CS, FS1265-1000CS, FS1265-10000CS, BY24-900, BY24-903, 3062, Q2-7785, SYL-OFF 7792, and SYL-OFF 7795 from Toray Dow Corning Co., Ltd. However, the examples are not limited to these.

[0027] The curable silicone having a fluorine substituent may be solvent-based, solvent-free, or a mixture thereof. Curable silicones having fluorine substituents may be used alone or in a mixture of two or more types.

[0028] Here, "solvent-free curable silicone" refers to a silicone with a viscosity that allows it to be applied without dilution with a solvent, consisting of short polysiloxane chains, and being a relatively low molecular weight silicone. The viscosity of the solvent-free curable silicone is preferably 1000 mPa·s or less, and more preferably 50 mPa·s or more or 900 mPa·s or less, and more preferably 80 mPa·s or more or 800 mPa·s or less. This also applies to (B) curable silicones that do not contain fluorine substituents.

[0029] On the other hand, "solvent-curable silicone" refers to a silicone with a high viscosity that cannot be applied without dilution in a solvent, and which has a relatively high molecular weight. This also applies to "(B) fluorine-free curable silicone." The viscosity of the solvent-curable silicone is preferably 1000 mPa·s or higher when used in a 30% toluene solution, more preferably 2000 mPa·s or higher or 20000 mPa·s or lower, and more preferably 3000 mPa·s or higher or 18000 mPa·s or lower. The high viscosity of the solvent-curable silicone tends to improve adhesion to the substrate film. This is also true for (B) curable silicones that do not contain fluorine substituents.

[0030] The fluorine atom content (percentage of atoms) of curable silicones containing fluorine substituents is generally in the range of several thousand ppm (less than 1% of the total number of atoms in the curable silicone containing fluorine substituents) to several hundred thousand ppm (several tens of percent of the total number of atoms in the curable silicone containing fluorine substituents).

[0031] ((B) Fluorine substituent-free curable silicone) The fluorine substituent-free curable silicone may be solvent-type, solvent-free, or a mixture of both. In particular, from the viewpoint of obtaining stable easy peelability to silicone adhesives, (B) the fluorine substituent-free curable silicone is preferably a solvent-type curable silicone.

[0032] Specific examples of curable silicones that do not contain fluorine substituents include, for example, KNS-3051, KNS-320A, KNS-316, KNS-3002, KNS-3300, X-62-1387, KS-837, X-62-2829, KS-3650, KS-847, KS-847T, KS-776L, KS-776A, KS-774, KS-3703T, KS-3601, KS-830E, X-62-2825, X-62-9201-A, X-62-9201B, KM3951, KM-768, X-52-6015, KF-2005, and X-62-7205, all manufactured by Shin-Etsu Chemical Co., Ltd. Examples include X-62-7028-A, X-62-7028-B, X-62-7052, X-62-7622, ​​X-62-7660, X-62-7655; and SP7017, SP7015, SP7025, SP7031, LTC1006L, LTC1063L, LTC1036M, LTC1056L, SRX357, SRX211, SRX345, SRX370, LTC300B, LTC310, LTC355A, LTC759, LTC755, LTC750A, LTC752, LTC761, LTC856, LTC851, etc., manufactured by Toray Dow Corning Co., Ltd. However, this list is not limited to these.

[0033] Furthermore, heavy peeling additives may be added to the non-fluorinated curing silicone. Examples include KS-3800 from Shin-Etsu Chemical Co., Ltd., and SD7292 and BY24-4980 from Toray Dow Corning Co., Ltd.

[0034] Non-fluorinated curing silicones may be used alone, or two or more types with different reactive functional groups and viscosities may be mixed and used together. By mixing two or more types of non-fluorinated curing silicones, the curing reaction can be adjusted, the viscosity of the coating solution can be adjusted, and even the wettability and reactivity can be enhanced. In this case, solvent-free silicones can be mixed with each other, solvent-type silicones can be mixed with each other, or solvent-free silicones and solvent-type silicones can be mixed together. In particular, when increasing the film thickness to obtain a release film with easier peeling, the solid content concentration of the coating solution that forms the cured layer tends to increase. As a result, the viscosity of the coating solution increases, which can lead to problems such as deterioration of the coating appearance and increased thickness unevenness. Therefore, by mixing solvent-free silicones and solvent-type silicones, the viscosity of the coating solution can be reduced, and a cured layer with a good coating appearance and small thickness variations can be formed. Furthermore, the solvent-curing silicone and solvent-free curing silicone are as described above, and the preferred viscosity ranges for each are also the same as those described above.

[0035] (The ratio of (A) to (B)) In this release layer composition, the mass ratio of (A) the curable silicone having a fluorine substituent to (B) the curable silicone not having a fluorine substituent is preferably 1:50 to 10:1, more preferably 1:20 to 5:1, more preferably 1:10 to 2:1, and more preferably 1:5 to 1:1.

[0036] As described above, in the present invention, it is preferable to use a curable silicone that hardens by a hydrosilylation addition reaction, particularly in the case of "(A) a curable silicone having a fluorine substituent," from the viewpoint of material availability and other factors. On the other hand, in manufacturing the release film, which is characterized by the "higher concentration of fluorine atoms on the surface of the release layer compared to the inside of the release layer in the thickness direction of the release layer," there are no particular restrictions on the curing method, and curing silicones such as condensation-type and UV-curing-type silicones may be used.

[0037] ((C) Silicone crosslinking agent) A "crosslinking agent" is a compound that links polymers together, for example, a compound that can link two or more molecules together through chemical covalent bonding.

[0038] Examples of silicone crosslinking agents include silicone crosslinking agents that do not contain (C1) fluorine substituents (also referred to as "non-fluorinated silicone crosslinking agents") and silicone crosslinking agents that contain (C2) fluorine substituents (also referred to as "non-fluorinated silicone crosslinking agents"). In particular, from the viewpoint of ensuring the effects of the pre-reaction described later, the uneven distribution of fluorine, that is, the improvement of easy peelability, and the improvement of residual adhesion, it is preferable to use (C1) non-fluorinated silicone crosslinking agent. Furthermore, when using a mixture of both, it is preferable to use a larger amount of (C1).

[0039] ((C1) Silicone crosslinking agent that does not contain fluorine substituents) The "(C1) fluorine substituent-free silicone crosslinking agent" is represented by the following general formula (1), and is preferably one having at least 2, preferably 3 or more (usually around 3 to 200), more preferably 3 to 100, and among these, 3 to 50 silicon atom-bonded hydrogen atoms (SiH groups) per molecule.

[0040] R b H c SiO (4-b-c) / 2 (1)

[0041] In equation (1), R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Also, b is a positive number satisfying 0.7 to 2.1, particularly 0.8 to 2.0, c is a positive number satisfying 0.001 to 1.0, and b+c is a positive number satisfying 0.8 to 3.0, particularly 1.0 to 2.5.

[0042] Here, R can be a group similar to R in alkenyl group-containing organopolysiloxanes, but preferably one that does not have an aliphatic unsaturated bond such as an alkenyl group.

[0043] This silicon atom-bonded hydrogen atom may be bonded to a silicon atom at the end of the molecular chain, to a silicon atom in the middle of the molecular chain (not at the end of the molecular chain), or to both.

[0044] The molecular structure of the "(C1) fluorine substituent-free silicone crosslinking agent" may be linear, cyclic, branched, or a three-dimensional network structure. Furthermore, the number of silicon atoms (or degree of polymerization) in one molecule is preferably 2 to 1,000, and more preferably 3 or more or 500 or less, of which 3 or more or 300 or less, and especially preferably 4 or more or 150 or less.

