Release film, film laminate, method for producing the same

Abstract

A novel release film with excellent easy peelability of silicone adhesive layer, thereby reducing the amount of fluorinated silicone used, is characterized in that a release layer is provided on at least one side of the substrate film, the release layer being formed by curing a release layer composition comprising (A) a fluorinated silicone, (B) a fluorine-free silicone and (D) a curing catalyst, wherein the fluorine atom concentration distribution in the thickness direction of the release layer is such that the fluorine atoms are biased towards the surface of the release layer.

Description

Technical Field

[0001] This invention relates to release films, film laminates using the same, methods of manufacturing them, and methods of using them. Background Technology

[0002] In recent years, the number of automobiles equipped with LCD panels has increased. For this automotive application, there is frequent exposure to high and low temperatures, requiring adhesives that bond the panel components to have high weather resistance and heat resistance. As a suitable adhesive, silicone-based adhesives have attracted considerable attention.

[0003] Silicone adhesives have excellent heat resistance, chemical resistance, and transparency. They also exhibit strong adhesion to silicone rubber, fluoropolymers, and metals that are difficult to bond with conventional adhesives, and have excellent re-adhesion properties.

[0004] Silicone adhesives are used to form strips (films) as adhesive layers. They are typically stored with one or both sides covered with a release film before use, and the release film is usually peeled off before use.

[0005] As a release film used in this application, most release films are silicone release films made by coating a silicone release agent onto a substrate film.

[0006] However, when covering such silicone release films with silicone adhesives, the release agent and adhesive have similar chemical structures, thus tending to adhere firmly between the adhesive and the release film, making them difficult to peel off. Therefore, to reduce the peel force on the silicone adhesive (lightening peelability), operations such as introducing fluorine into the silicone release agent have been performed. For example, to improve peelability against silicone adhesives, Patent Document 1 proposes a fluorinated silicone material with fluorine substituents.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2011-201035 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] The fluorinated organosilicon (also known as "fluorinated organosilicon") disclosed in Patent Document 1 has high chemical stability and is a low-toxicity substance. However, due to the high cost of fluorinated organosilicon, there is a need to reduce its usage. Furthermore, release films coated with fluorinated organosilicon release agents are difficult to recycle; therefore, it is also desirable to reduce the amount of fluorinated organosilicon used. Additionally, the durability of the release layer sometimes becomes a problem.

[0012] Therefore, regarding silicone release films formed using fluorinated silicone, the present invention provides: a novel release film that exhibits light peelability to the silicone adhesive layer and reduces the amount of fluorinated silicone used, and a film laminate formed using the release film. Additionally, it provides: a novel release film that improves the durability of the release layer, and a film laminate formed using the release film.

[0013] Solution for solving the problem

[0014] As a first release film having a release layer formed by curing a release layer composition comprising (A) a curable organosilicon with fluorine substituents, (B) a curable organosilicon without fluorine substituents, and (D) a curing catalyst on at least one side of a substrate film, the present invention provides a release film characterized in that, in the thickness direction of the fluorine atom concentration distribution within the release layer, the fluorine atoms are biased towards the surface of the release layer, and the fluorine atom concentration at the surface of the release layer is 39.0 atomic concentration% or more.

[0015] As a second release film having a release layer formed by curing a release layer composition comprising (A) a curable organosilicon with fluorine substituents, (B) a curable organosilicon without fluorine substituents, and (D) a curing catalyst on at least one side of a substrate film, the present invention also proposes a release film characterized in that, using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam), at a constant sputtering rate, the concentration distribution of fluorine atoms in the thickness direction within the aforementioned release layer is measured, and the obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atomic %), horizontal axis: sputtering time (minutes)) is divided equally into nine parts by the total sputtering time to determine the first measurement point (sputtering time 0), the second measurement point, ... the tenth measurement point.

[0016] The fluorine atom concentration (atomic %) at measurement points 2 to 10 is less than 80.0% of the fluorine atom concentration (atomic %) at measurement point 1 (sputtering time 0), that is, when the fluorine atom concentration (atomic %) at measurement point 1 (sputtering time 0) is set to 100.0%, it is less than 80.0% of it.

[0017] As a third release film having a release layer formed by curing a release layer composition comprising (A) a curable organosilicon with fluorine substituents, (B) a curable organosilicon without fluorine substituents, and (D) a curing catalyst on at least one side of a substrate film, the present invention also proposes a release film characterized in that, using XPS (X-ray photoelectron spectroscopy) with GC-IB (gas cluster ion beam), at a constant sputtering rate, the concentration distribution of fluorine atoms in the thickness direction within the aforementioned release layer is measured, and the obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atomic %), horizontal axis: sputtering time (minutes)) is divided equally into nine parts by the total sputtering time to determine the first measurement point (sputtering time 0), the second measurement point, ... the tenth measurement point.

[0018] The average fluorine atomic concentration (atomic %) at measurement points 6 to 10 is 2.2% higher than the fluorine atomic concentration (atomic %) at measurement point 1 (sputtering time 0). That is, when the fluorine atomic concentration (atomic %) at measurement point 1 (sputtering time 0) is set to 100.0%, it is 2.2% higher than that.

[0019] The present invention also proposes a method for manufacturing a release film, characterized in that (A) a curable organosilicon with fluorine substituents, (C) an organosilicon crosslinking agent and (D) a curing catalyst are mixed and stirred and / or allowed to stand (in the present invention, this treatment is also referred to as "pretreatment"), and then mixed with (B) a curable organosilicon without fluorine substituents to prepare a release layer composition, and the release layer composition is coated on at least one side of a substrate film.

[0020] The effects of the invention

[0021] Regarding the first and second release films proposed in this invention, concerning the release layer formed with fluorinated silicone, the concentration distribution of fluorine atoms in the thickness direction of the release layer is such that fluorine is biased towards the surface of the release layer, thereby providing light peelability to the silicone adhesive layer and reducing the amount of fluorinated silicone used.

[0022] Furthermore, regarding the third release film proposed in this invention, the durability of the release layer formed with fluorinated organosilicon can be improved by having fluorine present inside the release layer.

[0023] Furthermore, the method for manufacturing a release film according to the present invention is suitable for manufacturing such a release film. Attached Figure Description

[0024] Figure 1A graph showing the atomic concentration distribution of carbon (C), oxygen (O), silicon (Si), and fluorine (F) as measured by XPS (X-ray photoelectron spectroscopy) in Example 1 (vertical axis: atomic concentration (atomic %), horizontal axis: sputtering time (minutes)).

[0025] Figure 2 A graph showing the atomic concentration distribution of carbon (C), oxygen (O), silicon (Si), and fluorine (F) as measured by XPS (X-ray photoelectron spectroscopy) in Example 2 (vertical axis: atomic concentration (atomic %), horizontal axis: sputtering time (minutes)).

[0026] Figure 3 A graph showing the atomic concentration distribution of (C), oxygen (O), silicon (Si) and fluorine (F) as measured by XPS (X-ray photoelectron spectroscopy) in Example 5 (vertical axis: atomic concentration (atomic %), horizontal axis: sputtering time (minutes)).

[0027] Figure 4 A graph showing the atomic concentration distribution of carbon (C), oxygen (O), silicon (Si), and fluorine (F) in the XPS (X-ray photoelectron spectroscopy) measurements obtained in Comparative Example 1 (vertical axis: atomic concentration (atomic %), horizontal axis: sputtering time (minutes)).

[0028] Figure 5 A graph showing the atomic concentration distribution of carbon (C), oxygen (O), silicon (Si), and fluorine (F) in the XPS (X-ray photoelectron spectroscopy) measurements obtained in Comparative Example 2 (vertical axis: atomic concentration (atomic %), horizontal axis: sputtering time (minutes)).

[0029] Figure 6 A graph showing the atomic concentration distribution of carbon (C), oxygen (O), silicon (Si), and fluorine (F) in the XPS (X-ray photoelectron spectroscopy) measurements obtained in Comparative Example 3 (vertical axis: atomic concentration (atomic %), horizontal axis: sputtering time (minutes)). Detailed Implementation

[0030] Next, the present invention will be described based on exemplary embodiments. However, the present invention is not limited to the embodiments described below.

[0031] <<This release film>>

[0032] An example of an embodiment of the present invention is a release film (referred to as "this release film") having a release layer (referred to as "this release layer") formed by curing a release layer composition (referred to as "this release layer composition") comprising (A) a curable organosilicon having fluorine substituents (also referred to as "fluorinated curable organosilicon"), (B) a curable organosilicon without fluorine substituents (also referred to as "non-fluorinated curable organosilicon") and (D) a curing catalyst, and optionally further comprising (C) an organosilicon crosslinking agent.

[0033] <This release layer>

[0034] This release layer is a layer formed by curing the release layer composition. Preferably, in the thickness direction of the release layer, the concentration distribution of fluorine atoms is such that fluorine is biased towards the surface of the release layer.

[0035] By dispersing fluorine onto the surface of the release layer, excellent easy peelability of the silicone adhesive layer can be achieved, and the amount of fluorinated silicone used can be reduced.

[0036] For this release layer, XPS (X-ray photoelectron spectroscopy) using GC-IB (gas cluster ion beam) at a constant sputtering rate measures the concentration distribution (ratio) of fluorine (F) atoms in the thickness direction of the aforementioned release layer. The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atomic %), horizontal axis: sputtering time (minutes)) is divided equally into nine parts by the total sputtering time. When determining the first measurement point (sputtering time 0), the second measurement point, ..., the tenth measurement point, the fluorine atom concentration (atomic %) at the first measurement point (sputtering time 0), i.e., the surface of the release layer, is 39.0% or more, more preferably 39.5% or more, and 40.0% or more. On the other hand, there is no upper limit, but it is usually 60.0% or less, and 50.0% or less.

