Radiation-curable organopolysiloxane composition, cured product, and release sheet

Abstract

The present invention aims to provide a radiation-curable organopolysiloxane composition, a cured product, and a release sheet, wherein the radiation-curable organopolysiloxane composition can provide a release sheet that is easier to release and has high substrate adhesion than a release sheet having a cured product of a conventional composition containing a (meth)acryloyl group-containing free radical polymerizable organopolysiloxane. A radiation-curable organopolysiloxane composition comprises the following components (A), (B), and (C). (A) an organopolysiloxane represented by the following formula (1), (B) a compound having two or more acrylic groups in one molecule: 0.1 to 50 parts by mass relative to 100 parts by mass of the component (A), and (C) a free radical polymerization initiator: 0.1 to 15 parts by mass relative to 100 parts by mass of the component (A).

Description

Technical Field

[0001] The present invention relates to a radiation-curable organopolysiloxane composition and a release sheet which are excellent in radiation curability, easily peelable, and excellent in adhesion to a substrate. Background Art

[0002] The organopolysiloxane composition is applied to the surface of various substrates such as paper, laminated paper, synthetic film, transparent resin, and metal foil to form a hardened film by crosslinking reaction, thereby producing a release sheet such as release paper and release film that has release properties to adhesive or tacky substances.

[0003] There are various methods for curing polyorganosiloxane compositions, including condensation reaction based on organometallic compounds, vulcanization using organic peroxides, hydrosilylation reaction based on platinum group metal catalysts, etc. However, heating is required in the curing method, and curing at a lower temperature or room temperature is required to improve productivity or save energy. In addition, the use of substrates lacking heat resistance such as polyethylene terephthalate (PET) films has also increased recently as electronic components or optical materials.

[0004] Therefore, as a method of providing curing energy other than heat without heating, a curing method based on radiation has attracted attention. The curing method based on radiation can be listed as follows: free radical polymerization using (meth)acrylic acid modified polysiloxane, cationic polymerization based on the ring opening of epoxy groups of epoxy modified polysiloxane, curing based on ene-thiol reaction using mercapto modified polyorganosiloxane and alkenyl modified polyorganosiloxane, etc.

[0005] Among them, in the free radical polymerization using (meth) acrylic acid modified polysiloxane, curing is hindered by the presence of oxygen, so a device for reducing the oxygen concentration is required, but the curing property is very good, and the best advantage is the good adhesion to the substrate. Therefore, it is also possible to develop back treatment agents for adhesive tapes that use films that lack heat resistance and shrink due to heating as substrates, release papers for adhesive labels, release films and tapes, etc., and the market can be expected to expand in the future.

[0006] Many inventions related to release agents of free radical polymerizable organopolysiloxane containing (meth)acryloyl groups have been proposed, but there are several problems. For example, Japanese Patent Publication No. 5-83570 (Patent Document 1) describes a method of synthesizing a free radical polymerizable organopolysiloxane containing (meth)acryloyl groups by reacting a polyorganosiloxane containing epoxy groups with a mixture of (meth)acrylic anhydride and (meth)acrylic acid.

[0007] The (meth)acryloyl radical polymerizable organopolysiloxane obtained by the method described in Patent Document 1 has a large amount of hydroxyl groups contained therein, and therefore cannot satisfy the peeling property for adhesive substances. In addition, the adhesion to the support for matte paper or biaxially stretched polypropylene film (Oriented Polypropylene, OPP) is good, but the adhesion to PET film is not mentioned, and there is no record of the long-term adhesion test required in recent years under wet heat.

[0008] Patent Gazette No. 2669947 (Patent Document 2) describes a radiation-curable organopolysiloxane using a (meth)acryloyl group-containing free radical polymerizable organopolysiloxane containing a silsesquioxane unit in the molecule. Patent Document 2 describes that the radiation-curable organopolysiloxane is easy to release and the peeling force does not change with time, but does not mention the peeling property from a strong adhesive or the adhesion to a PET film.

