Curable silicone composition, release coating agent for silicone pressure sensitive adhesive, release film, and laminate comprising said composition

Abstract

[Problem] To provide a curable silicone composition for use in a release agent with which it is possible to form a release film that has low peel force from a silicone adhesive agent, particularly a silicone adhesive agent having a low storage elastic modulus at low temperature, even when in the form of a thin layer. Additionally, to provide a release film that has low peel force and that yields exceptional smoothness on the surface of an adhesive agent layer after release, a laminate, and a method for manufacturing the laminate. [Solution] Provided are: a curable silicone composition containing (A) a mixture of (A1) a fluoro(poly)ether-modified organopolysiloxane having alkenyl groups and (A2) a fluoroalkyl-group-containingorganopolysiloxane having alkenyl groups, (B) an organohydrogen polysiloxane, (C) an organopolysiloxane that has fluorine-atom-containing organic groups and that does not have any hydrosilylation-reactive groups, (D) a hydrosilylation reaction catalyst, and (E) an organic solvent; and a use for a release film, etc., that comprises a cured product of the curable silicone composition.

Description

[Technical Field]

[0001] The present invention relates to a curable silicone composition, a release coating comprising the composition, in particular a release coating for silicone pressure-sensitive adhesives (pressure-sensitive adhesives) that have a low storage modulus at low temperatures, a release film using the release coating, in particular a release film for silicone pressure-sensitive adhesives, and a laminate comprising the release film, in particular a laminate comprising a release film and a silicone pressure-sensitive adhesive. [Background technology]

[0002] Silicone pressure-sensitive adhesives (pressure-sensitive adhesives) have excellent heat resistance, cold resistance, weather resistance, chemical resistance, and electrical insulation properties, and have therefore been widely used as adhesives for industrial protective tapes, masking tapes, and various medical functional tapes. In recent years, they have also been used in so-called assembly applications, such as bonding optical components for liquid crystal displays (display devices, functional films, lenses, etc.). Because silicone pressure-sensitive adhesives adhere strongly to surfaces coated with silicone rubber or silicone-based materials, they cannot be used with conventional silicone release agents used for acrylic or organic rubber-based pressure-sensitive adhesives. Therefore, various curable silicone release agent compositions have been proposed for forming release films that can easily release silicone pressure-sensitive adhesives. These compositions are coated on flexible substrates such as plastic films as release coating agents to form release films, which are then laminated with silicone pressure-sensitive adhesives to form sheet- or roll-shaped tapes, etc.

[0003] For example, Patent Document 1 proposes a curable coating composition as a release agent for silicone pressure-sensitive adhesives, which comprises an organopolysiloxane having at least 300 silicon atoms and containing 0.5 to 2 mol % of vinyl group-containing siloxane units and 30 mol % of fluoroalkyl group-containing siloxane units, an organohydrogenpolysiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule and compatible with the organopolysiloxane, a hydrosilylation reaction catalyst, and a hydrosilylation reaction inhibitor.

[0004] Furthermore, Patent Document 2 proposes a release agent composition for silicone pressure-sensitive adhesives, which comprises an organopolysiloxane having at least two silicon-bonded alkenyl-containing organic groups per molecule and at least one silicon-bonded fluorine-containing substituent (selected from the group consisting of a plurality of fluoro(poly)ether groups) per molecule, an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms per molecule, and a hydrosilylation reaction catalyst.

[0005] Furthermore, Patent Document 3 proposes a release agent composition for silicone pressure-sensitive adhesives that contains two types of fluoroalkyl-modified polydimethylsiloxanes with different amounts of alkenyl groups to achieve light release, and a release sheet formed by applying this to a substrate.

[0006] Furthermore, Patent Document 4 proposes a silicone composition for forming a differential release agent for a silicone pressure-sensitive adhesive, which comprises an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in one molecule, and at least one fluoroalkyl group and at least one fluoropolyether group as two types of fluorine-containing substituents bonded to silicon atoms, with the fluoropolyether group content being 1 to 99 mol% of the total of the fluoroalkyl groups and the fluoropolyether groups; an organohydrogenpolysiloxane containing at least three hydrogen atoms bonded to silicon atoms in one molecule; and a platinum group metal catalyst. In the examples, compositions were prepared to compare the release performance of compositions containing an organopolysiloxane having at least one fluoroalkyl group and at least one fluoropolyether group as two types of fluorine-containing substituents bonded to silicon atoms, as well as compositions containing an organopolysiloxane having only 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl groups as fluorine-containing substituents and an organopolysiloxane having only fluoropolyether groups as fluorine-containing substituents.

[0007] Patent Document 5 proposes an organosiloxane release control agent that has a fluorine atom-containing organic group and does not contain a hydrosilylation reactive group, a release agent composition containing the same, and a release sheet that includes a cured layer made of the cured product of the same.

[0008] Patent Documents 6 and 7 propose a curable silicone composition characterized by containing, in specific proportions, a fluoro(poly)ether-modified organopolysiloxane having an alkenyl group and a fluoro(poly)ether-containing organic group, and a fluoroalkyl-group-containing organopolysiloxane having an alkenyl group and a fluoroalkyl group having 1 to 12 carbon atoms; a release sheet including a release layer made of the cured product obtained by curing the composition; and a laminate made of structural units in which a silicone pressure-sensitive adhesive layer is laminated on the release layer.

[0009] However, these documents do not describe or suggest anything about combining a specific release control agent with a specific curable silicone composition, and in particular, they do not describe or suggest anything about the significantly more significant effects that would be achieved in technical terms with silicone pressure-sensitive adhesives that have a low storage modulus at low temperatures, or about the industrial significance of such combinations. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2-245031 [Patent Document 2] Japanese Patent Application Publication No. 1-74268 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-60554 [Patent Document 4] Japanese Patent Application Laid-Open No. 2017-165893 [Patent Document 5] Special publication WO2016-006252 [Patent Document 6] Special publication WO2020-138399 [Patent Document 7] Special publication WO2020-138417 Summary of the Invention [Problem to be solved by the invention]

[0011] The inventors have discovered a new technical problem. Specifically, when a release film is peeled off from a release laminate containing a silicone pressure-sensitive adhesive (also known as a "pressure-sensitive adhesive," hereinafter), a lower and more stable peel force is required to improve the efficiency of the peeling process and to prevent the surface of the silicone pressure-sensitive adhesive from becoming rough after peeling. However, in recent years, there has been an increasing demand for silicone-based optically clear pressure-sensitive adhesives (OCAs) for bonding and constructing display devices such as flexible displays and touch panels. For these applications, a pressure-sensitive adhesive layer with sufficient viscoelasticity and a low storage modulus is required, particularly at low temperatures (such as -20°C).

[0012]

[0005] However, when a conventionally known composition is used as a release coating to form a release film and further a laminate, the peel force between the release layer and a silicone pressure-sensitive adhesive layer having a low storage modulus at the low temperatures described above cannot be sufficiently reduced, and even if peeling occurs, problems such as roughness or wrinkles may occur on the surface of the silicone pressure-sensitive adhesive after peeling of the release film, which may impair transparency and visibility and have adverse effects on yield and performance. If a release agent layer that can be peeled while maintaining a sufficiently small peel force and a good, smooth adhesive surface could be realized for a silicone pressure-sensitive adhesive with these new properties, silicone pressure-sensitive adhesives with excellent low-temperature properties could be more effectively utilized industrially.

[0013]

[0006] Specifically, the object of the present invention is to provide a release film that can be peeled off with a low peel force from a silicone pressure-sensitive adhesive adhered to the release layer, even if the release layer is thin, particularly from a silicone pressure-sensitive adhesive having a low storage modulus at low temperatures, and that has a stable release force for silicone pressure-sensitive adhesives, a release agent for such a release film, a curable silicone composition that can be used as a release agent, and a laminate comprising a substrate, a silicone pressure-sensitive adhesive layer, and a release agent layer. Release films generally have a release layer formed by coating a release agent on a flexible substrate such as a plastic film. [Means for solving the problem]

[0014] The present inventors discovered that the above-mentioned problems could be solved by a hydrosilylation-curable silicone composition that uses, in combination with (A) (A1) a mixture of a fluoro(poly)ether-modified organopolysiloxane that has at least two alkenyl groups in one molecule and a fluoro(poly)ether-containing organic group, and (A2) a fluoroalkyl-containing organopolysiloxane that has at least two alkenyl groups in one molecule and a fluoroalkyl group having 1 to 12 carbon atoms, as the fluorine-containing organopolysiloxane, and (C) an organopolysiloxane that has a fluorine atom-containing organic group but does not contain a hydrosilylation-reactive group, and completed the present invention.

[0015] That is, the curable silicone composition of the present invention is characterized by being hydrosilylation-curable and using a mixture of organopolysiloxanes having specific fluorine-containing organic groups and alkenyl groups as the main agent, with the further addition of an organopolysiloxane having a fluorine-containing organic group that does not contribute to the hydrosilylation reaction.Furthermore, the present invention is characterized by a release coating agent, a release film, and a laminate that utilize a release layer obtained by curing the curable silicone composition as a release layer for silicone pressure-sensitive adhesives, particularly silicone pressure-sensitive adhesives with a low storage modulus at low temperatures.