[0037] Furthermore, for this release layer, when the fluorine atom concentration (atomic %) at the first measurement point (sputtering time 0) is set to 100.0%, the fluorine atom concentration (atomic %) at the second to tenth measurement points is preferably 80.0% or less, more preferably 70.0% or less, 60.0% or less, 40.0% or less, and particularly preferably 30% or less. There is no particular limitation on the lower limit, but it is generally higher than 2.2%, preferably 3.0% or more, 4.0% or more, and 5.0% or more.

[0038] Here, the sputtering time is related to the depth from the surface of the release layer; therefore, the aforementioned sputtering time can be used as an indicator of the depth from the surface of the release layer.

[0039] In this release layer, as described above, when fluorine is desorbed onto the surface of the release layer, it is preferable, for example, to prepare the release layer composition by performing a "pretreatment" as described later. However, this method is not limited to this.

[0040] Furthermore, when the fluorine atom concentration (atomic %) at the first measurement point (sputtering time 0) is set to 100.0%, the average fluorine atom concentration (atomic %) at the 6th to 10th measurement points is preferably higher than 2.2%, more preferably 3.0% or more, 4.0% or more, and 5.0% or more. However, considering the viewpoint of making the fluorine more concentrated on the surface of the release layer, it is preferable to have 30.0% or less, more preferably 20.0% or less, and 10.0% or less.

[0041] By performing the "pretreatment" described later, fluorine becomes more distributed within the release layer (closer to the substrate) compared to the case without pre-reaction. The detailed mechanism is unclear, but it is speculated that fluorine is distributed as an intermediate (crosslinking agent alone or in combination with fluorinated silicone resin, but not to the point of crosslinking reaction between the fluorinated silicone resins) or a byproduct of the "pretreatment" reaction.

[0042] When the fluorine is thus concentrated on the surface of the release layer and also contains a certain amount of fluorine within the release layer, it is preferable to perform the "pretreatment" described later more thoroughly. However, this method is not the only option.

[0043] It should be noted that, as mentioned above, the sputtering time is related to the depth from the surface of the release layer. Therefore, the depth from the surface of the release layer can be used instead of the sputtering time to calculate the aforementioned ratios. In the determination of fluorine atomic concentration (atomic %), taking advantage of film thickness fluctuations during sample preparation, if the distance from the surface of the release layer to the substrate layer (i.e., the substrate film) does not exactly constitute nine intervals, other parameters are used to recalculate and divide the area into nine intervals. The fluorine atomic concentration (atomic %) at measurement points 1 to 10 can then be calculated.

[0044] Regarding the fluorine atom content in this release layer, from the viewpoint of achieving optimal light peelability for the silicone adhesive, it is preferably 500 ppm by mass or more, and more preferably 1000 ppm by mass or more, and 3000 ppm by mass or more. On the other hand, from the viewpoint of reducing the amount of fluorinated silicone and reducing the fluorine atom content, it is preferably 800,000 ppm by mass or less, and more preferably 700,000 ppm by mass or less, 500,000 ppm by mass or less, and 300,000 ppm by mass or less.

[0045] <This release layer composition>

[0046] This release layer composition comprises (A) a curable silicone with fluorine substituents, (B) a curable silicone without fluorine substituents, and (D) a curing catalyst, and optionally (C) a silicone crosslinking agent.

[0047] ((A) Cured organosilicon with fluorine substituents)

[0048] Curable silicones with fluorine substituents can impart stable, easy-peel properties to silicone adhesives.

[0049] It should be noted that "organosilicon" refers to a polymer with a backbone of siloxane bonds (≡Si-O-Si≡) formed by silicon and oxygen, and organic groups mainly composed of methyl (-CH3) bonded to the silicon (Si).

[0050] "Cureable silicone" refers to silicone that undergoes a cross-linking reaction and can be cured by heating or light irradiation (ultraviolet light).

[0051] The aforementioned "fluorine substituent" refers to a substituent containing a fluorine atom.

[0052] The substituent containing a fluorine atom (fluorine substituent) is not particularly limited as long as it contains a fluorine atom. Examples include fluorinated groups, trifluoromethyl groups, pentafluoroethyl groups, 2,2-trifluoroethyl groups, 1H,1H-heptafluorobutyl groups, 2H-hexafluoroisopropyl groups, perfluorotert-butyl groups, and perfluorohexyl groups, but it is not limited to these.

[0053] In addition, as a component with fluorine substituents, examples include resins in which fluorine substituents are contained in the side chain portion of the resin backbone.

[0054] Specific examples of cured organosilicones with fluorine substituents include KP-911, X-70-201S, and X-41-3035 manufactured by Shin-Etsu Chemical Industry Co., Ltd.; and FS1265-300CS, FS1265-1000CS, FS1265-10000CS, BY24-900, BY24-903, 3062, Q2-7785, SYL-OFF 7792, and SYL-OFF 7795 manufactured by Dow Corning Toray Co., Ltd. However, these are not the only examples.

[0055] Cured organosilicones with fluorine substituents can be solvent-based, solvent-free, or a mixture thereof.

[0056] Cured organosilicones with fluorine substituents can be used alone or in combination of two or more.

[0057] Here, "solvent-free curable silicone" refers to silicone with a viscosity that can be coated even without solvent dilution, and is a relatively low molecular weight silicone formed from short polysiloxane chains.

[0058] The viscosity of solvent-free curable silicone is preferably 1000 mPa·s or less, more preferably 50 mPa·s or more or 900 mPa·s or 80 mPa·s or more or 800 mPa·s or less. This also applies to (B) curable silicone without fluorine substituents.

[0059] On the other hand, "solvent-cured silicone" refers to silicone with such high viscosity that it cannot be coated without dilution with a solvent, and is formed from silicone with a relatively high molecular weight. This first point also applies to "(B) fluorine-free cured silicone".

[0060] For solvent-curable silicones, the viscosity when prepared as a 30% toluene solution is preferably 1000 mPa·s or higher, more preferably 2000 mPa·s or higher or 20000 mPa·s or lower, or 3000 mPa·s or higher or 18000 mPa·s or lower. Solvent-curable silicones tend to have improved adhesion to substrate films due to their high viscosity. This is also true for (B) fluorine-free curable silicones.

[0061] The fluorine atom content (atomic fraction) of fluorine-substituted curable organosilicon is typically several thousand ppm (less than 1% of the total number of atoms in "fluorine-substituted curable organosilicon") to several hundred thousand ppm (several tens of percent of the total number of atoms in "fluorine-substituted curable organosilicon").

[0062] (B) Cured silicone without fluorine substituents)

[0063] The fluorine-free curable silicone can be solvent-based, solvent-free, or a mixture thereof. From the viewpoint of obtaining stable, light peelability of silicone adhesives, (B) the fluorine-free curable silicone is preferably a solvent-based curable silicone.

[0064] Specific examples of fluorine-free, non-fluorinated, cured silicones include 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, and KS-370 manufactured by Shin-Etsu Chemical Co., Ltd. 3T, KS-3601, KS-830E, X-62-2825, X-62-9201-A, X-62-9201B, KM3951, KM-768, X-52-6015, KF-2 005, X-62-7205, X-62-7028-A, X-62-7028-B, X-62-7052, Corning Toray Co., Ltd. manufactures SP7017, SP7015, SP7025, SP7031, LTC1006L, LTC1063L, LTC1036M, LTC1056L, SRX357, SRX211, SRX345, SRX370, LTC300B, LTC310, LTC355A, LTC759, LTC755, LTC750A, LTC752, LTC761, LTC856, and LTC851, etc., but is not limited to these.

[0065] In addition, heavy-release additives can be added to the aforementioned non-fluorinated curable silicones. Examples of such additives include KS-3800 manufactured by Shin-Etsu Chemical Industry Co., Ltd., and SD7292 and BY24-4980 manufactured by Dow Corning Toray Co., Ltd.

[0066] Non-fluorinated curable silicones can be used alone or mixed with two or more types of reactive functional groups and different viscosities.

[0067] By mixing two or more non-fluorinated curable silicones, the curing reaction or the viscosity of the coating solution can be adjusted, further improving wettability and reactivity. Solvent-free silicones can be mixed with each other, solvent-based silicones can be mixed with each other, and solvent-free silicones can be mixed with solvent-based silicones. Especially when increasing film thickness to obtain a release film with lighter peel strength, there is a tendency for the solids concentration of the coating solution forming the cured layer to increase. Therefore, problems such as increased coating viscosity, deterioration of coating appearance, and increased thickness unevenness may occur. Therefore, by mixing solvent-free silicones with solvent-based silicones, the viscosity of the coating solution can be reduced, resulting in a cured layer with a good coating appearance and minimal thickness fluctuation.

[0068] It should be noted that, regarding solvent-cured silicones and solvent-free cured silicones, as described above, the preferred viscosity ranges are also the same as those described above.

[0069] (Ratio of (A) to (B))

[0070] In this release layer composition, the mass ratio of (A) the aforementioned cured organosilicon with fluorine substitution to (B) the aforementioned cured organosilicon without fluorine substitution is preferably 1:50 to 10:1, more preferably 1:20 to 5:1, 1:10 to 2:1, or 1:5 to 1:1.

[0071] It should be noted that, as explained above, in the present invention, "(A) Curable organosilicon with fluorine substituents", from the viewpoint of material availability, a cured organosilicon cured by a hydrosilylation addition reaction is particularly preferred.

[0072] On the other hand, when manufacturing "a release film characterized by the present invention, wherein the concentration of fluorine atoms on the surface of the release layer is higher than the concentration of fluorine atoms inside the release layer in the thickness direction of the release layer", there are no restrictions on the curing method, and curing type silicone such as condensation system or UV curing system can be used.

[0073] ((C) Organosilicon crosslinking agent)

[0074] "Crosslinking agent" refers to a compound that connects polymers together, such as a compound that can connect two or more molecules through chemical covalent bonds.

