Addition-curing type release silicone composition for silicone adhesives

Abstract

The present invention is an addition-curable mold-releasing silicone composition that is for a silicone adhesive and that comprises: (A) a fluorine-containing organopolysiloxane which has at least two alkenyl groups bonded to a silicon atom per molecule and at least one fluorine-containing substituent bonded to a silicon atom, which has a fluorine content of 25-50 mass%, and in which in a molecular weight distribution measurement performed via gel permeation chromatography analysis, the peak area of a component having a molecular weight of not more than 4,000 is 2-20% of the total peak area; (B) an organohydrogen polysiloxane which has at least three hydrogen atoms (SiH groups) bonded to a silicon atom per molecule; (C) a platinum group metal catalyst; and (D) a non-fluorine based solvent. Thus, provided is a silicone composition for a mold releasing agent that can be diluted with a non-fluorine based solvent, that exhibits high coatability and adhesiveness with respect to a film base material, that exhibits low peeling force, and that can provide a cured coating in which there is little reduction in residual adhesion rate.

Description

[Technical Field]

[0001] The present invention relates to an addition-curing type release silicone composition for silicone adhesives that can be diluted with non-fluorine solvents (i.e., organic solvents that do not contain halogen atoms in their molecules), including non-halogen solvents (i.e., organic solvents that do not contain halogen atoms in their molecules), exhibits good release properties for silicone adhesives, and has excellent transparency and adhesion. [Background technology]

[0002] Conventionally, to prevent adhesion or fixation between a substrate such as paper or plastic film and a pressure-sensitive adhesive substance such as silicone adhesive, a cured film of a silicone composition has been formed on the outer surface of the substrate to provide release properties against the pressure-sensitive adhesive substance. This is generally referred to as release paper.

[0003] Among the pressure-sensitive adhesive materials mentioned above, silicone adhesives with organopolysiloxane as the main component are used in a wide range of applications due to their excellent heat resistance, cold resistance, chemical resistance, electrical insulation properties, and low toxicity. Because silicone adhesives have very strong adhesive strength, in order to allow adhesive tapes and labels coated with them to be easily peeled off the substrate, it is necessary to make the silicone cured film formed on the substrate have excellent release properties.

[0004] Patent Document 1 describes a silicone composition that provides a silicone cured film with excellent mold release properties, C n F 2n+1 The document describes organopolysiloxane compositions having fluorine-containing substituents represented as CH2CH2- (where n is an integer greater than or equal to 1). Furthermore, Patent Document 2 describes F-[CF(CF3)CF2O] n Organopolysiloxane compositions having fluorine-containing substituents represented as CF(CF3)CF2OCH2CH2CH2- (where n is an integer from 1 to 5) have been proposed.

[0005] When applying these organopolysiloxane compositions to a substrate, they are used diluted with an organic solvent. In this case, a fluorine-based solvent (i.e., an organic solvent containing fluorine atoms in its molecule) is preferably used as the organic solvent due to its solubility of the fluorine-containing organopolysiloxane composition and its coating properties onto the substrate.

[0006] However, while fluorinated solvents can sufficiently dilute fluorinated organopolysiloxanes, they are expensive and pose a problem as they can have adverse effects on the natural environment if dispersed into the atmosphere.

[0007] Patent Document 3 proposes a silicone composition for release paper having a fluorine-containing substituent as a silicone composition that can be diluted with a non-fluorine solvent and provides a silicone cured coating with excellent release properties.

[0008] However, when this silicone release agent composition is dissolved in a non-fluorinated solvent, the release force tends to be higher than when diluted in a fluorinated solvent. Furthermore, although Patent Document 3 does not describe coating properties or adhesion, when the silicone release paper composition is dissolved in a non-fluorinated solvent, the coating properties to the substrate may be worse compared to when diluted in a fluorinated solvent. If the coating properties to the substrate are poor, the parts of the substrate that are not covered with the silicone release agent composition will come into contact with the adhesive, and the release force will become significantly heavier.

[0009] In addition, the silicone composition coating for release paper obtained by dissolving it in a non-fluorine solvent has poor adhesion to the film substrate, and the release layer may detach from the substrate over time.

[0010] Patent Document 4 proposes a method for improving coating properties by adding a linear perfluoropolyether-based defoaming agent to a silicone composition for mold release. However, since the above-mentioned linear perfluoropolyether-based defoaming agent does not have reactive functional groups, it is not incorporated into the crosslinking and may migrate to the adhesive layer side when the adhesive is peeled off, reducing the residual adhesion rate.

[0011] A known method for improving adhesion involves adding functional compounds that interact with the substrate. However, because these substrate functional compounds have low compatibility with silicone compositions, compositions containing these compounds may experience separation of the substrate functional compounds during long-term storage and transportation. Using a composition that has separated may result in a loss of performance. Furthermore, the substrate functional compounds may migrate to the adhesive layer during adhesive removal, reducing the residual adhesion rate.

[0012] As described above, no adhesive release silicone composition is known in the conventional technology that can be diluted with a non-fluorine solvent and possesses sufficient coating properties to completely cover the substrate, adhesion that prevents detachment from the substrate over time, release properties that show slight peeling even with highly adhesive adhesives, and a residual adhesion rate. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Special Publication No. 5-7434 [Patent Document 2] Special Publication No. 4-76391 [Patent Document 3] Japanese Patent Application Publication No. 7-18185 [Patent Document 4] Japanese Patent Publication No. 2004-300414 [Overview of the project] [Problems that the invention aims to solve]

[0014] The present invention has been made in view of the above circumstances, and aims to provide a silicone composition for mold release agents that can be diluted with a non-fluorine solvent, has high coatability and adhesion to film substrates, has low peeling force, and provides a cured film with minimal reduction in residual adhesion. [Means for solving the problem]

[0015] To solve the above problems, the present invention provides: (A) A fluorine-containing organopolysiloxane having at least two alkenyl groups bonded to a silicon atom and at least one fluorine-containing substituent bonded to a silicon atom in one molecule, having a fluorine content of 25-50% by mass, and having a peak area of ​​2-20% of the total peak area of ​​components with a molecular weight of 4,000 or less as measured by molecular weight distribution analysis by gel permeation chromatography: 100 parts by mass, (B) Organohydrogenpolysiloxane having at least 3 hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule: an amount such that the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.1 to 15. (C) Platinum group metal catalyst: 0.5 to 5,000 ppm of platinum group metal in terms of mass relative to the above (A) component. (D) Non-fluorinated solvent: 100 to 20,000 parts by mass, The present invention provides an addition-curing type release silicone composition for silicone adhesives that contains [the specified ingredient].