[0016] Specifically, the curable silicone composition of the present invention comprises: (A) A fluorine-containing organopolysiloxane mixture obtained by mixing the following components (A1) and (A2) in a mass ratio of 1 / 99 to 99 / 1: (A1) a fluoro(poly)ether-modified organopolysiloxane having at least two alkenyl groups in one molecule and having a fluoro(poly)ether-containing organic group; (A2) a fluoroalkyl group-containing organopolysiloxane having at least two alkenyl groups and a fluoroalkyl group having 1 to 12 carbon atoms in one molecule; (B) an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms in each molecule; (C) an organopolysiloxane having a fluorine atom-containing organic group and not containing a hydrosilylation reactive group; (D) a catalyst for a hydrosilylation reaction, and (E) Organic solvent It includes:

[0017] Furthermore, the above-mentioned problems can be solved by a release coating agent, a release film, and a laminate that utilize a release layer obtained by curing the curable silicone composition as a release layer for a silicone pressure-sensitive adhesive having a storage modulus of 5 MPa or less at -20°C. [Effects of the Invention]

[0018] By using the curable silicone composition of the present invention as a release coating agent, it is possible to form a release film that can peel a silicone pressure-sensitive adhesive adhered to the release layer, particularly a silicone pressure-sensitive adhesive with a low storage modulus at low temperatures, from the release layer with a low peel force, even if the release layer is thin. Furthermore, the release film and laminate of the present invention can stably peel a silicone pressure-sensitive adhesive arranged on the release layer (including both a pressure-sensitive adhesive formed by a curing reaction on the release layer and a release layer attached to an already formed pressure-sensitive adhesive) from the release layer with a low peel force, and can maintain a uniform adhesive surface with little roughness or wrinkles after peeling, making them suitable for use as components for display devices and electronic materials that require a uniform adhesive surface.

[0019] In particular, by utilizing a release layer obtained by curing the curable silicone composition of the present invention, it is possible to provide release films and release laminates that exhibit low release force and good release properties for silicone pressure-sensitive adhesives, particularly sheet-type / film-type pressure-sensitive adhesives, that have a storage modulus of 5 MPa or less at -20°C, which have been difficult to handle and produce release laminates from using conventional release agents.This makes it possible to expand the range of industrial uses of silicone pressure-sensitive adhesives that have good viscoelasticity at low temperatures. DETAILED DESCRIPTION OF THE INVENTION

[0020] First, the curable silicone composition of the present invention will be described in detail.

[0021] [Curable Silicone Composition] The curable silicone composition of the present invention comprises: (A) A fluorine-containing organopolysiloxane mixture obtained by mixing the following components (A1) and (A2) in a mass ratio of 1 / 99 to 99 / 1: (A1) a fluoro(poly)ether-modified organopolysiloxane having at least two alkenyl groups in one molecule and having a fluoro(poly)ether-containing organic group; (A2) a fluoroalkyl group-containing organopolysiloxane having at least two alkenyl groups and a fluoroalkyl group having 1 to 12 carbon atoms in one molecule; (B) an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms in each molecule; (C) an organopolysiloxane having a fluorine atom-containing organic group and not containing a hydrosilylation reactive group; (D) a catalyst for a hydrosilylation reaction, and (E) Organic solvent and optionally (F) a hydrosilylation reaction inhibitor and other optional components. These essential components and other components will be described below.

[0022] [Component (A)] The component (A) comprises (A1) a fluoro(poly)ether-modified organopolysiloxane having at least two alkenyl groups in the molecule and having a fluoro(poly)ether-containing organic group, and (A2) a fluoro(poly)ether-modified organopolysiloxane having at least two alkenyl groups in the molecule and having C s F 2s+1This is a fluorine-containing organopolysiloxane mixture obtained by mixing fluoroalkyl group-containing organopolysiloxanes having fluoroalkyl groups represented by the formula -R- (wherein each R is independently a divalent hydrocarbon group, and s is an integer of 1 to 20) in a mass ratio of 1 / 99 to 99 / 1. Component (A) contains components (A1) and (A2) in a mass ratio of 1 / 99 to 99 / 1, preferably components (A1) and (A2) in a mass ratio of 1.5 / 98.5 to 80 / 20, more preferably 2 / 98 to 70 / 30, and particularly preferably 2 / 98 to 45 / 55. When the (A1) component and the (A2) component are used in combination, a release force for a silicone pressure-sensitive adhesive is obtained that is lower than the release force estimated by arithmetic average based on the results when the (A1) component or the (A2) component is used alone. Furthermore, when the (A1) component and the (A2) component are used in combination, the release force between the silicone pressure-sensitive adhesive layer, which has a low storage modulus at low temperatures, and the release layer can be sufficiently reduced, and the surface of the silicone pressure-sensitive adhesive after peeling can be maintained as a uniform adhesive surface with little roughness or wrinkles.

[0023] The molecular structure of components (A1) and (A2) is not limited, and examples include linear, branched, partially branched linear, resinous, and cyclic structures, and are preferably linear or partially branched linear.

[0024] Such component (A1) is preferably a compound represented by the following average composition formula (I): (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (I) (In the formula, R 1are the same or different and each independently represent an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a fluoro(poly)ether-containing organic group having 2 to 30 carbon atoms, provided that at least two R 1 is an alkenyl group, at least one of which is a fluoro(poly)ether-containing organic group, a is a positive number, b is a positive number, c is 0 or a positive number, and d is 0 or a positive number. Preferably, the organopolysiloxane is represented by the formula (I). Furthermore, with respect to a to d in the formula (I), a is 2 or greater, preferably an integer of 2 to 6, b is 1 or greater, preferably an integer of 1 to 5,000, and more preferably an integer of 30 to 3,000, c is 0 or a positive number, and d is 0 or a positive number. If the siloxane polymerization degree is below the lower limit of the above range, it may be difficult to form a release layer when the curable silicone composition obtained using this component is used as a release coating agent. If the siloxane polymerization degree exceeds the upper limit of the above range, the coatability (particularly thin film coatability) of the resulting curable silicone composition may be reduced. Furthermore, in formula (I), R 1 may contain a small amount of hydroxyl groups or alkoxy groups as long as the object of the present invention is not impaired.

[0025] In formula (I), R 1 The alkyl group having 1 to 12 carbon atoms that can be represented by is preferably a methyl group.

[0026] In formula (I), R 1 The alkenyl group having 2 to 12 carbon atoms that can be represented by is preferably a vinyl group or a hexenyl group, and particularly preferably a vinyl group. 1is an alkenyl group, and the content of the alkenyl group, calculated as a vinyl group, is not particularly limited as long as it can be used to form a curable composition, but is preferably 2.0 mass% or less, more preferably 1.0 mass% or less, and even more preferably 0.5 mass% or less. This is because if the alkenyl group content is higher than necessary, when the curable silicone composition of the present invention is used as a release coating agent to form a release layer for a silicone pressure-sensitive adhesive, the peel strength of the release layer from the silicone pressure-sensitive adhesive layer may increase. Note that the content calculated as a vinyl group is calculated by replacing alkenyl groups other than vinyl groups with the mass of an equimolar amount of vinyl groups.

[0027] In formula (I), R 1 Examples of the aryl group having 6 to 12 carbon atoms that can be represented include a phenyl group, a tolyl group, and a xylyl group, with a phenyl group being preferred.

[0028] In formula (I), R 1 Examples of the aralkyl group having 7 to 12 carbon atoms that can be represented include a benzyl group and a phenylethyl group.

[0029] In formula (I), R 1 The fluoro(poly)ether-containing organic group is exemplified by a group represented by the following formula (1): Formula (1): F(CF2O) a1 (CF2CF2O) a2 (CF2CH2O) a3 [CF(CF3)CF2O] a4 [CF(CF3)CH2O] a5 (CF2CF2CF2O) a6 (CF2CF2CH2O) a7 (CF(CF3)) a8 (CF2) a9 (CH2) a10 -O-[CF(CF3)] a11 (CF2) a12 (CH2) a13 - (In the formula, a1 to a13 are integers of 0 or more, provided that at least one of a1 to a9 is an integer of 1 or more. The sum of a1 to a10 is preferably 21 or less, and the sum of a11 to a13 is preferably 6 or less. In addition, (CF2O) a1 (CF2CF2O) a2 (CF2CH2O) a3 [CF(CF3)CF2O] a4 [CF(CF3)CH2O] a5 (CF2CF2CF2O) a6 (CF2CF2CH2O) a7 [CF(CF3)] a8 (CF2) a9 (CH2) a10 Repeating units in (CH(CF3)) a11 (CF2) a12 (CH2) a13 The repeating units in may be bonded randomly.