[0009] US6268404B1 (Patent Document 3) describes a radiation-curable organopolysiloxane using a mixture of a polyorganosiloxane having a large number of (meth)acryloyl groups in the side chain and a polyorganosiloxane having (meth)acryloyl groups only at the terminal. Patent Document 3 describes that a cured film having good peeling properties and substrate adhesion is obtained by orienting the polyorganosiloxane having a large number of (meth)acryloyl groups in the side chain toward the substrate side and orienting the polyorganosiloxane having (meth)acryloyl groups only at the terminal toward the surface, but does not mention the substrate adhesion in detail.

[0010] US6548568B1 (Patent Document 4) describes a composition comprising a polyorganosiloxane having a hydroxyl group and a large number of (meth)acryloyl groups in the side chain, a polyorganosiloxane having a small number of hydroxyl groups and (meth)acryloyl groups at both ends or in the side chain, and a monomer having an acrylate or vinyl ether group. The present invention describes that a polyorganosiloxane having a small number of hydroxyl groups and (meth)acryloyl groups at both ends or in the side chain is used for easy peeling, and a monomer having an acrylate or vinyl ether group is used as a close contact enhancing component, thereby achieving easy peeling and high close contact, but does not mention a long-term close contact test under wet heat over time.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Publication No. 5-83570

[0014] Patent Document 2: Japanese Patent No. 2669947

[0015] Patent Document 3: U.S. Patent No. 6268404

[0016] Patent Document 4: U.S. Patent No. 6548568 Summary of the invention

[0017] Problems to be solved by the invention

[0018] Therefore, in view of the above circumstances, an object of the present invention is to provide a radiation-curable organopolysiloxane composition that can provide a release sheet that is easier to release (i.e., requires less force to be released from an adhesive layer) and has high substrate adhesion compared to a release sheet having a cured product of a conventional composition containing a (meth)acryloyl group-containing radically polymerizable organopolysiloxane.

[0019] Technical means of solving problems

[0020] The present inventors have repeatedly conducted in-depth studies to achieve the above-mentioned purpose, and as a result, it has been found that when an organic group containing a hydroxyl group is present in an organopolysiloxane having a (meth)acryloyl group, the greater the amount of hydroxyl group, the lower the adhesion during storage under humidity and heat over time. The reason for this is still unclear, but it is considered that: the more hydroxyl groups there are, the easier it is for moisture in the air to be absorbed into the hardened film, thereby reducing the strength of the hardened film, or the more hydroxyl groups there are, the more the siloxane bonds are cut by the hydroxyl groups due to humidity and heat over time, thereby reducing the strength of the hardened film.

[0021] Therefore, an object of the present invention is to ensure long-term adhesion such as storage over time under moist heat by reducing the amount of hydroxyl groups in an organopolysiloxane having a (meth)acryloyl group to a certain amount or less. As a result, it was found that the above-mentioned problem can be achieved by limiting the amount of hydroxyl groups in the radically polymerizable organopolysiloxane to a certain amount or less in a radiation-curable organopolysiloxane composition comprising a (meth)acryloyl group and a polyfunctional acrylate as follows, thereby completing the present invention.

[0022] That is, the present invention is a radiation-curable organopolysiloxane composition comprising the following components (A), (B) and (C);

[0023] (A) an organopolysiloxane represented by the following formula (1),

[0024] [Chemistry 1]

[0025]

[0026] (Where R 1 are independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, an organic group containing a hydroxyl group, or an organic group containing a (meth)acryloyl group, R1 At least one of them is an organic group containing a (meth)acryloyl group, a is an integer greater than 2, b is an integer greater than 0, c is an integer greater than 0, d is an integer greater than 0, 2≦a+b+c+d≦1,000, and R 1 The ratio of the number of the hydroxyl group and the hydroxyl group-containing organic group to the total number of the (meth)acryloyl group-containing organic group, the hydroxyl group and the hydroxyl group-containing organic group is 0.4 or less)

[0027] (B) a compound having two or more acrylic groups in one molecule: 0.1 to 50 parts by mass based on 100 parts by mass of the component (A); and

[0028] (C) Radical polymerization initiator: 0.1 to 15 parts by mass based on 100 parts by mass of the component (A).

