Curable organopolysiloxane composition, release coating agent, and release and release film

Abstract

The present invention provides a curable organopolysiloxane composition that can provide a release layer to a substrate that exhibits low peeling force at both low and high speeds, allowing for good peeling from adhesive tape with low peeling force at both speeds. [Solution] A curable organopolysiloxane composition containing the following components (A) to (C): (A) Alkenyl group-containing organopolysiloxane represented by the following average composition formula (1): 100 parts by mass, (B) Organohydrogenpolysiloxane having an average of 2 or more silicon atom-bonded hydrogen atoms (Si-H groups) per molecule: an amount in which the number of moles of Si-H groups in component (B) is 0.5 to 10 times the number of moles of alkenyl groups in component (A), and (C) Platinum group metal catalyst: catalyst amount. JPEG2026054988000030.jpg39170

Description

Technical Field

[0001] The present invention relates to a curable organopolysiloxane composition suitable for producing release paper and release films, and a release coating agent. More specifically, it relates to a curable organopolysiloxane composition that provides release paper and release films in which changes in release force due to differences in release rate are suppressed.

Background Art

[0002] Release paper and release films are obtained by applying a silicone-based release coating agent to the surface of a substrate such as paper or a plastic film and forming a cured film by a crosslinking reaction, and are widely used as a release agent film for adhesive or sticky substances.

[0003] As a composition for a release coating agent, an addition reaction curable silicone curable composition that is mainly composed of a vinyl group-containing organopolysiloxane and an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom and is cured by a hydrosilylation reaction is well known. Since this composition has advantages such as a high curing rate and relatively free adjustment of release characteristics, it is used in a wide range of applications. However, a composition for a release coating agent of the addition reaction curable type has a problem that when the film obtained by curing is exposed to the outside air, the release force becomes abnormally heavy, and in some cases, it becomes impossible to release. Therefore, in the process of manufacturing labels and adhesive tapes using release paper or release films formed with a release agent film obtained from an addition reaction curable composition for release, if the silicone coated film is exposed to the atmosphere, the required releasability of these products cannot be maintained, causing release failure and potentially leading to a significant decrease in quality.

[0004] Furthermore, release paper and release film are used in products that require protective release paper on both sides of the adhesive layer, such as double-sided adhesive tapes and coreless adhesive sheets with adhesive layers on both sides. Demand for these products is expected to grow in industrial applications. In these types of products, to improve handling convenience, the release force of the release paper on one side of the adhesive layer must always be smaller than the release force of the release paper on the other side. However, the release force of release paper generally differs between low-speed and high-speed peeling. If this difference is large, depending on the peeling speed, the difference in release force between the two sides of the adhesive layer may disappear, resulting in poor peeling. Therefore, it is necessary to reduce the difference in release force between low-speed and high-speed peeling.

[0005] While release paper generally plays a role in controlling the difference in peel force between low-speed and high-speed peeling, recent trends have led to a demand for consistently low peel force at various peeling speeds for a wide range of adhesive types. Conventionally, it has been known that using polyorganosiloxanes with a low vinyl group content as a base is a method to reduce peel force at low speeds. However, in this case, the peel force at high speeds becomes extremely high. On the other hand, when using polyorganosiloxanes with a high vinyl group content as a base, the peel force at high speeds can be reduced, but the peel force at low speeds increases. Thus, reducing both low-speed and high-speed peel force is a difficult challenge.

[0006] Therefore, there is a need for a silicone coating film that can reduce peeling force at both low and high speeds, and that also has excellent exposure resistance. Methods for reducing peeling force at both low and high speeds include, for example, a method of blending an unreactive aryl group-containing polyorganosiloxane with an addition reaction type peeling composition, a method of blending a polyorganosiloxane having hydroxyl groups at its ends and an aryl group with an addition reaction type peeling composition, and a method of blending a high molecular weight polydimethylsiloxane having hydroxyl groups and a polyorganosiloxane having hydroxyl groups and an aryl group with an addition reaction type peeling composition. However, in the method of blending an aryl group-containing polyorganosiloxane with an addition reaction type peeling composition as described above, although the effect of reducing peeling force when peeling from the adhesive layer at high speed can be confirmed, the amount of silicone migration increases, making it difficult to suppress the decrease in residual adhesion rate. Furthermore, a method combining a high molecular weight polydimethylsiloxane containing hydroxyl groups with a polyorganosiloxane containing both hydroxyl and aryl groups also resulted in an increase in silicone transfer and a decrease in residual adhesion. Therefore, these methods are not practical.

[0007] Japanese Patent Publication No. 2019-099715 describes a solvent-free silicone composition for release paper, characterized by combining an organopolysiloxane with a high vinyl group content and an organopolysiloxane with a low vinyl group content as base components. WO2018 / 190012 describes a solvent-type release agent composition characterized by blending an addition-curing silicone composition containing a vinyl group-containing organopolysiloxane with a non-reactive polyorganosiloxane that does not have aliphatic unsaturated groups and has a viscosity of 0.001 to 4 Pa·s at 25°C. It is stated that the non-reactive polyorganosiloxane reduces the peeling force in the low-speed and high-speed peeling speed ranges while suppressing an increase in the amount of silicone migration and a decrease in the residual adhesion rate. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2019-099715 [Patent Document 2] WO2018 / 190012 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above circumstances, and aims to provide a curable organopolysiloxane composition that can provide a release layer to a substrate that exhibits low peeling force when peeling from an adhesive layer at both low and high speeds, and can be easily peeled from an adhesive tape with low peeling force at both low and high speeds. More preferably, the present invention aims to provide a curable organopolysiloxane composition that exhibits superior curability compared to an addition reaction curable silicone curable composition containing an organopolysiloxane having a silicon atom bonded vinyl group.

[0010] As mentioned above, conventional solvent-type addition reaction curing release coating compositions have the problem that when the cured film is exposed to the outside air, the peeling force becomes abnormally heavy (heavy peeling), and in some cases, it becomes impossible to peel. The solvent-type release agent composition described in Patent Document 2 also does not have sufficient effect on exposure resistance. Therefore, the second object of the present invention is to provide a curable organopolysiloxane composition that can be peeled off adhesive tape well with low peeling force in both low-speed and high-speed peeling, and furthermore, the phenomenon of heavy peeling due to exposure to the atmosphere is well suppressed, that is, it provides a release layer with good exposure resistance. [Means for solving the problem]

[0011] The inventors of the present invention conducted diligent research to solve the above problems and found that a solvent-type or solvent-free silicone curable composition containing an organopolysiloxane having an alkenyl group with an ester structure as a reactive group can reduce both the peeling force of the resulting cured film during low-speed and high-speed peeling. They also found that the curable organopolysiloxane composition of the present invention has superior curability compared to conventional addition-reaction curable silicone curable compositions containing an organopolysiloxane having a vinyl group directly bonded to a silicon atom, thus completing the present invention.