[0030] R 1 The fluoro(poly)ether-containing organic group is more preferably a group represented by any one of the following formulas (2), (3), and (4). Formula (2): F[CF(CF3)CF2O] b1 [CF(CF3)CH2O] b2 -[CF(CF3)] b3 (CF2) b4 (CH2) b5 - (In the formula, b1 to b5 are each an integer of 0 or more, b1+b2 is an integer of 1 or more, and b3+b4+b5 is an integer of 0 or more. b1+b2 is preferably 21 or less, more preferably 11 or less, and even more preferably 6 or less. b3+b4+b5 is preferably 6 or less. In addition, (CF(CF3)) b3 (CF2) b4 (CH2) b5 The repeating units in may be bonded randomly. Formula (3): F(CF2CF2CF2O) c1 (CF2CF2CH2O) c2-[CF(CF3)] c3 (CF2) c4 (CH2) c5 - (In the formula, c1 to c5 are integers of 0 or more, c1+c2 is an integer of 1 or more, and c3+c4+c5 is an integer of 0 or more. c1+c2 is preferably 21 or less, more preferably 11 or less, and even more preferably 6 or less. c3+c4+c5 is preferably 6 or less. In addition, (CF(CF3)) c3 (CF2) c4 (CH2) c5 The repeating units in may be bonded randomly. Equation (4): F(CF2) d1 (CH2) d2 -O-(CH2) d3 - (In the formula, d1 and d2 are each an integer of 1 or more, and d3 is an integer of 0 or more. d1 is preferably 10 or less, and d2 and d3 are each preferably 6 or less.)

[0031] Particularly preferred examples of the fluoro(poly)ether-containing organic group include the following groups. F[CF(CF3)CF2O] n CF(CF3)CF2O(CH2)3- F[CF(CF3)CF2O] n CF(CF3)CH2O(CH2)3- F[CF(CF3)CF2O] n+1 CF(CF3)(CH2)2- F(CF2) m (CH2)2O(CH2)3- In each of the above formulas, n is preferably 1 to 20, more preferably 1 to 10, and most preferably 1 to 5. Also, m is preferably 1 to 6.

[0032] Furthermore, a small amount of the fluoro(poly)ether-containing organic group described below may be bonded to the silicon atom. F[CF(CF3)CF2O] o CF(CF3)CF2O- F[CF(CF3)CF2O] o CF(CF3)CH2O- F(CF2) p (CH2)2O- In the above formula, o is preferably 1 to 20, more preferably 1 to 10, and most preferably 1 to 5. Also, p is preferably 1 to 6.

[0033] When the organopolysiloxane of formula (I) has two or more fluoro(poly)ether-containing organic groups per molecule, they may be the same or different from one another.

[0034] Specific examples of component (A1) include, but are not limited to, the fluoro(poly)ether group-containing organopolysiloxanes shown below: In the following formula, Me and Vi represent a methyl group and a vinyl group, respectively, and F1a, F1b, F1c, F1d, and F1e represent the groups shown below, respectively. F1a: CF3CF2CF2O-CF(CF3)CH2O(CH2)3- F1b: F[CF(CF3)CF2O]2CF(CF3)CH2O(CH2)3- F1c: F[CF(CF3)CF2O]3CF(CF3)CH2O(CH2)3- F1d: F[CF(CF3)CF2O]5CF(CF3)CH2O(CH2)3- F1e: F[CF(CF3)CF2O]2CF(CF3)CF2O(CH2)3- Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 240 (Me(F1a)SiO 2 / 2 ) 120 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 245 (Me(F1b)SiO2 / 2 ) 120 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 240 (Me(F1b)SiO 2 / 2 ) 120 (MeViSiO 2 / 2 )3 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 240 (Me(F1b)SiO 2 / 2 ) 120 (MeViSiO 2 / 2 )6 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 660 (Me(F1b)SiO 2 / 2 ) 330 (MeViSiO 2 / 2 )6 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 300 (Me(F1c)SiO 2 / 2 ) 100 (MeViSiO 2 / 2 )3 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 240 (Me(F1d)SiO 2 / 2 ) 120 (MeViSiO 2 / 2 )3 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO1 / 2 )2(Me2SiO 2 / 2 ) 245 (Me(Fe)SiO 2 / 2 ) 120 Organopolysiloxane represented by the formula:

[0035] These polysiloxanes can be produced by conventional methods. For example, they can be produced by preparing a dichlorosilane having a fluoro(poly)ether group using the method proposed in JP-B-4-28273, substituting the chlorine atoms of the dichlorosilane with dimethylsiloxy groups to produce a bis(hydridosiloxy)silane having a fluoro(poly)ether group using the method proposed in JP-A-3-197484, and then subjecting this to intramolecular dehydrogenative condensation using the method proposed in JP-A-6-321968 to produce a cyclotrisiloxane substituted with a fluoro(poly)ether group, and then subjecting this to equilibrium polymerization with a vinyl group-containing siloxane using the method disclosed in JP-A-64-74268, or by non-equilibrium polymerization using the method proposed in JP-A-11-246772.

[0036] The alkenyl-functional fluoro(poly)ether-modified organopolysiloxane used as component (A1) of the present invention can also be produced by subjecting a silicon-bonded hydrogen atom-containing polysiloxane to a hydrosilylation reaction with a stoichiometric or less amount of a fluoro(poly)ether group-containing alkenyl ether to introduce fluoro(poly)ether groups, and then subjecting the remaining unreacted silicon-bonded hydrogen atoms to a hydrosilylation reaction with a large excess of acetylene or a terminal diene such as 1,5-hexadiene or 1,3-butadiene. Examples of such polysiloxanes include the following:

[0037] Specific examples of component (A1) produced by this method include, but are not limited to, the fluoro(poly)ether group-containing organopolysiloxanes shown below: In the following formula, Me, Vi, and Hex represent a methyl group, a vinyl group, and an n-hexenyl group, respectively, and F1b, F1f, and F1g represent the groups shown below, respectively.

[0038] F1b: F[CF(CF3)CF2O]2CF(CF3)CH2O(CH2)3- F1f: F[CF(CF3)CF2O]3CF(CF3)CH2O(CH2)3-, and F[CF(CF3)CF2O]4CF(CF3)CH2O(CH2)3-, Contains 1:1 molar ratio F1g: F[CF(CF3)CF2O] 10 CF(CF3)CH2O(CH2)3- Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 200 (Me(F1b)SiO 2 / 2 ) 100 (MeHexSiO 2 / 2 )4 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 250 (Me(Ff)SiO 2 / 2 ) 110 (MeHexSiO 2 / 2 )4 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 190 (Me(F1g)SiO 2 / 2 ) 30 (MeHexSiO 2 / 2 )2 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 230 (Me(F1g)SiO 2 / 2 ) 35 (MeHexSiO 2 / 2 )4 Organopolysiloxane represented by the formula:

[0039] The content of fluorine atoms from the fluoro(poly)ether-containing organic group in each molecule is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more. This is because when the fluorine atom content in component (A1) is 30% by mass or more, the release coating obtained by crosslinking the curable silicone composition exhibits good release strength from silicone pressure-sensitive adhesives. There are no particular restrictions on the upper limit of the fluorine atom content in component (A1), but if it is too high, the solubility of component (A1) itself in solvents will decrease, reducing handling and workability, so it is preferably at most 60% by mass, and at most 55% by mass.

[0040] Component (A1) can be a single fluoro(poly)ether group-containing organopolysiloxane, or a mixture of two or more fluoro(poly)ether group-containing organopolysiloxanes with different average compositional formulas. In this case, the two or more fluoro(poly)ether group-containing organopolysiloxanes may or may not be compatible with each other at 25°C when mixed without a solvent.

[0041] The component (A2) may also be a compound having the average composition formula (II): (R 2 3SiO 1 / 2 ) w (R 2 2SiO 2 / 2 ) x (R 2 SiO 3 / 2 ) y (SiO 4 / 2 ) z (II) (In the formula, R 2 are the same or different and are an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or a fluoroalkyl group having 1 to 12 carbon atoms, and at least two R 2 is an alkenyl group, and at least one R 2is a fluoroalkyl group having 1 to 12 carbon atoms, w is a positive number, x is a positive number, y is 0 or a positive number, and z is 0 or a positive number. Examples of organopolysiloxanes include those represented by the following formula:

[0042] With respect to w to z in formula (II), w is 2 or greater, preferably an integer of 2 to 6, x is 1 or greater, preferably an integer of 1 to 5,000, and more preferably an integer of 30 to 4,000, y is 0 or a positive number, and z is 0 or a positive number. If the degree of siloxane polymerization is below the lower limit of the above range, it may be difficult to form a release layer when the curable silicone composition obtained using these components is used as a release coating agent. If the degree of siloxane polymerization exceeds the upper limit of the above range, the coatability (particularly thin film coatability) of the resulting curable silicone composition may be reduced.

[0043] R 2 The alkyl group, alkenyl group, aryl group, and aralkyl group of R 1 Examples of the groups include the same groups as those mentioned above.

[0044] R 2 The fluoroalkyl group having 1 to 12 carbon atoms is preferably C s F 2s+1 It is a fluoroalkyl group represented by the formula -R- (wherein each R is independently a divalent hydrocarbon group and s is an integer of 1 to 20), and it is particularly preferred that s is an integer of 2 to 6 and R is an alkylene group having 2 to 6 carbon atoms. From the standpoint of the technical effects of the present invention, it is preferred that at least some of the fluoroalkyl groups in component (A2) are fluoroalkyl groups represented by C4F9-CH2CH2-, i.e., 3,3,4,4,5,5,6,6,6-nonafluorohexyl groups, and it is particularly preferred that all of the fluoroalkyl groups in component (A2) are fluoroalkyl groups represented by C4F9-CH2CH2-.

