Peel-off coating composition

Abstract

The curable release coating composition comprises: (A) an aliphatically unsaturated polyorganosiloxane having two or more alkenyl groups per molecule; (B) a crosslinker having two or more silicon-bonded hydrogen atoms per molecule in an amount sufficient to provide a molar ratio of silicon-bonded hydrogen atoms to alkenyl groups in the curable release coating composition of from 0.8:1 to 5:1; (C) a catalytic amount of a hydrosilylation reaction catalyst; and (D) from 0.01% to 5% by weight, based on the weight of the curable release coating composition excluding solvent, if present, of particles of the cured organosiloxane composition, optionally having a silica treated coating, having an average particle size of from 0.5 to 30 micrometers.

Description

[Technical Field]

[0001] The present invention relates to a curable release coating composition, and a release liner prepared by applying the release coating composition to a substrate such as a plastic film or paper, and curing the release coating composition by heat application. [Background technology]

[0002] (Introduction) Silicone release coatings are useful in applications where a relatively non-adhesive surface is required. Single-sided liners, such as backing paper or film for pressure-sensitive adhesive labels, are typically adapted to temporarily hold labels without affecting their adhesiveness. Double-sided liners, such as interleaving paper or film for double-sided tapes and transfer tapes, are used to protect adhesive tapes. These liners are generally manufactured in long sheets and then rolled up for easier transport and storage. Conventional silicone release coating compositions can typically achieve ultra-low release force against adhesives (e.g., <5.0 grams per inch) with a coat weight of >1.0 gram per square meter, but suffer from blocking problems, where adjacent layers often stick together between continuous liner rolls during storage. Incorporating silica particles into silicone release coating compositions can prevent blocking during coating onto substrates, but often results in a cloudy appearance in the resulting release coating, which limits the use of silicone release coatings for tape release, label release, and adhesive transfer film. Many electronic device applications, in particular, require a transparent release coating. The release coating should preferably have antiblocking properties to increase production efficiency and avoid potential coating damage when separating two coated surfaces that are in contact with each other and laminated or arranged during storage, packaging, and / or transport of the resulting release liners wound onto large rolls.

[0003] There remains a need to identify a release coating composition that can provide a release coating with a transparent appearance and antiblocking properties, while maintaining other properties, including subsequent adhesive strength, and having the low release force described above. [Overview of the Initiative]

[0004] The present invention provides a curable release coating composition that can cure into a curable release coating having a transparent appearance and antiblocking properties, and exhibiting low peel strength to adhesives. The release coating composition of the present invention comprises a novel combination of an aliphatic unsaturated polyorganosiloxane, a crosslinking agent, and a hydrosilylation reaction catalyst, a specific amount of particles of the curable organosiloxane composition, and optionally a silica-treated coating. The release coating composition can be coated onto at least one surface of a substrate and cured by a hydrosilylation reaction to prepare a release liner.

[0005] In a first aspect, the present invention relates to a curable peelable coating composition, (A) an aliphatic unsaturated polyorganosiloxane having two or more alkenyl groups per molecule, (B) A crosslinking agent having two or more silicon-bonded hydrogen atoms per molecule in an amount sufficient to result in a molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of 0.8:1 to 5:1 in the curable peelable coating composition, (C) A catalytic amount of hydrosilylation catalyst, (D) Based on the weight of the curable peelable coating composition excluding the solvent (if present), particles of a cured organosiloxane composition having a silica-treated coating of 0.01% to 5% by weight, with an average particle size of 0.5 to 30 micrometers, and optionally having such a coating. This is a curable peelable coating composition containing [the specified ingredient].

[0006] In a second aspect, the present invention relates to a method for preparing a release liner comprising a release coating on at least one surface of a substrate, Depending on the circumstances, this may involve treating at least one surface of the substrate, 1) Applying the curable peelable coating composition of the first embodiment to the surface of the substrate, and optionally, 2) removing the solvent if present. 3) Curing the composition to form a release coating on the surface of the substrate, This method includes [something].

[0007] In a third embodiment, the present invention relates to a release liner comprising a substrate and a release coating present on at least one surface of the substrate, wherein the release coating is formed by curing a curable release coating composition according to the first embodiment. It should be noted that the present invention also includes the following embodiments. [Aspect 1] A curable peelable coating composition, (A) an aliphatic unsaturated polyorganosiloxane having two or more alkenyl groups per molecule, (B) A crosslinking agent having two or more silicon-bonded hydrogen atoms per molecule in an amount sufficient to result in a molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of 0.8:1 to 5:1 in the curable peelable coating composition, (C) A catalytic amount of hydrosilylation catalyst, (D) Based on the weight of the curable peelable coating composition excluding the solvent (if present), particles of a cured organosiloxane composition having a silica-treated coating of 0.01% to 5% by weight, with an average particle size of 0.5 to 30 micrometers, and optionally having such a coating. A curable peelable coating composition containing the following: [Aspect 2] The peel-off coating composition according to embodiment 1, further comprising a hydrosilylation reaction inhibitor, a fixing additive, a solvent, or a mixture thereof. [Aspect 3] The peel-off coating composition according to embodiment 1 or 2, wherein the particles of the cured organosiloxane composition comprise a reaction product of (a) an aliphatic unsaturated polyorganosiloxane containing two or more alkenyl groups per molecule, and (b) a crosslinking agent having two or more silicon-bonded hydrogen atoms per molecule, wherein (a) is selected from dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), dimethylvinylsiloxy-terminated polydimethylsiloxane, trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), dimethylvinylsiloxy-terminated methylsilsesquioxane, vinyl-terminated polydimethylsiloxane, or a mixture thereof. [Aspect 4] A peelable coating composition according to any one of embodiments 1 to 3, comprising 0.1% to 2% by weight of particles of the curable organosiloxane composition, based on the weight of the curable peelable coating composition excluding the solvent (if present). [Aspect 5] The peel-off coating composition according to any one of embodiments 1 to 4, wherein the aliphatic unsaturated polyorganosiloxane is selected from Q-branched polyorganosiloxane, silsesquioxane, linear polyorganosiloxane, or a combination thereof. [Aspect 6] The aforementioned Q-branched polyorganosiloxane has the unit formula (AI): (R 1 3 SiO 1 / 2 ) a (R 2 R 1 2 SiO 1 / 2 ) b(R 1 2 SiO 2 / 2 ) c (R 2 R 1 SiO 2 / 2 ) c’ (SiO 4 / 2 ) d (AI) It has, in the formula, each R 1 Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R 2 These are independently alkenyl groups, with subscript a≧0, subscript b>0, 995≧c+c'≧15, and subscript d>0. The silsesquioxane mentioned above has the unit formula (A-II): (R 1 3 SiO 1 / 2 ) e (R 2 R 1 2 SiO 1 / 2 ) f (R 1 2 SiO 2 / 2 ) g (R 1 SiO 3 / 2 ) h (A-II) It has, in the formula, each R 1 Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R 2 These are independently alkenyl groups, where subscript e≧0, subscript f>0, subscript g is between 15 and 995, and subscript h>0. The linear polyorganosiloxane is (A-III-1), (A-III-2), or a combination thereof: (R 1 2 R 2 SiO 1 / 2 ) 2 (R 1 2 SiO 2 / 2 )n (R 1 R 2 SiO 2 / 2 ) o (A-III-1) (R 1 3 SiO 1 / 2 ) 2 (R 1 2 SiO 2 / 2 ) p (R 1 R 2 SiO 2 / 2 ) q (A-III-2) It has a unit formula selected from, in the formula, each R 1 Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R 2 The peel-off coating composition according to embodiment 5, wherein is independently an alkenyl group, the subscript n is 5 to 10,000, the subscript o has a value sufficient to provide an alkenyl content of 0.01% to 5.0% by weight based on the weight of the linear polyorganosiloxane of unit formula (A-III-1), the subscript p is 5 to 10,000, and the subscript q is sufficient to provide an alkenyl content of 0.01% to 5.0% by weight based on the weight of the linear polyorganosiloxane of unit formula (A-III-2). [Aspect 7] The aforementioned crosslinking agent has the following unit formula (BI): (R 1 3 SiO 1 / 2 ) 2 (R 1 2 SiO 2 / 2 ) k (R 1 HSiO 2 / 2 ) m (BI) It has, in the formula, each R 1 This is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, where the subscript k ≥ 0, the subscript m > 0, and the amount (m + k) is between 8 and 400. A peelable coating composition according to any one of embodiments 1 to 6. [Aspect 8] The peelable coating composition according to any one of embodiments 1 to 7, wherein the hydrosilylation reaction catalyst is present in an amount sufficient to provide 1 ppm by weight to 1000 ppm by weight of platinum group metals, based on the weight of the curable peelable coating composition excluding the solvent (if present). [Aspect 9] The peelable coating composition according to any one of embodiments 1 to 8, wherein the particles of the cured organosiloxane composition having the silica-treated coating include amorphous silica fine particles immobilized on the surface of the particles of the cured organosiloxane composition. [Aspect 10] A method for preparing a release liner comprising a release coating on at least one surface of a substrate, Depending on the circumstances, the process may involve treating at least one surface of the substrate, 1) Apply the curable peelable coating composition described in any one of embodiments 1 to 9 to the surface of the substrate, Depending on the circumstances, 2) remove the solvent (if present), 3) Curing the composition to form a release coating on the surface of the substrate, Methods that include... [Aspect 11] A release liner comprising a substrate and a release coating present on at least one surface of the substrate, wherein the release coating is formed by curing a curable release coating composition according to any one of embodiments 1 to 9. [Aspect 12] A peel-off liner according to embodiment 11, having a haze value of less than 3.5 as measured according to ASTM D1003. [Brief explanation of the drawing]