[0045] Examples of "(C1) fluorine substituent-free silicone crosslinking agents" include tris(dimethylhydrogensiloxy)methylsilane, tris(dimethylhydrogensiloxy)phenylsilane, 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, methylhydrogenpolysiloxane with trimethylsiloxy groups sealed at both ends, and dimethylsiloxane-methylhydroxane with trimethylsiloxy groups sealed at both ends. Rogensiloxane copolymer, dimethylpolysiloxane with dimethylhydrogensiloxy group blockade at both ends, methylhydrogenpolysiloxane with dimethylhydrogensiloxy group blockade at both ends, dimethylsiloxane / methylhydrogensiloxane copolymer with dimethylhydrogensiloxy group blockade at both ends, methylhydrogensiloxane / diphenylsiloxane copolymer with trimethylsiloxy group blockade at both ends, methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymer with trimethylsiloxy group blockade at both ends, (CH3)2HSiO 1 / 2 Units and SiO 4 / 2 A copolymer consisting of units, (CH3)2HSiO 1 / 2 Units and SiO 4 / 2 Units and (C6H5)SiO 3 / 2Examples include copolymers consisting of units, and in these exemplary compounds, some or all of the methyl groups are substituted with other alkyl groups such as ethyl groups and propyl groups, or aryl groups such as phenyl groups. However, the examples are not limited to these. Furthermore, it is preferable to use two or more crosslinking agents in combination. The purpose of using them together is also to expect them to promote the cross-linking reaction.

[0046] The content of "(C1) fluorine substituent-free silicone crosslinking agent" (total amount if multiple types are used) is preferably 0.1 to 50 parts by mass per 100 parts by mass of curable silicone ((A) + (B)), more preferably 0.3 parts by mass or more or 30 parts by mass or less, and more preferably 0.5 parts by mass or more or 20 parts by mass or less.

[0047] Furthermore, the molar ratio of (C) silicon-bonded hydrogen atoms (SiH groups) in the silicone crosslinker to the total amount of silicon-bonded alkenyl groups in (A) curable silicone having a fluorine substituent and (B) silicon-bonded alkenyl groups in curable silicone without a fluorine substituent is preferably 0.3 to 3.0, more preferably 0.5 or more or 2.5 or less, and more preferably 0.8 or more or 2.0 or less.

[0048] Specific examples of "(C1) Silicone crosslinking agents that do not contain fluorine substituents" include, for example, 3062A, 3062B, 3062D, and SP 7297 manufactured by Toray Dow Corning Co., Ltd.

[0049] ((C2) fluorine substituent-containing silicone crosslinking agent) On the other hand, examples of silicone crosslinking agents containing a (C2) fluorine substituent include those in formula (1) above in which R is a fluoro group. As a specific example, Toray Dow Corning Co., Ltd.'s 3062C, Q2-7560, can be cited.

[0050] ((D) Curing catalyst) A "curing catalyst" is a catalyst used to promote the hydrosilylation addition reaction between the alkenyl group bonded to the silicon atom of a curable silicone and the hydrogen silane (SiH) group of a (C) silicone crosslinking agent. Examples of curing catalysts include platinum-based catalysts such as platinum black, platinum-dicin chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, platinum-bisacetate, palladium-based catalysts, and rhodium-based catalysts. However, the catalysts are not limited to these.

[0051] The release layer composition or the curing catalyst content in the release layer is preferably 0.5 to 500 ppm by mass in terms of metal equivalent relative to the total amount of curing silicone ((A) + (B)), and more preferably 5 ppm or more or 500 ppm or less by mass, and more preferably 10 ppm or more or 200 ppm or less by mass.

[0052] ((E) Reaction control agent) The release layer composition and the release layer may, if necessary, contain reaction control agents in addition to the above components.

[0053] (E) As a reaction control agent, acetylene alcohol represented by the following general formula (2) can be used.

[0054] CH≡CC(R2)(OH)R1(2)

[0055] In formula (2), R1 is a linear or branched monovalent hydrocarbon group having 5 to 15 carbon atoms, and R2 is a linear monovalent hydrocarbon group having 1 to 3 carbon atoms.

[0056] In formula (2) above, R1 is preferably a linear or branched monovalent hydrocarbon group having 5 to 15 carbon atoms, more preferably 6 to 14, and particularly 8 to 12. Specific examples of R1 include alkyl groups such as pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups, and alkenyl groups such as pentenyl, hexenyl, and heptenyl groups. However, it is not limited to these. In formula (2) above, if the number of carbon atoms in the monovalent hydrocarbon group of R1 is less than 5, the volatility of the control agent may be high, resulting in insufficient control. On the other hand, if the number of carbon atoms is greater than 15, the amount of active ingredient in acetylene alcohol per mole tends to decrease, leading to a weaker control effect. This raises concerns that a large amount may need to be added to obtain the desired control effect.

[0057] In formula (2) above, R2 is a linear monovalent hydrocarbon group having 1 to 3 carbon atoms, preferably 1 to 2. Specific examples of R2 include alkyl groups such as methyl, ethyl, and n-propyl groups, and alkenyl groups such as vinyl, allyl, and n-propenyl groups. However, it is not limited to these. The fewer carbon atoms R2 has, the easier it is to control the silicone composition, and a methyl group is preferred.

[0058] One reaction control agent may be used, or two or more may be used in combination as needed. The reaction control agent content is preferably 0.001 to 5.0 parts by mass per 100 parts by mass of the total release layer composition, more preferably 0.01 parts by mass or more or 1.0 part by mass or less, and more preferably 0.05 parts by mass or more or 0.5 parts by mass or less.

[0059] (Other ingredients) This release layer composition and this release layer may contain other components as needed, in addition to the components described above. Examples include silicones other than curable silicones, silicone rubber, silicone resin, polyolefin resin, acrylic resin, urethane resin, epoxy resin, alkyd resin, cellulose, and other resins, or copolymers obtained by modifying these resins by graft polymerization, etc.; various particles such as silica particles, alumina particles, silicone rubber particles, silicone resin particles, and silicone rubber / resin composite particles; and silane coupling agents. However, the composition is not limited to these.

[0060] The release layer composition and the release layer may optionally contain, for example, a light release agent, a heavy release agent, a crosslinking agent, or an adhesion enhancer. Specific examples of light peeling agents, heavy peeling agents, and adhesion enhancers include KS-3800 and X-92-185 from Shin-Etsu Chemical Co., Ltd., and BY24-850, SD7292, BY24-4980, SP7297, BY24-808, and SD7200 from Toray Dow Corning Co., Ltd. However, these are not the only examples.

[0061] (Solid content) Furthermore, the solid content concentration of this release layer composition is preferably 0.1% to 100% by mass, and more preferably 0.5% or more by mass or 50% or less by mass, and more preferably 1.0% or more by mass or 20% or less by mass, and more preferably 1.5% or more by mass or 10% or less by mass.

[0062] The solid content of this release layer composition includes alkyl vinyl polysiloxane and alkyl hydrogen polysiloxane. Of these, the preferred amount of alkyl vinyl polysiloxane containing vinyl groups (alkenyl groups) is 85.0 to 99.9% by mass per unit of solid content, more preferably 90.0% or more by mass or 99.5% or less by mass, and more preferably 92.0% or more by mass or 99.0% or less by mass.

[0063] (Film thickness of this release layer) The thickness of the release layer is not particularly limited. A thicker release layer is preferable because it reduces the influence of the substrate, such as the hardness of the substrate, on the release surface of the release film. Therefore, a thickness of 0.01 μm or more is preferable, more preferably 0.05 μm or more, and more preferably 0.10 μm or more. On the other hand, if the thickness of the release layer is too thick, it may cause blocking and deterioration of the coating appearance. Therefore, a thickness of 10 μm or less is preferable, more preferably 5 μm or less, more preferably 1 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.25 μm or less.

[0064] <This base film> The material of this base film is not particularly limited as long as it exhibits a film-like structure. For example, it may be made of paper, resin, metal, etc. Among these, resin is preferred from the viewpoint of mechanical strength and flexibility.

[0065] Examples of resin-based base films include films formed by creating a film from polymers such as polyethylene, polypropylene, polyester, polystyrene, polycarbonate, polyethersulfone, polyamide, and polyimide. However, the film is not limited to these. Furthermore, any mixture of these materials (polymer blends) or composites of their constituent units (polymers) is acceptable, as long as it can be formed into a film.

[0066] Among the films exemplified above, polyester film is particularly preferred because it has excellent physical properties such as heat resistance, flatness, optical properties, and strength. The polyester film described above may be a single layer or a multilayer film (laminated film) having two or more layers with different properties. Furthermore, the polyester film may be an unoriented film (sheet) or an oriented film. In particular, an oriented film stretched in one or two axes is preferred. Among these, a biaxially oriented film is more preferred from the viewpoint of balance of mechanical properties and flatness.