[0012] In other words, the present invention is [1] A curable organopolysiloxane composition containing the following components (A) to (C) is provided. (A) Alkenyl group-containing organopolysiloxane represented by the following average composition formula (1): 100 parts by mass, [ka] (In the formula, R 1 These are, independently of each other, alkenyl groups having 3 to 20 carbon atoms, and R 2 R represents a linking group, which is a divalent hydrocarbon group having 1 to 10 carbon atoms, and also R 3 (Each group is independently selected from substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkyl halogen groups having 1 to 10 carbon atoms, organic groups having a hydroxyl group, and organic groups having an acyloxy group, and furthermore, a, b, c, d, e, f, and g satisfy a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, a+c+e is 1 or greater, and 2≦a+b+c+d+e+f+g≦15000) (B) Organohydrogenpolysiloxane having an average of 2 or more silicon-bonded hydrogen atoms (Si-H groups) per molecule: (A) an amount in which the number of moles of Si-H groups in component (B) is 0.5 to 10 times the number of moles of alkenyl groups in component (A), and (C) Platinum group metal catalyst: Catalyst amount.

[0013] Furthermore, the present invention provides an organopolysiloxane composition as shown in any of the following [2] to [9]. [2] In the above average composition formula (1), the R 1 The curable organopolysiloxane composition according to [1] above, wherein the siloxane units having the above-mentioned siloxanes constitute 0.1 to 50% of the total number of siloxane units. [3] In the above average composition formula (1), R 1 The curable organopolysiloxane composition according to [1] or [2] above, wherein each of the members is independently an alkenyl group having 5 to 12 carbon atoms. [4] In the above average composition formula (1), R 2 The curable organopolysiloxane composition according to any one of [1] to [3] above, wherein each is independently a divalent hydrocarbon group having 1 to 7 carbon atoms. [5] A curable organopolysiloxane composition according to any one of [1] to [4] above, wherein in the average composition formula (1) above, a=0 and e=0. [6] The organopolysiloxane is a linear organopolysiloxane which may have branching, and in the above average composition formula (1), a and b are 2≦a+b≦20, 1≦c, 0≦d, and 1≦c+d≦15000, e=0, 0≦f≦14, 0≦g≦8, and a+c is the R 1 A curable organopolysiloxane composition according to any one of [1] to [5] above, wherein the number of siloxane units having the above is 0.1 to 50% of the total number of siloxane units. [7] The curable organopolysiloxane composition according to any one of [1] to [6] above, further comprising (D) solvent in parts 10 to 100,000 parts by mass per 100 parts by mass of component (A). [8] Furthermore, the curable organopolysiloxane composition according to any one of [1] to [7] above, which contains (E) a reaction control agent in an amount of 0.01 to 5.00 parts by mass per 100 parts by mass of component (A). [9] A solvent-free, solvent-free curable organopolysiloxane composition according to any one of [1] to [6] and [8] above. Furthermore, the present invention provides a release coating agent comprising the curable organopolysiloxane composition according to any one of [1] to [9] above.

[0014] Furthermore, the present invention provides a release paper or a release film having a substrate and a cured product layer of the curable organopolysiloxane composition according to any one of [1] to [9] above, wherein the cured product layer is laminated on at least one surface of the substrate. Furthermore, the present invention provides a method for producing the release paper or the release film, including a step of applying the curable organopolysiloxane composition according to any one of [1] to [9] above on at least one surface of the substrate, and a step of curing the curable organopolysiloxane composition to obtain a cured product layer.

Effects of the Invention

[0015] The curable organopolysiloxane composition of the present invention can provide a substrate with a release layer having a small release force both at low speed and high speed peeling from an adhesive tape, for both solvent type and solvent-free type. Furthermore, the solvent type curable organopolysiloxane composition of the present invention provides a cured film with excellent exposure resistance, so that it can be peeled well from an adhesive tape with a low release force both at low speed and high speed peeling, and furthermore, it can provide a release paper and a release film having a release layer with good exposure resistance.

Modes for Carrying Out the Invention

[0016] Hereinafter, the present invention will be described in detail. <(A) Alkenyl Group-Containing Organopolysiloxane> The alkenyl group-containing organopolysiloxane according to the present invention is represented by the following average composition formula (1).

Chemical formula

[0017] In the average composition formula (1), R 1 is, independently of each other, an alkenyl group having 3 to 20 carbon atoms. R 2R represents a linking group and is a divalent hydrocarbon group having 1 to 10 carbon atoms. 3 These are groups independently selected from substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkyl halogens having 1 to 10 carbon atoms, organic groups having a hydroxyl group, and organic groups having an acyloxy group. Furthermore, a, b, c, d, e, f, and g satisfy a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, and a+c+e≧1, and 2≦a+b+c+d+e+f+g≦15000.

[0018] R 1 These are, independently of each other, alkenyl groups having 3 to 20 carbon atoms. The lower limit of the number of carbon atoms in the alkenyl group is 3 or more, preferably 4 or more, and preferably 5 or more. The upper limit of the number of carbon atoms in the alkenyl group may be 20 or less, preferably 19 or less, preferably 18 or less, preferably 17 or less, preferably 16 or less, and preferably 12 or less. Preferably, it is an alkenyl group having 3 to 19 carbon atoms, preferably 3 to 18, preferably 3 to 17, preferably 3 to 16 carbon atoms, more preferably an alkenyl group having 4 to 16 carbon atoms, and even more preferably an alkenyl group having 5 to 12 carbon atoms. When the organopolysiloxane of the present invention is applied to a curable silicone composition, particularly a release coating agent, R is used from the viewpoint of curability. 1 It is preferable that R be a long chain. 1 The larger the number of carbon atoms, the better.

[0019] R 1 Examples of alkenyl groups include propenyl, butenyl, pentenyl, hexenyl, octenyl, decenyl, undecenyl, and dodecenyl groups. Due to the ease of obtaining the raw materials for the functional groups, butenyl, pentenyl, octenyl, nonenyl, and decenyl groups are preferred, with the decenyl group being more preferred. Furthermore, the double bond in the alkenyl group may be located either at the end or in the interior of the molecule, but its location at the end is preferred. 1This is represented, for example, by the following structure. In the following formula, the dotted lines indicate the bonds with the ester structure. [ka]

[0020] R 2 R represents a linking group, which is a divalent hydrocarbon group having 1 to 10 carbon atoms, preferably a divalent hydrocarbon group having 1 to 7 carbon atoms, and more preferably a divalent hydrocarbon group having 1 to 5 carbon atoms. 2 Examples include alkylene groups such as methylene groups, ethylene groups, trimethylene groups, and tetramethylene groups, and allylene groups such as phenylene groups. From the viewpoint of the availability of raw materials for functional groups, R 2 The alkylene group is preferred, and the methylene group, ethylene group, and trimethylene group are more preferred.