[0008] [Figure 1] A partial cross-sectional view of the release liner 100 is shown. The release liner includes a release coating 101 prepared by curing the curable release composition of the present invention on a first surface 102 of the film substrate 103. The release liner 100 further includes a support 104 provided on the opposite surface 105 of the film substrate 103. [Modes for carrying out the invention]

[0009] Unless a date is indicated along with the test method number, the test method refers to the test method most recent to the priority date of this document. References to test methods include both references to the testing association and the test method number. The following abbreviations and identifiers for test methods apply in this specification: ASTM refers to ASTM International methods.

[0010] Products identified by trade names refer to compositions available under those trade names as of the priority date of this document.

[0011] "And / or" means "and, or alternatively." All ranges include the endpoint unless otherwise specified.

[0012] The viscosity of polysiloxanes is measured at 25 Celsius (°C) using a Brookfield DV2T viscometer equipped with a spindle LV1.

[0013] standard 1 H, 13 C, and 29 The chemical structure of polysiloxanes is determined by silicon nuclear magnetic resonance (NMR) analysis.

[0014] In this specification, "alkyl" means a cyclic, branched, or unbranched saturated monovalent hydrocarbon group. Examples of alkyl groups include methyl, ethyl, propyl (e.g., isopropyl and / or n-propyl), butyl (e.g., isobutyl, n-butyl, tert-butyl, and / or sec-butyl), pentyl (e.g., isopentyl, neopentyl, and / or tert-pentyl), hexyl, heptyl, octyl, nonyl, decyl, branched alkyl groups with six or more carbon atoms, and cyclic alkyl groups such as cyclopentyl and cyclohexyl.

[0015] In this specification, “aryl” means a cyclic, completely unsaturated hydrocarbon group. Examples of aryls include, but are not limited to, cyclopentadienyl, phenyl, anthracenyl, and naphthyl. Monocyclic aryl groups may have 5 to 9 carbon atoms, 6 to 7 carbon atoms, or 5 to 6 carbon atoms. Polycyclic aryl groups may have 10 to 17 carbon atoms, 10 to 14 carbon atoms, or 12 to 14 carbon atoms.

[0016] In this specification, "aralkyl" means an alkyl group having a pendant and / or terminal aryl group, or an aryl group having a pendant alkyl group. Examples of aralkyl groups include tolyl, xylyl, benzyl, phenylethyl, phenylpropyl, and phenylbutyl.

[0017] In this specification, "alkenyl" means a branched or unbranched monovalent hydrocarbon group having one or more carbon-carbon double bonds.

[0018] The curable peelable coating composition of the present invention comprises (A) one or more aliphatic unsaturated polyorganosiloxanes having two or more alkenyl groups per molecule. The aliphatic unsaturated polyorganosiloxane (A) can be selected from (A-1) Q-branched polyorganosiloxane, (A-2) silsesquioxane, (A-3) linear polyorganosiloxane, or two or more combinations of (A-1), (A-2), and (A-3).

[0019] The Q-branched polyorganosiloxane (A-1) useful in this invention has the unit formula (AI): (R 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (R 1 2SiO 2 / 2 ) c (R 2 R 1 SiO 2 / 2 ) c’ (SiO 4 / 2 ) d (AI), It may have, in the formula, each R 1 Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R 2 The groups are independently alkenyl groups, with subscript a≧0, subscript b>0, 995≧c+c'≧15, and subscript d>0.

[0020] R 1 The monovalent hydrocarbon group is exemplified by an alkyl group with 1 to 6 carbon atoms, an aryl group with 6 to 10 carbon atoms, an alkyl halide with 1 to 6 carbon atoms, or an aryl halide with 6 to 10 carbon atoms. 1Alkyl groups suitable for [description] include, for example, methyl, ethyl, propyl (e.g., iso-propyl and / or n-propyl), butyl (e.g., isobutyl, n-butyl, tert-butyl, and / or sec-butyl), pentyl (e.g., isopentyl, neopentyl, and / or tert-pentyl), hexyl, and may include branched saturated hydrocarbon groups of 6 carbon atoms. R 1 Examples of aryl groups suitable for [description] are exemplified by phenyl, tolyl, xylyl, naphthyl, benzyl, and dimethylphenyl. R 1 Halogenated alkyl groups suitable for [description] are exemplified by, but not limited to, the above alkyl groups in which one or more hydrogen atoms are substituted with a halogen atom such as F or Cl. For example, fluoromethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl, 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl, and 3,4-difluoro-5-methylcycloheptyl, chloromethyl, chloropropyl, 2-dichlorocyclopropyl, and 2,3-dichlorocyclopentyl are examples of suitable halogenated alkyl groups. R 1 Halogenated aryl groups suitable for [description] are exemplified by, but not limited to, the above aryl groups in which one or more hydrogen atoms are substituted with a halogen atom such as F or Cl. For example, chlorobenzyl and fluorobenzyl are suitable halogenated aryl groups. Each R 1 may be the same or different. Each R 1 can be an alkyl group. Desirably, each R 1 is independently methyl, ethyl, or propyl, and more desirably each R 1 is methyl.