[0016] Such an addition-curing type release silicone composition for silicone adhesives can be diluted with a non-fluorine solvent, and provides a release silicone composition that yields a cured film with high coatability and adhesion to film substrates, low peeling force, and minimal reduction in residual adhesion.

[0017] Furthermore, the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is preferably 0.5 to 5.

[0018] Such an addition-curing type release silicone composition for silicone adhesives can provide a release silicone composition with better coating properties, adhesion, and release properties.

[0019] Furthermore, the above-mentioned component (D) is preferably a non-fluorinated solvent with an SP value of 10.0 or less.

[0020] Such an addition-curing type release silicone composition for silicone adhesives can provide a release silicone composition in which component (A) dissolves more effectively.

[0021] Furthermore, it is preferable that component (D) is at least one selected from hydrocarbon solvents, ketone solvents, ether solvents, and ester solvents.

[0022] Such an addition-curing type release silicone composition for silicone adhesives can provide a release silicone composition in which component (A) dissolves more effectively.

[0023] Furthermore, the present invention provides a release film in which a cured layer of the above-mentioned addition-curing type release silicone composition for silicone adhesives is formed on at least one outer surface of the film substrate.

[0024] Such a release film can provide a release film with excellent release properties.

[0025] Furthermore, the present invention provides release paper in which a cured layer of the above-mentioned addition-curing type release silicone composition for silicone adhesives is formed on at least one outer surface of the paper substrate.

[0026] With this type of release paper, it is possible to provide release paper with excellent release properties. [Effects of the Invention]

[0027] As described above, the present invention provides a silicone composition for mold release agents that can be diluted with a non-fluorine solvent, has high coatability and adhesion to film substrates, low peeling force, and provides a cured film with minimal reduction in residual adhesion. [Modes for carrying out the invention]

[0028] The inventors conducted diligent studies to achieve the above objectives and have found that (A) a fluorine-containing organopolysiloxane having at least two alkenyl groups bonded to silicon atoms and at least one fluorine-containing substituent bonded to silicon atoms in one molecule, having a fluorine content of 25 to 50% by mass, and having a peak area of ​​components with a molecular weight of 4,000 or less that accounts for 2 to 20% of the total peak area in molecular weight distribution measurements by gel permeation chromatography analysis, and (B) having at least three hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. By blending organohydrogenpolysiloxane, (C) a platinum group metal catalyst, and (D) a non-fluorinated solvent in specific ratios, we were able to obtain a silicone composition for mold release that provides a cured film with high coatability and adhesion to film substrates, low peeling force, and minimal reduction in residual adhesion. Furthermore, since this composition does not contain a fluorinated solvent, a mold release silicone cured film can be produced inexpensively and without the risk of air pollution. Moreover, we discovered that this cured film has excellent water repellency, oil repellency, and heat resistance, leading to the present invention.

[0029] In other words, the present invention is (A) A fluorine-containing organopolysiloxane having at least two alkenyl groups bonded to a silicon atom and at least one fluorine-containing substituent bonded to a silicon atom in one molecule, having a fluorine content of 25-50% by mass, and having a peak area of ​​2-20% of the total peak area of ​​components with a molecular weight of 4,000 or less as measured by molecular weight distribution analysis by gel permeation chromatography: 100 parts by mass, (B) Organohydrogenpolysiloxane having at least 3 hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule: an amount such that the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.1 to 15. (C) Platinum group metal catalyst: 0.5 to 5,000 ppm of platinum group metal in terms of mass relative to component (A) above. (D) Non-fluorinated solvent: 100 to 20,000 parts by mass, This is an addition-curing type release silicone composition for silicone adhesives that contains [the specified ingredient].

[0030] The present invention will be described in more detail below, but the present invention is not limited thereto.

[0031] [(A) component] The fluorine-containing organopolysiloxane of component (A) has at least two alkenyl groups bonded to silicon atoms and at least one fluorine-containing substituent bonded to silicon atoms in one molecule, has a fluorine content of 25 to 50% by mass, and in molecular weight distribution measurement by gel permeation chromatography analysis, the peak area of ​​components with a molecular weight of 4,000 or less accounts for 2 to 20% of the total peak area. This fluorine-containing organopolysiloxane acts as the main component (base polymer) of the addition-curing type release silicone composition for silicone adhesives of the present invention.

[0032] (A) The fluorine-containing organopolysiloxane may be linear or branched, but is particularly represented by the following formula (1), in which the molecular chain main chain consists of repeating difunctional diorganosiloxane units, and some or all of the diorganosiloxane units in the main chain have a fluorine-containing substituent bonded to a silicon atom (i.e., a monovalent hydrocarbon group which may contain an ether-bonded oxygen atom (-O-) in which some or all of the hydrogen atoms bonded to a carbon atom are replaced by fluorine atoms). Preferably, a linear fluorine-containing organopolysiloxane is used, which is a unit in which both ends of the molecular chain are sealed with triorganosiloxy groups (alkenyldiorganosiloxy group, dialkenylorganosiloxy group, or trialkenylsiloxy group) having alkenyl groups, and which has at least two alkenyl groups bonded to silicon atoms at both ends of the molecular chain, or at least two alkenyl groups bonded to silicon atoms at the end of the molecular chain and silicon atoms at the non-terminus (middle of the molecular chain) of the molecular chain. [ka]

[0033] Here, R 1These are alkenyl groups having 2 to 10 carbon atoms, specifically including vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, hexenyl, and cyclohexenyl groups.