[0045] Examples of such component (A2) include the following organopolysiloxanes: In the following formula, Me, Vi, Hex, and F2a represent a methyl group, a vinyl group, an n-hexenyl group, and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, respectively. Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 750 (Me(F2a)SiO 2 / 2 ) 750 (MeViSiO 2 / 2 ) 20 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 440 (Me(F2a)SiO 2 / 2 ) 330 (MeViSiO 2 / 2 ) 10 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 440 (Me(F2a)SiO 2 / 2 ) 330 (MeHexSiO 2 / 2 ) 10 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 1450 (Me(F2a)SiO 2 / 2 ) 1100 (MeViSiO 2 / 2 )8 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 1450 (Me(F2a)SiO 2 / 2 )1100 (MeViSiO 2 / 2 ) 10 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 1250 (Me(F2a)SiO 2 / 2 ) 1250 (MeViSiO 2 / 2 ) 10 An organopolysiloxane represented by the formula: Average formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 900 (Me(F2a)SiO 2 / 2 ) 450 (MeViSiO 2 / 2 ) 10 Organopolysiloxane represented by the formula: One or a combination of two or more selected from these can be used.

[0046] The content of fluorine atoms from fluoroalkyl-containing organic groups in one molecule is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more. This is because when the fluorine atom content in component (A2) is 30% by mass or more, the release coating obtained by crosslinking the curable silicone composition exhibits good release strength from silicone pressure-sensitive adhesives. There are no particular restrictions on the upper limit of the fluorine atom content in component (A2), but if it is too high, the solubility of component (A2) itself in solvents will decrease, reducing handling and workability, so it is preferably at most 60% by mass, and at most 55% by mass.

[0047] Preferably, components (A1) and (A2) are a combination that is not completely miscible at 25°C when mixed without a solvent. The phrase "not completely miscible at 25°C when mixed without a solvent" means that when a mixture of two or more fluorine-containing organopolysiloxanes is placed in a 1:1 mass ratio in a capped transparent glass vial and thoroughly stirred at 25°C, the mixture becomes cloudy or separates into two phases and does not appear as a homogeneous, transparent liquid when observed visually immediately after and after 24 hours. If the fluorine-containing organopolysiloxane is in a non-liquid state, such as a gum or paste, at 25°C, the mixture must be heated to a temperature at which it becomes liquid, thoroughly stirred, and then cooled to 25°C. Then, when visually observed immediately after and after 24 hours, the mixture becomes cloudy or separates into two phases and does not appear as a homogeneous, transparent liquid.

[0048] Component (A2) can be a single fluoroalkyl group-containing organopolysiloxane, or a mixture of two or more fluoroalkyl group-containing organopolysiloxanes with different average compositional formulas. In this case, the two or more fluoroalkyl group-containing organopolysiloxanes may or may not be compatible with each other at 25°C when mixed without a solvent.

[0049] [(B) Component] Component (B) is an organopolysiloxane having at least three silicon-bonded hydrogen atoms (Si-H) per molecule, and undergoes a hydrosilylation addition reaction with component (A) to cure the composition of the present invention. In particular, component (B) may contain a certain amount of a fluorine-containing organic group selected from a fluoroalkyl group having 1 to 12 carbon atoms and a fluoro(poly)ether-containing organic group, and this is preferred from the viewpoint of the technical effects of the present invention.

[0050] Examples of groups other than hydrogen atoms bonded to silicon atoms in component (B) include alkyl groups having 1 to 12 carbon atoms, aryl groups having 6 to 12 carbon atoms, aralkyl groups having 7 to 12 carbon atoms, fluoroalkyl groups having 1 to 12 carbon atoms, and fluoro(poly)ether-containing organic groups having 2 to 100 carbon atoms. Furthermore, small amounts of hydroxyl groups or alkoxy groups may be bonded to silicon atoms in component (B) as long as the object of the present invention is not impaired.

[0051] The molecular structure of component (B) is not limited, and examples include linear, branched, partially branched linear, resinous, and cyclic structures, with linear or partially branched linear structures being preferred.

[0052] Such component (B) is preferably a compound represented by the following average composition formula (III): (R 3 3SiO 1 / 2 ) aa (R 3 2SiO 2 / 2 ) ab (R 3 SiO 3 / 2 ) ac (SiO 4 / 2 ) ad (III) Examples of organopolysiloxanes include those represented by the following formula:

[0053] In formula (III), R 3 are the same or different and independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a fluoroalkyl group having 1 to 12 carbon atoms, or a fluoro(poly)ether-containing organic group, with the proviso that R 3At least three of the groups are hydrogen atoms. Furthermore, aa is a positive number, ab is a positive number, ac is 0 or a positive number, and ad is 0 or a positive number. However, when aa is 2, the total of aa to ad is preferably within the range of 5 to 200, with the lower limit being 10 or 15, and the upper limit being 150, 120, 100, 80, 70, 60, 50, or 40. This is because, when aa is 2, if the total of aa to ad is equal to or greater than the lower limit of the above range, crosslinking of the composition proceeds sufficiently, whereas if it is equal to or less than the upper limit of the above range, handling and workability of the composition are good.

[0054] R 3 Examples of the alkyl group having 1 to 12 carbon atoms that can be represented include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group, and a methyl group is preferred.

[0055] Also, R 3 Examples of the aryl group having 6 to 12 carbon atoms that can be represented include a phenyl group, a tolyl group, and a xylyl group, with a phenyl group being preferred.

[0056] Also, R 3 Examples of the aralkyl group having 7 to 12 carbon atoms that can be represented include a benzyl group and a phenylethyl group.

[0057] Furthermore, R 3Examples of the fluoroalkyl group having 1 to 12 carbon atoms that can be represented by the formula (I) include a 3,3,3-trifluoropropyl group, a 3,3,4,4,4-pentafluorobutyl group, a 3,3,4,4,5,5,5-heptafluoropentyl group, a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, a 3,3,4,4,5,5,6,6,7,7,7-undecafluoroheptyl group, a 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl group, and a 3,3,4,4,5,5,6,6, An example is a 7,7,8,8,9,9,9-pentadecafluorononyl group, and a group selected from a 3,3,4,4,5,5,5-heptafluoropentyl group, a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, a 3,3,4,4,5,5,6,6,7,7,7-undecafluoroheptyl group, and a 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl group is preferred, with a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group being particularly preferred.

[0058] Also, R 3 The fluoro(poly)ether-containing organic group that can be represented by R 1 The fluoro(poly)ether-containing organic groups exemplified in are preferably used.

[0059] The component (B) of the present invention may have a group selected from a fluoroalkyl group and a fluoro(poly)ether-containing organic group, but it does not have to have one. Even if an organohydrogenpolysiloxane having a fluorine atom-containing group is not used as the component (B), by combining it with the above-mentioned component (A), when the composition of the present invention is used as a coating agent and cured, a release layer with excellent releasability, particularly excellent releasability for silicone pressure-sensitive adhesives, can be obtained. However, from the viewpoint of the technical effect of the present invention, it is particularly preferable that the component (B) has a certain amount of these fluorine atom-containing groups. As the component (B), an organohydrogenpolysiloxane represented by the above average composition formula (III), R 3 However, organopolyhydrogensiloxanes containing a combination of hydrogen atoms, alkyl groups (especially methyl groups), and fluoroalkyl groups and / or fluoro(poly)ether-containing organic groups are particularly preferred.

[0060] When component (B) of the present invention has a group selected from the group consisting of a fluoroalkyl group and a fluoro(poly)ether-containing organic group, the content of fluorine atoms derived from the fluoroalkyl group and / or the fluoro(poly)ether-containing organic group in the molecule is not particularly limited, but is preferably at least 20 mass%, at least 25 mass%, at least 30 mass%, or at least 35 mass%. The upper limit of the fluorine atom content in component (B) is preferably at most 60 mass%, or at most 50 mass%.

[0061] Specific examples of component (B) include, but are not limited to, the organopolysiloxanes shown below. In the following formula, Me, F2a, and F1b represent a methyl group, a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, and a group represented by the following formula: F[CF(CF3)CF2O]2CF(CF3)CH2O-(CH2)3- represents a group represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me(F2aSiO 2 / 2 ) 12 (MeHSiO 2 / 2 ) 27 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 55 (Me(FbSiO 2 / 2 ) 25 (MeHSiO 2 / 2 ) 25 An organopolysiloxane represented by the formula: Average formula: (MeSiO 1 / 2 )2(MeHSiO 2 / 2 ) 50 An organopolysiloxane represented by the formula: Average formula: (MeSiO1 / 2 )2(Me2SiO 2 / 2 ) 30 (MeHSiO 2 / 2 ) 30 An organopolysiloxane represented by the formula: Average formula: (MeHSiO 1 / 2 )2(Me2SiO 2 / 2 ) 30 (MeHSiO 2 / 2 ) 30 Organopolysiloxane represented by the formula: One or a combination of two or more selected from these can be used as component (B).