[0029] Effects of the Invention

[0030] The release sheet having a cured layer comprising the radiation-curable organopolysiloxane composition of the present invention is easier to release (ie, requires less force to release from the adhesive layer) than a release sheet obtained using a conventional release sheet composition and has high substrate adhesion. DETAILED DESCRIPTION

[0031] The present invention is a radiation-curable organopolysiloxane composition comprising (A) (meth)acryloyl organopolysiloxane, (B) a multifunctional acrylic compound and (C) a radical polymerization initiator. As described above, the amount of hydroxyl groups in component (A) is controlled. Each component is described in more detail below.

[0032] (A) (Meth)acryloyl organopolysiloxane

[0033] The component (A) is an organopolysiloxane having a (meth)acryloyl group and is represented by the following formula (1): The bonding order of the siloxane units shown in the following parentheses is not limited and may be arranged randomly or in a block structure.

[0034] [Chemistry 2]

[0035]

[0036] (Where R 1 are independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, an organic group containing a hydroxyl group, or an organic group containing a (meth)acryloyl group, R 1At least one of them is an organic group containing a (meth)acryloyl group, a is an integer greater than 2, b is an integer greater than 0, c is an integer greater than 0, d is an integer greater than 0, 2≦a+b+c+d≦1,000, and R 1 The ratio of the number of the hydroxyl group and the hydroxyl group-containing organic group to the total number of the (meth)acryloyl group-containing organic group, the hydroxyl group and the hydroxyl group-containing organic group is 0.4 or less)

[0037] The content of hydroxyl groups in the component (A) of the present invention is limited to a predetermined amount or less. 1 The ratio of the number of hydroxyl groups and hydroxyl-containing organic groups to the total number of (meth)acryloyl-containing organic groups, hydroxyl groups and hydroxyl-containing organic groups represented is 0.4 or less. It is preferably 0.3 mol or less, and more preferably 0.25 mol or less. The smaller the ratio of hydroxyl groups and hydroxyl-containing organic groups, the better, but the lower limit is preferably 0.0001 or more, more preferably 0.001 or more, and further preferably 0.01 or more. In addition, the ratio of hydroxyl groups and hydroxyl-containing organic groups may be less than 0.001 mol, and in particular, it is most preferred that the ratio is completely free of hydroxyl groups and hydroxyl-containing organic groups. By limiting the amount of hydroxyl groups in the (meth)acryloyl-containing organic polysiloxane as described above, the present invention can provide a hardened material for a release sheet having excellent long-term adhesion such as storage under wet heat and over time. Furthermore, the component (A) of the present invention can use two or more organic polysiloxanes in combination. In this case, in each siloxane, relative to R in the formula (1), 1 The ratio of the hydroxyl group and the hydroxyl group-containing organic group to the total number of the (meth)acryloyl group, the hydroxyl group, and the hydroxyl group-containing organic group represented by is preferably 0.4 or less. 1 An organopolysiloxane having a ratio of the number of hydroxyl groups and hydroxyl-containing organic groups to the total number of (meth)acryloyl group-containing organic groups, hydroxyl groups and hydroxyl-containing organic groups exceeding 0.4.

[0038] The hydroxyl-containing organic group is preferably a monovalent hydrocarbon group having a hydroxyl group at the end and having 3 to 20 carbon atoms, preferably 4 to 15 carbon atoms, which may have an ether bond. In addition, groups having a (meth)acryloyl group at the end and also having a hydroxyl group, such as those represented by the following formulas (a6) and (a7) are also included. The monovalent hydrocarbon group which may have an ether bond is preferably a group having an ethylene oxide and / or propylene oxide structure. The hydroxyl-containing organic group is preferably represented by the following formula (c).

[0039] [Chemistry 3]

[0040]

[0041] In the formula, c is an integer of 1 to 5, and f1 and f2 are mutually independent integers greater than 0. f1+f2 is 0 to 10, preferably 1 to 10, more preferably 1 to 7, and more preferably 1 to 4.

[0042] Examples of the group represented by the formula (c) include groups represented by the following formulae (a1) to (a7). Among them, groups represented by formulae (a1) to (a5) are preferred.