[0021] R 3 These are groups independently selected from substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkyl halogenated groups having 1 to 10 carbon atoms, organic groups having a hydroxyl group, and organic groups having an acyloxy group. Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, and propyl groups, cycloalkyl groups such as cyclohexyl groups, and aryl groups such as phenyl and tolyl groups. Examples of alkoxy groups having 1 to 20 carbon atoms include methoxy, ethoxy, isopropoxy, and butoxy groups. Examples of alkyl halogenated groups having 1 to 10 carbon atoms include chloromethyl, chloroethyl, chloropropyl, bromomethyl, bromoethyl, and bromopropyl groups. Examples of organic groups having a hydroxyl group include hydroxymethyl, hydroxyethyl, hydroxypropyl, and hydroxybutyl groups. Examples of organic groups having an acyloxy group include acetoxymethyl, 2-acetoxyethyl, 3-acetoxypropyl, and 6-acetoxyhexyl. 3 Preferably, this is a methyl group, ethyl group, methoxy group, ethoxy group, or hydroxyl group-containing organic group.

[0022] In the above average composition formula (1), the number of alkenyl groups (R) relative to the total number of siloxane units 1 The ratio of the number of siloxane units having (hereinafter referred to as the alkenyl modification rate) is preferably 0.1 to 50%, more preferably 0.2 to 40%, and more preferably 0.3 to 30%. The upper limit of the alkenyl modification rate is more preferably 20% or less, and more preferably 10% or less. Even more preferably 0.1 to 20% or less, and 0.1 to 10% or less. If the alkenyl modification rate is above the lower limit, the curability by heat curing will be good. If the alkenyl modification rate is below the upper limit, the pot life of the curable organopolysiloxane composition will be good, and handling will be easier. Also, if the alkenyl modification rate is too high, there is a risk that the peeling force when peeling the resulting peel layer at a low speed will be high.

[0023] In the average composition formula (1), a, b, c, d, e, f, and g satisfy a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, and a+c+e≧1, and a+b+c+d+e+f+g satisfies 2≦a+b+c+d+e+f+g≦15000, preferably 2≦a+b+c+d+e+f+g≦14000, and more preferably 2≦a+b+c+d+e+f+g≦13000. If a+b+c+d+e+f+g is lower than the above lower limit, when used as the main component of a silicone curable composition, the composition tends to wet and spread too easily, resulting in insufficient coating on the substrate surface. If it is higher than the above upper limit, it becomes difficult to wet and spread, reducing workability.

[0024] When the curable organopolysiloxane composition in the present invention is a solvent-type composition containing a diluent solvent, the total number of siloxane units (a+b+c+d+e+f+g) is preferably 500 to 15000, more preferably 600 to 10000, and even more preferably 700 to 7500. When the curable organopolysiloxane composition in the present invention is a solvent-free composition that does not contain a solvent, the organopolysiloxane is preferably low molecular weight. Therefore, the total number of siloxane units (a+b+c+d+e+f+g) is preferably 2 to 500, more preferably 3 to 400, and even more preferably 4 to 300.

[0025] The organopolysiloxane of the present invention may be linear, branched, or cyclic, but is preferably a linear organopolysiloxane which may have branches, and more preferably a linear organopolysiloxane.

[0026] In the above average composition formula (1), a, b, c, d, e, f, and g represent the number of M units of siloxane, c+d represents the number of D units of siloxane, e+f represents the number of T units of siloxane, and g represents the number of Q units of siloxane. c+d is preferably 1 to 10000, more preferably 2 to 7500, and more preferably 3 to 5000. a+b is 0 or 1 to 20, more preferably 2 to 16, and more preferably 2 to 12. e+f is preferably 0 to 14, more preferably 0 to 10. g is preferably 0 to 8, and more preferably 0 to 6.

[0027] The above alkenyl group (R 1 Esters having the above R 2 It may be bonded to any of M-unit, D-unit, or T-unit silicon atoms via the . Preferably, it is bonded to M-unit or D-unit silicon atoms, and more preferably to D-unit silicon atoms. Therefore, a, c, and e are preferably e=0 and a+c≧1, and more preferably a=0, e=0, and c≧1.

[0028] In the embodiment in which the organopolysiloxane of the present invention is a linear chain that may have branching, in the above average composition formula (1), 0 ≤ a, 0 ≤ b, and a + b is 2 to 20, more preferably 2 to 16, and more preferably 2 to 12. c and d are 0 ≤ d ≤ 15000, preferably 1 ≤ d ≤ 10000, more preferably 1 ≤ d ≤ 7500, even more preferably 1 ≤ d ≤ 5000, 1 ≤ c ≤ 1000, preferably 1 ≤ c ≤ 750, and even more preferably 1 ≤ c ≤ 500. 1 ≤ c + d ≤ 15000, preferably 2 ≤ c + d ≤ 10000, more preferably 2 ≤ c + d ≤ 7500, and even more preferably 2 ≤ c + d ≤ 5000. e, f, and g are such that 0≦e≦14, preferably 0≦e≦10, 0≦f≦14, preferably 0≦f≦10, and 0≦g≦8, preferably 0≦g≦6.

[0029] In a linear or branched linear organopolysiloxane, the ratio of alkenyl groups (R) to the total number of siloxane units in the above average composition formula (1) is 1 The ratio of siloxane units having ) is 0.1 to 50%. The upper limit is preferably 50% or less, preferably 40% or less, more preferably 30% or less, more preferably 20% or less, and more preferably 10% or less. The lower limit is preferably 0.1% or more, preferably 0.2% or more, more preferably 0.3% or more, more preferably 0.4% or more, more preferably 0.5% or more, more preferably 0.8% or more, and more preferably 1% or more. For example, it is preferable to have 0.1% to 50%, 0.2% to 40%, 0.3% to 30%, 0.4% to 20%, 0.5% to 10%, 0.8% to 10%, or 1% to 10%. a+c is R relative to the total number of siloxane units. 1 The ratio of siloxane units containing the above-mentioned properties falls within the above range.

[0030] More preferably, it is a linear chain without branching, a+b=2, more preferably a=0 and b=2, e=0, f=0, and g=0.

[0031] Examples of organopolysiloxanes represented by the average empirical formula (1) include the compound shown in the following structure. In the formula, Me represents a methyl group and Ph represents a phenyl group. [ka] (In the equation, h≧1, i≧0, j≧0, k≧0, and l≧0, satisfying 1≦h+i≦15000, 0≦i≦15000, 0≦i+j≦15000, and 1≦h+i+k+l≦15000.)