[0075] Examples of organosilicon crosslinking agents include (C1) organosilicon crosslinking agents without fluorine substituents (also known as "non-fluorinated organosilicon crosslinking agents") and (C2) organosilicon crosslinking agents containing fluorine substituents (also known as "fluorinated organosilicon crosslinking agents").

[0076] From the viewpoint of making the effects of improving the pre-reaction (described later), the fluorine bias, i.e., improving light peelability and residual adhesion more reliable, it is preferable to use a (C1) non-fluorinated silicone crosslinking agent. Furthermore, when using a mixture of both, it is preferable to use a larger amount of (C1).

[0077] ((C1) Organosilicon crosslinking agent without fluorine substituents)

[0078] As a "(C1) non-fluorine substituent organosilicon crosslinking agent", it is preferably as shown in the following general formula (1), having at least 2 in one molecule, preferably more than 3 (usually about 3 to 200), more preferably 3 to 100, wherein particularly 3 to 50 silicon atoms bonded to hydrogen atoms (SiH groups).

[0079] R b H c SiO (4-b-c) / 2 (1)

[0080] In formula (1), R is a monovalent hydrocarbon group with 1 to 10 carbon atoms, either unsubstituted or substituted. Additionally, b is 0.7 to 2.1, particularly 0.8 to 2.0, c is 0.001 to 1.0, and b+c is a positive number satisfying 0.8 to 3.0, particularly 1.0 to 2.5.

[0081] Here, R can be the same group as R in alkenyl-containing organopolysiloxanes, and it is preferable that it does not have aliphatic unsaturated bonds such as alkenyl groups.

[0082] The silicon atom can bond to a hydrogen 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.

[0083] The molecular structure of “(C1) organosilicon crosslinking agent without fluorine substituents” can be linear, cyclic, branched, or three-dimensional network structure.

[0084] Furthermore, the number of silicon atoms (or degree of polymerization) in one molecule is preferably 2 to 1000, more preferably 3 or more or 500 or less, 3 or more or 300 or less, and especially 4 or more or 150 or less.

[0085] Examples of "(C1) fluorine-free organosilicon crosslinking agents" include: tris(dimethylsiloxy)methylsilane, tris(dimethylsiloxy)phenylsilane, 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrocyclopolysiloxane, methylhydrosiloxane / dimethylsiloxane cyclic copolymer, bi-terminated trimethylsiloxy-capped methylhydropolysiloxane, bi-terminated trimethylsiloxy-capped dimethylsiloxane / methylhydrosiloxane copolymer, bi-terminated dimethylsiloxy-capped dimethylpolysiloxane, bi-terminated dimethylsiloxy-capped methylhydropolysiloxane, bi-terminated dimethylsiloxy-capped dimethylsiloxane / methylhydrosiloxane copolymer, bi-terminated trimethylsiloxy-capped methylhydrosiloxane / diphenylsiloxane copolymer, bi-terminated trimethylsiloxy-capped methylhydrosiloxane / diphenylsiloxane / dimethylsiloxane copolymer, (CH3)2HSiO 1 / 2 unit and SiO 4 / 2 The copolymer formed by the unit, (CH3)2HSiO 1 / 2 Unit, SiO 4 / 2 Unit and (C6H5)SiO 3 / 2These examples include copolymers formed from units, and compounds in which some or all of the methyl groups are replaced with other alkyl groups such as ethyl or propyl, or aryl groups such as phenyl. However, they are not limited to these.

[0086] It should be noted that it is preferable to use two or more crosslinking agents in combination.

[0087] The purpose of using them in combination is to facilitate cross-linking reactions.

[0088] The content of “(C1) non-fluorine substituent organosilicon crosslinking agent” (the total amount when multiple types are used) is preferably 0.1 to 50 parts by mass relative to 100 parts by mass of cured organosilicon ((A)+(B)), and more preferably 0.3 or more or 30 or less, or 0.5 or more or 20 or less.

[0089] Furthermore, relative to the total amount of silicon-bonded alkenyl groups in (A) cured organosilicon with fluorine substituents and (B) cured organosilicon without fluorine substituents, the molar ratio of silicon-bonded hydrogen atoms (SiH groups) in the organosilicon crosslinking agent is preferably 0.3 to 3.0, more preferably 0.5 or more or 2.5 or less, and particularly 0.8 or more or 2.0 or less.

[0090] Specific examples of "(C1) organosilicon crosslinking agents without fluorine substituents" include 3062A, 3062B, 3062D, and SP 7297 manufactured by Dow CorningToray Co., Ltd.

[0091] ((C2) Organosilicon crosslinking agent containing fluorine substituents)

[0092] On the other hand, as an organosilicon crosslinking agent containing fluorine substituents in (C2), examples of those in formula (1) above, where R has a fluorine group, can be cited.

[0093] As a specific example, we can cite 3062C and Q2-7560 manufactured by Dow Corning Toray Co., Ltd.

[0094] (D) Solidified catalyst)

[0095] "Cure catalyst" is a catalyst used to promote the hydrosilylation addition reaction of alkenyl groups bonded to silicon atoms of cured organosilicon with hydrosilane (SiH) groups of (C) organosilicon crosslinking agents.

[0096] Examples of platinum group metal catalysts that can be used as curing catalysts include platinum black, platinum chloride, platinum chloride acid, reactants of platinum chloride acid with monohydric alcohols, complexes of platinum chloride acid with olefins, platinum diacetate, palladium catalysts, and rhodium catalysts. However, they are not limited to these.

[0097] The content of the curing catalyst in the release layer composition or the release layer, relative to the total amount of curable organosilicon ((A)+(B)), is preferably 0.5 to 500 ppm by mass in metal equivalents, more preferably 5 ppm or more or 500 ppm or less, and 10 ppm or more or 200 ppm or less.

[0098] (E) Reaction control agent)

[0099] In addition to the above-mentioned components, this release layer composition and this release layer may also contain reaction control agents as needed.

[0100] As a reaction control agent for (E), acetylenol, etc., as shown in the following general formula (2) can be used.

[0101] CH≡CC(R2)(OH)R1(2)

[0102] In formula (2), R1 is a linear or branched monovalent hydrocarbon group with 5 to 15 carbon atoms, and R2 is a linear monovalent hydrocarbon group with 1 to 3 carbon atoms.

[0103] In the above formula (2), R1 is preferably a straight-chain or branched monovalent hydrocarbon group with 5 to 15 carbon atoms, more preferably 6 to 14, and especially 8 to 12.

[0104] Specific examples of R1 include alkyl groups such as pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl, as well as alkenyl groups such as pentenyl, hexenyl, and heptenyl. However, it is not limited to these.

[0105] In equation (2) above, when the number of carbon atoms in the monovalent hydrocarbon group of R1 is less than 5, the volatility of the control agent is high, and the control effect sometimes becomes insufficient. On the other hand, when the number of carbon atoms is greater than 15, the effective component per mol of ethynyl alcohol becomes less, and there is a tendency for the control effect to weaken. Therefore, there is a concern that a large amount must be added in order to obtain the desired control effect.

[0106] In formula (2) above, R2 is a linear hydrocarbon group with 1 to 3 carbon atoms and a monovalent valence, preferably 1 to 2. Specific examples of R2 include alkyl groups such as methyl, ethyl, and n-propyl, and alkenyl groups such as vinyl, allyl, and n-propenyl. However, it is not limited to these. The fewer carbon atoms in R2, the better the control effect of the organosilicon composition is achieved; methyl is preferred.

[0107] The reaction control agent can be one type, or two or more types can be used in combination as needed.

[0108] The content of the reaction control agent is preferably 0.001 to 5.0 parts by mass relative to the total amount of 100 parts by mass of the release layer composition, more preferably 0.01 parts by mass or more or 1.0 parts by mass, and 0.05 parts by mass or more or 0.5 parts by mass.

[0109] (Other ingredients)

[0110] In addition to the components mentioned above, this release layer composition and release layer may contain other components as needed. Examples include: silicones other than cured silicones, silicone rubber, silicone resins, polyolefin resins, acrylic resins, urethane resins, epoxy resins, alkyd resins, cellulose resins, and copolymers obtained by modifying these resins through graft polymerization, etc.; various particles such as silica particles, alumina particles, silicone rubber particles, silicone resin particles, and silicone rubber / resin composite particles; silane coupling agents, etc. However, these are not limited to these.

[0111] The release layer composition and the release layer itself may contain, as needed, a light release agent, a heavy release agent, a crosslinking agent, or an adhesion improver.

[0112] Specific examples of light-release agents, heavy-release agents, and adhesion improvers include KS-3800 and X-92-185 manufactured by Shin-Etsu Chemical Industry Co., Ltd.; and BY24-850, SD7292, BY24-4980, SP7297, BY24-808, and SD7200 manufactured by Dow Corning Toray Co., Ltd. However, these are not the only examples.

[0113] (Solid composition)

[0114] It should be noted that the concentration of solid components in this release layer composition is preferably 0.1% to 100% by mass, more preferably 0.5% or more or 50% by mass, 1.0% or more or 20% by mass, or 1.5% or more or 10% by mass.

[0115] The solid components of this release layer composition include alkyl vinyl polysiloxane and alkyl hydrogen polysiloxane. The amount of vinyl (alkenyl) alkyl vinyl polysiloxane containing vinyl groups is preferably 85.0 to 99.9% by mass, more preferably 90.0% or more or 99.5% by mass, and 92.0% or more or 99.0% by mass, relative to the mass of the solid components.

[0116] (Thickness of this release layer)

[0117] The thickness of this release layer is not particularly limited. However, a thicker release layer is preferable because it makes it difficult to transfer the influence of the substrate, such as the hardness of the substrate, to the release surface of the release film. A thickness of 0.01 μm or more is preferred, and more preferably 0.05 μm or more or 0.10 μm or more. On the other hand, if the thickness of this release layer is too thick, it may sometimes cause adhesion and deterioration of the coating appearance. Therefore, a thickness of 10 μm or less is preferred, and more preferably 5 μm or less, 1 μm or less, 0.5 μm or less, and particularly preferably 0.25 μm or less.