[0043] [Chemistry 4]

[0044]

[0045] R 2 is a hydrogen atom or a methyl group. e is an integer of 1 to 10, and f and g are independently integers of 1 to 5. Preferably, e is an integer of 1 to 7, and f and g are independently integers of 1 to 3. Further preferably, e is an integer of 1 to 4, and f and g are independently 1 or 2. In the formula, the bonding order of ethylene oxide and propylene oxide shown in brackets is not limited, and can be arranged randomly or form a block structure. Furthermore, in the formula, the dotted line represents the bond to the silicon atom of the polyorganosiloxane. As long as the hydroxyl ratio of the composition as a whole satisfies the above range, a compound having both a hydroxyl-containing organic group and a (meth)acryloyl group may be included, as in (a6) and (a7).

[0046] In the formula (1), a is an integer greater than or equal to 2, b is an integer greater than or equal to 0, c is an integer greater than or equal to 0, d is an integer greater than or equal to 0, and 2≦a+b+c+d≦1,000. a, b, c, and d may be any value as long as the amount of (meth)acryloyl groups in the organopolysiloxane having a (meth)acryloyl group and the amount of the hydroxyl-containing organic group are the values ​​shown above. a, b, c, and d are preferably a≧2, b≧10, c≧0, and d≧0, respectively, and more preferably a≧2, b≧15, c≧0, and d=0. In addition, 2≦a+b+c+d≦1,000, and preferably 2≦a+b+c+d≦500.

[0047] In the formula (1), R 1 are independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, a hydroxyl group-containing organic group, or an organic group having a (meth)acryloyl group, R 1At least one of them is an organic group having a (meth)acryloyl group. As substituted or unsubstituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, alkyl groups such as methyl, ethyl, propyl and butyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl and tolyl groups, etc., and further, groups selected from 3,3,3-trifluoropropyl, perfluorobutylethyl, perfluorooctylethyl groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms such as fluorine and chlorine; methoxypropyl groups, ethoxypropyl groups, etc. substituted with alkoxy groups can be listed. As alkoxy groups, methoxy, ethoxy, isopropoxy and butoxy groups can be listed. Preferably, the organopolysiloxane represented by the formula (1) is 100 to 1000 relative to all R 1 The ratio of the number of hydroxyl groups and hydroxyl-containing organic groups to the total number of (meth)acryloyl-containing organic groups, hydroxyl groups and hydroxyl-containing organic groups is preferably 0.4 or less, preferably 0.3 or less, and more preferably 0.25 or less. The lower limit is not limited and may be less than 0.001, and it is most preferred that there is no hydroxyl group or hydroxyl-containing organic group. If a lower limit is set, it is preferably 0.0001 or more, more preferably 0.001 or more, and further preferably 0.01 or more.

[0048] In the formula (1), R 1 At least two of them are organic groups having (meth)acryloyl groups. Preferably, the ratio of silicon atoms possessed by the organic group containing (meth)acryloyl groups is 1 mol% to 50 mol% in all silicon atoms, more preferably 2 mol% to 45 mol%, and further preferably 3 mol% to 40 mol%. If the ratio of the organic group containing (meth)acryloyl groups is less than the lower limit, there is a possibility that the curability of the radiation-curable organopolysiloxane composition decreases. In addition, if it is more than the upper limit, the cured product obtained from the radiation-curable organopolysiloxane composition may not be able to ensure sufficient demolding properties, so it is not preferred.

[0049] The (meth)acryloyl group-containing organic group is preferably a monovalent hydrocarbon group having 3 to 20 carbon atoms, preferably 4 to 15 carbon atoms, which has at least one (meth)acryloyloxy group in one molecule and may contain an ether bond. More preferably, it is a group represented by the following formula (a) or (b), which has one or more (meth)acryloyl groups and may have a (poly)ethylene oxide and / or (poly)propylene oxide structure.

[0050] [Chemistry 5]

[0051]

[0052] [Chemistry 6]

[0053]

[0054] In the formulas (a) and (b), R 2 is a hydrogen atom or a methyl group, a1 is 0 or 1, a2 is 1 or 2, and k is an integer of 1 to 5. f is an integer of 0 to 10, preferably 0 to 5, more preferably 1 to 3, and further preferably 1 or 2. g is an integer of 0 to 10, preferably 0 to 5, more preferably 1 to 3, and further preferably 1 or 2. f+g is 0 to 10, preferably f+g is 1 to 10, further preferably 1 to 7, and further preferably 1 to 4. Furthermore, one or more hydrogen atoms bonded to the carbon atoms of the alkylene group may be substituted with a hydroxyl group or an alkyl group having 1 to 5 carbon atoms and having a hydroxyl group. Furthermore, in the above formulas, the bonding order of the ethylene oxide and propylene oxide shown in brackets is not limited and may be arranged randomly or may form a block structure.