[0067] The polyester, which is the main component resin of the above-mentioned polyester film, may be either homopolyester or copolymerized polyester. The main component resin refers to the resin with the largest mass percentage among the resins constituting this polyester film, and is expected to account for 50% or more, 75% or more, 90% or more, or 100% of the total mass of the resins constituting this polyester film.

[0068] The homopolyester described above is preferably one obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of aliphatic glycols include ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. However, it is not limited to these. Typical examples of homopolyesters include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).

[0069] On the other hand, if the polyester is a copolymerized polyester, it is preferable that it is a copolymer containing 30 mol% or less of a third component. Examples of dicarboxylic acid components in copolymerized polyesters include one or more types of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, etc., and examples of glycol components include one or more types of ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, etc. However, the list is not limited to these.

[0070] In particular, polyethylene terephthalate, in which 60 mol% or more, preferably 80 mol% or more, are ethylene terephthalate units, is preferred as the main component resin of this base film.

[0071] This base film may contain particles primarily for the purpose of providing slipperiness and preventing scratches during each process. When particles are included, the type of particles is not particularly limited as long as they can provide slipperiness. Specific examples include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenolic resin, epoxy resin, and benzoguanamine resin. However, it is not limited to these. Furthermore, precipitated particles obtained by precipitating and finely dispersing a portion of metal compounds such as catalysts during the polyester manufacturing process can also be used.

[0072] On the other hand, there are no particular restrictions on the shape of the particles used; spherical, lumpy, rod-shaped, flattened, etc., may be used. Furthermore, there are no particular restrictions on their hardness, specific gravity, color, etc. Two or more types of these particles may be used in combination as needed.

[0073] The average particle size is preferably 5 μm or less, more preferably 0.1 μm or more, or 3 μm or less. By using an average particle size within the above range, the film can be given an appropriate surface roughness, ensuring good slipperiness and smoothness. The average particle size of the above particles can be measured as follows. The average particle size of the raw material particles can be measured as the average particle size (D50) obtained from the volume-based particle size distribution measured by dynamic light scattering or the like. The average particle size of the particles contained in this substrate film can be determined by observing the surface or cross-section of the substrate film using an optical microscope or scanning electron microscope (SEM), measuring the diameter of 10 or more particles, and calculating the average value. In the case of an elliptical cross-sectional shape, the average of the longest and shortest diameters can be used as the diameter of each particle.

[0074] Furthermore, the particle content in this base film is preferably 5% by mass or less, more preferably 0.0003% by mass or more, or 3% by mass or less. If there are no particles or only a small amount, the transparency of the film will be high and a good film will be produced, but the slipperiness may be insufficient, so it may be necessary to take measures such as adding particles to the coating layer to improve the slipperiness. Also, if the particle content is too high, the transparency of the film may be insufficient.

[0075] <Example of the composition of the release film> The release film only needs to have a release layer on one or both sides of the base film. As described later, the base film and the release layer may be directly laminated on one or both sides of the release film, or they may be laminated with other layers in between.

[0076] Examples of the aforementioned "other layers" include an anchor coat layer to enhance adhesion between the base film and the release layer, an oligomer sealing layer to prevent the seepage (bleed, plate-out) of compounding materials and oligomers onto the film surface, and an antistatic layer with antistatic properties. However, the layers are not limited to these.

[0077] Specific examples of the composition of this release film include the base film / release layer, the base film / anchor coat layer / release layer, the base film / antistatic layer / release layer, the base film / oligomer encapsulation layer / release layer, antistatic layer / base film / antistatic layer / release layer, oligomer encapsulation layer / base film / oligomer encapsulation layer / release layer, base film / antistatic layer / oligomer encapsulation layer / release layer, release layer / base film / release layer, release layer / anchor coat layer / base film / anchor coat layer / release layer, release layer / antistatic layer / base film / antistatic layer / release layer, release layer / oligomer encapsulation layer / base film / oligomer encapsulation layer / release layer, release layer / oligomer encapsulation layer / antistatic layer / base film / antistatic layer / oligomer encapsulation layer / release layer, etc. However, this is not limited to these examples.

[0078] (Anchor coat layer) Examples of the anchor coat layer include those containing polymer materials such as polyethylene, polypropylene, styrene copolymers, polyester, polyurethane, polyvinyl alcohol, polyethyleneimine, polyacrylate, polymethacrylate, and modified products thereof. However, it is not limited thereto.

[0079] (Oligomer sealing layer) The oligomer sealing layer may contain a hydrolyzable alkoxysilicate and / or its polycondensate. Examples of the hydrolyzable alkoxysilicate include those having the structure represented by the following general formula (3) (R 1 represents a hydrocarbon group having 1 to 10 carbon atoms.).

[0080] Si(OR 1 )4(3)

[0081] In formula (3), R 1 represents a hydrocarbon group having 1 to 10 carbon atoms.

[0082] The above oligomer sealing layer may further contain inorganic particles. Specific examples of the inorganic particles include silica, alumina, kaolin, calcium carbonate, titanium oxide, barium salts, etc. However, it is not limited thereto. In addition, the above oligomer sealing layer may contain an antifoaming agent, a coating property improver, a thickener, an organic lubricant, organic polymer particles, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, etc. However, it is not limited thereto.

[0083] (Antistatic layer) From the viewpoint of imparting antistatic properties, the antistatic layer preferably contains a conductive polymer and a binder polymer. In addition, the coating solution may contain other components as long as the gist of the present invention is not impaired.

[0084] The conductive polymer preferably contains a polythiophene represented by the following formula (4) and its derivative (I).

[0085] TIFF0007861826000001.tif33170

[0086] In formula (4) above, R1 and R2 independently represent a hydrogen element, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, cyclohexylene group, or benzene group. However, they are not limited to these.

[0087] The above-mentioned anchor coat layer, antistatic layer, oligomer encapsulation layer, and other layers can be formed using either an in-line coating method, which is performed simultaneously with the film formation of the film-like substrate, or an offline coating method, which is performed in a separate process on the pre-formed substrate film. A specific example of the in-line coating method is a method in which coating is performed at any stage from melt extrusion of polyester to biaxial stretching, heat fixing, and winding. Typically, this method involves coating either an unstretched sheet in a substantially amorphous state obtained by melting and rapidly cooling, a uniaxially oriented film that has been stretched in the longitudinal direction (vertical direction), or a biaxially oriented film before heat fixing.

[0088] <<Manufacturing method for the release film>> Next, an example of a method for manufacturing this release film will be described.

[0089] Generally, in release films, measures to reduce the amount of fluorinated silicone used include, for example, reducing the proportion of fluorinated silicone in the release layer or reducing the thickness of the release layer. However, the former method impairs the original purpose of easy release, and the latter method has problems such as not being able to form a uniform release layer or a decrease in the stability of the release force. Furthermore, by using a combination of (A) a curable silicone having a fluorine substituent (referred to as "fluorinated curable silicone") and (B) a curable silicone that does not contain a fluorine substituent (also referred to as "non-fluorinated curable silicone"), it is possible to reduce the amount of fluorinated silicone used while maintaining easy peelability. However, when a solution mixing two types of silicone, (A) fluorinated curing silicone and (B) non-fluorinated curing silicone, was applied to a film and dried, it was confirmed that the more hydrophobic (A) fluorinated curing silicone tended to segregate towards the surface (air interface). On the other hand, the silicone crosslinking agents and catalysts used in combination did not possess the same level of hydrophobicity as (A) fluorinated curing silicone due to their molecular structure, resulting in problems such as not being able to uniformly disperse in the film, failing to obtain a release layer with a good curing state, and being unable to mix in a large amount of (B) non-fluorinated curing silicone. Therefore, in the present invention, in forming a release layer, first, a “pretreatment” is performed in which (A) a curable silicone having a fluorine substituent, (C) a silicone crosslinking agent and (D) a curing catalyst are mixed and stirred and / or allowed to stand to react, and then (B) a curable silicone without a fluorine substituent is mixed in to prepare a release layer composition. As a result, even when (C1) a silicone crosslinking agent without a fluorine substituent is used as the (C) silicone crosslinking agent, uniform dispersion is possible, and a coating film that is easier to peel off from silicone adhesives (lightly peelable) can be formed.