[0118] <Substrate Film>

[0119] The substrate film can be in thin film form, and its material is not particularly limited. For example, it can be made of paper, resin, metal, etc. Among them, from the viewpoint of mechanical strength and flexibility, resin is preferred.

[0120] Examples of resin-based films include films formed from polymers such as polyethylene, polypropylene, polyester, polystyrene, polycarbonate, polyethersulfone, polyamide, and polyimide. However, these are not the only possibilities. Furthermore, any material capable of being made into a film can be used; it can be a mixture of these materials (polymer blend) or a composite structural unit (polymer).

[0121] Among the films in the above examples, polyester films are particularly preferred due to their excellent heat resistance, planarity, optical properties, strength, and other physical properties.

[0122] The aforementioned polyester film can be a single layer or a multilayer film (laminated film) with two or more layers having different properties.

[0123] Furthermore, the polyester film can be an unstretched film (sheet) or a stretched film. Preferably, it is a stretched film stretched along a uniaxial or biaxial direction. From the viewpoint of balanced mechanical properties and planarity, a biaxially stretched film is more preferred.

[0124] The polyester used as the main component resin of the aforementioned polyester film can be either homopolymer polyester or copolymer polyester.

[0125] It should be noted that the main component resin refers to the resin with the largest mass percentage among the resins constituting this polyester film, which is assumed to account for more than 50% by mass, or more than 75% by mass, or more than 90% by mass, or 100% by mass of the resin constituting this polyester film.

[0126] The homopolymer polyesters described above are preferably formed by the condensation polymerization of aromatic dicarboxylic acids and aliphatic diols. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, while examples of aliphatic diols include ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,4-cyclohexanediethanol. However, they are not limited to these.

[0127] Representative homopolymer polyesters include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).

[0128] On the other hand, when the above-mentioned polyester is a copolyester, it is preferable to be a copolymer containing 30 mol% or less of a third component.

[0129] Examples of dicarboxylic acid components in copolyesters include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, and sebacic acid. Examples of diol components include one or more of ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, and neopentyl glycol. However, these are not limited to these examples.

[0130] Among them, the resin that is the main component of the substrate film is preferably polyethylene terephthalate with 60 mol% or more, preferably 80 mol% or more of polyethylene terephthalate units.

[0131] The substrate film may contain particles primarily for the purpose of imparting slipability and preventing scratches during various processes. When particles are included, the type of particles is not particularly limited as long as they impart slipability. Specific examples include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, alumina, and titanium dioxide, as well as organic particles such as acrylic resins, styrene resins, urea resins, phenolic resins, epoxy resins, and benzoguanamine resins. However, it is not limited to these. Furthermore, precipitated particles obtained by precipitating and micro-dispersing a portion of a metal compound such as a catalyst during the polyester manufacturing process may also be used.

[0132] On the other hand, there are no particular restrictions on the shape of the granules used; they can be spherical, blocky, rod-shaped, flat, or any other shape. Furthermore, there are no particular restrictions on their hardness, specific gravity, or color. Two or more types of these granules can be combined as needed.

[0133] 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, a suitable surface roughness can be provided to the film, ensuring good sliding and smoothness.

[0134] It should be noted that the average particle size of the above-mentioned particles can be determined as follows.

[0135] The average particle size of the raw material particles can be determined by using the average particle size (D50) obtained from the volume reference particle size distribution measured by dynamic light scattering method, etc.

[0136] The average particle size of the particles contained in the substrate film can be determined as follows: Observe the surface or cross-section of the substrate film using an optical microscope or scanning electron microscope (SEM), and measure the diameter of more than 10 particles, taking the average value as the result. In the case of an elliptical cross-section, the average of the longest and shortest diameters can be measured as the diameter of each particle.

[0137] Furthermore, the particle content in the substrate film is preferably in the range of 5% by mass or less, more preferably 0.0003% by mass or more, or 3% by mass or less. In the absence of particles or with few particles, the film has higher transparency and becomes a good film, but the slip properties sometimes become insufficient. Therefore, it is sometimes necessary to improve slip properties by incorporating particles into the coating layer. Conversely, if the particle content is too high, the film's transparency may sometimes be insufficient.

[0138] <Example of the composition of this release film>

[0139] This release film only needs to have the release layer on one or both sides of the substrate film. Therefore, as described later, the substrate film and the release layer can be directly laminated on one or both sides of the release film, or they can be laminated on one or both sides of the release film with the help of other layers.

[0140] Examples of the aforementioned "other layers" include, for instance: an anchor coating for improving the adhesion between the substrate film and the release layer; a compound for encapsulating the film surface; an oligomer encapsulation layer for preventing oligomer bleeding (plate out); and an antistatic layer with antistatic properties. However, these are not the only options.

[0141] Specific examples of the composition of this release film include: the substrate film / release layer, the substrate film / anchor coating / release layer, the substrate film / antistatic layer / release layer, the substrate film / oligopolymer encapsulation layer / release layer, the antistatic layer / substrate film / antistatic layer / release layer, the oligopolymer encapsulation layer / substrate film / oligopolymer encapsulation layer / release layer, the substrate film / antistatic layer / oligopolymer encapsulation layer / release layer, the release layer / substrate film / release layer, the release layer / anchor coating / substrate film / anchor coating / release layer, the release layer / antistatic layer / substrate film / antistatic layer / release layer, the release layer / oligopolymer encapsulation layer / substrate film / oligopolymer encapsulation layer / release layer, the release layer / oligopolymer encapsulation layer / substrate film / oligopolymer encapsulation layer / release layer, the release layer / oligopolymer encapsulation layer / antistatic layer / substrate film / antistatic layer / oligopolymer encapsulation layer / release layer, etc. However, it is not limited to these.

[0142] (Anchor coating)

[0143] Examples of anchor coatings include those made of polymers such as polyethylene, polypropylene, styrene copolymers, polyester, polyurethane, polyvinyl alcohol, polyethyleneimine, polyacrylate, polymethyl methacrylate, and modifiers thereof. However, they are not limited to these.

[0144] (Oligomer encapsulation layer)

[0145] The aforementioned oligomer encapsulation layer may contain hydrolyzable alkoxysilicates and / or their condensation polymers. Examples of hydrolyzable alkoxysilicates include the structure shown in general formula (3) below (R1 represents a hydrocarbon group having 1 to 10 carbon atoms).

[0146] Si(OR 1 )4 (3)

[0147] In equation (3), R 1 It represents a hydrocarbon group with 1 to 10 carbon atoms.

[0148] The aforementioned oligomer encapsulation layer may further contain inorganic particles. Specific examples of inorganic particles include silica, alumina, kaolin, calcium carbonate, titanium dioxide, and barium salts. However, it is not limited to these.

[0149] In addition, the aforementioned oligomer encapsulation layer may contain defoamers, coatability modifiers, thickeners, organic lubricants, organic polymer particles, antioxidants, ultraviolet absorbers, foaming agents, dyes, etc., but is not limited to these.

[0150] (Antistatic layer)

[0151] From the perspective of imparting antistatic properties, the antistatic layer preferably contains conductive polymers and binder polymers.

[0152] It should be noted that the coating liquid may contain other components without compromising the spirit of the present invention.

[0153] Specifically, the aforementioned conductive polymer preferably contains polythiophene and its derivatives (I) as shown in formula (4).

[0154] Equation (4)

[0155]

[0156] In the above formula (4), R1 and R2 independently represent hydrogen, aliphatic hydrocarbon group with 1 to 12 carbon atoms, alicyclic hydrocarbon group, or aromatic hydrocarbon group, such as methyl, ethyl, propyl, isopropyl, butyl, cyclohexylene, phenyl, etc., but are not limited to these.

[0157] It should be noted that the aforementioned anchor coating, antistatic layer, oligomer encapsulation layer, etc., can be formed using either an online coating method formed simultaneously with the substrate in the form of a thin film, or an offline coating method formed in a process different from the completed substrate film. As a specific example of an online coating method, it may be performed at any stage from the melt extrusion of polyester to biaxial stretching followed by heat setting and rolling. Typically, this involves coating any of the following: an unstretched sheet that is substantially amorphous after melting / quenching; a uniaxially stretched film subsequently stretched along its length (longitudinal direction); or a biaxially stretched film before heat setting.

[0158] <<Method for Manufacturing Release Film>>

[0159] Next, an example of the manufacturing method of this release film will be described.

[0160] Typically, in release films, measures to reduce the amount of fluorinated silicone (fluorinated silicone) are taken, such as reducing the content ratio of fluorinated silicone in the release layer or thinning the release layer. However, the former method compromises the intended easy peelability, while the latter method suffers from problems such as uneven formation of the release layer or reduced stability of the peeling force.

[0161] Furthermore, it is believed that by combining (A) a fluorinated curing silicone (referred to as "fluorinated curing silicone") with (B) a fluorine-free curing silicone (referred to as "non-fluorinated curing silicone"), light peelability can be maintained and the amount of fluorinated silicone used can be reduced.

[0162] However, when a solution containing a mixture of (A) fluorinated curable silicone and (B) non-fluorinated curable silicone was coated onto a film and dried, it was confirmed that the more hydrophobic (A) fluorinated curable silicone tended to segregate at the surface (air interface). On the other hand, the silicone crosslinking agent and catalyst used in combination did not possess the same level of high hydrophobicity as (A) fluorinated curable silicone due to their molecular structure. Therefore, they could not be uniformly dispersed in the film, resulting in problems such as not obtaining a release layer with a good cured state or being unable to mix a large amount of (B) non-fluorinated curable silicone.