[0032] The method for producing the organopolysiloxane represented by the average composition formula (1) above is not particularly limited. For example, an alkenyl group-containing cyclic organopolysiloxane can be produced by reacting an alkyl halide-containing cyclic organopolysiloxane with an alkenyl group-containing metal carboxylate salt in the presence of a phase transfer catalyst selected from phosphonium salts, ammonium salts, and crown ethers, and then the organopolysiloxane represented by the average composition formula (1) above can be produced by subjecting the alkenyl group-containing cyclic organopolysiloxane to at least one other organo(poly)siloxane by ring-opening polymerization. Alternatively, an organopolysiloxane represented by the average composition formula (1) above can also be obtained by reacting a branched linear organopolysiloxane having an alkyl halide-containing cyclic organopolysiloxane with an alkenyl group-containing metal carboxylate salt in the presence of a phase transfer catalyst selected from phosphonium salts, ammonium salts, and crown ethers.

[0033] <(B) Organohydrogenpolysiloxane> Component (B) is an organohydrogenpolysiloxane having an average of two or more silicon-bonded hydrogen atoms (Si-H groups) per molecule. Component (B) is a crosslinking agent and forms a crosslinked structure with the alkenyl group-containing organopolysiloxane (A), contributing to the formation of a cured film.

[0034] (B) Examples of components include those represented by the following average composition formula (2). [R 4 3SiO1 / 2 ] Z1 [HR 4 2SiO 1 / 2 ] Z2 [R 4 2SiO 2 / 2 ] Z3 [HR 4 SiO 2 / 2 ] Z4 [R 4 SiO 3 / 2 ] Z5 [HSiO 3 / 2 ] Z6 [SiO 4 / 2 ] Z7 (2) (In equation (2), Z1, Z2, Z3, and Z5 are mutually independent of each other, Z4 is 0 or a positive number less than or equal to 200, Z6 is 0 or a positive number less than or equal to 10, Z7 is 0 or a positive number less than or equal to 10, Z2, Z4, and Z6 cannot be 0 at the same time, and 2 ≤ Z2 + Z4 + Z6 ≤ 200)

[0035] In equation (2) above, R 4 The group is an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond. Examples include alkyl groups preferably having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups preferably having 5 to 8 carbon atoms, such as cyclohexyl groups; aryl groups preferably having 6 to 10 carbon atoms, such as phenyl and tolyl groups; aralkyl groups preferably having 7 to 10 carbon atoms, such as benzyl groups; or hydroxypropyl groups, 1-chloropropyl groups, and 3,3,3-trifluoropropyl groups, in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with hydroxyl groups, alkoxy groups, polyether groups, alkoxyalkyl groups, epoxy groups, halogen atoms, etc. Among these, alkyl and aryl groups are preferred, and methyl groups are even more preferred from the viewpoint of improving the rate of addition reaction.

[0036] In equation (2), Z1, Z2, Z3, and Z5 are each independently 0 or a positive number, with Z1 preferably being a positive number between 0 and 10, and more preferably between 0 and 6. Z2 preferably being a positive number between 0 and 10, and more preferably between 0 and 6. Z1 + Z2 is preferably 2 or greater. Z3 preferably being a positive number between 0 and 200, and more preferably between 0 and 100. Also, Z4 is a positive number between 0 and 200, preferably between 2 and 100, and more preferably between 10 and 80. Z3 + Z4 is preferably 1 or greater. Z5 preferably being a positive number between 0 and 10, and more preferably between 0 and 5. Z6 is a positive number between 0 and 10, preferably between 0 and 5. Z7 is a positive number between 0 and 10, and preferably between 0 and 5. Also, Z2, Z4, and Z6 cannot be 0 at the same time, and Z2 + Z4 + Z6 is between 2 and 100, and preferably between 10 and 80.

[0037] The organohydrogenpolysiloxane represented by formula (2) above can include polysiloxanes containing hydrogensilyl groups at both ends, polysiloxanes containing hydrogensilyl groups in the side chains, polysiloxanes containing hydrogensilyl groups at one end and in the side chains, and polysiloxanes containing hydrogensilyl groups at both ends and in the side chains. The organohydrogenpolysiloxane may be linear, branched, or cyclic, or a mixture thereof. Preferably, it is linear or linear with branching, and more preferably linear. The SiH group content is preferably 0.1 to 3 moles / 100g, particularly 0.2 to 2 moles / 100g, in the polyorganosiloxane. Furthermore, the viscosity of this organohydrogenpolysiloxane at 25°C is preferably 0.1 to 1000 mPa·s, particularly 1 to 500 mPa·s. Viscosity values ​​were measured at 25°C using a BM-type rotational viscometer.

[0038] Examples of organohydrogenpolysiloxanes include, but are not limited to, the following compounds. In the following formulas, Me and Ph represent a methyl group and a phenyl group, respectively. [ka] (In the formula, 0 ≤ Z3 ≤ 200, 0 ≤ Z4 ≤ 200, and 0 ≤ Z6 ≤ 10. However, each molecule contains an average of 2 or more Si-H groups.)

[0039] The amount of (B) organohydrogenpolysiloxane is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 15 parts by mass, and even more preferably 0.5 to 10 parts by mass, per 100 parts by mass of (A) alkenyl group-containing polyorganosiloxane. Within this range, an appropriate crosslinking density can be obtained in the resulting cured product. Furthermore, the amount of component (B) is preferably such that the ratio of moles of hydrogen atoms bonded to silicon atoms in component (B) to 1 mole of alkenyl groups in component (A) is in the range of 0.5 to 10, and more preferably in the range of 0.8 to 5.0. If the molar ratio is smaller than the lower limit, the curability of the composition will decrease, and the adhesion of the resulting cured product to the substrate may be poor. If the molar ratio is larger than the upper limit, the resulting release layer may undergo severe peeling.

[0040] <(C) Platinum group metal catalyst> (C) Platinum group metal catalysts are used to promote the crosslinking reaction between (A) alkenyl group-containing organopolysiloxane and (B) organohydrogenpolysiloxane, and to form a hardened film. Any common platinum group metal catalyst can be used as the catalyst for the addition reaction, for example, platinum, platinum black, chloroplatinic acid, complexes of platinum or chloroplatinic acid with various olefins or vinylsiloxanes, chloroplatinic acid-alcohol coordination compounds, rhodium, rhodium-olefin complexes, etc. These may be used individually or in combination of two or more as appropriate.

[0041] The amount of platinum group metal catalyst added should be a catalytic amount, that is, an effective amount for the crosslinking reaction to proceed. Preferably, the amount of platinum group metal should be 10 to 1000 ppm (mass ratio) relative to the total mass of components (A) and (B) to form a sufficiently cured film. More preferably, it should be 15 to 500 ppm. The amount of platinum group metal catalyst added can be appropriately increased or decreased depending on the reactivity of components (A) and (B) or the desired curing rate.