[0090] In other words, as an example of a preferred method for manufacturing the release film, for example, a “pre-treatment” is performed by mixing (A) fluorinated curing silicone, (C) silicone crosslinking agent, and (D) curing catalyst, followed by stirring and / or standing; then, the pre-treatment composition obtained from the pre-treatment is mixed with (B) non-fluorinated curing silicone to prepare the release layer composition; and the release layer composition is applied to at least one side of the base film to manufacture the release film. However, the manufacturing method is not limited to this method.

[0091] (A) Fluorinated curing silicone, (C) silicone crosslinking agent, and (D) curing catalyst are mixed, and then a “pre-treatment” is performed by stirring and / or letting it stand. By allowing some time to pass, the crosslinking reaction (also called “pre-crosslinking”) can be carried out in the mixture at room temperature. In this case, the "stirring and / or standing" i.e., "pre-treatment" can be carried out by other means as long as it allows the crosslinking reaction to proceed, and the duration is preferably 10 seconds or more, more preferably 1 minute or more, more preferably 3 minutes or more, more preferably 5 minutes or more, and most preferably 15 minutes or more. There is no particular upper limit on the pre-treatment time. From the viewpoint of solvent volatilization and workability, it is preferably within 1 week, more preferably within 3 days, and most preferably within 1 day. If the crosslinking reaction proceeds too far, depending on the material, the liquid may become cloudy or gel. Therefore, it is preferable to add a reaction control (inhibitor) agent (such as an acetylene alcohol derivative) after a predetermined pre-crosslinking time. The reaction control agent may also be added to the non-fluorinated curable silicone (or its compound solution) described later.

[0092] (C) As the silicone crosslinking agent, it is preferable to use a silicone crosslinking agent that does not contain a fluorine substituent, as described above.

[0093] It is preferable to prepare the release layer composition by mixing the pre-treatment composition obtained in the above pre-treatment with (B) non-fluorinated curable silicone and then diluting it with a solvent as needed. The solvent used for dilution may be a polar solvent or a nonpolar solvent. Furthermore, two or more of the above solvents may be mixed and used. Examples of the aforementioned polar solvents include alcohols such as ethanol and (iso)propyl alcohol; esters such as methyl acetate, ethyl acetate, (iso)propyl acetate, (iso)butyl acetate, (iso)pentyl acetate, ethyl lactate, and ethyl benzoate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, diacetone alcohol, and diisobutyl ketone; glycols such as ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether; and N-methyl-2-pyrrolidone, N,N-dimethylformamide, tetrahydrofuran, and acetonitrile. However, the solvents are not limited to these. Examples of the aforementioned nonpolar solvents include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, and octane; branched hydrocarbons such as isohexane, isooctane, and isononane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and cyclooctane; ethers such as diisopropyl ether; and dioxane. Examples of fluorine solvents include hydrofluoroethers, metaxylene hexafluoride, and tridecafluorooctane. However, the solvents are not limited to these.

[0094] As a method for applying this release layer composition to the substrate film, coating techniques such as those described in "Coating Methods" (by Yuji Harasaki, Maki Shoten, 1979) can be used. Examples of coating heads include air doctor coaters, blade coaters, rod coaters, knife coaters, squeeze coaters, impregnation coaters, reverse roll coaters, transfer roll coaters, gravure coaters, kiss roll coaters, cast coaters, spray coaters, curtain coaters, calendar coaters, and extrusion coaters. However, the method is not limited to these.

[0095] (Methods for forming other layers) As described above, this release film can be formed by first forming "other layers" such as an anchor coat layer, an antistatic layer, or an oligomer encapsulation layer on one or both sides of a base film, as needed, and then applying and curing the release layer composition. In this case, when forming "other layers," the release layer is formed by first forming "other layers," such as an anchor coat layer, an antistatic layer, or an oligomer encapsulation layer, on at least one side of the base film unwound from the roll, as needed, and then applying and curing the release layer composition.

[0096] <Physical properties of this release film> This release film can have the following physical properties.

[0097] (Normal peeling force) The normal release force of this release layer is preferably 75 mN / cm or less, more preferably 60 mN / cm or less, more preferably 50 mN / cm or less, and more preferably 40 mN / cm or less. The lower the normal release force, the less force is required to separate it from the silicone adhesive, which helps to suppress problems such as peeling failures and deformation of the adhesive layer in the production process. Furthermore, by using a release film with excellent easy peeling properties, it is possible to prevent the phenomenon of the release film on the unintended side peeling off in double-sided adhesive tapes that have release films on both sides of the adhesive sheet. On the other hand, there is no particular limitation on the lower limit. When storing laminates formed by laminating release film and adhesive for a long period of time, it is preferable that the value is 1 mN / cm or higher. The normal peel strength can be measured by applying a 5cm wide strip of adhesive tape "Polyimide Tape with Silicone Adhesive No. 5413 (manufactured by 3M)" to a peel tester at room temperature (23°C) under conditions of 180° peeling and a peeling rate of 0.3m / min.

[0098] (Packing force) The heat release force of this release layer is preferably 100 mN / cm or less, more preferably 80 mN / cm or less, and even more preferably 60 mN / cm or less. The heat-release strength is thought to be correlated with the reactive groups (such as hydrogensilane groups (Si-H groups)) remaining on the surface of the release layer after curing and formation on the film. A value closer to the normal release strength indicates a smaller amount of reactive groups remaining on the surface. The heat-peel strength is obtained by applying the adhesive tape "Silicone Adhesive Polyimide Tape No. 5413 (manufactured by 3M)," cutting it to a size of 50 mm x 300 mm, heat-treating it in a hot-air oven at 100°C for 1 hour, then removing the sample and measuring the peel strength after leaving it at room temperature for 1 hour. This peel strength can be measured using, for example, Shimadzu Corporation's "EZ Graph" by performing a 180° peel under a tensile speed of 0.3 (m / min).

[0099] (Residual adhesion rate) The residual adhesion rate of this release layer is preferably 80% or higher, more preferably 90% or higher, and even more preferably 95% or higher. By satisfying the above range, the transfer of release layer components from the surface to the surface of the mating object to which it is bonded is reduced. The residual adhesion rate is an indicator used to confirm the migration of the release agent. It is typically calculated by applying adhesive tape to a surface coated with a release agent, removing it, and then dividing the resulting adhesive strength by the initial adhesive strength at room temperature (23°C) (JIS Z 0109:2015).

[0100] <<This film laminate>> One example of an embodiment of the present invention is a film laminate (referred to as "this film laminate") which has a configuration in which the above-mentioned release film is bonded to a "laminated film having a functional layer" via a silicone adhesive layer.

[0101] <Laminated film (1)> Examples of the aforementioned "laminated film having a functional layer" include a laminated film having a crosslinked resin layer, i.e., a layer with a structure in which resin is crosslinked, on at least one side of a base film (referred to as "laminated film (1)").

[0102] In this case, the crosslinked resin layer can be exemplified by being formed from a crosslinked resin layer composition containing, for example, a conductive polymer and a binder polymer, and optionally a crosslinking agent and particles.

[0103] (Conductive polymer) Preferably, the conductive polymer contains a composition comprising polythiophene and a polyanion, or a composition comprising the above-mentioned polythiophene derivative and a polyanion.

[0104] The aforementioned polyanions refer to "acidic polymers in a free acid state," and are preferably high molecular weight carboxylic acids, high molecular weight sulfonic acids, or polyvinyl sulfonic acids. Specific examples of high molecular weight carboxylic acids include polyacrylic acid, polymethacrylic acid, and polymaleic acid. A specific example of high molecular weight sulfonic acid is polystyrene sulfonic acid. Among these, polystyrene sulfonic acid is most preferred in terms of conductivity. It is also possible to use them in the form of salts in which some of the free acid has been neutralized. By using these polyanions during polymerization, it is thought that polythiophene compounds, which are originally insoluble in water, can be easily dispersed or made aqueous, and that their acidic function also functions as a doping agent for polythiophene compounds.