[0163] Therefore, in the formation of the release layer in this invention, firstly, a "pretreatment" is performed by mixing (A) a fluorine-substituted curable silicone, (C) a silicone crosslinking agent and (D) a curing catalyst, stirring and / or allowing it to react. Then, (B) a non-fluorine-substituted curable silicone is mixed to prepare a release layer composition. Thus, when using (C1) a non-fluorine-substituted silicone crosslinking agent as the aforementioned (C) silicone crosslinking agent, it can be uniformly dispersed and a (lightly peelable) coating film that is easier to peel off from silicone adhesives can be formed.

[0164] That is, as an example of a preferred manufacturing method for this release film, a method can be described as follows: performing a "pretreatment" by mixing (A) a fluorinated curable silicone, (C) a silicone crosslinking agent and (D) a curing catalyst, followed by stirring and / or standing; then, mixing the pretreated composition obtained in the pretreatment with (B) a non-fluorinated curable silicone to prepare the release layer composition; and coating the release layer composition onto at least one side of the substrate film to manufacture the release film. However, this manufacturing method is not limited to this method.

[0165] In order to carry out the "pretreatment" of mixing (A) fluorinated curing silicone, (C) silicone crosslinking agent and (D) curing catalyst and then stirring and / or letting stand, the crosslinking reaction can be carried out at room temperature in the aforementioned mixture by spacing out a short time (also known as "pre-crosslinking").

[0166] At this point, the aforementioned "stirring and / or settling," i.e., "pretreatment," can be any other means as long as it allows the cross-linking reaction to proceed. The duration is preferably 10 seconds or more, more preferably 1 minute or more, and particularly preferably 3 minutes or more, 5 minutes or more, or 15 minutes or more. There is no particular upper limit to the pretreatment time. From the viewpoint of solvent volatility and workability, it is preferably within 1 week, more preferably within 3 days, and particularly preferably within 1 day.

[0167] It should be noted that if the crosslinking reaction is excessively advanced, it may lead to turbidity or gelation of the liquid, depending on the type of material. Therefore, it is preferable to add (or supplement) a reaction control (inhibitor) (such as an ethynyl alcohol derivative) after a predetermined pre-crosslinking time. The reaction control agent can be added to the non-fluorinated curable silicone (or its mixture) described later.

[0168] As for (C) the organosilicon crosslinking agent, an organosilicon crosslinking agent without fluorine substituents is preferably used, as described above.

[0169] Preferably, the pretreatment composition obtained in the above pretreatment is mixed with (B) non-fluorinated curable organosilicon and then diluted with a solvent as needed to prepare the release layer composition.

[0170] The solvent used for dilution can be either a polar solvent or a non-polar solvent. Furthermore, two or more of the above solvents can be mixed for use.

[0171] Examples of polar solvents include alcohols such as ethanol and isopropanol; esters such as methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, isoamyl 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; N-methyl-2-pyrrolidone; N,N-dimethylformamide; tetrahydrofuran; and acetonitrile. However, these are not the only examples.

[0172] Examples of 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 fluorinated solvents include hydrofluoroethers, m-xylene hexafluoride, and tridecafluorooctane. However, these are not the only examples.

[0173] As a method for coating this release layer composition onto the substrate film, the coating technology described in "Coating Methods" (by Yuji Harasaki, Maki Shoten, 1979) can be used, for example. Examples of coating heads include air blade coaters, blade coaters, bar coaters, doctor blade coaters, pressure coaters, dip coaters, reverse roller coaters, transfer roller coaters, gravure coaters, roller coaters, casting coaters, spray coaters, curtain coaters, calendering coaters, extrusion coaters, etc. However, these are not the only options.

[0174] (Methods for forming other layers)

[0175] As described above, this release film can be formed by coating a release layer composition and curing it after forming an anchor coating, antistatic layer, oligomer encapsulation layer, or other "other layers" on one or both sides of the substrate film as needed.

[0176] In the case of forming "other layers", after forming "other layers" such as anchor coating, antistatic layer, oligomer encapsulation layer, etc. as needed on at least one side of the substrate film rolled out from the roll state, a release layer composition is applied and cured to form a release layer.

[0177] <Properties of this release film>

[0178] This release film may have the following physical properties.

[0179] (Normal peeling force)

[0180] The normal peel strength of this release layer is preferably 75 mN / cm or less, more preferably 60 mN / cm or less, 50 mN / cm or less, and particularly 40 mN / cm or less. The lower the normal peel strength, the less force is required for peeling from the silicone adhesive, which can suppress peeling failures and adhesive layer deformation during the production process. Furthermore, by using a release film with excellent light peel strength, it is possible to prevent the release film from peeling off from the unintended side of the adhesive strip on both sides of the adhesive sheet.

[0181] On the other hand, there is no particular limitation on the lower limit. However, for long-term storage of laminates containing release films and adhesives, a value of 1 mN / cm or higher is preferred.

[0182] It should be noted that the normal peel strength can be measured as follows: the adhesive tape "polyimide tape No. 5413 (manufactured by 3M) with silicone adhesive" is bonded together with a width of 5cm, and the peel strength is measured at room temperature (23°C) using a peel tester under the conditions of 180° peel and 0.3m / min.

[0183] (Heated peeling force)

[0184] The heat-peeling force of this release layer is preferably below 100 mN / cm, more preferably below 80 mN / cm, and especially below 60 mN / cm.

[0185] It is believed that the heat-induced peel force is correlated with the reactive groups (hydrosilane (Si-H group), etc.) remaining on the surface of the release layer after curing on the film. The results show that the closer the value is to the normal peel force, the less reactive groups remain on the surface.

[0186] It should be noted that the heat-induced peel strength was obtained as follows: After adhering the adhesive tape "Polyimide Tape with Silicone Adhesive No. 5413 (manufactured by 3M)," it was cut into 50mm × 300mm pieces, heat-treated at 100°C for 1 hour in a hot air oven, and then the sample was removed and the peel strength was measured after being left at room temperature for 1 hour. This peel strength can be measured, for example, using the "EZ Graph" manufactured by Shimadzu Corporation, by performing a 180° peel at a tensile speed of 0.3 m / min.

[0187] (Residual Adhesion Rate)

[0188] The residual adhesion rate of this release layer is preferably above 80%, and even more preferably above 90% or above, and above 95%.

[0189] By satisfying the above range, the transfer of the release layer components from the surface to the surface of the bonded object is reduced.

[0190] It should be noted that the residual adhesion rate is an indicator used to confirm the transfer of the release agent. Generally, the adhesive tape is applied to the surface coated with the release agent, and the value is expressed as a ratio obtained by dividing the adhesive force after peeling by the initial adhesive force at room temperature (i.e., 23°C) (JIS Z 0109:2015).

[0191] <<This thin film laminate>>

[0192] As an example of an embodiment of the present invention, the film laminate (referred to as "this film laminate") can be a construct comprising the above-described release film bonded to a "laminated film having a functional layer" by means of an organosilicon adhesive layer.

[0193] <Laminated Thin Film (1)>

[0194] As an example of the aforementioned "laminated film with a functional layer", a laminated film (referred to as "laminated film (1)") has a layer having a cross-linked resin layer, i.e., a structure formed by cross-linking of resin, on at least one side of the substrate film.

[0195] At this time, the aforementioned cross-linked resin layer can be, for example, formed of a cross-linked resin layer composition containing a conductive polymer and a binder polymer, or, as needed, a cross-linking agent or particles.

[0196] (Conductive polymer)

[0197] The aforementioned conductive polymer preferably contains: a composition comprising the above-mentioned polythiophene and polyanion, or a composition comprising the above-mentioned polythiophene derivative and polyanion.

[0198] The aforementioned polyanion refers to an "acidic polymer in a free acid state," preferably a high molecular weight carboxylic acid, or a high molecular weight sulfonic acid, polyvinyl sulfonic acid, etc. Specific examples of high molecular weight carboxylic acids include polyacrylic acid, polymethacrylic acid, and polymaleic acid. Specific examples of high molecular weight sulfonic acids include polystyrene sulfonic acid. Polystyrene sulfonic acid is most preferred in terms of conductivity. It should be noted that it can be in the form of a salt formed by neutralizing a portion of the free acid. It is believed that by using these polyanions during polymerization, the water-insoluble polythiophene compounds can be easily dispersed or aqueousized, and their function as an acid is also that of a dopant for the polythiophene compounds.

[0199] In addition, high molecular weight carboxylic acids and high molecular weight sulfonic acids can also be used in copolymerization with other monomers that can copolymerize, such as acrylates, methacrylates, and styrene. The molecular weight of the high molecular weight carboxylic acids and high molecular weight sulfonic acids used as polyanions is not particularly limited, but in terms of coating stability and conductivity, their mass-average molecular weight is preferably 1,000 to 1,000,000, more preferably 5,000 to 150,000. Within a range that does not impair the characteristics of the present invention, a portion of alkaline salts such as lithium salts and sodium salts, and ammonium salts may be included. In the case of neutralized salts, it is known that polystyrene sulfonic acid and ammonium salts, which function as very strong acids, shift their equilibrium towards the acidic side due to the neutralization equilibrium reaction, and are therefore considered to function as dopants.

[0200] Regarding conductivity, it is preferable that the polyanion exists in a greater excess of the solid content by mass ratio relative to the polythiophene or polythiophene derivative, preferably 1 to 5 parts by mass, more preferably 1 to 3 parts by mass, relative to 1 part by mass of the polythiophene or polythiophene derivative. Examples of compositions comprising the aforementioned polythiophene or polythiophene derivative and polyanion are described, for example, in Japanese Patent Application Publication Nos. 6-295016, 7-292081, 1-313521, 2000-6324, European Patent EP602731, and US Patent No. 5391472, but other methods may also be used. To cite one example, an alkali metal salt of 3,4-dihydroxythiophene-2,5-dicarboxylic acid ester is used as a starting material to obtain 3,4-ethylenedioxythiophene. Then, potassium persulfate, ferric sulfate, and the 3,4-ethylenedioxythiophene obtained above are introduced into an aqueous solution of polystyrene sulfonic acid to allow them to react and obtain a composition in which poly(3,4-ethylenedioxythiophene) and other polythiophenes are complexed with polyanions such as polystyrene sulfonic acid.