[0062] The content of component (B) in the curable silicone composition of the present invention is an amount such that the molar ratio of silicon-bonded hydrogen atoms to alkenyl groups in component (A) is within the range of 0.1 to 20 (silicon-bonded hydrogen atoms / alkenyl groups), and is preferably within any combination of upper and lower limits such that the lower limit is 0.5, 0.8, or 1, and the upper limit is 18, 17, 16, 15, 14, 13, or 12. This is because when the content of component (B) is at or above the lower limit of this range, crosslinking of the curable silicone composition proceeds sufficiently, while when the content is below the upper limit of this range, the properties of the resulting release coating can be stabilized.

[0063] [(C) component] Component (C) is an organopolysiloxane that has a fluorine atom-containing organic group in the molecule but does not contain a hydrosilylation reactive group, and is a release control agent component that imparts excellent release properties to the film obtained by curing the silicone release agent composition. By using the above-mentioned components (A) and (C) in combination, the curable silicone composition of the present invention and the release agent layer obtained thereby not only achieve low release properties, but also achieve a sufficiently low release force for silicone pressure-sensitive adhesives for which conventional release agents have not been able to achieve sufficient release properties, particularly for silicone pressure-sensitive adhesives with a low storage modulus at low temperatures, and make it possible to maintain a uniform pressure-sensitive adhesive surface after release.

[0064] The molecular structure of component (C) is not limited, and examples include linear, branched, partially branched linear, resinous, and cyclic structures, with linear or partially branched linear structures being preferred. Such component (C) is preferably a compound represented by the following average composition formula (IV): (R 4 3SiO 1 / 2 ) ba (R 4 2SiO 2 / 2 ) bb (R 4 SiO 3 / 2 ) bc (SiO 4 / 2 ) bd (IV) It is desirable that the organopolysiloxane is represented by the following formula:

[0065] In formula (IV), R 4 are the same or different and independently represent an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a fluoroalkyl group having 1 to 12 carbon atoms, or a fluoro(poly)ether-containing organic group. ba is a positive number, bb is a positive number, bc is 0 or a positive number, and bd is 0 or a positive number. However, when ba is 2, the sum of ba to bd is preferably within a range of 1 to 5,000, and more preferably an integer of 30 to 3,000.

[0066] R 4 The alkyl group having 1 to 12 carbon atoms that can be represented by is preferably a methyl group.

[0067] Also, R 4 The aryl group having 6 to 12 carbon atoms that can be represented by is preferably a phenyl group.

[0068] Also, R 4 Examples of the aralkyl group having 7 to 12 carbon atoms that can be represented include a benzyl group and a phenylethyl group.

[0069] Furthermore, R 4The fluoroalkyl group having 1 to 12 carbon atoms that can be represented by R 2 The fluoroalkyl groups having 1 to 12 carbon atoms exemplified in are preferably used.

[0070] Also, R 4 The fluoro(poly)ether-containing organic group that can be represented by R 1 The fluoro(poly)ether-containing organic groups exemplified in are preferably used.

[0071] The content of fluorine atoms from the fluorine atom-containing organic groups in component (C) is preferably 20 to 40 mass%, more preferably 23 to 35 mass%, and particularly preferably 27 to 34 mass%. On the other hand, if the content of fluorine atom-containing organic groups per molecule is less than the above lower limit or exceeds the above upper limit, excellent releasability may not be obtained.

[0072] The organopolysiloxane is characterized by the content of fluorine atom-containing organic groups and the absence of hydrosilylation reactive groups in the molecule. When the organopolysiloxane contains hydrosilylation reactive groups, particularly in silicone release agent compositions that cure by hydrosilylation reactions, the organopolysiloxane is likely to form covalent bonds with the crosslinking agent or base compound in the silicone cured product that has release properties, and this may prevent the release control agent from achieving excellent release properties.

[0073] The molecular chain terminals of the organopolysiloxane are preferably trimethylsiloxy groups or silanol groups, and it is more preferable that one or more of the molecular chain terminals be trimethylsilyl groups.

[0074] Specific examples of such organopolysiloxanes include methyl(3,3,3-trifluoropropyl)polysiloxanes terminated at both molecular chain ends with trimethylsiloxy groups, methyl(3,3,3-trifluoropropyl)siloxane-dimethylsiloxane copolymers terminated at both molecular chain ends with trimethylsiloxy groups, methyl(3,3,4,4,5,5,6,6,6-nonafluorohexyl)siloxane-dimethylsiloxane copolymers terminated at both molecular chain ends with trimethylsiloxy groups, methyl(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)siloxane-dimethylsiloxane copolymers terminated at both molecular chain ends with trimethylsiloxy groups, and silanols terminated at both molecular chain ends. Examples include methyl(3,3,3-trifluoropropyl)siloxane-dimethylsiloxane copolymers capped with silanol groups at both molecular chain ends, methyl(3,3,4,4,5,5,6,6,6-nonafluorohexyl)siloxane-dimethylsiloxane copolymers capped with silanol groups at both molecular chain ends, methyl(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)siloxane-dimethylsiloxane copolymers capped with silanol groups at both molecular chain ends, and methyl(3,3,4,4,5,5,6,6,6-nonafluorohexyl)siloxane-dimethylsiloxane copolymers in which one molecular chain end is capped with a silanol group and the other end is capped with a trimethylsiloxy group.

[0075] The content of component (C) is in the range of 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of component (A). If the content of component (C) is less than 0.01 part by mass per 100 parts by mass of component (A), the easy release properties of the film (cured release film) obtained upon curing may be significantly reduced against adhesive substances. If the content of component (C) exceeds 20 parts by mass, the strength of the film obtained upon curing may be significantly reduced, making it difficult to obtain the desired release agent composition.

[0076] Furthermore, as the component (C) of the present invention, these organopolysiloxanes can be used alone or in combination of two or more.

[0077] [(D) component] Component (D) is a hydrosilylation catalyst that promotes curing of the curable silicone composition via a hydrosilylation reaction, and examples thereof include platinum catalysts, rhodium catalysts, and palladium catalysts, with platinum catalysts being preferred. Examples of platinum catalysts include platinum fine powder, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, alcohol solutions of chloroplatinic acid, platinum olefin complexes, and platinum alkenylsiloxane complexes.

[0078] The content of component (D) is an amount that promotes the curing of the present curable silicone composition, specifically an amount such that the metal atoms, preferably platinum atoms, in the catalyst are in the range of 0.1 to 1,000 ppm by mass relative to the present curable silicone composition. This is because if the content of component (D) is at or above the lower limit of the above range, the curing of the resulting curable silicone composition will proceed sufficiently, whereas if it is below the upper limit of the above range, the resulting cured product will be less likely to be discolored.

[0079] [(E) component] Component (E) is any organic solvent that can uniformly dissolve the fluorine-containing organopolysiloxane mixture (component (A)) and the entire composition. "Dissolved" here means that the solvent gives a homogeneous, transparent liquid at 25°C that is not turbid in appearance.

[0080] Furthermore, the addition of an organic solvent can reduce the viscosity of the curable silicone composition, improving application workability and wettability to substrates.

[0081] The component (E) is preferably one solvent or a mixed solvent of two or more solvents selected from the group consisting of diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisobutyl ether, di-sec-butyl ether, di-tert-butyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, pentane, m-xylene hexafluoride, methyl heptafluoropropyl ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, and 3-methoxy-1,1,1,2,2,3,4,4,5,5,6,6,6-tridecafluorohexane.

[0082] In addition to the organic solvents described above, other organic solvents may also be used, provided that the appearance of the curable silicone composition can be maintained as transparent and uniform at 25°C from the time the composition is prepared until it is used. Such additional organic solvents are not particularly limited, and examples thereof include aromatic hydrocarbon solvents such as toluene and xylene; aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane, decane, cyclohexane, methylcyclohexane, and isoparaffin; hydrocarbon solvents such as industrial gasoline (rubber volatiles, etc.), petroleum benzine, and solvent naphtha; ketone solvents such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, methyl isobutyl ketone, diisobutyl ketone, acetonylacetone, and cyclohexanone; ester solvents such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, and isobutyl acetate; and esters such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, and 2-butoxyethyl acetate. and solvents having an ether moiety; siloxane-based solvents such as hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tris(trimethylsiloxy)methylsilane, and tetrakis(trimethylsiloxy)silane; fluorine-modified solvents other than the above-mentioned m-xylene hexafluoride, methyl heptafluoropropyl ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, and 3-methoxy-1,1,1,2,2,3,4,4,5,5,6,6,6-tridecafluorohexane, for example, fluorine-modified aromatic hydrocarbon-based solvents such as benzotrifluoride, fluorine-modified ether-based solvents such as perfluoro(2-butyltetrahydrofuran), and fluorine-modified alkylamine-based solvents such as perfluorotributylamine and perfluorotripentylamine; and mixed solvents of two or more selected from these.