[0105] Furthermore, polymeric carboxylic acids and polymeric sulfonic acids can also be used in copolymerized form with other copolymerizable monomers, such as acrylic acid esters, methacrylic acid esters, and styrene. The molecular weight of the polymeric carboxylic acid or polymeric sulfonic acid used as a polyanion is not particularly limited, but in terms of the stability and conductivity of the coating, its mass-average molecular weight is preferably 1,000 to 1,000,000, and more preferably 5,000 to 150,000. Some alkali salts such as lithium salts and sodium salts, or ammonium salts, may be included as long as they do not impair the properties of the present invention. Even in the case of neutralized salts, polystyrene sulfonic acid and ammonium salts, which function as very strong acids, are known to shift the equilibrium to the acidic side as the equilibrium reaction proceeds after neutralization, and it is thought that they act as dopants as a result.

[0106] With respect to polythiophene or polythiophene derivatives, it is preferable in terms of conductivity to have a greater excess of polyanions in terms of solid content mass ratio, preferably 1 to 5 parts by mass, and more preferably 1 to 3 parts by mass, of polyanions per 1 part by mass of polythiophene or polythiophene derivative. Examples of compositions comprising the above polythiophene or polythiophene derivative and polyanions are described in, for example, Japanese Patent Publication No. 6-295016, Japanese Patent Publication No. 7-292081, Japanese Patent Publication No. 1-313521, Japanese Patent Publication No. 2000-6324, European Patent No. EP602731, and US Patent No. US5391472, but other methods may also be used. For example, using an alkali metal salt of 3,4-dihydroxythiophene-2,5-dicarboxyester as a starting material, 3,4-ethylenedioxythiophene is obtained. Then, potassium peroxodisulfate, iron sulfate, and the previously obtained 3,4-ethylenedioxythiophene are introduced into an aqueous solution of polystyrene sulfonic acid and reacted to obtain a composition in which polythiophenes such as poly(3,4-ethylenedioxythiophene) are complexed with polyanions such as polystyrene sulfonic acid.

[0107] For example, it can be found in "Latest Trends in Conductive Polymer Technology" (published by Toray Research Center, Inc., first edition June 1, 1999).

[0108] (Binder polymer) The binder polymer constituting the crosslinked resin layer composition is defined as a polymer compound having a number-average molecular weight (Mn) of 1000 or more, as measured by gel permeation chromatography (GPC), and possessing film-forming properties, in accordance with the Polymer Compound Safety Evaluation Flow Scheme (November 1985, sponsored by the Chemical Substances Council).

[0109] The binder polymer constituting the crosslinked resin layer composition may be a thermosetting resin or a thermoplastic resin, as long as it is compatible with or can be mixed and dispersed with the ionic polymer. Examples include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyimides such as polyimide and polyamide-imide; polyamides such as polyamide 6, polyamide 6,6, polyamide 12, and polyamide 11; fluororesins such as polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethylene, ethylene tetrafluoroethylene copolymer, and polychlorotrifluoroethylene; vinyl resins such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, and polyvinyl chloride; epoxy resins; oxetane resins; xylene resins; aramid resins; polyimide silicones; polyurethanes; polyureas; melamine resins; phenolic resins; polyethers; acrylic resins and copolymers thereof. These may be used individually or in combination of two or more. However, the composition is not limited to these.

[0110] The binder polymer may be dissolved in an organic solvent as a raw material, or it may be prepared by adding functional groups such as hydroxyl groups, sulfo groups, or carboxyl groups to make it an aqueous solution, or by using a surfactant in combination to disperse it in water. In addition, the binder polymer may be used with crosslinking agents, polymerization initiators or other curing agents, polymerization accelerators, solvents, viscosity modifiers, etc., as needed.

[0111] Among the binder polymers mentioned above, it is preferable to use one or more selected from polyester resin, acrylic resin, urethane resin, and vinyl resin, from the viewpoint of adhesion to the release layer.

[0112] The binder polymer content in the crosslinked resin layer composition is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and even more preferably 10 to 60% by mass, based on the mass ratio of solid content. When the binder polymer content is within the above range, sufficient strength and adhesion to the release layer can be obtained in the resulting crosslinked resin layer.

[0113] (Crosslinking agent) The crosslinked resin layer composition may contain a crosslinking agent as needed. Crosslinking agents can improve the cohesiveness, surface hardness, scratch resistance, solvent resistance, and water resistance of crosslinked resin layers primarily through crosslinking reactions with functional groups contained in other resins or compounds, or through self-crosslinking.

[0114] Any type of crosslinking agent can be used. For example, melamine compounds, guanamine-based, alkylamide-based, and polyamide-based compounds, glyoxal-based, carbodiimide-based compounds, epoxy compounds, oxazoline compounds, aziridine compounds, isocyanate compounds, silane coupling agents, dialcoholaluminate-based coupling agents, dialdehyde compounds, zircoaluminate-based coupling agents, peroxides, thermally or photoreactive vinyl compounds, and photosensitive resins are preferably used. Among these, from the viewpoint of synergistically obtaining good adhesion to the release layer, it is preferable to use melamine compounds, epoxy compound crosslinking agents, or silane coupling agents. Furthermore, these crosslinking agents also include polymer-type crosslinking reactive compounds, which have reactive groups attached to other polymer backbones. In addition, in the present invention, one or more of these crosslinking agents may be used in combination.

[0115] The crosslinking agent content in the crosslinked resin layer composition is preferably 1 to 90% by mass, more preferably 3 to 50% by mass, and even more preferably 5% to 40% by mass, based on the mass ratio of solids. When the ratio of the crosslinking agent is within the above range, sufficient adhesion to the release layer can be obtained through a synergistic effect with the binder polymer.

[0116] (particle) To improve the adhesion and slipperiness of the cross-linked resin layer, the cross-linked resin layer may contain particles. There are no particular restrictions on the average particle size of the particles. For example, when used in optical applications, from the viewpoint of film transparency, it is preferably 1.0 μm or less, more preferably 0.5 μm or less, and even more preferably 0.2 μm or less. Furthermore, from the viewpoint of improving the adhesion and slipperiness of the crosslinked resin layer, it is preferably 0.01 μm or more. Specific examples of particles include inert inorganic particles such as silica, alumina, calcium carbonate, and titanium dioxide, as well as organic particles such as fine particles obtained from polystyrene resins, polyacrylic resins, and polyvinyl resins, or cross-linked particles thereof.

[0117] The average particle size of the above particles can be measured as follows. The average particle size of the raw material particles can be measured as the average particle size (D50) obtained from the volume-based particle size distribution measured by dynamic light scattering or the like. The average particle size of particles contained within a cross-linked resin layer can be determined by observing the surface or cross-section of the cross-linked resin layer using an optical microscope or scanning electron microscope (SEM), measuring the diameters of 10 or more particles, and calculating the average value. In the case of an elliptical cross-sectional shape, the average of the longest and shortest diameters can be used as the diameter of each individual particle.

[0118] (others) The crosslinked resin layer may contain, as needed, surfactants, defoamers, coating improvers, mold release agents, thickeners, organic lubricants, antistatic agents, conductive agents, UV light absorbers, antioxidants, foaming agents, dyes, pigments, etc.

[0119] The components in the cross-linked resin layer can be analyzed by methods such as TOF-SIMS, ESCA, and X-ray fluorescence.

[0120] (Method for forming a cross-linked resin layer) Regarding the method for forming the crosslinked resin layer, it may be provided by in-line coating, which treats the film surface during the stretching process of the polyester film, or by off-line coating, which is applied outside the system to the film after it has been manufactured. In-line coating is preferred because it can be applied simultaneously with film formation, making it inexpensive to manufacture, and the thickness of the crosslinked resin layer can be changed according to the stretching ratio.

[0121] In line coating is not limited to the following, but for example, in sequential biaxial stretching, the coating process can be applied particularly before transverse stretching after longitudinal stretching is completed. When a crosslinked resin layer is provided on the polyester film by inline coating, coating can be applied simultaneously with film formation, and the crosslinked resin layer can be treated at high temperatures, making it possible to produce a film suitable as a polyester film.

[0122] When a crosslinked resin layer is provided by in-line coating, it is preferable to apply the coating solution onto the polyester film as an aqueous solution or aqueous dispersion of the crosslinked resin layer composition containing the series of compounds described above. Furthermore, within the limits that do not impair the spirit of the present invention, a small amount of organic solvent may be contained in the coating solution for the purpose of improving dispersibility in water, improving film-forming properties, etc. One or more organic solvents may be used in combination.