[0021] R 2 's alkenyl group can undergo a hydrosilylation reaction. R 2The alkenyl group represented by has typically 2 to 8 carbon atoms, 2 to 6 carbon atoms, or 2 to 4 carbon atoms. R 2 Alkenyl groups suitable for are exemplified by vinyl, allyl, butenyl, and hexenyl. Each R 2 may be the same or different. Desirably, each R 2 is selected from vinyl or hexenyl. Each R 2 may be a vinyl group.

[0022] In the unit formula (A-I), the subscript a can be 0 or more (≧0), generally 22 or less, 20 or less, 15 or less, 10 or less, or even 5 or less. The subscript b is greater than 0 (>0), >1, or 2 or more, 3 or more, or even 4 or more, and at the same time, generally 22 or less, 20 or less, 15 or less, or even 10 or less. The subscript c can be in the range of 15 to 995, 15 or more, 50 or more, or even 100 or more, and at the same time, generally 995 or less, 800 or less, or even 400 or less. The subscript c' can be 0 or more, 1 or more, 5 or more, or even 10 or more, and at the same time, generally 995 or less, 800 or less, or even 400 or less. The subscript d is greater than 0 (>0), 1 or more, and at the same time, generally 10 or less, 5 or less, or even 1 or less. Desirably, the subscript d is 1 or 2. When the subscript d = 1, the subscript a can be 0 and the subscript b can be 4.

[0023] The subscripts in the above unit formula (A-I) can have values sufficient to provide a vinyl content of 0.1% or more of the Q-branched polyorganosiloxane (A-1), 0.15% or more, or even 0.2% or more, and at the same time, based on the weight of the Q-branched polyorganosiloxane (A-1), by weight, generally 5.0% or less, 2.0% or less, 1.5% or less, 1.0% or less, or even 0.8% or less.

[0024] The Q-branched polyorganosiloxane (A-1) has at least two groups of the formula (R 1 2SiO2 / 2 ) y It contains a polydiorganosiloxane chain, where each subscript y in the formula is independently between 2 and 100. Alternatively, branched siloxanes are four formulas (R 1 2SiO 2 / 2 ) z Formula (SiO 4 / 2 The expression may contain at least one unit of ) where each subscript z in the expression is independently between 1 and 100.

[0025] A Q-branched polyorganosiloxane (A-1) may be a single Q-branched polyorganosiloxane or a combination of two or more Q-branched polyorganosiloxanes of unit formula (AI), which may differ in one or more properties selected from molecular weight, structure, siloxane units, and sequence. Suitable Q-branched polyorganosiloxanes may be those disclosed in U.S. Patent No. 6,806,339.

[0026] The silsesquioxane (A-2) useful in this invention has the unit formula (A-II): (R 1 3SiO 1 / 2 ) e (R 2 R 1 2SiO 1 / 2 ) f (R 1 2SiO 2 / 2 ) g (R 1 SiO 3 / 2 ) h (A-II) It may have, in the formula, R 1 and R 2 In the unit formula (AI), as described above, the subscript e ≥ 0, the subscript f > 0, the subscript g is between 15 and 995, and the subscript h > 0. Preferably, each R 1 is methyl. Preferably, R 2 It is vinyl.

[0027] The subscript e can be 0 or greater, 1 or greater, 2 or greater, or even 3 or greater, and at the same time generally 12 or less, and 10 or less, 7 or less, 5 or less, or even 3 or less. The subscript f may be greater than 0 (>0), 1 or greater, or 1 or greater, and at the same time generally 12 or less, and 10 or less, 7 or less, 5 or less, 3 or less, or 2 or less. The subscript g may be 15 or greater, 20 or greater, 50 or greater, or even 100 or greater, and at the same time generally 995 or less, and 800 or less, 400 or less, or even 200 or less. The subscript h may be greater than 0 (>0), 1 or greater, or even 2 or greater, and at the same time generally 10 or less, 8 or less, 5 or less, 2 or less, or even 1 or less. If the subscript h=1, then the subscript f can be 3 and the subscript e can be 0.

[0028] The value of the subscript f may be sufficient to provide a silsesquioxane of unit formula (A-II) with an alkenyl content of 0.1% or more, which may be 0.15% or more, 0.2% or more, or even 0.24% or more by weight, based on the weight of silsesquioxane (A-2), and at the same time, may be generally 1% or less, 0.8% or less, or even 0.6% or less.

[0029] The silsesquioxane may be a single silsesquioxane or a combination of two or more silsesquioxanes of unit formula (A-II), which may differ in one or more properties selected from molecular weight, structure, siloxane units, and sequence. Suitable silsesquioxanes (A-II) may include those disclosed in U.S. Patent No. 4,374,967.

[0030] Linear polymer useful in the present invention Rio Luganosiloxane (A-3) may have alkenyl groups located at the terminal position, the pendant position, or both the terminal and pendant positions. Preferably, The Po Rio Luganosiloxane has an average of one or more terminal alkenyl groups per molecule. RioLuganosiloxane (A-3) is (A-III-1), (A-III-2), or a combination thereof: (R 1 2R 2 SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) n (R 1 R 2 SiO 2 / 2 ) o (A-III-1) (R 1 3SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) p (R 1 R 2 SiO 2 / 2 ) q (A-III-2) It may contain one or more polysiloxanes having a unit formula selected from, where R 1 and R 2 This is described above in the unit formula (AI), where the subscript n is 5 to 10,000, and the subscript o is the po of the unit formula (A-III-1). Rio Based on the weight of lucanosiloxane, the values ​​provided are sufficient to offer alkenyl content of 0.01%~5.0%, 0.05%~2.0%, 0.10%~1.5%, and 0.2%~1.0% by weight. The subscript p is 5~10,000, and the subscript q is the po of the unit formula (A-III-2). Rio Based on the weight of lucanosiloxane, it is sufficient to provide an alkenyl content of 0.01% to 5.0% by weight, which may be 0.01% or more, 0.05% or more, 0.10% or more, or even 0.2% or more, and at the same time, generally 5.0% or less, which may be 2.0% or less, 1.5% or less, or even 1.0% or less.