[0201] For example, it is also recorded in the latest developments in conductive polymer technology (Toray Research Center Co., Ltd., 1st edition, June 1, 1999).

[0202] (Binder Polymer)

[0203] The binder polymer constituting the crosslinked resin layer composition is defined as a polymer compound with a number-average molecular weight (Mn) of 1000 or more, determined by gel permeation chromatography (GPC) according to the polymer safety evaluation procedure (November 1941, organized by the Chemical Substances Council), and possessing film-forming properties.

[0204] As a binder polymer constituting the crosslinked resin layer composition, it can be either a thermosetting resin or a thermoplastic resin, as long as it is miscible or dispersible 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; fluoropolymers 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; aromatic polyamide resins; polyimide silicones; polyurethanes; polyurea; melamine resins; phenolic resins; polyethers; acrylic resins and their copolymers. One or more of these can be used, or in combination. However, they are not limited to these.

[0205] The aforementioned binder polymers, as raw materials, can be dissolved in organic solvents, or they can be aqueously hydrated by being endowed with functional groups such as hydroxyl, sulfonyl, and carboxyl groups, or dispersed in water by combining them with surfactants. Furthermore, crosslinking agents, polymerization initiators and other curing agents, polymerization accelerators, solvents, viscosity modifiers, etc., can be combined in the binder polymer as needed.

[0206] From the viewpoint of adhesion to the release layer, it is preferable to use one or more of the aforementioned adhesive polymers selected from polyester resins, acrylic resins, polyurethane resins, and vinyl resins.

[0207] The content of the binder polymer in the crosslinked resin layer composition, based on the mass ratio of solid components, is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and even more preferably 10 to 60% by mass. If the content of the binder polymer is within the above range, sufficient strength of the resulting crosslinked resin layer and good adhesion to the release layer can be obtained.

[0208] (Cross-linking agent)

[0209] The crosslinked resin layer composition may include a crosslinking agent as needed.

[0210] Crosslinking agents can improve the aggregation, surface hardness, scratch resistance, solvent resistance, and water resistance of crosslinked resin layers mainly through crosslinking reactions with functional groups contained in other resins and compounds, and through self-crosslinking.

[0211] Any type of crosslinking agent can be used. Suitable examples include: melamine compounds, guanidine compounds, alkylamide compounds, polyamide compounds, glyoxal compounds, carbodiimide compounds, epoxy compounds, oxazoline compounds, aziridine compounds, isocyanate compounds, silane coupling agents, aluminol-based coupling agents, dialdehyde compounds, zirconium aluminate coupling agents, peroxides, thermally or photosensitive vinyl compounds, and photosensitive resins. From the viewpoint of synergistically achieving good adhesion to the release layer, melamine compounds, epoxy compounds, and silane coupling agents are preferred.

[0212] In addition, these crosslinking agents also include polymer-type crosslinking reactive compounds that give other polymer backbones reactive groups. Furthermore, in this invention, one or more of these crosslinking agents may be used in combination.

[0213] The content of the crosslinking agent in the crosslinked resin layer composition, based on the mass ratio of solid components, is preferably 1 to 90% by mass, more preferably 3 to 50% by mass, and even more preferably 5% to 40% by mass. If the ratio of the crosslinking agent is within the above range, sufficient adhesion to the release layer based on the synergistic effect with the adhesive polymer can be obtained.

[0214] (Particles)

[0215] To improve the adhesion and sliding properties of the cross-linked resin layer, the cross-linked resin layer may contain particles.

[0216] There is no particular limitation on the average particle size of the particles. For example, in the case of optical applications, from the viewpoint of film transparency, a particle size of 1.0 μm or less is preferred, more preferably 0.5 μm or less, and even more preferably 0.2 μm or less is preferred. Moreover, from the viewpoint of improving the adhesion and lubrication of the crosslinked resin layer, a particle size of 0.01 μm or more is preferred.

[0217] Specific examples of particles include: inactive inorganic particles such as silica, alumina, calcium carbonate, and titanium dioxide; microparticles obtained from polystyrene resins, polyacrylic resins, and polyethylene resins; or organic particles represented by these cross-linked particles.

[0218] It should be noted that the average particle size of the above-mentioned particles can be determined as follows.

[0219] The average particle size of the raw material particles can be determined by using the average particle size (D50) obtained from the volume reference particle size distribution measured by dynamic light scattering method, etc.

[0220] The average particle size of the particles contained in the cross-linked resin layer can be determined as follows: Using an optical microscope or scanning electron microscope (SEM), observe the surface or cross-section of the cross-linked resin layer and measure the diameter of more than 10 particles. The average value can then be used to calculate the particle size. In the case of an elliptical cross-section, the average of the longest and shortest diameters can be measured as the diameter of each particle.

[0221] (other)

[0222] The cross-linked resin layer may contain surfactants, defoamers, coatability modifiers, release agents, thickeners, organic lubricants, antistatic agents, conductive agents, ultraviolet light absorbers, antioxidants, foaming agents, dyes, pigments, etc., as needed.

[0223] The components in the cross-linked resin layer can be analyzed, for example, by TOF-SIMS, ESCA, or fluorescence X-ray analysis.

[0224] (Method for forming cross-linked resin layer)

[0225] Regarding the method for forming the crosslinked resin layer, the following method can be used: online coating is used to treat the film surface during the stretching process of the polyester film, while offline coating is applied to a temporarily manufactured film outside the system. Since online coating can be used simultaneously with film formation, it is preferable in terms of cost-effective manufacturing and the ability to adjust the thickness of the crosslinked resin layer according to the stretch ratio.

[0226] For online coating, it is not limited to the following, for example, coating can be performed during sequential biaxial stretching, especially before transverse stretching after longitudinal stretching. When a crosslinked resin layer is formed on a polyester film by online coating, coating can be performed simultaneously with film formation, and the crosslinked resin layer can be treated at high temperature, thus producing a film suitable for use as a polyester film.

[0227] When applying a crosslinked resin layer via online coating, it is preferable to apply the coating solution onto a polyester film using an aqueous solution or dispersion of a crosslinked resin layer composition comprising the aforementioned series of compounds. Furthermore, without departing from the spirit of the invention, a small amount of organic solvent may be included in the coating solution for purposes such as improving water dispersibility and film-forming properties. One type of organic solvent or a combination of two or more may be used.

[0228] The content of organic solvent in the coating solution is preferably 10% by mass or less, more preferably 5% by mass or less. Specific examples of organic solvents include aliphatic or alicyclic alcohols such as n-butanol, n-propanol, isopropanol, ethanol, and methanol; diols such as propylene glycol, ethylene glycol, and diethylene glycol; diol derivatives such as n-butyl cellosolve, ethyl cellosolve, and methyl cellosolve; 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.

[0229] In addition, whether coating is done offline or online, heat treatment and active energy radiation such as ultraviolet irradiation can be combined as needed.

[0230] Methods for forming the crosslinked resin layer include conventionally known coating methods 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, impregnated coating, kiss coating, spray coating, calendar coating, and extrusion coating.

[0231] (Thickness of the cross-linked resin layer)

[0232] When considered as the final coating, from the viewpoint of embodying various functions, the thickness of the crosslinked resin layer is preferably 0.01 μm to 3 μm, more preferably 0.02 μm or more or 1 μm or less, and 0.03 μm or more or 0.3 μm or less.

[0233] It should be noted that the coating amount of the coating liquid containing the crosslinked resin layer composition is typically 0.01–3 g / m². 2 Preferred concentration: 0.01–1 g / m 2 Further optimization is needed for a concentration of 0.01–0.3 g / m³. 2 If it is 0.01g / m 2The above results in sufficient performance in terms of adhesion (easy bonding) and antistatic properties of the release layer, if it is 3g / m 2 The cross-linked resin layer has good appearance and transparency, so there is no concern about film adhesion or reduced productivity due to decreased linear speed.

[0234] In this invention, the coating amount can be calculated from the liquid mass per unit time of coating (before drying), the concentration of non-volatile components in the coating liquid, the coating width, the stretch ratio, the linear velocity, etc.

[0235] <Laminated film (2)>

[0236] As an example of the aforementioned "laminated film with functional layers", a release film (referred to as "laminated film (2)") having "other release layers" on one side of the substrate film can be cited.

[0237] As an example of the aforementioned "other release layers", one can be an example of a structure having a first layer and a second layer in sequence, wherein the first layer is formed of an organosilicon composition containing (B) a curable organosilicon without fluorine substituents as the main component, and the second layer contains a component having fluorine substituents.

[0238] As another example of the aforementioned "other release layers", a layer formed from an organosilicon composition containing (A) a fluorine-substituent organosilicon as the main component can be cited.

[0239] As another example of the aforementioned "other release layers", a layer formed from an organosilicon composition containing (B) a fluorine-free substituent as the main component can be cited.

[0240] The aforementioned "principal component" refers to the component with the largest mass ratio among the constituent components.

[0241] <Applications of this thin film laminate>

[0242] From the viewpoint that a durable and transparent silicone adhesive can be used, this film laminate is preferably used for bonding automotive components.

[0243] <Instructions for use of this release film and its laminate>

[0244] This release film exhibits excellent release properties against silicone adhesives; therefore, it can be used as a light-release film for silicone adhesives as follows.

[0245] That is, in a film laminate comprising a release film (referred to as a "light release film") laminated on one side of an organosilicon adhesive layer formed of organosilicon adhesive, and a release film (referred to as a "heavy release film") with a peel strength higher than that of the aforementioned release film laminated on the other side of the organosilicon adhesive layer, after peeling off the aforementioned light release film, the exposed surface of the organosilicon adhesive layer is attached to the "adhesive," and after the organosilicon adhesive layer is cured, the aforementioned heavy release film can be peeled off and used. However, the method of use is not limited to the above.