[0034] R 2 These are monovalent hydrocarbon groups excluding unsubstituted or substituted aliphatic unsaturated groups having 1 to 10 carbon atoms. Specifically, examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, 2-ethylhexyl, nonyl, and decyl groups, aryl groups such as phenyl and tolyl groups, aralkyl groups such as benzyl and phenylethyl groups, and hydroxypropyl and cyanoethyl groups, in which some or all of the hydrogen atoms of these groups are substituted with hydroxyl or cyano groups.

[0035] In the above formula, a is 1, 2, or 3, and x, y, and z are integers such that x≧1, y≧0, and z≧0, respectively. Preferably, x is an integer from 10 to 150, y is an integer from 50 to 400, and z is an integer from 0 to 10. More preferably, x is an integer from 50 to 130, y is an integer from 100 to 350, and z is an integer from 0 to 5. The values ​​of x+y+z are appropriately controlled so that the fluorine content in the molecule is 25 to 50% by mass.

[0036] In formula (1), examples of fluorine-containing substituents represented by Rf (i.e., monovalent hydrocarbon groups in which some / all of the hydrogen atoms bonded to a carbon atom are replaced with fluorine atoms, and which may contain ether-bonded oxygen atoms (-O-)) include monovalent fluorine-containing substituents represented by formula (2) below (i.e., perfluoroalkyl groups, polyfluoroalkyl groups, perfluorooxyalkyl groups (monovalent perfluoropolyether groups), or polyfluorooxyalkyl groups (monovalent polyfluoropolyether groups)).

[0037] Formula (2): F(CH n1 F 2-n1 O) b1 (CHn2 F 2-n2 CH n3 F 2-n3 O) b2 (CH n4 F 2-n4 CH n5 F 2-n5 CH n6 F 2-n6 ) b3 [CF(CF3)CH n7 F 2-n7 O] b4 [CH n8 F 2-n8 CF(CF3)O] b5 (CH n9 F 2-n9 CH n10 F 2-n10 CH n11 F 2-n11 CH n12 F 2-n12 ) b6 [CF(CF3)CH n13 F 2-n13 CH n14 F 2-n14 ] b7 [CH n15 F 2-n16 CF(CF3)CH n17 F 2-n17 ] b8 [CH n18 F 2-n18 CH n19 F 2-n19 CF(CF3)] b9 (CH n20 F 2-n20 CH n21 F 2-n21 CH n22 F 2-n22 CH n23 F 2-n23 CH n24 F 2-n24 ) b10 [CF(CF3)CH n25 F 2-n25 CH n26 F 2-n26 CH n27 F 2-n27 ] b11 [CH n28 F 2-n28 CF(CF3)CH n29 F 2-n29 CH n30 F2-n30 ] b12 [CH n31 F 2-n31 CH n32 F 2-n32 CF(CF3)CH n33 F 2-n33 ] b13 [CH n34 F 2-n34 CH n35 F 2-n35 CH n36 F 2-n36 CF(CF3)] b14 (CH n37 F 2-n37 CH n38 F 2-n38 CH n39 F 2-n39 CH n40 F 2-n40 CH n41 F 2-n42 CH n43 F 2-n43 ) b15 [CF(CF3)CH n44 F 2-n44 CH n45 F 2-n45 CH n46 F 2-n46 CH n47 F 2-n47 O] b16 [CH n48 F 2-n48 CF(CF3)CH n49 F 2-n49 CH n50 F 2-n50 CH n51 F 2-n51 O] b17 [CH n52 F 2-n52 CH n53 F 2-n53 CF(CF3)CH n54 F 2-n54 CH n55 F 2-n55 O] b18 [CH n56 F 2-n56 CH n57 F 2-n57 CH n58 F 2-n58 CF(CF3)CH n59 F 2-n59 O] b19 [CHn60 F 2-n60 CH n61 F 2-n61 CH n62 F 2-n62 CH n63 F 2-n63 CF(CF3)O] b20 [CF(CF3)] b21 (CH n64 F 2-n64 ) b22 -X-[CF(CF3)] b23 (CH n65 F 2-n65 ) b24 - (In the formula, b1 to b24 are integers of 0 or greater, provided that at least one of b1 to b22 is an integer of 1 or greater. Preferably, the sum of b1 to b22 is 25 or less, and preferably the sum of b23 and b24 is 8 or less. n1 to n65 are each independently 0, 1, or 2. X is an oxygen atom or a single bond.)

[0038] In the above formula, each repeating unit to the left of "-X-" may be randomly combined with the repeating unit to the right of "-X-", namely the [CF(CF3)] unit and (CH n65 F 2-n65 The units themselves may also be combined randomly.

[0039] Among the fluorine-containing substituents represented by Rf, it is more preferable that the fluoro(poly)ether-containing organic group (perfluorooxyalkyl group or polyfluorooxyalkyl group) is a group represented by any of the following formulas (3), (4), or (5).

[0040] Equation (3): F[CF(CF3)CF2O] c1 [CF(CF3)CH2O] c2 (CF2) c3 (CH2) c4 - (In the formula, c1 to c4 are each integers greater than or equal to 0, c1 + c2 is an integer greater than or equal to 1, and c3 + c4 is an integer greater than or equal to 0. It is preferable that c1 + c2 is 25 or less, more preferably 15 or less, and even more preferably 9 or less. It is preferable that c3 + c4 is 8 or less. Also, F[CF(CF3)CF2O] c1 [CF(CF3)CH2O] c2 (CF2) c3 (CH2) c4 The repeating units within the dashes may be combined randomly.