[0031] Po Rio Luganosiloxane (A-3) may comprise one polydiorganosiloxane or a combination of two or more polydiorganosiloxanes that differ in one or more properties selected from molecular weight, structure, siloxane units, and sequence. RioLuganosiloxane (A-3) may contain any one or more of the following polydiorganosiloxanes in any combination. i) Dimethylvinylsiloxy-terminated polydimethylsiloxane, ii) Dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), iii) Dimethylvinylsiloxy-terminated polymethylvinylsiloxane, iv) Trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), v) Trimethylsiloxy-terminated polymethylvinylsiloxane, vi) Dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), vii) Dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane), viii) Dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenylsiloxane), ix) Phenyl,methyl,vinyl-siloxyterminated polydimethylsiloxane, x) Dimethylhexenylsiloxy-terminated polydimethylsiloxane, xi) Dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), xii) Dimethylhexenylsiloxy-terminated polymethylhexenylsiloxane, xiii) Trimethylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), xiv) Trimethylsiloxy-terminated polymethylhexenylsiloxane, xv) Dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), and xvi) Dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane).

[0032] The curable peelable coating composition of the present invention also comprises (B) one or more crosslinking agents (also called "SiH crosslinking agents") having two or more, or even three or more, silicon-bonded hydrogen (SiH) atoms per molecule. The SiH crosslinking agent may have a concentration of hydrogen atoms (H) as SiH (i.e., a concentration of silicon-bonded hydrogen atoms) of 0.1% or more, and based on the weight of the SiH crosslinking agent, it may be 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 0.6% or more, 0.7% or more, 0.8% or more, or even 0.9% or more by weight, and at the same time generally 1.0% or less, and may be 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, or even 0.3% or less. The content of silicon-bonded hydrogen atoms can be determined by NMR analysis.

[0033] SiH crosslinking agent, unit formula (BI): (R 1 3SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) k (R 1 HSiO 2 / 2 ) m (BI), It may be a polyorganohydrogensiloxane crosslinking agent, where R 1 As described above in the unit formula (AI), the subscript k ≥ 0, the subscript m > 0, and the quantity (m + k) is 8 to 400. The subscripts m and k represent the polyorganohydrogensiloxane crosslinking agent at 5 to 1,000 millipascals at 25°C. *The viscosity can be selected to have a value such that it is in seconds (mPa·s), 10 to 350 mPa·s at 25°C, or 20 to 100 mPa·s at 25°C. Suitable polyorganohydrogensiloxane crosslinking agents include, for example, trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), trimethylsiloxy-terminated polymethylhydrogensiloxane, or mixtures thereof. The crosslinking agent may be a single polyorganohydrogensiloxane crosslinking agent, or a combination of two or more crosslinking agents that may differ in one or more properties selected from molecular weight, structure, siloxane units, and sequence. Suitable commercially available SiH crosslinking agents include those available from Gelest under the names HMS-071, HMS-301, and DMS-H11.

[0034] The relative concentrations of the aliphatic unsaturated polyorganosiloxane (A) and the SiH crosslinking agent are such that the molar ratio (SiH / Vi ratio) of silicon-bonded hydrogen atoms from the crosslinking agent to alkenyl groups (e.g., alkenyl groups in the aliphatic unsaturated polyorganosiloxane (A)) in the curable peelable coating composition is in the range of 0.8:1 to 5:1, and may be 0.8:1 or greater, 0.9:1 or greater, 1.0:1 or greater, 1.1:1 or greater, 1.2:1 or greater, 1.3:1 or greater, 1.4:1 or greater, 1.5:1 or greater, or even 1.6:1 or greater, and at the same time, it is generally 5:1, and may be 4:1 or less, 3:1 or less, 2:1 or less, 1.9:1 or less, 1.8:1 or less, 1.7:1 or less, or even 1.6:1 or less.

[0035] Typically, the SiH crosslinking agent is present in a concentration of 0.1% or more by weight, based on the total weight of the alkenyl group-containing components in the curable peelable coating composition, and may be 1% or more, 1.5% or more, 1.8% or more, or even 2% or more, while generally being 5% or less, and may be 4% or less, 3% or less, or even 2.5% or less.

[0036] The curable peelable coating composition of the present invention comprises (C) one or more hydrosilylation reaction catalysts. Examples of hydrosilylation reaction catalysts include platinum group metal catalysts. Such hydrosilylation catalysts may include (C1) a metal selected from platinum, rhodium, ruthenium, palladium, osmium, and iridium, preferably platinum; (C2) a compound of such a metal, including, for example, rhodium diphosphine chelates such as chloride tris(triphenylphosphane)rhodium(I) (Wilkinson catalyst), [1,2-bis(diphenylphosphino)ethane]dichlorodirhodium or [1,2-bis(diethylphosphino)ethane]dichlorodirhodium, chloroplatinic acid (Speier catalyst), chloroplatinic acid hexahydrate, or platinum dichloride; and (C3) a complex of the metal compound (C2) with an organopolysiloxane, for example, a 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complex with platinum (Karstedt catalyst). The hydrosilylation catalyst may be encapsulated (typically in a phenyl resin) or unencapsulated. Exemplary hydrosilylation catalysts are described in U.S. Patents No. 3,159,601 and No. 3,220,972.

[0037] The amount of hydrosilylation catalyst used is catalytic, i.e., sufficient to catalyze the hydrosilylation reaction of silicon-bonded hydrogen atoms and alkenyl groups in the curable peelable coating composition. Typically, the concentration of the hydrosilylation catalyst is a platinum group metal that is sufficient by weight to provide a concentration of 1,000 ppm or less, 500 ppm or less, 300 ppm or less, 130 ppm or less, or even 100 ppm or less, based on the weight of the curable peelable coating composition excluding the solvent (if present) (e.g., the total weight of components (A), (B), and (C) above, as well as (D) below, and (if present) the optional components (E), (F), and (H) below), and at the same time, generally sufficient to provide a concentration of 1,000 ppm or less, 500 ppm or less, 300 ppm or less, 130 ppm or less, or even 100 ppm or less.

[0038] The curable peelable coating composition of the present invention comprises (D) particles of a cured organosiloxane composition (also called "cured organosiloxane particles"), optionally together with a silica-treated coating. The shape of the particles of the cured organosiloxane composition may be spherical, flat, or amorphous. Spherical is preferred. The particles of the cured organosiloxane composition may have an average particle size of 0.5 micrometers (μm) or more, measured using a Malvern Mastersizer Hydro 2000SM, and may be 1 μm or more, 2 μm or more, or even 3 μm or more, and at the same time generally 30 μm or less, and may be 25 μm or less, 20 μm or less, 15 μm or less, 14 μm or less, 13 μm or less, 12 μm or less, 10 μm or less, 9 μm or less, 8 μm or less, or even 6 μm or less (further details are provided below under the particle sizes of the cured organosiloxane composition).