[0055] Examples of the group represented by the formula (a) or (b) include the groups represented by the following (a6) to (a13). Among them, the groups represented by the following (a8) to (a13) are preferred.

[0056] [Chemistry 7]

[0057]

[0058] In the above formulas, R 2 is a hydrogen atom or a methyl group. e is an integer of 1 to 10, and f and g are independently integers of 1 to 5. Preferably, e is an integer of 1 to 7, and f and g are independently integers of 1 to 3. Further preferably, e is an integer of 1 to 4, and f and g are independently 1 or 2. In the formula, the bonding order of ethylene oxide and propylene oxide shown in brackets is not limited, and can be arranged randomly or form a block structure. Furthermore, in the formula, the dotted line represents the bond to the silicon atom of the polyorganosiloxane.

[0059] The (meth)acryloyl-containing organopolysiloxane with limited hydroxyl amount can be obtained by known methods. For example, it can be obtained by an acid equilibration reaction using an acid catalyst as described in Patent Gazette 2669947, or an esterification reaction of an organopolysiloxane containing an ether-containing hydroxyl group and (meth)acrylic acid using an acid catalyst as described in Patent Gazette 3780113, and an ester exchange reaction of an organopolysiloxane containing an hydroxyl group and (meth)acrylate using a metal catalyst. Alternatively, it can also be obtained by an ester exchange reaction of an organopolysiloxane containing an hydroxyl group and (meth)acrylate using a metal catalyst.

[0060] More specifically, in the acid equilibration reaction using an acid catalyst as described in Patent Gazette 2669947, a polyorganosiloxane containing a hydroxyl-containing organic group is not used, or even if a hydroxyl-containing organic group is present, the hydroxyl-containing ratio is very small, so that the ratio of the hydroxyl-containing organic group relative to the total number of (meth)acryloyl groups and the hydroxyl-containing organic group can be made 0.4 or less. In addition, in the esterification reaction of a polyorganosiloxane containing a hydroxyl-containing organic group having an ether bond and (meth)acrylic acid using an acid catalyst as described in Patent Gazette 3780113, the ratio of the hydroxyl-containing organic group decreases as the esterification reaction proceeds. That is, the more the production amount of the target (meth)acryloyl-containing organopolysiloxane increases, the more the amount of the hydroxyl-containing organic group can be reduced.

[0061] (B) Multifunctional acrylic compound

[0062] (B) Component is a multifunctional acrylic compound, which functions as a component for improving adhesion in the radiation-curable organopolysiloxane composition of the present invention. The so-called multifunctional acrylic compound is any compound having multiple (i.e., two or more) acrylic groups in one molecule, and any known multifunctional acrylic compound. Preferably, it is a compound having three or more acrylic groups in one molecule, more preferably a compound having 3 to 20, and more preferably 3 to 15 acrylic groups. By including a compound having three or more acrylic groups in one molecule, the adhesion of the resulting cured product to the substrate can be improved, so it is preferred. As the multifunctional acrylic compound, for example, a hydrocarbon group having 4 to 25 carbon atoms which has an acrylic group and may have a heteroatom, and an organic silane having an acrylic group or its hydrolysis condensate.

[0063] Examples of the hydrocarbon group having 4 to 25 carbon atoms which has two or more acrylic groups in one molecule and may have a hetero atom include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, tricyclodecane dimethanol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, and Biscoat #700HV (bisphenol fatty alcohol polyoxyethylene ether) manufactured by Osaka Organic Chemical Co., Ltd. (AEO) 3.8 mol adduct diacrylate) and other difunctional acrylic compounds; trimethylolpropane triacrylate, pentaerythritol triacrylate, tris(2-acryloyloxyethyl) isocyanurate, α,α',α"-propane-1,2,3-triyltris[ω-(acryloyloxy)poly(oxyethylene)], TMPEOTA (trimethylolpropane ethoxy triacrylate) manufactured by Daicel-Allnex, OTA manufactured by Daicel-Allnex and tetrafunctional or higher acrylic compounds such as pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, tripentaerythritol octaacrylate, ATM-4E (pentaerythritol ethylene oxide (EO) adduct tetraacrylate), ATM-4P (pentaerythritol propylene oxide (PO) adduct tetraacrylate) manufactured by Shin-Nakamura Chemical, and A-9550 (dipentaerythritol polyacrylate) manufactured by Shin-Nakamura Chemical.