[0083] The content of component (E) is the amount necessary to uniformly dissolve the entire curable silicone composition, and is preferably 10,000 parts by mass or less, and more preferably within the range of 20 to 5,000 parts by mass, per 100 parts by mass of component (A).

[0084] [Component (F)] The curable silicone composition may contain (F) a hydrosilylation reaction inhibitor to inhibit the crosslinking reaction. Component (F) may be an alkyne alcohol such as 1-ethynylcyclohexane-1-ol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, or 2-phenyl-3-butyn-2-ol; an enyne compound such as 3-methyl-3-penten-1-yne or 3,5-dimethyl-3-hexen-1-yne; a methyl alkenyl compound such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane or 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane; or a methyl alkenyl compound such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane or 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane. Examples include siloxane oligomers; alkyneoxysilanes such as dimethylbis(3-methyl-1-butyn-3-oxy)silane and methylvinylbis(3-methyl-1-butyn-3-oxy)silane; alkyneoxysilane compounds such as methyltris(1-methyl-1-phenylpropynoxy)silane, dimethylbis(1-methyl-1-phenylpropynoxy)silane, methyltris(1,1-dimethylpropynoxy)silane, and dimethylbis(1,1-dimethylpropynoxy)silane; and other compounds such as benzotriazole, diallyl maleate, diallyl fumarate, and (tris((1,1-dimethyl-2-propynyl)oxy)methylsilane).

[0085] There are no restrictions on the amount of component (F), and in order to provide the present curable silicone composition with a sufficient pot life, when component (F) is used, the amount thereof is preferably within a range from 0.01 to 5 parts by mass, from 0.05 to 5 parts by mass, or from 0.05 to 3 parts by mass per 100 parts by mass of component (A).

[0086] [Other additives] The curable silicone composition may contain additives selected from photopolymerization initiators, antioxidants, reactive diluents, leveling agents, fillers, antistatic agents, antifoaming agents, pigments, and the like, as long as the object of the present invention can be achieved.

[0087] [Application] The curable silicone composition of the present invention is preferably used as a release coating agent, and is suitable for use as a release coating agent for silicone pressure-sensitive adhesives. In particular, it is most suitable for use as a release coating agent for silicone pressure-sensitive adhesives with a low storage modulus at low temperatures. Specifically, it is capable of maintaining low release force and a uniform adhesive layer surface after release for silicone pressure-sensitive adhesives with a storage modulus at -20°C of 5 MPa or less, preferably 2.5 MPa or less, and more preferably 1.0 MPa or less, and therefore greatly expands the industrial applicability of silicone pressure-sensitive adhesive films / sheets, which could not be handled or worked with using conventional release agents.

[0088] The present invention also relates to a release film comprising a substrate, particularly a film-like substrate, and a release layer formed from a cured product obtained by curing the release coating agent of the present invention. Such a release film can be produced, for example, by applying the curable silicone composition of the present invention to the film-like substrate and curing the curable silicone composition. The release film of the present invention is particularly suitable for use with silicone pressure-sensitive adhesives.

[0089] The substrate used for the release film can be a film-like substrate selected from paper, plastic film, glass, metal, etc. When a product having a release layer provided on a substrate is used as a release film, the substrate is preferably a plastic film, more preferably a polyester film. In particular, it is preferable that both the substrate and the release layer are light-transmitting.

[0090] The thickness of the release layer is preferably 2.0 μm or less, 1.0 μm or less, or 0.5 μm or less, more preferably 0.4 μm or less, and even more preferably 0.3 μm or less. Also, it is preferably 0.05 μm or more, more preferably 0.1 μm or more. This is because, if the film thickness is above the lower limit of the above range, the peeling force of the resulting release layer is sufficiently low, while, if it is below the upper limit of the above range, the light transmittance of the release layer is particularly excellent.

[0091] [Laminate] The present invention also relates to a laminate including at least a release layer made of a cured product obtained by curing the curable silicone composition of the present invention and a pressure-sensitive adhesive layer, particularly a silicone pressure-sensitive adhesive layer, disposed opposite the release layer. In this case, the curable silicone composition can also be referred to as a release coating agent. In this case, the term "opposite" means that the release layer and the pressure-sensitive adhesive layer are in direct contact. Therefore, in general, in the present invention, the release layer and the pressure-sensitive adhesive layer are disposed opposite each other. In the following description, the structure of the laminate of the present invention will be described using a silicone pressure-sensitive adhesive as an example of the pressure-sensitive adhesive, but the pressure-sensitive adhesive is not limited to a silicone pressure-sensitive adhesive.

[0092] The laminate of the present invention may have any structure as long as it includes the above-mentioned structure in which the release layer and the silicone pressure-sensitive adhesive layer are disposed facing each other. Specific examples of laminates are described below.

[0093] Examples of the configuration of the laminate of the present invention include the following (a) to (d). These specific configurations are the same as those disclosed by the present applicant in, for example, Patent Document 6 and Patent Document 7, except that the release layer is replaced with a cured layer obtained by curing the curable silicone composition of the present invention, and preferably the silicone pressure-sensitive adhesive layer has a storage modulus at -20°C of 5 MPa or less. (a) a structure consisting of a first substrate / a release layer / a silicone adhesive layer / a second substrate; (b) A structure in which two or more structural units each consisting of a substrate / release layer / silicone adhesive layer are stacked in succession; (c) a structure consisting of a first substrate / a first release layer / a silicone adhesive layer / a second release layer / a second substrate; (d) A structure in which two or more structural units each consisting of a substrate / first release layer / silicone adhesive layer / second release layer are stacked in succession. In the structures (b) and (d), the substrate can be discontinuous or continuous. Generally, when the substrate is discontinuous, the laminate is in the form of a sheet, and when a continuous substrate is used, the laminate is in the form of a roll.

[0094] Such a substrate is preferably in the form of a sheet or film, and is particularly preferably in the form of a film, and the same substrate as that used for the release film can be used. The substrate may be either light-transmitting or light-non-transmitting, and when a plurality of substrates are used, they may be arbitrarily combined depending on the purpose.

[0095] The laminate of the present invention may be in the form of a laminated sheet in which multiple sheet-like members, each consisting of a substrate / release layer / silicone pressure-sensitive adhesive layer, are stacked vertically, or may be in the form of a roll, for example, wound around a suitable cylindrical or tubular core.

[0096] In the laminate of the present invention, when a first release layer is arranged facing one of the two surfaces of a silicone adhesive layer and a second release layer is arranged facing the other surface (e.g., corresponding to structure (c) or (d)), at least one of the first release layer and the second release layer must be a release layer made of a cured product obtained by curing the release coating agent of the present invention, and here, it is preferable that the peel force (F1) when peeling the silicone adhesive from the first release layer is different from the peel force (F2) when peeling the silicone adhesive from the second release layer.

[0097] If the difference in peel strength between F1 and F2 is small, after the operation of peeling one release layer from the silicone adhesive layer (peeling of the first opposing surface), when peeling the other release layer (second opposing surface), the second opposing surface may unintentionally peel partially during peeling of the first opposing surface, destroying the silicone adhesive layer and making it difficult to use it as an adhesive as originally intended. The peel force difference is preferably, for example, 10 gf / inch or more, and more preferably 20 gf / inch or more.

[0098] Methods for realizing the above-mentioned difference in peeling force include selecting a method for forming the opposing surfaces as described below, and using different types of two release layers.

[0099] In the laminate of the present invention, the thickness of the release layer is preferably 2.0 μm, 1.0 μm, or 0.5 μm or less, more preferably 0.4 μm or less, and even more preferably 0.3 μm or less. Also, it is preferably 0.05 μm or more, more preferably 0.1 μm or more. This is because, when the film thickness of the release layer is above the lower limit of the aforementioned range, the peel strength of the release layer from the silicone pressure-sensitive adhesive is sufficiently low, while, when the film thickness is below the upper limit of the aforementioned range, the light transmittance of the release layer is particularly excellent and it is also economical.

[0100] The silicone pressure-sensitive adhesive composition or curable silicone pressure-sensitive adhesive composition that can be used in the laminate of the present invention is not limited to any particular one, and any composition that is suitable for the intended use of the laminate, such as use as a pressure-sensitive adhesive tape, can be used. In particular, silicone pressure-sensitive adhesives that have a low storage modulus at low temperatures are preferably used.

[0101] There are no particular restrictions on the curing mechanism of the curable silicone pressure-sensitive adhesive, and hydrosilylation-curable, peroxide-curable, photocurable, or other types may be used. However, hydrosilylation-curable pressure-sensitive adhesives are preferred because they can be cured at relatively low temperatures, minimizing the thermal impact on the substrate or applied materials, while also being economical in terms of process simplicity.