[0041] Equation (4): F(CF2O) d1 (CF2CF2O) d2 (CF2CF2CF2O) d3 [CF(CF3)CF2O] d4 (CF2) d5 -O-(CH2) d6 - (In the formula, d1 to d6 are integers greater than or equal to 0, and d1+d2+d3+d4 is an integer greater than or equal to 1. d1+d2+d3+d4 is preferably 25 or less, more preferably 15 or less, and even more preferably 9 or less. d6 is preferably 8 or less. Also, F(CF2O) d1 (CF2CF2O) d2 (CF2CF2CF2O) d3 [CF(CF3)CF2O] d4 (CF2) d5 The repeating units within the expression may be combined randomly.

[0042] Formula (5):F(CF2) e1 (CH2) e2 -O-(CH2) e3 - (In the formula, e1 and e2 are integers of 1 or more, and e3 is an integer of 0 or more. e1 is preferably 8 or less, and e2 and e3 are preferably 6 or less.)

[0043] Particularly preferred fluoro(poly)ether-containing organic groups include the following: F[CF(CF3)CF2O] f CF(CF3)CF2O(CH2)3- F[CF(CF3)CF2O] f CF(CF3)CH2O(CH2)3- F[CF(CF3)CF2O] f (CF2)2(CH2)2- F(CF2O) g [CF(CF3)CF2O] h CF2-O-(CH2)3- F(CF2O) g (CF2CF2O) h CF2-O-(CH2)3- F(CF2) i (CH2)2O(CH2)3- F(CF2) i (CH2)2-

[0044] In the above formula, f is preferably between 1 and 20, more preferably between 2 and 12, and most preferably between 3 and 9. g+h is preferably between 1 and 20, more preferably between 2 and 12, and most preferably between 3 and 9. i is preferably 15 or less, more preferably 10 or less, and most preferably 6 or less.

[0045] Examples of fluorine-containing organopolysiloxanes in component (A) include those represented by the following formula. [ka] (In the formula, Rf, x, y, and z have the same meanings as above, Me represents a methyl group, and Vi represents a vinyl group.)

[0046] The fluorine-containing organopolysiloxane in component (A) must have a fluorine content of 25 to 50% by mass, preferably 30 to 48% by mass, and more preferably 35 to 46% by mass. If the fluorine content in component (A) is less than 25% by mass, the resulting cured film will have high peeling strength against silicone adhesives, and if it is greater than 50% by mass, it will be insoluble in non-fluorine solvents.

[0047] Furthermore, the fluorine-containing organopolysiloxane of component (A) must be such that, in molecular weight distribution measurement by gel permeation chromatography (GPC) analysis, the peak area of ​​components with a molecular weight of 4,000 or less (for example, components with a molecular weight greater than 0 and 4,000 or less) is 2-20% (area %) of the total peak area (i.e., the total peak area of ​​component (A)). If the peak area of ​​components with a molecular weight of 4,000 or less is less than 2% of the total peak area in GPC analysis, the solubility in non-fluorine solvents and coating properties on substrates will be poor, and if it is greater than 20%, the adhesion to the substrate will be poor, and the residual adhesion rate will decrease significantly.

[0048] In this invention, the peak area ratio of components with a molecular weight of 4,000 or less refers to the ratio (area %) of the peak area of ​​components in the lower molecular weight region (i.e., components with a molecular weight greater than 0 and less than or equal to 4,000) to the total peak area (total peak area) of all components contained in the fluorine-containing organopolysiloxane of component (A), with the peak corresponding to a molecular weight of 4,000 serving as the boundary.

[0049] (A) The fluorine-containing organopolysiloxane may be used alone or in combination of two or more types.

[0050] [(B) Component] The organohydrogenpolysiloxane component (B) has at least three hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule, and a cured film is formed when these SiH groups and the alkenyl groups in component (A) undergo a hydrosilylation addition reaction, resulting in crosslinking and curing.

[0051] The organohydrogenpolysiloxane of component (B) may be linear, cyclic, branched, or have a three-dimensional network structure. It may also have a fluorine-containing substituent similar to Rf in formula (1) of component (A) above (i.e., a monovalent hydrocarbon group in which some / all of the hydrogen atoms bonded to a carbon atom are replaced by fluorine atoms, and which may contain an ether-bonded oxygen atom (-O-)) in the molecule (fluorine-containing organohydrogenpolysiloxane). For example, the main chain of the molecular chain represented by the following formula consists of repeating difunctional organo(hydrogen)siloxane units, or a copolymer of difunctional organo(hydrogen)siloxane units and difunctional diorganosiloxane units, and both ends of the molecular chain are sealed with a triorganosiloxy group or a diorgano(hydrogen)siloxy group, with hydrogen atoms (Si) bonded to silicon atoms at the non-terminus (middle of the molecular chain) being fused. A linear organohydrogenpolysiloxane (i.e., a triorganosiloxy-bound organo(hydrogen)polysiloxane has at least three of these in the molecule, or has at least three hydrogen atoms (SiH groups) bonded to silicon atoms at the non-terminus (middle of the molecule) and at least three hydrogen atoms (SiH groups) bonded to silicon atoms at both ends of the molecule. Organosiloxane / organo(hydrogen)siloxane copolymers, diorganopolysiloxanes with diorgano(hydrogen)siloxy group-blocked at both ends of the molecular chain, organo(hydrogen)polysiloxanes with diorgano(hydrogen)siloxy group-blocked at both ends of the molecular chain, and diorganosiloxane / organo(hydrogen)siloxane copolymers with diorgano(hydrogen)siloxy group-blocked at both ends of the molecular chain are preferably used. [ka]

[0052] In the above formula, R 3 R in equation (1) above 2and at least one group selected from groups similar to Rf, j is 0 or 1, and p and q are integers p≧1 and q≧0, respectively, preferably p is an integer from 3 to 150 and q is an integer from 0 to 150, more preferably p is an integer from 10 to 100 and q is an integer from 10 to 100. However, p is the number such that the number of hydrogen atoms (SiH groups) bonded to the silicon atom in the molecule is 3 or more.