[0039] The particles of the cured organosiloxane composition may or may not have a silica-treated coating. Having a "silica-treated coating" or having such a coating means that these particles are treated or coated with silica so that silica microparticles are present on the surface of the particles of the cured organosiloxane composition and are typically fixed. Preferably, particles of the cured organosiloxane composition having a silica-treated coating include amorphous silica microparticles fixed to the surface of the particles of the cured organosiloxane composition. The amorphous silica microparticles may have an average particle size of 1 μm or less, 0.5 μm or less, 0.1 μm or less, 0.05 μm or less, 0.02 μm or less, or even 0.01 μm or less, as determined by Malvern Mastersizer Hydro 2000SM (further details are provided under the particle size of amorphous silica microparticles). The amorphous silica microparticles have a particle size of 2.0 units / square nanometer (nm). 2 The surface silanol group density may be 2.2 groups / nm or higher. 2 More than 2.5 units / nm 2 More than 3.0 units / nm 2 Above, 3.5 groups / nm 2 More than 4.0 units / nm2 The above, or even 4.2 units / nm 2 The above may also be applicable. The silanol group density on the silica surface of the silica-treated coating is calculated from the BET specific surface area, and the silanol group content is calculated from the amount of hydrogen generated after drying the silica-treated coating at 120°C for 3 hours under a vacuum of at least 2 kilopascals (15 mmHg) and reacting it with lithium aluminum hydride. Amorphous silica nanoparticles are measured using the Micromeritics Accelerated Surface Area & Porosimetry instrument (ASAP2420) according to ASTM D1993, at a rate of 50 square meters / gram (m²). 2 It may have a BET specific surface area of ​​80m² ( / g) or more. 2 / g or more, 100m 2 / g or more, 150m 2 / g or more, or even 200m 2 It may be 1 / g or more. The concentration of the silica-treated coating may be 0 or more by weight, based on the total weight of the particles of the cured organosiloxane composition and, if present, the silica-treated coating, and may be 0.05% or more, 0.1% or more, 0.5% or more, or even 1.0% or more, and at the same time generally 5% or less, 4% or less, 3% or less, or even 1% or less.

[0040] (D) Processes for preparing particles of cured organosiloxane compositions are known in the art and typically include (i) preparing an aqueous dispersion of a curable organosiloxane composition, (ii) curing the composition to produce an aqueous dispersion of cured organosiloxane particles, and (iii-1) finally removing water from the aqueous dispersion, preferably by heating. In the preparation of cured organosiloxane particles having a silica-treated coating, the process may include steps (i) and (ii) above, then (iii-2) mixing the aqueous dispersion of cured organosiloxane particles obtained from step (ii) with amorphous silica microparticles or an aqueous dispersion of amorphous silica microparticles to form an aqueous mixture of cured organosiloxane particles and amorphous silica microparticles, and (iv) subjecting the mixture obtained from step (iii-2) to rubbing integration, or heating the mixture obtained from step (iii-2) and then removing water. The heating of the aqueous dispersion or mixture can be carried out in the temperature range of 40-95°C or 60-90°C, which, if present, allows the silica particles to be immobilized on the surface of the cured organosiloxane particles by interaction in water between the silanol groups on the surface of the silica and functional groups such as silanol, silicon-bonded hydrogen, and silicon-bonded alkoxy located on the surface of the cured organosiloxane particles in step (iv). Examples of suitable cured organosiloxane materials as (D) and methods for preparing them are disclosed, for example, in European Patent No. 0685508(B1) and European Patent No. 0647672(B1).

[0041] One common method for preparing an aqueous dispersion of the curable organosiloxane composition in step (i) above involves dispersing the curable organosiloxane composition in water or an aqueous surfactant solution, and then generating a homogeneous dispersion therefrom using a suitable device such as a homogenizer or colloid mill, or a mixing device such as an ultrasonic transducer. Suitable curable organosiloxane compositions for preparing curable organosiloxane particles include addition reaction curable organosiloxane compositions, condensation reaction curable organosiloxane compositions, organoperoxide curable organosiloxane compositions, and ultraviolet (UV) curable organosiloxane compositions.

[0042] Examples of materials for the addition reaction curable organosiloxane composition include (a) an aliphatic unsaturated polyorganosiloxane containing two or more alkenyl groups per molecule, including the one described in (A) of the above curable peelable coating composition; (b) a crosslinking agent having two or more silicon-bonded hydrogen atoms per molecule, including the one described in (B) of the above curable peelable coating composition; and (c) a hydrosilylation reaction catalyst, preferably a platinum catalyst, including the one described in (C) of the above curable peelable coating composition. The resulting cured organosiloxane particles contain the reaction product of (a) and (b). Preferably, material (a) in the curable organosiloxane composition contains one or more linear poly Rio(a) The material comprises lucanosiloxane (A-3). Examples of materials include dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), dimethylvinylsiloxy-terminated polydimethylsiloxane, trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), dimethylvinylsiloxy-terminated methylsilsesquioxane, vinyl-terminated polydimethylsiloxane, or mixtures thereof. Preferably, material (b) in the curable organosiloxane composition is selected from trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), trimethylsiloxy-terminated polymethylhydrogensiloxane, hydrogen-terminated polydimethylsiloxane, hydrogen-terminated poly(dimethylsiloxane / methylhydrogensiloxane), hydrogen-terminated polymethylhydrogensiloxane, or mixtures thereof. More preferably, the cured organosiloxane particles include reaction products of poly(dimethylsiloxane / methylhydrogensiloxane) and dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), reaction products of poly(dimethylsiloxane / methylhydrogensiloxane) and dimethylvinylsiloxy-terminated methylsilsesquioxane and vinyl-terminated dimethylsiloxane, reaction products of poly(dimethylsiloxane / methylhydrogensiloxane) and dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), or mixtures thereof.

[0043] The curable peelable coating composition of the present invention may contain (D) particles of a cured organosiloxane composition having a silica-treated coating, in a concentration of 0.1% or more by weight, based on the weight of the curable peelable coating composition excluding the solvent, if present, and may be 0.15% or more, 0.2% or more, 0.25% or more, 0.3% or more, 0.35% or more, 0.4% or more, 0.45% or more, or even 0.5% or more, and at the same time generally 5% or less, and may be 4.5% or less, 4% or less, 3.5% or less, 3% or less, 2.5% or less, 2% or less, 1.8% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1% or less, 0.8% or less, or even 0.5% or less.

[0044] The curable peelable coating composition of the present invention may or may not contain (E) one or more hydrosilylation reaction inhibitors (also called "inhibitors"), which is useful for changing the reaction rate of silicon-bonded hydrogen atoms and alkenyl groups in the composition compared to the reaction rate of the same composition but without the inhibitors. Examples of suitable inhibitors include acetylene alcohol, e.g., 2-methyl-3-butyne-2-ol, dimethylhexylol, 3,5-dimethyl-1-hexyne-3-ol, 1-butyne-3-ol, 1-propyne-3-ol, 2-methyl-3-butyne-2-ol, 3-methyl-1-butyne-3-ol, 3-methyl-1-pentin-3-ol, 3-phenyl-1-butyne-3-ol, 4-ethyl-1-octin-3-ol, 3,5-dimethyl-1-hexyne-3-ol, and 1-ethynyl-1-cyclohexanol (ETCH); cycloalkenylsiloxane, e.g., methylvinylcyclosiloxane, e.g., 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,3,5, Enyne compounds such as 7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane:3-methyl-3-penten-1-yine and 3,5-dimethyl-3-hexen-1-yine; triazoles such as benzotriazole; phosphines; mercaptans; hydrazines; amines, such as tetramethylethylenediamine, 3-dimethylamino-1-propyne, n-methylpropargylamine, propargylamine, and 1-ethynylcyclohexylamine; dialkyl fumarates such as diethyl fumarate, dialkenyl fumarates such as diallyl fumarate, fumarates including dialkoxyalkyl fumarates; maleates, such as diallyl maleate and diethyl maleate; nitriles; ethers; or mixtures thereof.