[0102] Furthermore, it is extremely useful for the release layer of the present invention to be applied to a silicone pressure-sensitive adhesive with a low storage modulus at low temperatures. In assembly applications, particularly OCA applications, high adhesive strength and high flexibility may be required over a wide temperature range, including low temperatures. For this reason, it is preferable to use a silicone pressure-sensitive adhesive that can be designed so that the glass transition temperature of the cured pressure-sensitive adhesive composition is low, for example, below room temperature, and that has a low storage modulus at low temperatures and a sufficiently large elongation at break. For example, a silicone pressure-sensitive adhesive layer having a storage modulus of 5 MPa or less, preferably 2.5 MPa or less, and more preferably 1.0 MPa or less at -20°C, obtained by curing the silicone pressure-sensitive adhesive composition proposed by the applicant in International Publication Nos. 2017 / 188308, 2020 / 32285, and 2020 / 32286, etc., can be particularly suitably used in the present invention. Here, the release layer of the present invention can be applied to silicone adhesives with a high storage modulus at low temperatures, and can maintain a sufficiently reduced peel force against silicone adhesives and a uniform adhesive layer surface after peeling.

[0103] There are no particular limitations on the thickness of the silicone pressure-sensitive adhesive layer of the laminate of the present invention, but it is preferably 0.1 to 300 μm, and more preferably 0.5 to 200 μm.

[0104] Furthermore, in the laminate of the present invention, the silicone pressure-sensitive adhesive layer can be formed on the entire surface that constitutes the layer, or can be formed only on a part of the surface.The form in which the silicone pressure-sensitive adhesive layer is formed only on a part of the surface is not particularly limited, and the silicone pressure-sensitive adhesive can be applied to form, for example, one or more dots, one or more straight or curved lines, concentric circles, or any other arbitrary shape.The release layer can also be formed on the entire surface that constitutes the release layer, or it can be formed to match the shape formed by the silicone pressure-sensitive adhesive formed on the silicone pressure-sensitive adhesive layer.

[0105] [Method of manufacturing laminate] The method for producing the laminate of the present invention is not particularly limited, but some preferred methods will be listed below. First, in producing the laminate of the present invention, the following two methods are exemplified as methods for preparing the opposing surfaces of the silicone adhesive layer and the release layer.

[0106] <Method for preparing the opposing surfaces of the silicone adhesive layer and the release layer (1)> The first method for preparing the opposing surfaces is as follows: a step (1) of applying a release coating agent comprising the curable silicone composition of the present invention to a film-like substrate and curing the coating agent to form a first release film having a first release layer; Step (2) of applying a curable silicone pressure-sensitive adhesive composition to the same film substrate as the film substrate or a second film substrate different from the film substrate and curing the composition to form a silicone pressure-sensitive adhesive layer; and Step (3) of laminating the release layer of the first release film obtained in step (1) above onto the silicone pressure-sensitive adhesive layer obtained in step (2); This preparation method involves bringing an already cured release layer into contact with an already cured silicone pressure-sensitive adhesive layer to form opposing surfaces of the two layers.

[0107] <Method for preparing the opposing surfaces of the silicone adhesive layer and the release layer (2)> The second method for preparing the opposing surfaces is as follows: a step (1) of applying a release coating agent comprising the curable silicone composition of the present invention to a film-like substrate and curing the coating agent to form a first release film having a first release layer; Step (2) of applying a curable silicone pressure-sensitive adhesive composition to the first release film obtained in step (1) and curing the composition to form a silicone pressure-sensitive adhesive layer; and Step (3) of laminating a film-like substrate identical to the film-like substrate or a film-like substrate different from the film-like substrate onto the silicone pressure-sensitive adhesive layer obtained in step (2). This preparation method involves coating a curable silicone adhesive onto an already cured release layer, followed by curing to form opposing surfaces of the two layers. Generally, the second method often results in a larger difference in release force between the silicone pressure-sensitive adhesive and the release agent than the first method.

[0108] The laminate configuration examples (a) to (d) described above can be produced by the same production method as that disclosed by the applicant in the aforementioned Patent Documents 6 and 7. In this case, the release layer can be replaced with a cured layer obtained by curing the curable silicone composition of the present invention, and the silicone pressure-sensitive adhesive layer can preferably have a storage modulus at −20° C. of 5 MPa or less, preferably 2.5 MPa or less, and more preferably 1.0 MPa or less. The opposing surfaces of the silicone pressure-sensitive adhesive and the release agent can be prepared by a method corresponding to the aforementioned opposing surface preparation method (1) or (2), as appropriate. [Example]

[0109] The curable silicone composition and release film of the present invention will be described in detail using examples, but the present invention is not limited to these examples in any way. In the average composition formula shown below, the symbol Me represents a methyl group, and Vi represents a vinyl group. The method for measuring the peel force when peeling the silicone pressure-sensitive adhesive from the release film is as follows.

[0110] Reference Example 1 Preparation of "Hydrosilylation-curable Silicone Pressure-Sensitive Adhesive Composition Solution 1" 36.4 parts by weight of vinyl-functional polydimethylsiloxane (gum-like (plasticity index 152), vinyl content 0.013% by weight), (CH3)3SiO 1 / 2 Units and SiO 4 / 2A homogeneous solution was prepared by thoroughly mixing 84.3 parts by weight of an MQ silicone resin (molecular weight 3300, hydroxyl group content 3.5 mol% (0.8 mass%) xylene solution (solids content 75.5%) consisting of methylsiloxane units and hydroxyl groups, 101.6 parts by weight toluene, 0.807 parts by weight of a dimethylsiloxane-methylhydrogensiloxane copolymer (molecular weight 1600, SiH content 0.73%) terminated at both molecular chain ends with trimethylsiloxy groups, and 0.577 parts by weight of 1-ethynyl-1-cyclohexanol (20% toluene solution) at room temperature. 0.484 parts by weight of a platinum-based hydrosilylation catalyst (containing 0.62 mass% platinum) was then thoroughly mixed with the mixture. The molar ratio of SiH groups in the dimethylsiloxane-methylhydrogensiloxane copolymer, in which both ends of the molecular chain are capped with trimethylsiloxy groups, to the amount of alkenyl groups in the vinyl-functional polydimethylsiloxane (SiH / Vi ratio) was 33.7, and the platinum metal content relative to the solid content was 30 ppm.

[0111] Reference Example 2: Measurement of adhesive strength of "Hydrosilylation-curable silicone adhesive composition solution 1" The "Hydrosilylation-Curable Silicone Pressure-Sensitive Adhesive Composition Solution 1" from the Reference Example was applied to a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., product name: Lumirror® S10, thickness: 50 μm) using an applicator to a thickness of 50 μm after curing. The applied film was then heated at 150°C for 3 minutes to form a silicone pressure-sensitive adhesive layer. After leaving the sample for 1 day, the sample was cut into 20 mm wide pieces, and the adhesive layer surface was attached to a PMMA plate (manufactured by Partec, Acrylite L001, 50 x 120 x 2 mm) using a roller to prepare a test specimen. The adhesive strength of the PMMA plate test specimen was measured using an Orientec RTC-1210 tensile tester at a 180° peel test speed of 300 mm / min in accordance with JIS Z0237 (measured at a 20 mm wide width and converted to gf / inch). The result was 1490 gf / inch.

[0112] Reference Example 3: Measurement of storage modulus of "Hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 1" The "Hydrosilylation-curable Silicone Pressure-Sensitive Adhesive Composition Solution 1" from the above Reference Example was applied to a release liner coated with a fluoro-modified organopolysiloxane release agent using an applicator so that the cured film would have a thickness of 100 μm. The applied layer was then heated to 150°C for 3 minutes to cure, forming a silicone pressure-sensitive adhesive layer. Five or more of these pressure-sensitive adhesive layers were stacked to obtain a film sample with a thickness of 500 μm or more, sandwiched between release liners on both sides. An 8 mm diameter section was cut out from the film and attached to the parallel plate probe of a dynamic viscoelasticity analyzer (Anoton Paar, MCR301). The storage modulus at -20°C was measured, finding a value of 0.52 MPa. The measurement temperature ranged from -70°C to 200°C, with a frequency of 1 Hz and a heating rate of 3°C / min.

[0113] <Method for measuring peel strength> A curable silicone release agent composition was applied to a polyethylene terephthalate (hereinafter abbreviated as PET) film (manufactured by Toray Industries, Inc., product name: Lumirror (registered trademark) S10, thickness 50 μm) using a Mayer bar so that the release agent layer would be 0.2 μm thick after curing, and the mixture was heated at 150°C for 3 minutes to prepare a "release film" with a cured silicone release layer. The "hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 1" from the above Reference Example was applied to the release layer of the "release film" using an applicator so that the film would be 50 μm thick after curing, and the mixture was heated at 150°C for 3 minutes to cure, forming a silicone pressure-sensitive adhesive layer. The PET film was then laminated to the resulting silicone pressure-sensitive adhesive layer using a 2 kg hand roller. The obtained film was cut into 1-inch widths, and the "Release Film 1" was pulled in a 180° direction at a rate of 0.3 m / min using a tensile tester (RTC-1210 manufactured by Orientec Co., Ltd.), and the force (peel force) required to peel the "Release Film" from the silicone adhesive layer at 25°C was measured.