[0053] (B) Examples of organohydrogenpolysiloxanes of component (B) are those represented by the following formula. [ka] (In the formula, Me represents a methyl group, p has the same meaning as above, q' is an integer from 1 to 100, r is an integer from 1 to 100, and q'+r is an integer from 2 to 150.)

[0054] The amount of organohydrogenpolysiloxane in component (B) is such that the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.1 to 15 (moles / mol), preferably 0.3 to 10, and more preferably 0.5 to 5. If the molar ratio of SiH groups in component (B) to alkenyl groups in component (A) is less than 0.1 or greater than 15, the curability of the desired addition-curing type release silicone composition for silicone adhesives will decrease, or the physical properties of the cured product will decrease.

[0055] (B) The organohydrogenpolysiloxane may be used alone or in combination of two or more types.

[0056] [(C) component] The platinum group metal catalyst of component (C) is a catalyst for promoting the hydrosilylation addition reaction between the alkenyl group in component (A) and the SiH group in component (B), and known reaction catalysts can be used. Examples of such platinum group metal catalysts include platinum-based, palladium-based, and rhodium-based catalysts, with platinum-based catalysts being particularly preferred among these. Examples of such platinum-based catalysts include chloroplatinic acid, alcoholic solutions of chloroplatinic acid, and complexes of chloroplatinic acid with various olefins or vinylsiloxanes.

[0057] The amount of these platinum group metal catalysts added should be in catalytic amounts, but from the viewpoint of reactivity and economics when obtaining a cured film, the amount is 0.5 to 5,000 ppm, preferably 1 to 1,000 ppm, and more preferably 5 to 300 ppm, as a mass equivalent of the platinum group metal relative to component (A). Below 0.5 ppm, curability decreases or adhesion to the substrate decreases. Above 5,000 ppm, the pot life of the treatment bath is shortened.

[0058] [(D) component] Component (D) is a non-fluorinated solvent (i.e., an organic solvent that does not contain fluorine atoms in its molecule), and the SP value of the non-fluorinated solvent is preferably 10.0 or less, more preferably 9.5 or less, and even more preferably 9.0 or less. If the SP value of the non-fluorinated solvent of component (D) is 10.0 or less, the fluorine-containing organopolysiloxane of component (A) can be sufficiently dissolved. There is no particular lower limit to the SP value, but for example it can be 5.0 or more, preferably 6.0 or more, and even more preferably 7.0 or more.

[0059] (D) The nonfluorine solvent is preferably a hydrocarbon solvent, ketone solvent, ether solvent or ester solvent, specifically aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane, nonane, isononane, decane, cyclohexane, methylcyclohexane, petroleum benzine, ligroin, industrial gasoline, naphtha solvent, aromatic hydrocarbon solvents such as toluene, xylene, acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, 2- Examples of solvents include ketone solvents such as heptanone, 3-heptanone, 4-heptanone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, and methyl propionate; and ether solvents such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, and 1,4-dioxane. These can be used individually or in combination of two or more.

[0060] The amount of the non-halogenated solvent for component (D) used is preferably such that the viscosity of the diluted silicone composition is 100 cp or less, from the viewpoint of workability and ease of controlling the amount of application when applying the silicone composition dissolved with it, and is 100 to 20,000 parts by mass per 100 parts by mass of component (A), preferably 500 to 15,000 parts by mass, more preferably 800 to 12,000 parts by mass, and even more preferably 1,000 to 3,000 parts by mass.

[0061] [Other ingredients] The addition-curing type release silicone composition for silicone adhesives of the present invention is obtained by blending predetermined amounts of the above components (A) to (D). In addition to the above components, other optional components, such as activity regulators such as various organic nitrogen compounds, organophosphorus compounds, organosilicon compounds, acetylene compounds, and oxime compounds, can be added for the purpose of controlling the catalytic activity of platinum group metal catalysts. Among the activity regulators, acetylene compounds such as 3-methyl-1-butyne-3-ol and their silylated compounds, and silicon compounds such as divinyltetramethyldisiloxane and tetravinyltetramethylcyclotetrasiloxane are preferably used.

[0062] The amount of activity regulator added is preferably 0.05 to 3 parts per 100 parts of component (A). If the amount is 0.05 parts or more, the target silicone composition will not gel, and if it is 3 parts or less, the curing of the silicone composition will not be inhibited. In addition, the amount of other optional components added can be the usual amount depending on the purpose.

[0063] [Preparation of addition-curing type release silicone composition for silicone adhesives] In preparing the addition-curing type release silicone composition for silicone adhesives of the present invention, it is preferable to uniformly mix components (A), (B), and (D) beforehand, and then add component (C) immediately before use. Each component may be used individually or in combination of two or more.

[0064] [Silicone hardened coating] The substrates to which the addition-curing type release silicone composition for silicone adhesives of the present invention is coated include paper, plastic film, metal, cloth, glass, etc. Examples of plastic films include polyester, polypropylene, polyethylene, polystyrene, polycarbonate, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyimide, polyamide, and polyphenylene sulfide. Examples of paper include paper substrates such as glassine paper, kraft paper, and clay-coated paper, and laminated paper substrates such as polyethylene laminated fine paper and polyethylene laminated kraft paper. Examples of metals include aluminum foil, copper foil, gold foil, and silver foil. Examples of cloth include natural fiber cloth, synthetic fiber cloth, and artificial leather. There are no particular restrictions on the thickness or type of glass, and it may be chemically strengthened or surface treated, and glass fibers can also be used.