[0123] The content of the organic solvent in the coating solution is preferably 10% by mass or less, and more preferably 5% by mass or less. Specific examples of organic solvents include aliphatic or alicyclic alcohols such as n-butyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl alcohol, and methyl alcohol; glycols such as propylene glycol, ethylene glycol, and diethylene glycol; glycol derivatives such as n-butyl cellosolve, ethyl cellosolve, methyl cellosolve, and propylene glycol monomethyl ether; ethers such as dioxane and tetrahydrofuran; esters such as ethyl acetate and amyl acetate; ketones such as methyl ethyl ketone and acetone; and amides such as N-methylpyrrolidone.

[0124] Furthermore, regardless of whether it is offline coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as needed.

[0125] Conventional coating methods can be used to form the cross-linked resin layer, such as gravure coating, reverse roll coating, die coating, air doctor coating, blade coating, rod coating, bar coating, curtain coating, knife coating, transfer roll coating, squeeze coating, curtain coating, impregnation coating, kiss coating, spray coating, calender coating, and extrusion coating.

[0126] (Thickness of the cross-linked resin layer) The thickness of the crosslinked resin layer is preferably 0.01 μm to 3 μm, and more preferably 0.02 μm or more or 1 μm or less, and more preferably 0.03 μm or more or 0.3 μm or less, when viewed as a final coating, from the viewpoint of exhibiting various functionalities. The application amount of the coating solution containing the crosslinked resin layer composition is typically 0.01 to 3 g / m². 2 Preferably 0.01 to 1 g / m 2 More preferably 0.01 to 0.3 g / m 2 It is 0.01 g / m³. 2If the above is achieved, sufficient performance can be obtained in terms of adhesion to the release layer (easy adhesion performance) and antistatic performance, 3g / m 2 If the following conditions are met, the cross-linked resin layer will have good appearance and transparency, and will not cause film blocking or a decrease in productivity due to reduced line speed. In this invention, the coating amount can be calculated from the liquid mass per unit time of coating (before drying), the non-volatile content concentration of the coating liquid, the coating width, the stretching ratio, the line speed, etc.

[0127] <Laminated film (2)> Examples of the aforementioned "laminated film having a functional layer" include a release film (referred to as "laminated film (2)") which has "another release layer" on one side of the base film.

[0128] As an example of the aforementioned "other release layer," (B) a configuration comprising a first layer formed from a silicone composition mainly containing a curable silicone that does not contain a fluorine substituent, and a second layer containing a component having a fluorine substituent, in sequence.

[0129] Another example of the aforementioned "other release layer" is (A) a layer formed from a silicone composition mainly containing a curable silicone containing a fluorine substituent.

[0130] Furthermore, as another example of the "other release layer," (B) a layer formed from a silicone composition mainly containing a curable silicone that does not contain fluorine substituents can be cited.

[0131] The aforementioned "main component" refers to the component that has the largest mass proportion among the constituent components.

[0132] <Applications of this film laminate> This film laminate is preferable for bonding automotive components, as it allows the use of a silicone adhesive with good durability and transparency.

[0133] <How to use this release film and this film laminate> Because this release film has excellent release properties for silicone adhesives, it can be used as a light release film for silicone adhesives as follows. In other words, in a film laminate having a structure in which the release film (referred to as "light release film") is laminated on one side of a silicone adhesive layer made of a silicone adhesive, and a release film with higher peel strength than the release film (referred to as "heavy release film") is laminated on the other side of the silicone adhesive layer, the light release film can be peeled off, the exposed surface of the silicone adhesive layer is attached to the "adhered object", the silicone adhesive layer is cured, and then the heavy release film is peeled off. However, the method of use is not limited to this.

[0134] Examples of the adherends include various process papers, interleaving papers, and optical components. Examples of the optical component include polarizing plates or touch sensors. Furthermore, taking advantage of the heat resistance, cold resistance, weather resistance, and high transparency inherent in silicone adhesives themselves, they can also be used for automotive applications such as touch panels installed in automobiles.

[0135] (Silicone adhesive) The aforementioned silicone adhesive may be any adhesive whose main component is silicone resin. The term "main component resin" refers to the resin that makes up the adhesive by the largest proportion (mass) of the resins in the adhesive. Examples of the silicone adhesives include addition reaction type, peroxide curing type, or condensation reaction type silicone adhesives. Among these, addition reaction type silicone adhesives are preferred from the viewpoint of being able to cure at low temperatures and in a short time. These addition reaction type silicone adhesives cure when the adhesive layer is formed on the support. When an addition-reaction type silicone adhesive is used as the silicone adhesive, the silicone adhesive may contain a catalyst such as a platinum catalyst. For example, the addition-reaction type silicone adhesive can be cured by, if necessary, diluting a silicone resin solution with a solvent such as toluene, adding a catalyst such as a platinum catalyst, stirring until homogeneous, applying it to a support, and curing it at 100-130°C for 1-5 minutes. Furthermore, if necessary, a crosslinking agent and additives for controlling adhesive strength may be added to the addition-reaction type silicone adhesive, or the support may be treated with a primer before the formation of the adhesive layer.

[0136] Commercially available silicone resins used in the aforementioned addition-reaction type silicone adhesives include SD4580PSA, SD4584PSA, SD4585PSA, SD4587LPSA, SD4560PSA, SD4570PSA, SD4600FCPSA, SD4593PSA, DC7651ADHESIVE, DC7652ADHESIVE, LTC-755, LTC-310 (all manufactured by Toray Dow Corning), KR-3700, KR-3701, X-40-3237-1, X-40-3240, X Examples include -40-3291-1, X-40-3229, X-40-3323, X-40-3306, X-40-3270-1 (all manufactured by Shin-Etsu Chemical Co., Ltd.), AS-PSA001, AS-PSA002, AS-PSA003, AS-PSA004, AS-PSA005, AS-PSA012, AS-PSA014, PSA-7465 (all manufactured by Arakawa Chemical Industries, Ltd.), TSR1512, TSR1516, TSR1521 (all manufactured by Momentive Performance Materials, Inc.), etc. However, this is not an exhaustive list.

[0137] (Polarizing plate) The materials and configuration of the polarizing plate described above are arbitrary. For example, a stretched polyvinyl alcohol film using iodine as an orientation dye, laminated with a TAC (triacetylcellulose) film as a protective film, is widely used as this type of polarizing plate. Furthermore, the polarizing plate may have a layer structure on its surface that has functions such as a hard coat with substantially no phase difference, anti-glare, low reflectivity, and antistatic properties.

[0138] (Touch sensor) The above-mentioned touch sensor is a component that detects the touch point when a user touches an image displayed on the screen with their finger or a stylus. Examples of sensor technologies include capacitive touch, resistive touch, and surface wave techniques using infrared or ultrasonic waves. Touch sensors are generally incorporated into display devices such as liquid crystal displays and organic EL displays. Furthermore, in recent years, there has been a trend to use substrate films as an alternative to glass substrates, focusing on their flexibility. Touch sensor films typically have a patterned, transparent conductive layer to perform the function of a sensing electrode.

[0139] <Explanation of terms, etc.> Generally, a "sheet," according to the JIS definition, refers to a thin, flat product whose thickness is small relative to its length and width, while a "film," generally, refers to a thin, flat product whose thickness is extremely small relative to its length and width, with a maximum thickness arbitrarily limited, and which is usually supplied in roll form (Japanese Industrial Standard; JIS K6900). However, the boundary between sheets and films is not clear, and there is no need to distinguish between the two in the wording of this invention, so in this invention, the term "film" includes "sheets," and the term "sheet" includes "film."

[0140] In this invention, when "X~Y" (where X and Y are any numbers) is written, unless otherwise specified, it means "X or greater and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, when "X or greater" (where X is any number) is written, unless otherwise specified, it includes the meaning of "preferably greater than X," and when "Y or less" (where Y is any number) is written, unless otherwise specified, it also includes the meaning of "preferably less than Y." [Examples]

[0141] The present invention will be described more specifically below using examples. However, the present invention is not limited to the following examples.

[0142] <Evaluation Method> (1) Normal peeling force A 5cm wide strip of adhesive tape, "Polyimide Tape No. 5413 with Silicone Adhesive (manufactured by 3M)," was applied to the release surface of the sample film. Under room temperature conditions (23°C), the peel strength was measured using a peel test machine at 180° and a peel rate of 0.3m / min.