[0042] <(D) Solvent> The curable organopolysiloxane composition of the present invention may be a solvent-free composition obtained by blending predetermined amounts of components (A) to (C), or it may be a solvent-type composition obtained by diluting components (A) to (C) with an organic solvent or other solvent as needed. Diluting the composition with an organic solvent provides practical advantages such as improved coating workability and improved coating film condition, including the thickness of the coating film and the surface finish.

[0043] Examples of solvents include aromatic hydrocarbon compounds such as toluene and xylene, aliphatic hydrocarbon compounds such as hexane, heptane, and isoparaffin, ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester compounds such as ethyl acetate and butyl acetate, and organic solvents such as diisopropyl ether and 1,4-dioxane. Any compound capable of dissolving silicone is acceptable. The solvent may be used alone or in appropriate combinations of two or more solvents.

[0044] In the curable organopolysiloxane composition of the present invention, the solvent is an optional component, and its amount can be any amount. That is, it may be 0 parts by mass. If the risk or decrease in safety due to the organic solvent is undesirable, the organic solvent may not be included, and a solvent-free curable organopolysiloxane composition may be made. When a solvent is included, the amount is 10 to 100,000 parts by mass per 100 parts by mass of the alkenyl group-containing polyorganosiloxane, preferably 100 to 20,000 parts by mass, more preferably 200 to 10,000 parts by mass, even more preferably 200 to 5,000 parts by mass, and more preferably 200 to 2,000 parts by mass. If the amount of solvent is above the lower limit, practical advantages in improving the coating film condition, such as the thickness of the coating film and the surface finish, can be obtained. Also, if the amount of solvent is below the upper limit, a sufficient effect in improving the coating workability can be obtained, which is preferable.

[0045] The curable organopolysiloxane composition of the present invention can be obtained by blending a predetermined amount of the above components, but other optional components can be added as needed, within a range that does not impair the purpose and effects of the present invention. The other optional components can be any components that are commonly used in silicone-based release agent compositions, and known components can be added in normal blending amounts.

[0046] Other optional components include, for example, (E) reaction control agents. Examples of reaction control agents include various organic nitrogen compounds, organophosphorus compounds, acetylene compounds, oxime compounds, organochloro compounds, maleic acid derivatives, etc. Examples include acetylene alcohols such as 3-methyl-1-butyne-3-ol, 3,5-dimethyl-1-hexyne-3-ol, 3-methyl-1-pentin-3-ol, and 2-phenyl-3-butyne-2-ol; acetylene compounds such as 3-methyl-3-penten-1-yine and 3,5-dimethyl-3-hexen-1-yine; reaction products of these acetylene compounds with alkoxysilanes, siloxanes, or hydrogensilanes; vinylsiloxanes such as tetramethylvinylsiloxane cyclic compounds; organic nitrogen compounds such as benzotriazole; maleic acid derivatives such as dimethyl maleate; and other organophosphorus compounds, oxime compounds, and organochloro compounds.

[0047] (E) The amount of reaction control agent added should be such that a good pot life can be obtained, and generally, 0.01 to 5 parts by mass per 100 parts by mass of (A) alkenyl group-containing polyorganosiloxane is preferred.

[0048] Furthermore, as necessary and within the limits that do not hinder the effects of the present invention, other optional components such as known antioxidants, pigments, stabilizers, defoamers, adhesion enhancers, thickeners, and inorganic fillers such as silica may be added. The amount of these components added is preferably 0 to 30% by mass, and more preferably 0 to 15% by mass, in the total composition.

[0049] [Preparation method] The preparation of the curable organopolysiloxane composition of the present invention is not particularly limited, but a method in which an alkenyl group-containing polyorganosiloxane, an organohydrogenpolysiloxane, an organic solvent if necessary, and an optional component are homogeneously mixed beforehand, and then a platinum group metal catalyst is added immediately before use, is preferred in terms of pot life.

[0050] [Release paper and release film] The present invention provides a release coating agent comprising the above-mentioned curable organopolysiloxane composition, and release paper and release film having a release layer formed by curing the composition. The release paper and release film comprise a paper substrate or a film substrate, and a release layer formed on the substrate, which is made of a cured product of the curable organopolysiloxane composition. The release layer only needs to be formed on at least one surface of the substrate, and may be on one surface or both surfaces.

[0051] Examples of substrates include polyethylene laminated paper, glassine paper, fine paper, kraft paper, clay-coated paper and other coated papers, synthetic paper such as Yupo, polyethylene film, polypropylene film such as CPP and OPP, polyester film such as polyethylene terephthalate film, polyamide film, polyimide film, polylactic acid film, polyphenol film, and polycarbonate film. To improve the adhesion between these substrates and the release layer, substrates that have been treated with corona, etching, or plasma may be used.

[0052] The method for manufacturing release paper and release film is not particularly limited and can be carried out according to conventionally known manufacturing methods. For example, a method can be made which includes the steps of applying a curable organopolysiloxane composition to at least one surface of a substrate, for example, one or both surfaces, and drying and curing the curable organopolysiloxane composition to form a cured layer (i.e., a release layer). Examples of application methods include coating by a comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, kiss coater, gravure coater, wire bar coater, etc., as well as screen coating, dipping coating, cast coating, etc. When applying the coating, the curable organopolysiloxane composition may be used as is, or it may be further diluted with the above-mentioned dilution solvent or water within the above-mentioned range.

[0053] There are no particular restrictions on the coating amount of the curable organopolysiloxane composition, but it is usually 0.01 to 100 g / m² as solid content.2 Preferably, 0.03 to 10 g / m 2 This is more preferable. As for drying methods, methods that remove volatile components and solvent components by heating are possible. For example, a hot air dryer, an IR dryer, etc. Alternatively, it may be dried by leaving it at room temperature. The curing method can be a conventionally known method. For example, the curing temperature is preferably 50 to 200°C, and more preferably 70 to 180°C. The curing time is preferably 1 to 120 seconds, and more preferably 5 to 90 seconds. When creating a release layer on both sides of the substrate, it is preferable to perform the curing film formation operation on one side of the substrate at a time. [Examples]

[0054] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0055] The components used in the examples and comparative examples are as follows:

[0056] As the main component of the solvent-curable organopolysiloxane composition, the alkenyl group-containing organopolysiloxanes shown in (A-1) to (A-7) below, and the alkenyl group-containing organopolysiloxanes shown in (a-8) and (a-9) below were used. [Preparation Example 1] (A-1) Production of organopolysiloxanes 51.23 g of 10-undecenoic acid and 29.80 g of N-methyl-2-pyrrolidinone were charged into a separable flask equipped with a stirrer, dropping funnel, thermometer, and Dean-Stark apparatus. 32.07 g of 48% potassium hydroxide aqueous solution was added to the dropping funnel and added dropwise to prepare a potassium 10-undecenoate solution (the amount of potassium 10-undecenoate being 0.75 equivalents of the halogen groups in organopolysiloxane (I-1) described below). Subsequently, 50.00 g of the organopolysiloxane shown in the average composition formula (I-1) below (viscosity 200 mPa·s at 25°C) and 5.00 g of tetrabutylphosphonium bromide were added, and the reaction was carried out by heating and stirring at a temperature of 120°C for 4 hours. To this reaction mixture, 17.97 g of potassium acetate (an amount equivalent to 0.50 equivalents relative to the halogen groups in (I-1)) was added, and the reaction was carried out by heating and stirring at a temperature of 120°C for 4 hours. After that, the salt was removed from the reaction mixture by washing with water, and then impurities were removed by tape stripping under reduced pressure at 15 mmHg at 70°C for 4 hours to obtain 80.24 g of a yellow, transparent organopolysiloxane represented by the following average composition formula (a-1). [ka]

[0057] In a separable flask equipped with a stirrer and reflux tubing, 11.45 g of organopolysiloxane represented by the above average composition formula (a-1), 120.10 g of octamethylcyclotetrasiloxane, 0.10 g of hexamethyldisiloxane, and 0.17 g of trifluoromethanesulfonic acid were charged, and the mixture was heated and stirred for 8 hours at a temperature of 50°C. To this mixture, 306.95 g of toluene and synthetic hydrotalcite Mg 1-x Al x (OH)2(CO3) x / 2 · 1.02 g of mH2O (Kyowa Chemical Industry Co., Ltd., Kyoward® 500SH) was added and the mixture was stirred at room temperature for 2 hours to neutralize it. After removing the solid by filtration, 92.29 g of pale yellow transparent organopolysiloxane was obtained by vacuum stripping at 15 mmHg for 3 hours at 120°C. The obtained product was 29 Si-NMR and1 ¹H-NMR measurement confirmed that the substance is an organopolysiloxane as shown in (A-1) below. This organopolysiloxane has a viscosity of 262,000 mPa·s and an alkenyl group content of 0.028 mol / 100g. [ka] (In the equation, b=2, c=25, d1=8, d2=1215, and c / (b+c+d1+d2)=0.02, -C 10 H 19 (It has a double bond at the end of its molecular chain.)

[0058] [Preparation Example 2] The above Preparation Example 1 was repeated except that the amount of hexamethyldisiloxane was increased to 0.25 g to obtain 92.54 g of the organopolysiloxane shown in (A-2) below. This organopolysiloxane has a viscosity of 20,900 mPa·s and an alkenyl group content of 0.028 mol / 100 g. [ka] (In the equation, b=2, c=15, d1=5, d2=728, and c / (b+c+d1+d2)=0.02, -C 10 H 19 (It has a double bond at the end of its molecular chain.)

[0059] [Preparation Example 3] In the above preparation example 1, 11.45 g of organopolysiloxane represented by formula (a-1) is given by the following formula (a-2) [ka] The preparation example 1 was repeated, except that 8.60 g of the organopolysiloxane represented by was used, to obtain 89.70 g of the organopolysiloxane shown in (A-3) below. This organopolysiloxane has a viscosity of 250,000 mPa·s and an alkenyl group content of 0.029 mol / 100 g. [ka] (In the formula, b=2, c=24, d1=8, d2=1190, c / (b+c+d1+d2)=0.02, and -C4H7 has a double bond at the end of the molecular chain.)

[0060] [Preparation Example 4] In the above preparation example 1, 11.45 g of organopolysiloxane represented by formula (a-1) is used in the following formula (a-3) [ka] Example 5 was repeated, except that 13.35 g of the organopolysiloxane represented by (A-4) was used to obtain 93.56 g of the organopolysiloxane shown below. This organopolysiloxane has a viscosity of 283,000 mPa·s and an alkenyl group content of 0.028 mol / 100 g. [ka] (In the equation, b=2, c=26, d1=9, d2=1270, and c / (b+c+d1+d2)=0.02, -C 10 H 19 (It has a double bond at the end of its molecular chain.)

[0061] [Preparation Example 5] In the above preparation example 1, 11.45 g of organopolysiloxane represented by (a-1) is given by the following formula (a-4) [ka] The preparation example 1 was repeated, except that 9.64 g of the organopolysiloxane represented by the formula shown below was used to obtain 89.88 g of the organopolysiloxane represented by the average composition formula (A-4) below. This organopolysiloxane has a viscosity of 274,000 mPa·s and an alkenyl group content of 0.028 mol / 100 g. [ka] (In the equation, b=2, c=24, d=1170, and c / (b+c+d)=0.02, -C 10 H 19 (It has a double bond at the end of its molecular chain.)

[0062] Organopolysiloxanes shown in the following average composition formulas (A-6) and (A-7) were obtained by the same manufacturing method as in the above preparation examples 1 to 5. (A-6): [ka] (In the equation, b=2, c=39, d1=13, d2=1900, and c / (b+c+d1+d2)=0.02, -C 10 H 19 (It has a double bond at the end of its molecular chain.) Organopolysiloxanes represented by [a specific symbol / method]. (A-7): [ka] (In the equation, b=2, c=66, d1=22, d2=1220, and c / (b+c+d1+d2)=0.05, -C 10 H 19 (It has a double bond at the end of its molecular chain.) Organopolysiloxanes represented by [a specific symbol / method].

[0063] The following organopolysiloxanes were used as comparative components. (a-8): Average composition formula [ka] (In the equation, a=2, b=25, c=1225, and b / (a+b+c)=0.02) An organopolysiloxane represented by (manufactured by Shin-Etsu Chemical Co., Ltd.). (a-9): Average composition formula [ka] (In the equation, a=2, b=32, and c=8000, and (3a+b) / (a+b+c+d)=0.0047) An organopolysiloxane represented by (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0064] As the main component of the solvent-free curable organopolysiloxane composition, alkenyl group-containing organopolysiloxanes shown in (A-10) to (A-15) below, and alkenyl group-containing organopolysiloxanes shown in (a-16) and (a-17) below were used.