[0114] <Surface condition of silicone pressure-sensitive adhesive layer after release liner removal> After measuring the peel strength, the surface condition of the silicone pressure-sensitive adhesive layer after the release liner was removed was visually observed, and the results were defined as follows: ○: The adhesive surface is uniform and free of roughness or wrinkles ×: Roughness and / or wrinkles occurred on the adhesive surface

[0115] [Examples 1 to 5] and [Comparative Examples 1 to 3] The curable silicone compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were prepared using the ingredients listed below and by uniformly mixing the ingredients according to the ratios shown in Table 1. In the formulas, Me, Vi, Fp, and Pf represent a methyl group, a vinyl group, an F(CF(CF3)CF2O)2(CF(CF3))(CH2)O(CH2)3- group, and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, respectively.

[0116] The following components were used as component (A). (A1) Average composition formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 245 (MeFpSiO 2 / 2 ) 120 The organopolysiloxane has a vinyl group content of 0.06% by mass and a fluorine atom content of 44% by mass. (A2) Average composition formula: (Me2ViSiO 1 / 2 )2(Me2SiO 2 / 2 ) 900 (MePfSiO 2 / 2 ) 450 (MeViSiO 2 / 2 ) 10 and the vinyl group content is 0.16 mass % and the fluorine atom content is 38 mass %.

[0117] The following components were used as component (B): Average formula: (MeSiO 1 / 2 )2(MePfSiO 2 / 2 ) 12 (MeHSiO 2 / 2 ) 27 and having a fluorine atom content of 38 mass % and a silicon-bonded hydrogen atom content of 0.50 mass %.

[0118] The following components were used as component (C). (MeSiO 1 / 2 )2(Me2SiO 2 / 2 ) 900 (MePfSiO 2 / 2 ) 300 and the fluorine atom content is 32 mass %.

[0119] As the component (D), a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex (D) was used (in an amount such that the amount of platinum metal was 270 ppm relative to the amount of solids in the curable composition).

[0120] Diisopropyl ether was used as component (E).

[0121] As component (F), 2-methyl-3-butyn-2-ol was used.

[0122] A curable silicone composition was prepared according to the formulation shown in Table 1 below, and a release film was prepared using this as a release coating agent according to the method described above. The peel force when peeling the release film from the silicone pressure-sensitive adhesive layer was measured. In addition, the surface condition of the silicone pressure-sensitive adhesive layer after peeling the release film was visually observed.

[0123] [Table 1]

[0124] [Reference examples 4~7] As mentioned above, the release layer of the present invention is suitable for use with silicone adhesives that have a low storage modulus at low temperatures, but it can also be applied to silicone adhesives that have a high storage modulus at low temperatures, as shown in Reference Examples 4 to 7.

[0125] Reference Example 4: Preparation of "Hydrosilylation-curable Silicone Pressure-Sensitive Adhesive Composition Solution 2" A homogeneous solution was prepared by thoroughly mixing 100.0 parts by mass of the hydrosilylation-curable adhesive DOWSIL™ 7657 ADHESIVE (solids content 56% by mass) manufactured by The Dow Chemical Company, 0.42 parts by mass of 4000 CATALYST (platinum metal-containing hydrosilylation reaction catalyst) manufactured by the same company, and 33.3 parts by mass of toluene.

[0126] Reference Example 5: Measurement of adhesive strength of "Hydrosilylation-curable silicone adhesive composition solution 2" The adhesive strength was measured in the same manner as in Reference Example 2 above, except that "hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 1" was replaced with "hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 2" and the heat curing conditions were changed from 150°C for 3 minutes to 140°C for 5 minutes. The result was 1450 gf / inch.

[0127] Reference Example 6: Measurement of storage modulus of "Hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 2" In the same manner as in Reference Example 3 above, "hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 1" was changed to "hydrosilylation-curable silicone pressure-sensitive adhesive composition solution 2," and the heat curing conditions were changed from 150°C for 3 minutes to 140°C for 5 minutes. The storage modulus at -20°C was measured and found to be 9.5 MPa.

[0128] <Reference Example 7> The curable silicone composition of Example 3 above was prepared, and this was used as a release coating agent to prepare a release film according to the method described above. The peel force when peeling the release film from the silicone pressure-sensitive adhesive layer was measured. In addition, the surface condition of the silicone pressure-sensitive adhesive layer after peeling the release film was visually observed. As a result, the peel force was 9 gf / inch, and the surface condition of the silicone pressure-sensitive adhesive was uniform and free of roughness or wrinkles, so it was evaluated as "Good".

[0129] [Summary] The curable silicone compositions of Examples 1 to 5 according to the present invention achieved much lower release forces than those of Comparative Examples 1 to 3. Furthermore, after the release liners made of the curable compositions of Examples 1 to 5 were removed, the surface of the silicone pressure-sensitive adhesive layer was uniform, with no roughness or wrinkles observed. In contrast, when component (A) was used alone, or when component (C) was not used, a sufficient reduction in release force could not be achieved for silicone pressure-sensitive adhesives with low storage moduli at low temperatures. In particular, the silicone pressure-sensitive adhesive layer remained non-uniform after removal, raising serious concerns that this could limit the scope of industrial application. (Comparative Examples 1 to 3) As confirmed in Reference Example 7, the curable silicone compositions according to the examples of the present invention are also fully usable for silicone pressure-sensitive adhesives with a storage modulus of more than 5 MPa at low temperatures. [Industrial Applicability]

[0130] As shown in the examples, a release film equipped with a release layer formed using the curable silicone composition of the present invention as a release coating agent for silicone pressure-sensitive adhesives can release silicone pressure-sensitive adhesives, particularly those with a low storage modulus at low temperatures, with little force, and can maintain a uniform surface of the silicone pressure-sensitive adhesive after the release film has been removed, preventing roughness and wrinkles. Therefore, the curable silicone composition of the present invention is useful not only for conventional commercially available silicone pressure-sensitive adhesives, but also as a release coating agent for release films for silicone pressure-sensitive adhesives with a low storage modulus at low temperatures. Furthermore, despite their excellent performance, silicone pressure-sensitive adhesives with a low storage modulus at low temperatures have tended to have limited application because there are few release agents that are compatible with them. However, the availability of the release coating agent of the present invention makes it easy to provide silicone pressure-sensitive adhesive films / sheets with good release properties and low release properties, and it is strongly expected that their industrial application will expand.

Claims

1. (A) A fluorine-containing organopolysiloxane mixture obtained by mixing the following components (A1) and (A2) in a mass ratio of 1 / 99 to 99 / 1: (A1) a fluoro(poly)ether-modified organopolysiloxane having at least two alkenyl groups in one molecule and having a fluoro(poly)ether-containing organic group; (A2) a fluoroalkyl group-containing organopolysiloxane having at least two alkenyl groups and a fluoroalkyl group having 1 to 12 carbon atoms in one molecule; (B) an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms in each molecule; (C) an organopolysiloxane having a fluorine atom-containing organic group and not containing a hydrosilylation reactive group; (D) a hydrosilylation catalyst, and (E) Organic Solvent A release coating agent for silicone pressure-sensitive adhesives, which comprises a curable silicone composition containing the compound (I) and has a storage modulus at -20°C of 1.0 MPa or less.

2. At least a part of the fluoroalkyl groups of the component (A2) is C ｓ F ２ｓ＋１ 2. The release coating agent for silicone pressure-sensitive adhesives according to claim 1, wherein the fluoroalkyl group is represented by the formula -R- (wherein each R is independently a divalent hydrocarbon group, and s is an integer of 1 to 20).

3. 3. The release coating agent for silicone pressure-sensitive adhesives according to claim 1, wherein component (A) is a fluorine-containing organopolysiloxane mixture obtained by mixing components (A1) and (A2) at a mass ratio of 2 / 98 to 45 / 55.

4. The component (C) has a trimethylsilyl group at one or more of its molecular chain terminals, the fluorine atom-containing organic group is one or more groups selected from a fluoroalkyl group having 1 to 12 carbon atoms and a fluoro(poly)ether-containing organic group, 4. The release coating agent for silicone pressure-sensitive adhesives according to claim 1, which is an organopolysiloxane having a fluorine atom content due to fluorine atom-containing organic groups in the molecule in the range of 20 to 40 mass %.

5. 5. The release coating agent for silicone pressure-sensitive adhesives according to claim 1, wherein component (B) is an organohydrogenpolysiloxane further having a fluoroalkyl group having 1 to 12 carbon atoms or a fluoro(poly)ether-containing organic group.

6. 6. A release coating agent for silicone pressure-sensitive adhesives according to any one of claims 1 to 5, comprising, per 100 parts by mass of component (A), 0.1 to 40 parts by mass of component (B), 0.01 to 20 parts by mass of component (C), a quantity of component (D) such that the platinum metal content is 0.1 to 500 ppm, and 20 to 10,000 parts by mass of component (E).

7. a film-like substrate, and A release layer comprising a cured product obtained by curing the release coating agent for silicone pressure-sensitive adhesives according to any one of claims 1 to 6. A release film for silicone pressure sensitive adhesives comprising:

8. A laminate having a structure in which a silicone adhesive having a storage modulus of 1.0 MPa or less at -20°C is arranged opposite at least one release layer, the release layer being a release layer made of a cured product obtained by curing a release coating agent for silicone adhesives described in any one of claims 1 to 6.

9. The laminate according to claim 8, wherein the entire laminate is in at least one shape selected from i) a laminated sheet shape and ii) a roll shape.

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