[0143] (2) Heat-peelable force After applying adhesive tape "Silicone Adhesive Polyimide Tape No. 5413 (manufactured by 3M)" to the release surface of the sample film, it was cut to a size of 50 mm x 300 mm and heat-treated in a hot air oven at 100°C for 1 hour. The sample was then removed and the peel strength was measured after being left at room temperature (23°C) for 1 hour. The peeling force was measured using Shimadzu Corporation's "EZ Graph" at a tensile speed of 0.3 m / min and 180° peeling at room temperature (23°C). A lower value for the heat-peelable force indicates better peeling characteristics.

[0144] (3) Residual adhesion rate (substitute evaluation for the migration properties of the release layer) A silicone adhesive tape (3M No. 5413) was applied to the release surface of a sample film using a 2kg rubber roller. The resulting 50mm x 250mm strip was then used as the sample for measuring residual adhesion. After heating in an oven preheated to 100°C for 1 hour, the strip was cut to a width of 20mm and left at room temperature and humidity for 1 hour. The adhesive tape peeled off the sample was then pressed onto a cleaned stainless steel plate (60mm x 150mm) using a rubber roller. The peeling force was measured using Shimadzu Corporation's "EZ Graph" at a tensile speed of 0.3 m / min and 180° peeling at room temperature (23°C). Then, the peel force of the evaluation film with the measured residual adhesion rate and the peel force of the reference film (a sample in which No. 5413 tape was laminated onto Nafuron tape instead of the sample film) were substituted into the following formula to determine the residual adhesion rate (%). Residual adhesion rate (%) = (Peel strength of migration evaluation film / Peel strength of reference film) × 100

[0145] (4) Fluorine atom concentration (atom%) in the thickness direction of the release layer Using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam), the concentration distribution (ratio) of carbon (C), oxygen (O), silicon (Si), and fluorine (F) atoms in the thickness direction within the release layer of a sample film was measured under constant sputtering speed (sputtering condition setting).

[0146] The XPS configuration requirements are as follows: Equipment: ULVAC-PHI PHI5000 VersaProbe II =Analysis conditions= X-ray intensity: AlKα / 15kV・25W Measurement range: 100 μmφ Passage energy: 58.70 eV Charge correction: 284.6 eV (C1s) =Spatter Conditions= Ar-GCIB 10kV, 60 minutes (3 minute intervals, 20 levels)

[0147] The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) was divided equally into 9 sections based on the total sputtering time. The 1st measurement point (sputtering time 0 seconds, surface of the release layer) to the 10th measurement point (underlayment, reaching the substrate PET film) were determined, and the fluorine atom concentration (atom%) at each measurement point was calculated. Then, the ratio (%) of the fluorine atom concentration (atom%) at the second measurement point to the fluorine atom concentration (atom%) at the first measurement point, and the ratio (%) of the average fluorine atom concentration (atom%) at the sixth to tenth measurement points to the fluorine atom concentration (atom%) at the first measurement point were calculated and are shown in Table 1.

[0148] <Example 1> Solution a1 was prepared by mixing (A) a curable silicone having a fluorine substituent, (C1) a silicone crosslinking agent, and (D1) curing catalyst 1. After stirring for 1 minute, solution b1 ((B) a curable silicone without a fluorine substituent + (D2) curing catalyst 2) was mixed in a mass ratio (solution a1:solution b1) of 1:2 to prepare coating solution A1 with a solid content concentration of 3.6% by mass. Then, the coating solution A1 was applied to one side of a base film (PET film manufactured by Mitsubishi Chemical Corporation ("T100-38", thickness 38 μm)) using a No. 4 bar, and a release film (sample film) was obtained by heat treatment at 150°C for 15 seconds to cure it and provide a release layer.

[0149] (Release layer composition) Solution a1: (A) Curable silicone having a fluorine substituent (Toray Dow Corning Co., Ltd. "3062", 10% by mass, viscosity 10 mm) 2 / s) 100 parts by mass (C1) Silicone crosslinking agent that does not contain fluorine substituents (Toray Dow Corning Co., Ltd. "3062A") 0.50 parts by mass (D1) Platinum catalyst 1 (Toray Dow Corning Co., Ltd. "FS XK-3077") 0.50 parts by mass Diisopropyl ether / ethyl acetate (3:7)

[0150] Solution b1: (B) Fluorine substituent-free curable silicone (Shin-Etsu Chemical Co., Ltd. "KS-847H", solvent type, 30% by mass, contains crosslinking agent / reaction control agent, viscosity 11000 mPa·s (25℃)) 67 parts by mass (D2) Platinum catalyst 2 (“CAT-PL-50T” manufactured by Shin-Etsu Chemical Co., Ltd.) 0.67 parts by mass Diisopropyl ether / ethyl acetate (3:7)

[0151] <Example 2> to <Example 5> In Example 1, a release film (sample film) was obtained by manufacturing in the same manner as in Example 1, except that after preparing solution a1, stirring was performed for 1 minute, and then the standing time was added as shown in the table.

[0152] <Example 6> In Example 1, a release film (sample film) was obtained by preparing solution a1 with a solid content concentration of 10% by mass, stirring for 1 minute, letting it stand for 15 minutes, and then diluting it with a solvent to a solid content concentration of 3.6% by mass, except that the preparation was carried out in the same manner as in Example 1.

[0153] <Comparative Example 1> In Example 1, a release film (sample film) was obtained by manufacturing in the same manner as in Example 1, except that no stirring was performed at all. Furthermore, "no stirring was performed at all" means that "(C1) silicone crosslinking agent and (D1) curing catalyst 1 were mixed to prepare solution a1, and then solution b2 was immediately mixed in without stirring to prepare coating solution A1."

[0154] <Comparative Example 2> In Example 1, a release film (sample film) was obtained by manufacturing in the same manner as in Example 1, except that (B) a curable silicone without fluorine substituents and (D2) curing catalyst 2 were not mixed.

[0155] <Comparative Example 3> In Example 2, a release film (sample film) was obtained by manufacturing in the same manner as in Example 2, except that (C1) a fluorine substituent-containing crosslinking agent (Toray Dow Corning Co., Ltd. "3062C") (0.5 parts by mass) was added instead of a silicone crosslinking agent that does not contain a fluorine substituent.

[0156] <Comparative Example 4> In Comparative Example 2, a release film (sample film) was obtained in the same manner as in Example 1, except that (C1) a fluorine substituent-containing crosslinking agent (C2) 0.5 parts by mass of Toray Dow Corning Co., Ltd. "3062C") was added instead of a silicone crosslinking agent that does not contain a fluorine substituent.

[0157] <Comparative Example 5> Solution b2 was prepared by mixing 100 parts by mass of TPR6600 (manufactured by Momentive), a curable silicone (containing a crosslinking agent that does not contain a fluorine substituent), with 3 parts by mass of LC600 (manufactured by Momentive) as a curing catalyst. Solution a2 was prepared by mixing 100 parts by mass of BY24-900 (manufactured by Toray Dow Corning Co., Ltd.), a fluorine substituent-containing curable silicone (including a crosslinking agent), with 0.5 parts by mass of NC-25 (manufactured by Toray Dow Corning Co., Ltd.), a curing catalyst. Solution a2 containing the curable silicone having the fluorine substituent was mixed with solution b2 containing the curable silicone without the fluorine substituent in a ratio of 100 parts by mass. A solvent containing n-heptane and methyl isobutyl ketone in a 1:1 weight ratio was added to dissolve the polymer components, thereby preparing coating solution A2 with a solid content concentration of 3.0% by mass. Furthermore, no stirring was performed before mixing solution a2 and solution b2. Here, "no stirring was performed at all" means that "after preparing solution a2, solution b2 was immediately mixed in without stirring to create coating solution A2." Then, the coating solution A2 was applied to one side of a base film (PET film manufactured by Mitsubishi Chemical Corporation ("T100-38", thickness 38 μm)) using a No. 10 bar, and a release film (sample film) was obtained by heat treatment at 120°C for 120 seconds to cure it and provide a release layer.