[0246] Examples of materials that can be adhered to include various types of craft paper, backing paper, and optical components.

[0247] Examples of such optical components include polarizing plates or touch sensors.

[0248] In addition, the inherent heat resistance, cold resistance, weather resistance, and high transparency of silicone adhesives can also be used in automotive applications such as touch panels.

[0249] (Silicone adhesive)

[0250] The aforementioned silicone adhesives are any adhesives whose main component is silicone resin.

[0251] The term "main component resin" refers to the resin that constitutes the adhesive and has the highest proportion (by mass) of it.

[0252] Examples of the aforementioned silicone adhesives include addition-reactive, peroxide-curing, and condensation-reactive silicone adhesives. From the viewpoint of curing at low temperatures for a short time, addition-reactive silicone adhesives are preferred. It should be noted that these addition-reactive silicone adhesives cure when an adhesive layer is formed on the support.

[0253] When using an addition-reaction type silicone adhesive as the aforementioned silicone adhesive, the aforementioned silicone adhesive may contain a catalyst such as a platinum catalyst.

[0254] For example, for the aforementioned addition reaction type silicone adhesive, a catalyst such as a platinum catalyst can be added, and the silicone resin solution diluted with a solvent such as toluene as needed can be stirred to make it uniform, and then applied to the support and cured at 100-130°C for 1-5 minutes.

[0255] Additionally, crosslinking agents or additives for controlling adhesion can be added to the aforementioned addition-reactive silicone adhesives as needed, or a primer can be applied to the aforementioned support before forming the aforementioned adhesive layer.

[0256] 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, and LTC-310 (all Dow Corning). Toray Company), KR-3700, KR-3701, X-40-3237-1, X-40-3240, X-40-3291-1, X-40-3229, X-40-3323, X-40-3306, X-40-3270-1 (all manufactured by Shin-Etsu Chemical Industry Co., Ltd.), AS-PSA001, AS-PSA002, AS-PSA003, AS-PSA004, AS-PSA005, AS-PSA012, AS-PSA014, PSA-7465 (all manufactured by Arakawa Chemical Industry Co., Ltd.), TSR1512, TSR1516, TSR1521 (all manufactured by Momentive Performance Materials Inc.), etc., but not limited to these.

[0257] (Polarizing plate)

[0258] The materials and composition of the aforementioned polarizing plates are arbitrary. For example, a polarizing plate made by laminating a TAC (triacetyl cellulose) film as a protective film onto a stretched polyvinyl alcohol film using iodine as the orientation pigment is widely used.

[0259] In addition, polarizing plates can be composed of a hard coating on the surface that has no substantial phase difference, and layers that have functions such as anti-glare, low reflection, and antistatic properties.

[0260] (Touch sensor)

[0261] The aforementioned touch sensor is a component that responds to the contact and grasps the touch point when a user touches an image displayed on the screen with their finger, stylus, or other means. According to sensor technology, examples include electrostatic capacitive type, impedance film type, and surface wave method that utilizes infrared or ultrasonic waves.

[0262] Touch sensors are typically mounted on display devices such as LCD panels and OLED displays.

[0263] In addition, in recent years, there has been a trend towards using substrate films as a substitute for glass substrates, focusing on flexibility.

[0264] Touch sensor films typically have a patterned transparent conductive layer for performing the function of sensing electrodes.

[0265] <Explanation of terms, etc.>

[0266] In JIS, "sheet" is generally defined as a thin, flat product whose thickness is small throughout its length and width. "Film" is generally defined as a thin, flat product with extremely small thickness compared to its length and width, and whose maximum thickness is arbitrarily defined; it is usually supplied in roll form (Japanese Industrial Standard; JIS K6900). However, the boundary between sheet and film is uncertain, and in this invention, there is no need to distinguish between the two terms. Therefore, in this invention, the term "film" also includes "sheet," and vice versa.

[0267] In this invention, when denoted as "X~Y" (X and Y are arbitrary numbers), unless otherwise specified, it includes both the meaning of "X or more and Y or less" and the meaning of "preferably greater than X" or "preferably less than Y".

[0268] In addition, when it is written as "X or above" (where X is any number), unless otherwise specified, it includes the meaning of "preferably greater than X", and when it is written as "Y or below" (where Y is any number), unless otherwise specified, it also includes the meaning of "preferably less than Y".

[0269] Example

[0270] The present invention will now be described in more detail with reference to embodiments. However, the present invention is not limited to the following embodiments.

[0271] <Evaluation Methods>

[0272] (1) Normal peeling force

[0273] The adhesive tape “polyimide tape with silicone adhesive No. 5413 (manufactured by 3M)” was applied to the release surface of the sample film with a width of 5 cm. The normal peel force was measured using a peel tester at room temperature (23°C) under the conditions of 180° peel and 0.3 m / min.

[0274] (2) Heating peel force

[0275] After adhering the adhesive tape "Polyimide tape with silicone adhesive No. 5413 (manufactured by 3M)" to the release surface of the sample film, it was cut into 50mm × 300mm pieces and heat-treated in a hot air oven at 100°C for 1 hour. The sample was then removed, and its peel strength was measured after being left at room temperature (23°C) for 1 hour.

[0276] The peel strength was tested using "EZ Graph" manufactured by Shimadzu Corporation, with a tensile speed of 0.3 m / min and a 180° peel at room temperature (23°C).

[0277] It can be evaluated that the lower the value of the heating peel force, the better the peeling characteristics.

[0278] (3) Residual adhesion rate (evaluation of the transferability of the release layer)

[0279] A strip with silicone adhesive (3M "No. 5413") was adhered to the release surface of the sample film using a 2kg rubber roller, and then cut into 50mm × 250mm lengths as samples for residual adhesion testing. After being heated in an oven to 100°C for 1 hour, the strips were cut into 20mm wide pieces and left to stand at room temperature and humidity for 1 hour. The adhesive strip peeled from the test sample was then pressed onto a cleaned stainless steel plate (60mm × 150mm) using a rubber roller.

[0280] The peel strength was tested using the "EZ Graph" manufactured by Shimadzu Corporation, at a tensile speed of 0.3 m / min and at room temperature (23°C) with a 180° peel.

[0281] Then, the residual adhesion rate (%) is calculated by substituting the peel force of the evaluation film and the peel force of the reference film (the sample obtained by attaching No. 5413 tape to Naflon tape) into the following formula.

[0282] Residual adhesion rate (%) = (Peel force of transferability evaluation film / Peel force of reference film) × 100

[0283] (4) Fluorine atom concentration (atomic %) in the thickness direction of the release layer

[0284] XPS (X-ray photoelectron spectroscopy) uses GC-IB (gas cluster ion beam) to determine 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 under constant sputtering rate (sputtering conditions set).

[0285] At this point, the XPS settings are as follows.

[0286] Device: ULVAC PHI PHI5000 VersaProbe II

[0287] =Analysis Conditions=

[0288] X-ray intensity: AlKα / 15kV·25W

[0289] Measurement range:

[0290] Path energy: 58.70 eV

[0291] Charge correction: 284.6 eV (C1s)

[0292] =Splashing conditions=

[0293] Ar-GCIB

[0294] 10kV, 60 minutes (3-minute intervals, level 20)

[0295] The obtained fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atomic %), horizontal axis: sputtering time (minutes)) is divided equally into nine parts by the total sputtering time. The fluorine atom concentration (atomic %) at each measurement point is determined from the 1st measurement point (sputtering time 0 seconds, surface of the release layer) to the 10th measurement point (substrate, PET film reaching the substrate).

[0296] Then, the ratio (%) of the concentration of fluorine atoms (atomic%) at the second measurement point to the concentration of fluorine atoms (atomic%) at the first measurement point, and the ratio (%) of the average concentration of fluorine atoms (atomic%) at the sixth to tenth measurement points to the concentration of fluorine atoms (atomic%) at the first measurement point were calculated and are shown in Table 1.

[0297] <Example 1>

[0298] Solution a1 is prepared by mixing the following (A) fluorine-substituted curable silicone, the following (C1) silicone crosslinking agent, and the following (D1) curing catalyst 1. After stirring for 1 minute, solution b1 ((B) fluorine-free curable silicone + (D2) curing catalyst 2) is mixed at a mass ratio (solution a1:solution b1) of 1:2 to prepare coating liquid A1 with a solid component concentration of 3.6% by mass.

[0299] Then, the aforementioned coating liquid A1 was applied to one side of the substrate film (PET film manufactured by Mitsubishi Chemical Corporation (“T100-38”, thickness 38μm)) using Rod No.4, and heat-treated at 150°C for 15 seconds to cure it, thereby obtaining a release film (sample film) with a release layer.

[0300] (Mold release layer composition)

[0301] Solution a1:

[0302] (A) Cured organosilicon with fluorine substituents

[0303] (Dow Corning Toray Co., Ltd. "3062", 10% by mass, viscosity 10 mm) 2 100 parts by weight

[0304] (C1) Organosilicon crosslinking agent without fluorine substituents

[0305] (Dow Corning Toray Co., Ltd. "3062A") 0.50 parts by weight

[0306] (D1) Platinum catalyst 1

[0307] (Dow Corning Toray Co., Ltd. "FS XK-3077") 0.50 parts by weight

[0308] Diisopropyl ether / ethyl acetate (3:7)

[0309] Solution b1:

[0310] (B) Cured silicone without fluorine substituents

[0311] (Shin-Etsu Chemical Industry Co., Ltd. "KS-847H", solvent-based, 30% by weight, contains crosslinking agent / reaction control agent, viscosity 11000 mPa·s (25°C)) 67 parts by weight

[0312] (D2) Platinum catalyst 2 (Shin-Etsu Chemical Co., Ltd. "CAT-PL-50T") 0.67 parts by weight, diisopropyl ether / ethyl acetate (3:7)

[0313] <Example 2> to <Example 5>

[0314] In Example 1, solution a1 was prepared and stirred for 1 minute, and then allowed to stand for an additional time as shown in the table. Otherwise, the same process as in Example 1 was used to prepare the release film (sample film).