[0065] Known methods such as bar coating, roll coating, gravure coating, knife coating, blade coating, spin coating, dipping, and cast coating can be used to apply the addition-curing type release silicone composition for silicone adhesives to these substrates.

[0066] Curing conditions for the addition-curing type release silicone composition for silicone adhesives of the present invention include, but are not limited to, heating the substrate coated with the silicone composition at a temperature of 80 to 250°C for 1 to 120 seconds, or curing by volatilizing the non-halogen solvent and then irradiating it with ultraviolet light from an ultraviolet irradiation device such as a high-pressure mercury lamp for 0.2 seconds or more.

[0067] The addition-curing type release silicone composition for silicone adhesives of the present invention provides a cured film with excellent coating properties, adhesion, and release properties to the substrate. Therefore, it is suitable for use as release paper for adhesive tapes and adhesive labels, and can also be suitably used as a release agent for molds used to mold rubber, plastics, etc., as a fiber treatment agent for paper, cloth, etc., as a water repellent, oil repellent, and heat-resistant coating agent for food packaging, etc. [Examples]

[0068] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. Note that "parts" means "parts by mass."

[0069] [Molecular weight distribution measurement] For the fluorine-containing organopolysiloxanes of component (A), the molecular weight distribution was measured using gel permeation chromatography (GPC) under the following conditions, and for each fluorine-containing organopolysiloxane, the ratio (%) of the peak area of ​​components with a molecular weight greater than 0 and less than or equal to 4,000 relative to the total peak area in the molecular weight distribution measurement of GPC was calculated.

[0070] Measurement conditions Developing solvent: Hydrochlorofluorocarbon (HCFC)-225 Flow rate: 1mL / min Detector: Evaporative light scattering detector Columns: Two TSKgel Multipore HXL-M columns (7.8mm diameter x 30cm) manufactured by Tosoh Corporation were used. Column temperature: 35℃ Sample injection volume: 100 μL (solution with a concentration of 0.1% by mass) Standard sample: PMMA CALIBRATION KIT ML-10, manufactured by Agilent Technologies.

[0071] (Synthesis Example 1) Synthesis of fluorine-containing organopolysiloxane (A-1) [ka] Me represents a methyl group.

[0072] [ka] Vi represents the vinyl group.

[0073] [ka]

[0074] 100 parts of cyclotrisiloxane (6) having a fluorine substituent, 0.27 parts of cyclomethylvinyltrisiloxane (7), and 0.21 parts of 1,1,3,3,-tetramethyl-1,3-divinyldisiloxane (8) were mixed and stirred, and 0.01 parts of trifluoromethanesulfonic acid were added. The mixture was reacted (equilibriumized) at 50°C for 7 hours. Then, 0.2 parts of 28% aqueous ammonia were added and the mixture was stirred at room temperature for 1 hour. The resulting salt was filtered through filter paper, stripped at 200°C and 3 mmHg for 30 minutes, and then GPC measurement was performed. If the area of ​​components with a molecular weight greater than 0 and less than or equal to 4,000 in the GPC measurement did not fall within the range of 2-20% of the total peak area, the strip was repeated under the same conditions and GPC measurement was performed again. This procedure was repeated until the area of ​​the components with a molecular weight greater than 0 and less than or equal to 4,000 in the GPC measurement fell within the range of 2-20% of the total peak area, thereby obtaining the fluorine-containing organopolysiloxane (A-1) shown in Table 1. The fluorine content of this fluorine-containing organopolysiloxane was 44.0% by mass, and the peak area of ​​the components with a molecular weight of 4,000 or less in the total peak area in the GPC measurement was 14%.

[0075] (A-1) [ka]

[0076] (Synthesis Example 2) Synthesis of fluorine-containing organopolysiloxane (A-2) [ka]

[0077] Fluorine-containing organopolysiloxane (A-2) was synthesized in the same manner as in Synthesis Example 1, except that 100 parts of cyclotrisiloxane (6) having a fluorine substituent, 0.36 parts of cyclomethylvinyltrisiloxane (7), 0.28 parts of 1,1,3,3,-tetramethyl-1,3-divinyldisiloxane (8), and 10.2 parts of cyclodimethyltrisiloxane (9) were used. The fluorine content of the fluorine-containing organopolysiloxane was 40.0% by mass, and the peak area of ​​components with a molecular weight of 4,000 or less accounted for 8% of the total peak area in the GPC measurement.

[0078] (A-2) [ka]

[0079] (Synthesis Example 3) Synthesis of fluorine-containing organopolysiloxane (A-3) Fluorine-containing organopolysiloxane (A-3) was synthesized in the same manner as in Synthesis Example 1, except that 100 parts of cyclotrisiloxane (6) having a fluorine substituent, 0.49 parts of cyclomethylvinyltrisiloxane (7), 0.39 parts of 1,1,3,3,-tetramethyl-1,3-divinyldisiloxane (8), and 25.4 parts of cyclodimethyltrisiloxane (9) were used. The fluorine content of the fluorine-containing organopolysiloxane was 35.0% by mass, and the peak area of ​​components with a molecular weight of 4,000 or less accounted for 16% of the total peak area in the GPC measurement.

[0080] (A-3) [ka]

[0081] (Synthesis Example 4) Synthesis of fluorine-containing organopolysiloxane (A-4) [ka]

[0082] Fluorine-containing organopolysiloxane (A-4) was synthesized in the same manner as in Synthesis Example 1, except that 100 parts of cyclotrisiloxane (10) having a fluorine substituent, 0.22 parts of cyclomethylvinyltrisiloxane (7), 0.17 parts of 1,1,3,3,-tetramethyl-1,3-divinyldisiloxane (8), and 11.8 parts of cyclodimethyltrisiloxane (9) were used. The fluorine content of the fluorine-containing organopolysiloxane was 52.0% by mass, and the peak area of ​​components with a molecular weight of 4,000 or less accounted for 8% of the total peak area in the GPC measurement.