[0045] In the present invention, useful inhibitors, if present, may be present in a concentration of 0 or more by weight, based on the weight of the peel-off coating composition excluding the solvent, and may be 0.001% or more, 0.0025% or more, or even 0.01% or more, and at the same time, generally 5% or less, 1% or less, 0.5% or less, or even 0.25% or less.

[0046] The curable peelable coating composition of the present invention may or may not contain (F) one or more fixing additives. Suitable fixing additives include, for example, reaction products of vinyl alkoxysilane and epoxy-functionalized alkoxysilane; reaction products of vinyl acetoxysilane and epoxy-functionalized alkoxysilane; and blends and / or reaction products of polyorganosiloxanes having at least one aliphatic unsaturated hydrocarbon group and at least one hydrolyzable group per molecule with epoxy-functionalized alkoxysilanes (e.g., blends or reaction products of hydroxy-terminated vinyl-functionalized polydimethylsiloxane and glycidoxypropyltrimethoxysilane). Suitable examples of epoxy-functionalized alkoxysilanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (epoxycyclohexyl)ethyldimethoxysilane, (epoxycyclohexyl)ethyldiethoxysilane, or mixtures thereof. Suitable fixing additives and methods for preparing them are disclosed, for example, in U.S. Patent Applications Publications 2003 / 0088042, 2004 / 0254274, and 2005 / 0038188, and European Patent No. 0556023. Suitable commercially available fixing additives include, for example, SYL-OFF® 297, SYL-OFF® 397, and SYL-OFF® SL9250, all available from Dow Silicones Corporation (Midland, Michigan, USA) (SYL-OFF is a trademark of Dow Silicones Corporation).

[0047] If present, the fixing additive useful in the present invention may be present in a concentration of 0 or more by weight, based on the weight of the curable peelable coating composition excluding the solvent, and may be 0.01% or more, 0.05% or more, 0.1% or more, 0.2% or more, 0.3% or more, 0.4% or more, or even 0.5% or more, and at the same time, generally 5% or less, and may be 4% or less, 3% or less, 2% or less, 1.5% or less, or even 1% or less.

[0048] The curable peelable coating composition of the present invention may or may not contain (G) one or more solvents. Suitable solvents may include, for example, polyalkylsiloxanes, alcohols, ketones, aromatic hydrocarbons, aliphatic hydrocarbons, glycol ethers, tetrahydrofurans, mineral spirits, naphtha, tetrahydrofurans, mineral spirits, naphtha, or mixtures thereof. The solvent may include one or more organic solvents containing alcohols such as methanol, ethanol, isopropanol, butanol, or n-propanol; ketones such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; aromatic hydrocarbons such as benzene, toluene, or xylene; aliphatic hydrocarbons such as heptane, hexane, or octane; glycol ethers such as propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, or ethylene glycol n-butyl ether, tetrahydrofuran; mineral spirits, naphtha, or combinations thereof. Preferably, the solvent is heptane.

[0049] The solvent may be present in a concentration of 0% or more, 2% or more, 20% or more, or even 50% or more by weight, based on the weight of the curable release coating composition, and at the same time, it may generally be 99% or less, 50% or less, 20% or less, or even 2% or less. The solvent may be added during the preparation of the release coating composition, for example, to assist in the mixing and delivery of one or more components in the release coating composition. For example, a hydrosilylation catalyst may be delivered in the solvent. All or part of the solvent may be removed after the preparation of the release coating composition, if applicable.

[0050] The curable peelable coating composition of the present invention may or may not contain (H) organically modified functional silica particles having an average particle size of 3 μm to 15 μm, as measured using a Malvern Mastersizer Hydro 2000SM according to ASTM D4464-15. The organically modified silica particles may be highly porous silica particles having a porosity of more than 90%. The functional silica particles have one or more organic functional groups on their surface, such as trimethylsilyl, triethylsilyl, dimethylvinylsilyl, and dimethylphenylsilyl. The method for producing component (H) is not limited; for example, U.S. Patent No. 7,470,725 describes a method comprising the steps of a) modifying the surface of a silica aerogel with a silylating agent, and b) drying the surface-modified gel obtained in step a). Such organically modified functional silica particles are commercially available from The Dow Chemical Company as DOWSIL® VM-2270 Aerogel Fine Particles (DOWSIL is a registered trademark of The Dow Chemical Company). Organically modified functional silica particles may be present in concentrations of 5% or less, 0.5% or less, 0.1% or less, or even 0% by weight of the curable release coating composition excluding the solvent (if present). To further improve the transparency of the release coating, it is desirable that the curable release coating composition is substantially free of organically modified functional silica particles. "Substantially free of organically modified functional silica particles" means less than 0.1%, less than 0.05%, less than 0.01%, less than 0.005%, or even 0% by weight, based on the weight of the curable release coating composition excluding the solvent, if present.

[0051] The curable peelable coating composition of the present invention can be prepared by mixing particles of an aliphatic unsaturated polyorganosiloxane (A), a crosslinking agent (B), a hydrosilylation reaction catalyst (C), and a curable organosiloxane composition (D), and optionally a hydrosilylation reaction inhibitor (E), a fixing additive (F), and / or a solvent (G). The curable peelable coating composition can be prepared as a one-part composition or as a multi-part composition, with the crosslinking agent and catalyst being stored separately until their parts are combined at the time of use (e.g., immediately before application to a substrate).

[0052] The curable release coating compositions of the present invention are suitable for use in forming release coatings containing cured products of the curable release coating composition, i.e., release coatings formed by curing a curable release coating composition. Release coatings having excellent transparency and antiblocking properties, as well as desirable low peeling force and high sustained adhesive strength, make them suitable for use in release liners for silicone pressure-sensitive adhesives used in electronic device applications, such as touch panels for tape release, label release and / or adhesive transfer films, especially when transparency is desired. The present invention also relates to a release line comprising a substrate and a release coating formed by curing a release coating composition present on at least one surface of the substrate (e.g., via a hydrosilylation reaction).

[0053] The present invention also relates to a method for preparing a release liner, comprising applying a curable release coating composition to at least one surface of a substrate such as a film, and curing the curable release coating composition to form a release coating (also called a "cured release coating") on the surface of the substrate, thereby forming a release liner. The release liner comprises a substrate and a release coating on at least one surface of the substrate. The curable release coating composition can be applied to both sides of the substrate. The curable release coating composition can be applied to the substrate by any convenient means such as spraying, doctor blade, dipping, screen printing, or by a roll coater, such as an offset web coater, kiss coater, etched cylinder coater, or multi-roll coater. The curable release coating composition can be applied to any substrate, typically a sheet-like substrate, including polymer films containing polyester such as polyethylene terephthalate (PET), polyethylene, polypropylene, or polystyrene film; paper substrates including plastic-coated paper such as polyethylene, glassine, supercalendered paper, or paper coated with clay-coated kraft; and metal foils such as aluminum foil. Preferably, the substrate may be a PET film. Preferably, the curable release coating composition is applied to at least one surface of a sheet-like substrate using a multiple roll coater.