[0315] <Example 6>

[0316] In Example 1, solution a1 was prepared with a solid component concentration of 10% by mass, stirred for 1 minute, and then allowed to stand for 15 minutes. After that, it was diluted with solvent to a solid component concentration of 3.6% by mass. Otherwise, it was prepared in the same manner as in Example 1 to obtain a release film (sample film).

[0317] <Comparative Example 1>

[0318] In Example 1, no stirring was performed at all; otherwise, the release film (sample film) was prepared in the same manner as in Example 1.

[0319] It should be noted that "without stirring at all" means: "After mixing (C1) organosilicon crosslinking agent and (D1) curing catalyst 1 to prepare solution a1, solution b1 is immediately mixed without stirring to prepare coating liquid A1."

[0320] <Comparative Example 2>

[0321] In Example 1, the curable silicone without fluorine substituent (B) and curing catalyst 2 (D2) were not mixed. Otherwise, a release film (sample film) was prepared in the same manner as in Example 1.

[0322] <Comparative Example 3>

[0323] In Example 2, 0.5 parts by weight of a crosslinking agent (C2) with fluorine substituents (Dow Corning Toray Co., Ltd. "3062C") was mixed in place of the organosilicon crosslinking agent (C1) without fluorine substituents. Otherwise, a release film (sample film) was prepared in the same manner as in Example 2.

[0324] <Comparative Example 4>

[0325] In Comparative Example 2, 0.5 parts by mass of a crosslinking agent (C2) having fluorine substituents (Dow Corning Toray Co., Ltd. "3062C") was mixed in place of the organosilicon crosslinking agent (C1) without fluorine substituents. Otherwise, a release film (sample film) was prepared in the same manner as in Example 1.

[0326] <Comparative Example 5>

[0327] For TPR6600 (manufactured by Momentive) as a fluorine-free curable silicone (containing a fluorine-free crosslinking agent): 100 parts by weight, and LC600 (manufactured by Momentive) as a curing catalyst: 3 parts by weight, are mixed to form solution b2.

[0328] For BY24-900 (manufactured by Dow Corning Toray Co., Ltd.) as a fluorine-substituted curable organosilicon (including crosslinking agent): 100 parts by weight, and NC-25 (manufactured by Dow Corning Toray Co., Ltd.) as a curing catalyst: 0.5 parts by weight, are mixed to form solution a2.

[0329] For a solution a2:100 parts by mass containing the aforementioned fluorine-substituted curable organosilicon, a solution b2:100 parts by mass containing the aforementioned non-fluorine-substituted curable organosilicon is mixed and added. A solvent containing n-heptane and methyl isobutyl ketone in a 1:1 weight ratio is added to dissolve the polymer components, thereby preparing a coating liquid A2 with a solid component concentration of 3.0% by mass.

[0330] It should be noted that solution a2 and solution b2 are not stirred at all before mixing.

[0331] Here, "without stirring at all" means: "After preparing solution a2, solution b2 is immediately mixed without stirring to prepare coating liquid A2."

[0332] Then, the aforementioned coating liquid A2 was applied to one side of the substrate film (PET film manufactured by Mitsubishi Chemical Corporation (“T100-38”, thickness 38μm)) using a No.10 rod, and heat-treated at 120°C for 120 seconds to cure it, thereby obtaining a release film (sample film) with a release layer.

[0333] <Comparative Example 6>

[0334] For BY24-900 (manufactured by Dow Corning Toray Co., Ltd.) as a fluorine-substituted curable organosilicon (including crosslinking agent): 100 parts by weight, and NC-25 (manufactured by Dow Corning Toray Co., Ltd.) as a curing catalyst: 0.5 parts by weight, are mixed to form solution a2.

[0335] Add a solvent containing n-heptane and methyl isobutyl ketone in a 1:1 weight ratio to the aforementioned solution a2 to dissolve the polymer components and prepare a coating solution A3 with a solid component concentration of 3.6% by mass.

[0336] Then, the aforementioned coating liquid A3 was applied to one side of the substrate film (PET film manufactured by Mitsubishi Chemical Corporation (“T100-38”, thickness 38μm)) using Rod No.4, and heat-treated at 120°C for 120 seconds to cure it, thereby obtaining a release film (sample film) with a release layer.

[0337] [Table 1]

[0338]

[0339] [Table 2]

[0340]

[0341] <Inspection>

[0342] As can be seen from the above embodiments and the test results conducted by the inventors to date, when the release layer formed on at least one side of the substrate film is a release layer composition comprising (A) a curable silicone with fluorine substituents, (B) a curable silicone without fluorine substituents and (D) a curing catalyst, it has excellent easy peelability, which allows for easy peeling of the silicone adhesive layer even with a reduced amount of fluorinated silicone.

[0343] Moreover, if we investigate the commonalities of such release layers, we can find the following characteristics: in the thickness direction of the release layer, the concentration distribution of fluorine atoms is biased towards the surface of the release layer.

[0344] More specifically, the following characteristics can be observed: In the fluorine atom concentration distribution (vertical axis: fluorine atom concentration (atomic %), horizontal axis: sputtering time (minutes)) obtained in the above embodiment, when the total sputtering time is equally divided into nine points to determine the first measurement point (sputtering time 0), the second measurement point, ... the tenth measurement point, the fluorine atom concentration (atomic %) in the second to tenth measurement points is less than 80.0% of the fluorine atom concentration (atomic %) in the first measurement point (sputtering time 0).

[0345] Furthermore, it can be seen that if the average fluorine atom concentration (atomic %) in the 6th to 10th measurement points is higher than 2.2% of the fluorine atom concentration (atomic %) in the 1st measurement point (sputtering time 0), then further superior effects can be obtained, namely, excellent light peelability that makes the silicone adhesive layer easy to peel off even with a reduced amount of fluorinated silicone.

[0346] On the other hand, the following can be seen from the above-mentioned method for forming the release layer.

[0347] It has been confirmed that when a solution containing two types of curable silicone, (A) with fluorine-substituted groups and (B) without fluorine-substituted groups, is coated onto a film and dried, the more hydrophobic (A) curable silicone with fluorine-substituted groups tends to segregate towards the surface (air interface) side.

[0348] On the other hand, the organosilicon crosslinking agents and catalysts used in combination do not possess the same level of high hydrophobicity as (A) fluorine-substituted cured organosilicon due to their molecular structure. Therefore, they are not uniformly dispersed in the film, resulting in a release layer with a good cured state, or it is impossible to mix (B) fluorine-free cured organosilicon in large quantities.

[0349] Therefore, in this invention, it is known that: firstly, a "pretreatment" is performed by mixing (A) a fluorinated curable silicone, (C) a silicone crosslinking agent and (D) a curing catalyst, stirring and / or allowing it to stand to react; the pretreated composition obtained in the pretreatment is then mixed with (B) a fluorine-free curable silicone to prepare a release layer composition. As a result, even when using (C1) a fluorine-free silicone crosslinking agent, it can be uniformly dispersed, and a lightly peelable coating film that is easier to peel off from silicone adhesives can be formed.

[0350] The exact mechanism is unclear, but it can be inferred that moderate entanglement (pre-crosslinking) occurs in the mixture over time after its preparation. Simultaneously, it is inferred that (A) fluorinated, cured organosilicones are more prevalent on the surface (air interface) side.

[0351] As a result, it can be inferred that even after coating the film, the fluorine substituents are more concentrated near the surface of the release layer, thus forming a coating with light peeling properties.

[0352] Furthermore, more (B) fluorine-free curable silicone can be mixed in, thus reducing the total amount of fluorine atoms in the film during the formation of the release layer coating, which can effectively improve the release properties.

Claims

1. A method for manufacturing a release film, characterized in that, (A) a fluorinated curable silicone, (C) a fluorine-free silicone crosslinking agent, and (D) a curing catalyst are mixed, stirred, and allowed to stand for at least 3 minutes. Then, the mixture is mixed with (B) a fluorine-free curable silicone to prepare a release layer composition. This release layer composition is then coated onto at least one side of a substrate film. The release film is a release film in which a release layer composition is cured to form a release layer on at least one side of a substrate film. In the thickness direction of the release layer, the concentration of fluorine atoms is concentrated on the surface of the release layer, where the concentration of fluorine atoms is above 40.0 atomic concentration%. XPS, or X-ray photoelectron spectroscopy, uses GC-IB (gas cluster ion beam) to measure the concentration distribution of fluorine atoms along the thickness direction within the release layer at a constant sputtering rate. The obtained fluorine atom concentration distribution is then divided into nine equal parts by the total sputtering time to determine the 1st, 2nd, ... 10th measurement points. The atomic concentration of fluorine in measurement points 2 through 10 is less than 30.0% of the atomic concentration of fluorine in measurement point 1. The average fluorine atomic concentration (in atomic percent) at measurement points 6 through 10 is at least 5.0% of the fluorine atomic concentration (in atomic percent) at measurement point 1. In the fluorine atom concentration distribution, the vertical axis represents the fluorine atom concentration in atomic percent, and the horizontal axis represents the sputtering time in minutes. The sputtering time at the first measurement point is 0. The normal peel force of the release layer is below 40 mN / cm, and the residual adhesion rate is above 95%. The heat-peeling force of the release layer is below 60 mN / cm.

2. The method for manufacturing the release film according to claim 1, wherein, The mass ratio of (A) cured organosilicon with fluorine substituents to (B) cured organosilicon without fluorine substituents is 1:50 to 10:

1.

3. The method for manufacturing the release film according to claim 1 or 2, wherein, (B) Cured organosilicones without fluorine substituents are solvent-cured organosilicones.

4. The method for manufacturing a release film according to claim 1 or 2, wherein, The fluorine atom content in the release layer is above 500 ppm by mass and below 800,000 ppm by mass.

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