[0064] In addition, an organosilane having two or more acrylic groups in one molecule (hereinafter referred to as a polyfunctional acrylic organosilane) is represented by, for example, the following formula (2).

[0065] [Chemistry 8]

[0066]

[0067] [wherein, n is an integer of 1 to 3, m is an integer of 1 to 10, X is an alkoxy group having 1 to 4 carbon atoms, and R 3 is an alkyl group having 1 to 4 carbon atoms, R 4 is a group represented by the following formula (3):

[0068] [Chemistry 9]

[0069]

[0070] (A is a linear, branched or cyclic trivalent to hexavalent hydrocarbon group having 1 to 10 carbon atoms, which may contain oxygen atoms or nitrogen atoms but does not contain any other heteroatoms, and p is an integer of 2 to 5)

[0071] As the group represented by the formula (2), a polyfunctional acrylic organosilane represented by formula (4) to formula (7) is more preferable.

[0072] [Chemistry 10]

[0073]

[0074] (n is 1 to 3)

[0075] The method for producing the multifunctional acrylic organosilane represented by the formula (2) is not particularly limited. For example, it can be produced by the method described in Japanese Patent Laid-Open No. 2016-041774. In detail, it can be obtained by reacting a compound having an acrylic group and a hydroxyl group in the same molecule with an organosilane having an isocyanate group. As the organosilane having an isocyanate group, 3-isocyanate propyl trimethoxy silane, 3-isocyanate propyl methyl dimethoxy silane, 3-isocyanate propyl triethoxy silane, and 3-isocyanate propyl methyl diethoxy silane can be listed. In terms of the availability of raw materials, 3-isocyanate propyl trimethoxy silane or 3-isocyanate propyl triethoxy silane is preferred. In addition, as a compound having an acrylic group and a hydroxyl group in the same molecule, difunctional acrylic alcohols such as 2-hydroxy-3-acryloxypropyl methacrylate can be listed; and multifunctional acrylic alcohols such as pentaerythritol triacrylate and dipentaerythritol pentaacrylate can be listed.

[0076] When manufacturing multifunctional acrylic organosilane, a catalyst may be used as needed. The catalyst may be a reaction catalyst for isocyanate commonly used, preferably a tin compound. The amount of the catalyst used is 1 mol to 0.0000001 mol, more preferably 0.01 mol to 0.000001 mol, relative to 1 mol of organosilane having an isocyanate group. When used in excess of 1 mol, the effect is saturated, which is not economical. In the case of less than 0.0000001 mol, there is a possibility that the catalyst effect is insufficient, the reaction rate is low, and the productivity decreases. In addition, when manufacturing an organosilane having multiple acrylic groups in one molecule, the reaction is an exothermic reaction. If the temperature becomes too high, there is a possibility that a side reaction occurs. Therefore, the preferred reaction temperature during manufacturing is 20°C to 150°C, more preferably 30°C to 130°C, and further preferably in the range of 40°C to 110°C. In the case of less than 20°C, the reaction rate is low and the productivity decreases. On the other hand, when the temperature exceeds 150° C., there is a possibility that side reactions such as polymerization reaction of organosilane having an isocyanate group and polymerization of an acrylic group may occur.