[0054] The method for preparing the release liner may optionally further include treating the surface of the substrate before applying the curable release coating composition. The substrate treatment can be carried out by any convenient means, such as applying a primer before coating with the curable release coating composition, or by subjecting the substrate to corona discharge treatment, etching, or plasma treatment.

[0055] A method for preparing a release liner may further include, optionally, removing any solvent present before or during the curing of the curable release coating composition, which can be done by any conventional means, such as heating at 50°C to 100°C for a time sufficient to remove all or part of the solvent. A method for preparing a release liner may further include curing the curable release coating composition to form a release coating on the surface of a substrate. Curing can be carried out by any conventional means, such as heating at a temperature in the range of 100 to 240°C, typically 110 to 160°C, or 120 to 150°C, depending on the coating line used, for a time sufficient to cure the release coating composition. For example, curing can be done at 120 to 160°C for offline coating in an oven, or at 200 to 240°C for in-line coating in an oven. Curing times can be 1 to 10 seconds, 2 to 20 seconds, or 5 to 30 seconds. The above heating and curing steps can be carried out in an oven, such as an air circulation oven or tunnel furnace, or by passing the coated film around a heated cylinder.

[0056] The coating weight of the peel-off coating is 0.05 grams / square meter (g / m²). 2 ) ~2.0g / m 2 This is possible. The curable release coating composition of the present invention provides the following properties to a release liner manufactured therefrom (i.e., a release liner comprising a substrate and a release coating on at least one surface of the substrate): a clear appearance (haze value < 3.5), antiblocking properties, and a low coat weight (e.g., 1.3 g / m²). 2 It can provide one or more of the following: low peel strength (RF-RT < 5.0 grams / inch (g / in)) and high subsequent adhesive strength (SAS > 85%). These properties are determined according to the test methods described below in the Examples section.

[0057] The pressure-sensitive adhesive can be protected using the release liner prepared as described above. The user can coat the liquid pressure-sensitive adhesive composition directly onto the release liner, remove the solvent or water by heat or UV curing, and then laminate it with the substrate and rewind it onto a roll. Alternatively, the user may laminate the release liner with a dry pressure-sensitive adhesive or adhesive film for tape, label, or die-cutting applications. The present invention also relates to the use of release liners for silicone pressure-sensitive adhesive articles in electronic device applications. [Examples]

[0058] Herein, several embodiments of the present invention are described in the following examples, and unless otherwise specified, weight percentage (W%) values ​​are relative to the weight of the composition. Table 1 lists the substances for use in the sample peel-off coating compositions described below in this specification. Note: "Vi" represents vinyl and "Me" represents methyl.

[0059] [Table 1] * The particle size of Epowder was determined using Malvern Mastersizer Hydro 2000 SM (further details are provided below under Particle Size of Cured Organosiloxane Compositions).

[0060] IE1-10 and CE A-H samples The formulations for the peel-off coating composition samples are shown in Table 2, and unless otherwise specified, the amount of each component is reported in grams (g).

[0061] Samples were prepared by mixing the components together using a SpeedMixer® DAC 400 FVZ mixer from FlackTek Inc. (South Carolina, USA). Vi polymer, Epowder or silica particles, fixing additive, SiH crosslinking agent, and inhibitor were added to the SpeedMixer cup. The mixture was mixed several times at 3,000 revolutions per minute (RPM) for 30 seconds until homogeneous. An appropriate amount of heptane solvent was added as needed to reach the target coat weight (CW) shown in Table 2. The catalyst was added, and the resulting mixture was mixed for 10 minutes to form a release coating composition.

[0062] Next, the release coating composition was coated onto a PET film substrate (thickness: 50 μm) using a coater and cured by heat curing in an oven at 140°C for 30 seconds, thereby forming a release liner containing the cured release coating on the substrate. Three samples of each release coating composition were prepared and evaluated according to the test method described below, and the results were averaged.

[0063] Court weight (CW) Using an Oxford lab-x 3500 instrument manufactured by Oxford Instruments PLC (Oxon, United Kingdom), X-rays were used to detect the coat weight (g / m²) of a hardened peel-off coating on a PET film substrate. 2 The following was evaluated: Uncoated PET was used as a control sample (blank). The test method was FINAT Test Method No. 7 (FINAT Technical Handbook 7). th (edition, 2005).

[0064] Peeling force - room temperature ("RF-RT") RF-RT in units of g / in (0.386 centineutons / cm) was evaluated using a 180-degree peel test to measure the peel force from the release liner. Tesa 7475 standard tape was laminated onto a cured release coating and rated at 20 g / cm².2 The loading was placed on the resulting layered sample and left at room temperature (25°C) for 20 hours. After 20 hours, the loading weight was removed and the sample was left for 30 minutes. Then, the peel force ("RF-RT") was tested using ChemInstruments' AR-1500 according to FINAT Test Method No. 10 (FINAT Technical Handbook 7th edition, 2005).

[0065] Peeling force - Aging ("RF-70℃ Aging") RF-70°C aging was evaluated by measuring the peel force from the release liner using a 180° peel test. Tesa 7475 standard tape was laminated onto the cured release coating, and 20 g / cm³ was applied to the resulting laminated sample. 2 The loading weight was applied and left at 70°C for 20 hours. After 20 hours, the loading weight was removed and the sample was left for 30 minutes. Then, the peeling force ("RF-70°C aging") was measured according to FINAT Test Method No. 10 (FINAT Technical Handbook 7 th Tested using ChemInstruments AR-1500 (edition, 2005).

[0066] SAS (Subsequent adhesive strength, migration index) The percentage of SAS was evaluated as follows: Test tape was applied to a hardened peel-off coating using Nitto Denko 31B tape at 20 g / cm². 2 The samples were laminated with the specified loading weight and left at 70°C for 20 hours. After 20 hours, the loading weight was removed and the samples were left at room temperature for 30 minutes. Then, the 31B tape was transferred onto a PET substrate and left for another hour. The peel strength ("RF (Peel)") was determined according to FINAT Test Method No. 11 (FINAT Technical Handbook 7 thThe tests were performed using ChemInstruments AR-1500 with the (edition, 2005) method. In this SAS test, laminated 31B tape on a polytetrafluoroethylene (PTFE) substrate was tested, and then the PTFE sample was treated and evaluated in the same manner as the cured peel-off coating sample described above, and the peel strength ("RF(PTFE)") was recorded. The SAS value was recorded as RF(peel) / RF(PTFE) × 100%.

[0067] Antiblocking test An uncoated PET film measuring 25 mm x 150 mm was laminated with a release liner of the same size prepared above by rolling it twice in each direction at a speed of approximately 10 mm per second using a standard FINAT test roller to obtain close contact between the release liner and the surface of the PET film. Visual inspection was performed to determine whether there was any visible "wetting" at the interface between the PET film and the release liner. If there was no visible wetting, the sample passed and was reported as "P". Otherwise, if there was visible wetting, the sample failed and was reported as "F".