[0083] (A-4) [ka]

[0084] (Synthesis Example 5) Synthesis of fluorine-containing organopolysiloxane (A-5) Fluorine-containing organopolysiloxane (A-5) was synthesized in the same manner as in Synthesis Example 1, except that 100 parts of cyclotrisiloxane (6) having a fluorine substituent, 1.52 parts of cyclomethylvinyltrisiloxane (7), 1.21 parts of 1,1,3,3,-tetramethyl-1,3-divinyldisiloxane (8), and 141.9 parts of cyclodimethyltrisiloxane (9) were used. The fluorine content of the fluorine-containing organopolysiloxane was 18.0% by mass, and the peak area of ​​components with a molecular weight of 4,000 or less accounted for 14% of the total peak area in the GPC measurement.

[0085] (A-5) [ka]

[0086] (Synthesis Example 6) Synthesis of fluorine-containing organopolysiloxane (A-6) Fluorine-containing organopolysiloxane (A-6) was synthesized in the same manner as in Synthesis Example 1, except that the GPC measurement was repeated until the peak area of ​​components with a molecular weight of 4,000 or less accounted for less than 2% of the total peak area. The fluorine content of the fluorine-containing organopolysiloxane was 44.0% by mass, and the peak area of ​​components with a molecular weight of 4,000 or less accounted for 0.5% of the total peak area in the GPC measurement.

[0087] (Synthesis Example 7) Synthesis of fluorine-containing organopolysiloxane (A-7) Fluorine-containing organopolysiloxane (A-7) was synthesized in the same manner as in Synthesis Example 1, except that the strip conditions were limited to 100°C and 30 mmHg for 30 minutes. The fluorine content of the fluorine-containing organopolysiloxane was 44.0% by mass, and the peak area of ​​components with a molecular weight of 4,000 or less accounted for 28% of the total peak area in the GPC measurement.

[0088] (Synthesis Example 8) Synthesis of fluorine-containing organohydrogenpolysiloxane (B-1) [ka]

[0089] [ka]

[0090] 100 parts of organohydrogenpolysiloxane (11) and 194 parts of allyl ether derivative of perfluoropolyether (12) were mixed and stirred, and an addition reaction was carried out using platinum vinylsiloxane complex CAT-PL-50T (manufactured by Shin-Etsu Chemical Co., Ltd.) as a catalyst. After activated carbon treatment, filtration, and stripping, a fluorine-containing organohydrogenpolysiloxane (B-1) represented by the following molecular formula was obtained. [ka]

[0091] (Examples and Comparative Examples) For each of the alkenyl substituent and fluorine substituent-containing organopolysiloxanes shown in (A-1) to (A-7) above, organohydrogenpolysiloxane (B-1) was mixed with (B-1) such that the molar ratio of hydrogen atoms bonded to silicon atoms in component (B) to vinyl groups in component (A) (molar ratio of Si-H groups / Si-CH=CH2 groups) was 3.0. 100 parts of this mixture was diluted with 1,900 parts of a non-halogenated solvent (isooctane:isobutyl acetate = 1:1), and a complex salt of chloroplatinic acid and vinylsiloxane was added to this mixture in an amount of platinum equal to 30 ppm relative to component (A) (Tables 1 and 2).

[0092] The silicone composition solution obtained in this manner was measured for solubility in non-fluorinated solvents, coating properties on film substrates, adhesion, peel strength, and residual adhesion rate using the methods described below. The results are shown in Table 3.

[0093] (a) Solubility 50g of the sample (solid content concentration 5%) prepared in the above examples and comparative examples was placed in a 100ml clear glass bottle with a lid. After shaking it in a shaker for 5 minutes, the appearance of the sample was observed. ○: Clear △: Slightly turbid ×: Cloudy or separated

[0094] (b) Coatability to film substrates The sample prepared in the above example (diluted solvent: isooctane / isobutyl acetate = 50:50) was coated onto a 50 μm thick PET film using a bar coater at a coating rate of 0.3 g / m². 2 The film was coated in this manner. The appearance of the coated film was observed. ○: No liquid repelling or uneven application. △: There are some areas where the liquid repels or the application is uneven. ×: The liquid repels or the application is uneven.

[0095] (c) Adhesion to the substrate The film obtained in (b) above was heated and cured in a 150°C hot air dryer for 60 seconds to form a release layer. After storing the film with the release layer at room temperature for 24 hours, the release layer was visually observed to see if it could be removed by rubbing it 10 times with a finger. ○: No eliminations △: The color of the coating changed, but it did not fall off. ×: Some were eliminated.

[0096] (d) Peeling force A 25mm wide silicone adhesive tape (Kapton Tape 650S, manufactured by Teraoka Seisakusho) is laminated onto the release film obtained in (c), and the density is 20g / cm². 2 The tapes were bonded and aged for 20 hours each at 25°C and 70°C under the specified load. The bonded tapes were peeled off at a 180-degree angle at a peeling speed of 0.3 m / min using a tensile testing machine, and the force required for peeling (N / 25 mm) was measured. ○: 0.2N / less than 25mm △: 0.2N / 25mm or more, less than 1.0N / 25mm ×:1.0N / 25mm or more

[0097] (e) Residual adhesion rate (c) The release film obtained in (c) is covered with the same adhesive tape used for the release measurement, and 20 g / cm² is applied. 2 The adhesive tape was bonded and aged for 20 hours at 25°C under the specified load. After aging, the adhesive tape was peeled off and attached to a SUS plate. This adhesive tape was peeled off at a 180-degree angle at a peeling speed of 0.3 m / min using a tensile testing machine, and the force required for peeling (N / 25mm) was measured. On the other hand, the force required to peel the adhesive tape that was not bonded to the release film from the SUS plate (N / 25mm) was measured, and the ratio of these two values ​​was expressed as a percentage. ○: 90% or more △: 75% or more, less than 90% ×: Less than 75%