[0065] [Preparation Example 6] 20.27 g of the organopolysiloxane represented by (a-1) above, 81.57 g of octamethylcyclotetrasiloxane, 1.62 g of hexamethyldisiloxane, and 0.17 g of trifluoromethanesulfonic acid were charged into a separable flask equipped with a stirrer and reflux tubing. The mixture was heated and stirred for 8 hours at a temperature of 50°C. 1.02 g of Kyoward® 500SH was added to this mixture and the mixture was stirred at room temperature for 2 hours to neutralize it. Subsequently, the low molecular weight siloxane was removed by tape stripping under reduced pressure of 15 mmHg at 120°C for 3 hours, and the solid was removed by filtration to obtain 82.77 g of a pale yellow, transparent organopolysiloxane. The obtained product was, 29 Si-NMR and 1 ¹H-NMR measurement confirmed that the substance was an organopolysiloxane as shown in (A-10) below. The obtained organopolysiloxane had a viscosity of 200 mPa·s and an alkenyl group content of 0.058 mol / 100g. [ka] (In the equation, b=2, c=6, d1=2, d2=110, and c / (b+c+d1+d2)=0.05, -C 10 H 19 (It has a double bond at the end of its molecular chain.) Organopolysiloxanes represented by [a specific symbol / method].

[0066] [Preparation Example 7] In Preparation Example 6 described above, 20.27 g of the organopolysiloxane represented by formula (a-1) was replaced with 15.22 g of the organopolysiloxane represented by formula (a-2) described above, and Preparation Example 6 was repeated to obtain 77.43 g of the organopolysiloxane represented by the following formula (A-11). This organopolysiloxane has a viscosity of 190 mPa·s and an alkenyl group content of 0.061 mol / 100 g. [ka] (In the formula, b=2, c=6, d1=2, d2=108, c / (b+c+d1+d2)=0.05, and -C4H7 has a double bond at the end of the molecular chain.) Organopolysiloxanes represented by [a specific symbol / method].

[0067] [Preparation Example 8] The above preparation example 6 was repeated except that 20.27 g of the organopolysiloxane represented by formula (a-1) was replaced with 23.64 g of the organopolysiloxane represented by formula (a-3) to obtain 83.24 g of the organopolysiloxane represented by the following formula (A-12). This organopolysiloxane has a viscosity of 210 mPa·s and an alkenyl group content of 0.056 mol / 100 g. [ka] (In the equation, b=2, c=6, d1=2, d2=112, and c / (b+c+d1+d2)=0.05, -C 10 H 19 (It has a double bond at the end of its molecular chain.)

[0068] [Preparation Example 9] The above preparation example 6 was repeated except that 20.27 g of the organopolysiloxane represented by formula (a-1) was replaced with 17.07 g of the organopolysiloxane represented by formula (a-4) to obtain 79.89 g of the organopolysiloxane represented by the following formula (A-13). This organopolysiloxane has a viscosity of 190 mPa·s and an alkenyl group content of 0.059 mol / 100 g. [ka] (In the equation, b=2, c=6, d=111, and c / (b+c+d)=0.05, -C 10 H 19 (It has a double bond at the end of its molecular chain.)

[0069] Organopolysiloxanes shown in the following average composition formulas (A-14) and (A-15) were obtained using the same manufacturing method as in the above preparation examples 6 to 9. (A-14): [ka] (In the equation, b=2, c=10, d1=3, d2=180, and c / (b+c+d1+d2)=0.05, -C 10 H 19 (It has a double bond at the end of its molecular chain.) Organopolysiloxanes represented by [a specific symbol / method]. (A-15): Average composition formula [ka] (In the equation, b=2, c=12, d1=4, d2=105, and c / (b+c+d1+d2)=0.098, -C 10 H 19 (It has a double bond at the end of its molecular chain.) Organopolysiloxanes represented by [a specific symbol / method].

[0070] The following organopolysiloxanes were used as comparative components. (a-16): Organopolysiloxane represented by the following average composition formula (manufactured by Shin-Etsu Chemical Co., Ltd.). [ka] (In the equation, a=2, b=6, and c=112, and b / (a+b+c)=0.05.) (a-17): Organopolysiloxane represented by the following average composition formula (manufactured by Shin-Etsu Chemical Co., Ltd.). [ka] (In the equation, a'=2 and c=100, and a' / (a'+c)=0.02.)

[0071] (B) The crosslinking agents used in the examples and comparative examples are as follows. (B-1): Average unit formula: [(CH3)3SiO 1 / 2 ]2[H(CH3)SiO 2 / 2 ] 38 Organohydrogenpolysiloxanes (B-2): Average unit formula: [(CH3)3SiO 1 / 2 ]2[(CH3)2SiO 2 / 2 ] 28 [H(CH3)SiO 2 / 2 ] 70 Organohydrogenpolysiloxanes

[0072] (C) The platinum group metal catalysts used in the examples and comparative examples are as follows. (C-1): A platinum group metal catalyst prepared by diluting the reaction product of platinum and 1,3-divinyltetramethyldisiloxane with toluene to a platinum content of 0.50% by mass.

[0073] Other components used in the examples and comparative examples are as follows: (D-1) Toluene (D-2) Methyl ethyl ketone (E-1)1-ethynyl-1-cyclohexanol

[0074] [Manufacture and curing of solvent-based curable organopolysiloxane compositions] A solvent-curable silicone composition was obtained by mixing components (A) to (E) as shown in Table 1 below. Each of the resulting solvent-curable organopolysiloxane compositions was coated onto polyethylene laminate paper using a bar coater and heated in a hot air dryer at 120°C for 30 seconds to a thickness of 0.6-0.8 g / m². 2 A release paper having a cured coating was obtained.

[0075] [Manufacture and curing of solvent-free curable organopolysiloxane compositions] A solvent-free curable silicone composition was obtained by mixing components (A) to (C) and (E) as shown in Table 2 below. Each of the obtained solvent-free curable organopolysiloxane compositions was applied to a metal roll of an RI tester (manufactured by IHI Machinery Systems Co., Ltd.), the metal roll was pressed against a rubber roll, and the two rolls were rotated for 45 seconds to stretch the composition uniformly. The composition was then transferred from the rubber roll to polyethylene laminate paper. The polyethylene laminate paper with the transferred composition was heated in a 120°C hot air dryer for 30 seconds to a thickness of 0.9-1.1 g / m². 2 A release paper having a cured coating was obtained.

[0076] [Low-speed peeling force] The release paper obtained as described above was aged at 25°C for 24 hours. Then, a 25mm wide acrylic adhesive tape, TESA-7475 (tesa UK Ltd), was attached to the hardened surface of the release paper, and it was cut to a size of 25mm x 23cm. This was sandwiched between glass plates and aged at 25°C at a rate of 70g / cm². 2 The sample was prepared after aging for 24 hours under the specified load. The TESA-7475 tape sample was peeled off at a 180° angle at 0.3 m / min using a tensile testing machine (DSC-500, manufactured by Shimadzu Corporation), and the force required for peeling was measured. The results are shown in Tables 1 and 2.