[0068] Hayes The haze of the release liner prepared above was tested with BYK Gardner Haze Gard Plus according to ASTM D1003.

[0069] transparency The transparency of the release liner prepared above was evaluated by visual inspection and reported as "transparent" or "cloudy."

[0070] Particle size of the cured organosiloxane composition One gram of cured organosiloxane particles and 100 milliliters (mL) of ethanol were placed in a 300 mL plastic cup and mixed for 30 seconds using a disperser. The resulting mixture was mixed ultrasonically for 3 minutes, and the particle size was measured in water using a Malvern Mastersizer Hydro 2000SM.

[0071] Particle size of amorphous silica fine particles 1 g of amorphous silica microparticles and 100 mL of ethanol were placed in a 300 mL plastic cup and mixed in a disperser for 30 seconds. The resulting mixture was mixed ultrasonically for 3 minutes, and the particle size was measured in water using a Malvern Mastersizer Hydro 2000SM.

[0072] Table 2 shows the results of the characterization evaluation of the peel-off coating composition samples.

[0073] As shown in Table 2, samples IE1-10 achieved a low peel force (RF-RT < 5.0 g / in) with a clear appearance (e.g., haze value less than 3.5) and antiblocking properties against the back surface of the film, while maintaining comparable SAS and RF-70°C aging characteristics under the same conditions as samples CE A-H. In contrast, samples CE A-H, shown in Table 2, failed to achieve at least one of the transparency and antiblocking requirements.

[0074] [Table 2] Note: "SiH / Vi ratio" refers to the molar ratio of SiH functionality to vinyl functionality from the crosslinking agent. * The solvent (heptane) used for each sample was added in an amount suitable for achieving the target coat weight (CW) shown in Table 2.

Claims

1. A curable peelable coating composition, (A) an aliphatic unsaturated polyorganosiloxane having two or more alkenyl groups per molecule, (B) A crosslinking agent having two or more silicon-bonded hydrogen atoms per molecule in an amount sufficient to result in a molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of 0.8:1 to 5:1 in the curable peelable coating composition, (C) A catalytic amount of hydrosilylation catalyst, (D) Based on the weight of the curable peelable coating composition excluding the solvent (if present), particles of a cured organosiloxane composition having a silica-treated coating of an average particle size of 0.5 to 30 micrometers, in an amount of 0.01% to 5% by weight, Includes, The curable peel-off coating composition comprises particles of the cured organosiloxane composition, wherein the particles contain a reaction product of (a) an aliphatic unsaturated polyorganosiloxane containing two or more alkenyl groups per molecule and (b) a crosslinking agent having two or more silicon-bonded hydrogen atoms per molecule, and (a) is selected from dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), dimethylvinylsiloxy-terminated polydimethylsiloxane, trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), dimethylvinylsiloxy-terminated methylsilsesquioxane, vinyl-terminated polydimethylsiloxane, or a mixture thereof.

2. The peel-off coating composition according to claim 1, further comprising a hydrosilylation reaction inhibitor, a fixing additive, a solvent, or a mixture thereof.

3. The peelable coating composition according to claim 1, comprising 0.1% to 2% by weight of particles of the curable organosiloxane composition, based on the weight of the curable peelable coating composition excluding the solvent (if present).

4. The peel-off coating composition according to claim 1, wherein the aliphatic unsaturated polyorganosiloxane is selected from Q-branched polyorganosiloxane, silsesquioxane, linear polyorganosiloxane, or a combination thereof.

5. The aforementioned Q-branched polyorganosiloxane has the unit formula (A-I): (R １ ３ SiO １／２ ) ａ (R ２ R １ ２ SiO １／２ ) ｂ (R １ ２ SiO ２／２ ) ｃ (R ２ R １ SiO ２／２ ) ｃ’ (SiO ４／２ ) ｄ (A-I) It has, in the formula, each R １ Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R ２ These are independently alkenyl groups, with subscript a ≥ 0, subscript b > 0, 995 ≥ c + c' ≥ 15, and subscript d > 0. The silsesquioxane mentioned above has the unit formula (A-II): (R １ ３ SiO １／２ ) ｅ (R ２ R １ ２ SiO １／２ ) ｆ (R １ ２ SiO ２／２ ) ｇ (R １ SiO ３／２ ) ｈ (A-II) It has, in the formula, each R １ Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R ２ These are independently alkenyl groups, where the subscript e ≥ 0, the subscript f > 0, the subscript g is between 15 and 995, and the subscript h > 0. The linear polyorganosiloxane is (A-III-1), (A-III-2), or a combination thereof: (R １ ２ R ２ SiO １／２ ) ２ (R １ ２ SiO2 / 2) ｎ (R １ R ２ SiO2 / 2) ｏ (A-III-1) (R １ ３ SiO １／２ ) ２ (R １ ２ SiO2 / 2) ｐ (R １ R ２ SiO2 / 2) ｑ (A-III-2) It has a unit formula selected from, in the formula, each R １ Each R is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, and each R ２ The peel-off coating composition according to claim 4, wherein is independently an alkenyl group, the subscript n is 5 to 10,000, the subscript o has a value sufficient to provide an alkenyl content of 0.01% to 5.0% by weight based on the weight of the linear polyorganosiloxane of unit formula (A-III-1), the subscript p is 5 to 10,000, and the subscript q is sufficient to provide an alkenyl content of 0.01% to 5.0% by weight based on the weight of the linear polyorganosiloxane of unit formula (A-III-2).

6. The aforementioned crosslinking agent has the following unit formula (B-I): (R １ ３ SiO １／２ ) ２ (R １ ２ SiO ２／２ ) ｋ (R １ HSiO ２／２ ) ｍ (B-I) It has, in the formula, each R １ The peel-off coating composition according to claim 1, wherein is independently a monovalent hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons or a monovalent halogenated hydrocarbon group that does not contain aliphatic unsaturated hydrocarbons, the subscript k ≥ 0, the subscript m > 0, and the amount (m + k) is 8 to 400.

7. The peelable coating composition according to claim 1, wherein the hydrosilylation reaction catalyst is present in an amount sufficient to provide 1 ppm by weight to 1,000 ppm by weight of platinum group metals, based on the weight of the curable peelable coating composition excluding the solvent (if present).

8. The peelable coating composition according to claim 1, wherein the particles of the cured organosiloxane composition having the silica-treated coating include amorphous silica fine particles immobilized on the surface of the particles of the cured organosiloxane composition.

9. A method for preparing a release liner comprising a release coating on at least one surface of a substrate, Depending on the circumstances, at least one surface of the substrate may be treated, Applying the curable peelable coating composition according to any one of claims 1 to 8 to the surface of the substrate, Depending on the circumstances, 2) remove the solvent (if present), 3) Curing the composition to form a release coating on the surface of the substrate, Methods that include...

10. A release liner comprising a substrate and a release coating present on at least one surface of the substrate, wherein the release coating is formed by curing a curable release coating composition according to any one of claims 1 to 8.

11. The release liner according to claim 10, having a haze value of less than 3.5 as measured according to ASTM D1003.

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