[0098] [Table 1]

[0099] [Table 2]

[0100] [Table 3]

[0101] In Comparative Example 1, the material did not dissolve in the non-fluorine solvent, so its coating properties, adhesion, peel strength, and residual adhesion rate could not be measured. In Comparative Example 2, the fluorine content was less than 25% by mass, resulting in a heavy peel strength and a low residual adhesion rate. In Comparative Example 3, the ratio of the peak area of ​​components with a molecular weight of 4,000 or less to the total peak area in the GPC measurement was less than 2%, resulting in poor solubility and coating properties, and thus the measurement of peel strength and residual adhesion rate could not be performed. In Comparative Example 4, the ratio of the peak area of ​​components with a molecular weight of 4,000 or less to the total peak area in the GPC measurement was greater than 20%, resulting in poor adhesion and a low residual adhesion rate.

[0102] Compared to these comparative examples, the sample of the example showed superior solubility in non-fluorine solvents, coating properties and adhesion to substrates, easy peeling from silicone adhesives, and a high residual adhesion rate. The results showed that the fluorine content of component (A), which is the base polymer, and the amount of components with a molecular weight of 4,000 or less are extremely important for the addition-curing type release silicone composition for silicone adhesives of the present invention.

[0103] This specification includes the following embodiments: [1](A) Fluorine-containing organopolysiloxane having at least two alkenyl groups bonded to a silicon atom and at least one fluorine-containing substituent bonded to a silicon atom in one molecule, having a fluorine content of 25-50% by mass, and having a peak area of ​​2-20% of the total peak area of ​​components with a molecular weight of 4,000 or less in molecular weight distribution measurement by gel permeation chromatography: 100 parts by mass, (B) Organohydrogenpolysiloxane having at least 3 hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule: an amount such that the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.1 to 15. (C) Platinum group metal catalyst: 0.5 to 5,000 ppm of platinum group metal in terms of mass relative to component (A) above. (D) Non-fluorinated solvent: 100 to 20,000 parts by mass, An addition-curing type release silicone composition for silicone adhesives, containing the above. [2] The addition-curing type release silicone composition for silicone adhesives according to [1], wherein the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.5 to 5. [3] The addition-curing type release silicone composition for silicone adhesives according to [1] or [2] above, wherein the component (D) is a non-fluorine solvent with an SP value of 10.0 or less. [4] The addition-curing type release silicone composition for silicone adhesives according to [1], [2], or [3], wherein component (D) is at least one selected from hydrocarbon solvents, ketone solvents, ether solvents, and ester solvents. [5] A release film having a cured layer of the addition-curing type release silicone composition for silicone adhesives described in [1], [2], [3], or [4] formed on at least one outer surface of the film substrate. [6] Release paper having a cured layer of the addition-curing type release silicone composition for silicone adhesives described in [1], [2], [3], or [4] formed on at least one outer surface of a paper substrate.

[0104] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention. [Industrial applicability]

[0105] The addition-curing type release silicone composition for silicone adhesives of the present invention possesses both high handling properties and good release performance, making it suitable for use as a release agent. A sheet-like substrate having a cured film made of this silicone composition is useful for adhesive tapes, adhesive labels, process paper, and the like.

Claims

1. (A) A fluorine-containing organopolysiloxane having at least two alkenyl groups bonded to a silicon atom and at least one fluorine-containing substituent bonded to a silicon atom in one molecule, having a fluorine content of 25 to 50% by mass, and having a peak area of ​​2 to 20% of the total peak area of ​​components with a molecular weight of 4,000 or less as measured by molecular weight distribution analysis by gel permeation chromatography: 100 parts by mass, (B) Organohydrogenpolysiloxane having at least three hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule: an amount such that the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.1 to 15. (C) Platinum group metal catalyst: 0.5 to 5,000 ppm of platinum group metal by mass relative to component (A) above. (D) Non-fluorinated solvent: 100 to 20,000 parts by mass, An addition-curing type release silicone composition for silicone adhesives, containing the above.

2. The addition-curing type release silicone composition for silicone adhesives according to claim 1, wherein the molar ratio of hydrogen atoms (SiH groups) bonded to silicon atoms in component (B) to alkenyl groups in component (A) is 0.5 to 5.

3. The addition-curing type release silicone composition for silicone adhesives according to claim 1, wherein the (D) component is a non-fluorinated solvent with an SP value of 10.0 or less.

4. The addition-curing type release silicone composition for silicone adhesives according to claim 2, wherein the (D) component is a non-fluorinated solvent with an SP value of 10.0 or less.

5. The addition-curing type release silicone composition for silicone adhesives according to claim 1, wherein the (D) component is at least one selected from hydrocarbon solvents, ketone solvents, ether solvents, and ester solvents.

6. The addition-curing type release silicone composition for silicone adhesives according to claim 2, wherein the (D) component is at least one selected from hydrocarbon solvents, ketone solvents, ether solvents, and ester solvents.

7. The addition-curing type release silicone composition for silicone adhesives according to claim 3, wherein the (D) component is at least one selected from hydrocarbon solvents, ketone solvents, ether solvents, and ester solvents.

8. The addition-curing type release silicone composition for silicone adhesives according to claim 4, wherein the (D) component is at least one selected from hydrocarbon solvents, ketone solvents, ether solvents, and ester solvents.

9. A release film having a cured layer of the addition-curing type release silicone composition for silicone adhesives described in any one of claims 1 to 8 formed on at least one outer surface of the film substrate.

10. Release paper having a cured layer of the addition-curing type release silicone composition for silicone adhesives described in any one of claims 1 to 8 formed on at least one outer surface of a paper substrate.

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