[0077] [High-speed peeling force] After aging the release paper obtained by the above curing method at 25°C for 24 hours, a 25mm wide acrylic adhesive tape TESA-7475 (tesa UK Ltd) was attached to the cured surface of the release paper, and it was cut to a size of 25mm x 23cm. This was sandwiched between glass plates and cured at 25°C at a rate of 70g / cm². 2 The sample was prepared after aging under a load for 24 hours. The TESA-7475 tape sample was peeled off at a 180° angle at 60 m / min using a tensile testing machine (DSC-500, manufactured by Shimadzu Corporation), and the force required for peeling was measured. The results are shown in Tables 1 and 2.

[0078] [Residual adhesion rate] A release layer was formed in the same manner as the above-mentioned curability evaluation. An acrylic adhesive tape TESA-7475 (tesa UK Ltd) with a width of 25 mm was attached to the surface of the release layer, and it was heat-treated for 20 hours under a load of 70 g / cm in a dryer at 25°C. 2 After that, the 25-mm-wide adhesive tape of the sample was peeled off from the release layer and attached to a stainless steel plate. Then, using a tensile testing machine (AGS-50G type manufactured by Shimadzu Corporation), the 25-mm-wide adhesive tape was peeled off from the stainless steel plate, and the peel strength X was measured. Also, a 25-mm-wide adhesive tape that was not laminated to the release layer was attached to the stainless steel plate, and using a tensile testing machine, the 25-mm-wide adhesive tape was peeled off from the stainless steel plate, and the peel strength Y was measured. And the residual adhesion rate was determined from the formula of (peel strength X / peel strength Y)×100 (%). The higher the residual adhesion rate, the better the peelability of the release layer, which indicates that the decrease in the adhesive strength of the 25-mm-wide adhesive tape due to lamination to the release layer is suppressed, that is, the bleed-out from the film is suppressed. The results are shown in Tables 1 and 2.

[0079] [Exposure resistance] The exposure resistance of the release agent layer was evaluated for the above solvent-type curable organopolysiloxane. The release paper obtained by the above curing method was aged for 24 hours in each case when stored indoors at 25°C with the release agent layer facing down (no atmospheric exposure) and when stored with the release agent layer facing up (with atmospheric exposure). Then, a 50-mm-wide acrylic double-sided adhesive tape Nitto 502 (manufactured by Nitto Denko Corporation) was laminated to the cured film surface of the release paper and cut into a size of 50 mm×23 cm. This was sandwiched between glass plates and at room temperature under 35 g / cm 2Samples were prepared after aging for 24 hours under a load. The Nitto 502 tape samples were peeled at a 180° angle at 0.3 m / min using a tensile testing machine (Shimadzu Corporation DSC-500). The force required to peel the adhesive tape was measured for both the release agent layer exposed to air and the release agent layer not exposed to air. A smaller difference between the release agent layer exposed to air and the release agent layer indicates better exposure resistance. The results are shown in Table 1.

[0080] [Table 1]

[0081] [Table 2]

[0082] As shown in Tables 1 and 2 above, the curable organopolysiloxane composition of the present invention exhibits light peeling force at both low-speed and high-speed peeling, regardless of whether it is a solvent-based or solvent-free type. Furthermore, as shown in Table 1 above, the solvent-curable organopolysiloxane composition of the present invention can form a cured film that exhibits good exposure resistance. Therefore, the curable organopolysiloxane composition of the present invention is suitable as a release coating agent for release paper and release sheets.

Claims

1. A curable organopolysiloxane composition containing the following components (A) to (C) (A) Alkenyl group-containing organopolysiloxane represented by the following average composition formula (1): 100 parts by mass, 【Chemistry 1】 (In the formula, R １ These are, independently of each other, alkenyl groups having 3 to 20 carbon atoms, and R ２ R represents a linking group, which is a divalent hydrocarbon group having 1 to 10 carbon atoms, and R ３ (These groups are independently selected from substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkyl halogen groups having 1 to 10 carbon atoms, organic groups having a hydroxyl group, and organic groups having an acyloxy group, and furthermore, a, b, c, d, e, f, and g satisfy a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, a+c+e is 1 or greater, and 2≦a+b+c+d+e+f+g≦15000) (B) Organohydrogenpolysiloxane having an average of two or more silicon-bonded hydrogen atoms (Si-H groups) in one molecule: an amount in which the number of moles of Si-H groups in component (B) is 0.5 to 10 times the number of moles of alkenyl groups in component (A), and (C) Platinum group metal catalyst: catalyst amount.

2. In the above average composition formula (1), the R １ The curable organopolysiloxane composition according to claim 1, wherein the siloxane units having the above are 0.1 to 50% of the total number of siloxane units.

3. In the above average composition formula (1), R １ The curable organopolysiloxane composition according to claim 1, wherein each of the members is an alkenyl group having 5 to 12 carbon atoms, independently of the others.

4. In the above average composition formula (1), R ２ The curable organopolysiloxane composition according to claim 1, wherein each is independently a divalent hydrocarbon group having 1 to 7 carbon atoms.

5. The curable organopolysiloxane composition according to claim 1, wherein in the above average composition formula (1), a = 0 and e = 0.

6. The organopolysiloxane is a linear organopolysiloxane that may have branching, and in the above average composition formula (1), a and b are 2 ≤ a + b ≤ 20, 1 ≤ c, 0 ≤ d, and 1 ≤ c + d ≤ 15000, e = 0, 0 ≤ f ≤ 14, 0 ≤ g ≤ 8, and a + c is the R １ The curable organopolysiloxane composition according to claim 1, wherein the number of siloxane units having the specified value is 0.1 to 50% of the total number of siloxane units.

7. Furthermore, the curable organopolysiloxane composition according to claim 1, further containing (D) solvent in parts 10 to 100,000 parts by mass per 100 parts by mass of component (A).

8. Furthermore, the curable organopolysiloxane composition according to claim 1, further comprising (E) a reaction control agent in an amount of 0.01 to 5 parts by mass per 100 parts by mass of component (A).

9. The curable organopolysiloxane composition according to claim 1, which is solvent-free and does not contain any solvents.

10. A release coating agent comprising a curable organopolysiloxane composition according to any one of claims 1 to 9.

11. Release paper comprising a base material and a cured layer of a curable organopolysiloxane composition according to any one of claims 1 to 9, wherein the cured layer is laminated on at least one surface of the base material.

12. A release film comprising a substrate and a cured layer of a curable organopolysiloxane composition according to any one of claims 1 to 9, wherein the cured layer is laminated on at least one surface of the substrate.

13. A method for producing release paper according to claim 11, comprising the steps of applying a curable organopolysiloxane composition according to any one of claims 1 to 9 to at least one surface of the substrate, and curing the curable organopolysiloxane composition to obtain a cured layer.

14. A method for producing a release film according to claim 12, comprising the steps of applying a curable organopolysiloxane composition according to any one of claims 1 to 9 to at least one surface of the substrate, and curing the curable organopolysiloxane composition to obtain a cured layer.

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