[0158] <Comparative Example 6> Solution a2 was prepared by mixing 100 parts by mass of BY24-900 (manufactured by Toray Dow Corning Co., Ltd.), a fluorine substituent-containing curable silicone (including a crosslinking agent), with 0.5 parts by mass of NC-25 (manufactured by Toray Dow Corning Co., Ltd.), a curing catalyst. A solvent containing a 1:1 weight mixture of n-heptane and methyl isobutyl ketone was added to solution a2 to dissolve the polymer components, thereby preparing coating solution A3 with a solid content concentration of 3.6% by mass. Then, the coating solution A3 was applied to one side of a base film (PET film manufactured by Mitsubishi Chemical Corporation ("T100-38", thickness 38 μm)) using a No. 4 bar, and a release film (sample film) was obtained by heat treatment at 120°C for 120 seconds to cure it and provide a release layer.

[0159] [Table 1]

[0160] [Table 2]

[0161] <Consideration> From the above examples and the test results conducted by the inventors to date, it has been found that a release layer formed on at least one side of a base film, which is made by curing a release layer composition containing (A) a curable silicone having a fluorine substituent, (B) a curable silicone without a fluorine substituent, and (D) a curing catalyst, has excellent easy peelability, allowing it to be easily peeled off from the silicone adhesive layer, even when the amount of fluorinated silicone used is reduced. Furthermore, upon investigating the common characteristics of such release layers, we were able to find a feature in the concentration distribution of fluorine atoms in the thickness direction within the release layer in which fluorine is unevenly distributed on the surface of the release layer. More specifically, in the fluorine atom concentration distribution obtained as described in the above example (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)), when the total sputtering time was evenly divided into 9 sections to determine the 1st measurement point (sputtering time 0), the 2nd measurement point, ..., the 10th measurement point, it was found that the fluorine atom concentration (atom%) at the 2nd to 10th measurement points was 80.0% or less of the fluorine atom concentration (atom%) at the 1st measurement point (sputtering time 0). Furthermore, it was found that if the average fluorine atom concentration (atom%) at the 6th to 10th measurement points is higher than the fluorine atom concentration (atom%) at the 1st measurement point (sputtering time 0), which is 2.2%, an even better effect can be obtained, namely, excellent easy peelability that makes it easy to peel off the silicone adhesive layer, even when the amount of fluorinated silicone used is reduced.

[0162] On the other hand, the following was found regarding the above method for forming the release layer. When a solution made by mixing two types of curable silicone, (A) having a fluorine substituent and (B) not having a fluorine substituent, was applied to a film and dried, it was confirmed that the more hydrophobic curable silicone (A) having a fluorine substituent was more likely to segregate towards the surface (air interface). On the other hand, the silicone crosslinking agents and catalysts used in combination do not possess the same level of hydrophobicity as (A) curable silicones with fluorine substituents, due to their molecular structure. As a result, they do not disperse uniformly in the film, making it impossible to obtain a release layer with a good cured state, or (B) it is not possible to mix in a large amount of curable silicone that does not contain fluorine substituents. Therefore, in the present invention, first, a "pre-treatment" is performed in which (A) a curable silicone having a fluorine substituent, (C) a silicone crosslinking agent, and (D) a curing catalyst are mixed and stirred and / or allowed to stand to react. A release layer composition is then prepared by mixing the pre-treatment composition obtained in this pre-treatment with (B) a curable silicone without a fluorine substituent. It was found that even when using (C1) a silicone crosslinking agent without a fluorine substituent, uniform dispersion is possible, and a coating film that is easier to peel off from silicone adhesives (lightly peelable) can be formed. Although the details of this mechanism are unknown, it is presumed that, after the formulation is prepared, a moderate amount of entanglement (pre-crosslinking) occurs in the formulation over time. Consequently, it is presumed that (A) the curable silicone having fluorine substituents tends to be more abundant on the surface (air interface) side. As a result, it is presumed that even after application to the film, the fluorine substituents are more unevenly distributed near the surface of the release layer, enabling the formation of a coating with easily peelable properties. Furthermore, it was found that by mixing in more (B) fluorine substituent-free curable silicones, the total amount of fluorine atoms in the film can be further reduced during the process of forming the release layer film, thereby enabling more efficient release properties.

Claims

1. A method for producing a release film, characterized by mixing (A) a curable silicone having a fluorine substituent, a silicone crosslinking agent (C1) that does not have a fluorine substituent, and (D) a curing catalyst, stirring or stirring and then letting it stand, then mixing with (B) a curable silicone that does not have a fluorine substituent to prepare a release layer composition, and applying this release layer composition to at least one side of a base film. The release film produced by this manufacturing method is a release film having a release layer on at least one side of a base film, which is formed by curing a release layer composition comprising (A) a curable silicone having a fluorine substituent, (B) a curable silicone without a fluorine substituent, a silicone crosslinking agent (C1) without a fluorine substituent, and (D) a curing catalyst. In the concentration distribution of fluorine atoms in the thickness direction within the release layer, fluorine atoms are unevenly distributed on the surface of the release layer, and the fluorine atom concentration on the surface of the release layer is 39.0% or higher. Using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam), the concentration distribution of fluorine atoms in the thickness direction within the release layer was measured under a constant sputtering rate. The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) was then divided equally into nine points based on the total sputtering time to determine the first measurement point (sputtering time 0), the second measurement point, ..., the tenth measurement point. A method for manufacturing a release film, characterized in that the fluorine atom concentration (atom%) at the second to tenth measurement points is 80.0% or less of the fluorine atom concentration (atom%) at the first measurement point (sputtering time 0).

2. A method for producing a release film, characterized by mixing (A) a curable silicone having a fluorine substituent, a silicone crosslinking agent (C1) that does not have a fluorine substituent, and (D) a curing catalyst, then stirring for 1 minute or more, or stirring and letting stand for 1 minute or more, then mixing with (B) a curable silicone that does not have a fluorine substituent to prepare a release layer composition, and applying this release layer composition to at least one side of a base film. The release film produced by this manufacturing method is a release film having a release layer on at least one side of a base film, which is formed by curing a release layer composition comprising (A) a curable silicone having a fluorine substituent, (B) a curable silicone without a fluorine substituent, a silicone crosslinking agent (C1) without a fluorine substituent, and (D) a curing catalyst. In the concentration distribution of fluorine atoms in the thickness direction within the release layer, fluorine atoms are unevenly distributed on the surface of the release layer, and the fluorine atom concentration on the surface of the release layer is 39.0% or higher. Using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam), the concentration distribution of fluorine atoms in the thickness direction within the release layer was measured under a constant sputtering rate. The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) was then divided equally into nine points based on the total sputtering time to determine the first measurement point (sputtering time 0), the second measurement point, ..., the tenth measurement point. A method for manufacturing a release film, characterized in that the fluorine atom concentration (atom%) at the second to tenth measurement points is 80.0% or less of the fluorine atom concentration (atom%) at the first measurement point (sputtering time 0).

3. When a release film manufactured by the manufacturing method described in Claim 1 or 2 is measured using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam) at a constant sputtering rate to measure the concentration distribution of fluorine atoms in the thickness direction within the release layer, and the obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atom%), horizontal axis: sputtering time (min)) is divided equally into nine parts based on the total sputtering time to determine the first measurement point (sputtering time 0), the second measurement point, ..., the tenth measurement point, A method for manufacturing a release film according to claim 1 or 2, characterized in that the average fluorine atom concentration (atom%) at the 6th to 10th measurement points is higher than 2.2% of the fluorine atom concentration (atom%) at the 1st measurement point (sputtering time 0).

4. A method for producing a release film according to any one of claims 1 to 3, wherein the mass ratio of (A) the curable silicone having a fluorine substituent to (B) the curable silicone not having a fluorine substituent is 1:50 to 10:

1.

5. A method for producing a release film according to any one of claims 1 to 4, wherein the fluorine atom content in the release layer is 500 ppm by mass or more and 800,000 ppm by mass or less.

6. (B) The method for producing a release film according to any one of claims 1 to 5, wherein the curable silicone that does not contain a fluorine substituent is a solvent-curable silicone.

7. A method for manufacturing a release film according to any one of claims 1 to 6, wherein the normal peeling force of the release layer is 75 mN / cm or less, and the residual adhesion rate is 80% or more.

8. A method for manufacturing a release film according to any one of claims 1 to 7, wherein the heat release force of the release layer is 100 mN / cm or less.

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