[0077] In addition, as component (B), the hydrolysis condensate of the multifunctional acrylic organosilane can also be used. As a method for performing hydrolysis condensation, a known method can be applied. As a catalyst for hydrolysis condensation, there can be exemplified acids such as hydrochloric acid, nitric acid, acetic acid, and maleic acid; alkali metal hydroxides such as NaOH and KOH; amine compounds such as ammonia, triethylamine, dibutylamine, hexylamine, and octylamine, and salts of amine compounds; bases such as quaternary ammonium salts such as benzyltriethylammonium chloride, tetramethylammonium hydroxide, and tetrabutylammonium hydroxide; fluoride salts such as potassium fluoride and sodium fluoride; solid acid catalysts or solid basic catalysts (ion exchange resin catalysts, etc.); iron 2-ethylhexanoate; titanium naphthoate (Titanium naphthenate), zinc stearate, dibutyltin diacetate and other metal salts of organic carboxylic acids; organic titanium esters such as tetrabutoxytitanium and dibutoxy-(bis-2,4-pentanedione)titanium; organic zirconium esters such as tetrabutoxyzirconium and dibutoxy-(bis-2,4-pentanedione)zirconium; alkoxyaluminum compounds such as triisopropoxide aluminum (Aluminum Triisopropoxide), aluminum chelate compounds such as acetylacetonate aluminum complex and other organic metal compounds; aminoalkyl substituted alkoxysilanes such as 3-aminopropyltrimethoxysilane and N-(β-aminoethyl) 3-3-aminopropyltrimethoxysilane, which can be used alone or in combination. That is, the multifunctional acrylic organosilane can be hydrolyzed and condensed in the presence of the hydrolysis-condensation catalyst, water and an organic solvent as needed.

[0078] Relative to 100 parts by mass of component (A), the amount of component (B) is 0.1 to 50 parts by mass, preferably 0.5 to 30 parts by mass, and more preferably 1 to 20 parts by mass. If the amount of component (B) is less than the lower limit, the adhesion enhancement effect cannot be fully obtained. In addition, if it is more than the upper limit, the adhesion enhancement effect cannot be improved, and the peelability decreases.

[0079] (C) Radical Polymerization Initiator

[0080] (C) component is a radical polymerization initiator that generates free radicals by radiation irradiation. The radical polymerization initiator is not particularly limited as long as it has the ability to generate free radicals by radiation irradiation. For example, it can be listed as: diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, 2-hydroxymethyl-2-methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, p-dimethylaminoacetophenone, p-tert-butyldichloroacetophenone, p-tert-butyltrichloroacetophenone, p-azidobenzylideneacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1 -[4-(Methylthio)phenyl]-2-morpholinoacetone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzil, anisil, benzophenone, methyl o-benzoylbenzoate, Michler's ketone ketone), 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyr-1-yl)titanium, and 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxydi-2-methyl-1-propane-1-one. These free radical polymerization initiators may be used alone or in combination of two or more depending on the desired performance.

[0081] The amount of the radical polymerization initiator (C) is 0.1 to 15 parts by mass, preferably 0.5 to 12 parts by mass, and more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the component (A). If the amount of the component (C) is less than the lower limit, the curability decreases. In addition, even if it is more than the upper limit, the curability is not improved, and the peelability decreases.

[0082] The radiation-curable organopolysiloxane composition of the present invention can be obtained by mixing the above-mentioned components. In addition to the above-mentioned components (A) to (C), as optional components, silicone resin, polydimethylsiloxane, filler, antistatic agent, flame retardant, defoamer, flow regulator, light stabilizer, solvent, non-reactive resin and free radical polymerizable compound and other additives may be contained. The amount of the optional component added can be appropriately selected based on the existing known release agent composition within the range that does not hinder the effect of the present invention.

[0083] By applying the radiation-curable organopolysiloxane composition of the present invention on various substrates and performing radiation curing, a release sheet can be formed. The substrate is not particularly limited as long as it is a substrate commonly used in release sheets. Examples include: glassine paper, clay-coated paper, woodfree paper, polyethylene laminated paper, or plastic films such as polyester film, polystyrene film, polyethylene film, and polypropylene film, transparent resins such as polycarbonate, and metal foils such as aluminum foil. In addition, the amount of the radiation-curable organopolysiloxane composition applied is not particularly limited, and is generally 0.05 g / m 2 ~3.0g / m 2 Just left or right.

[0084] Radiation irradiation curing can be carried out according to existing known methods. For example, as a radiation energy line, it is preferred to use an energy line in the ultraviolet region to the visible light region (about 100nm to about 800nm) obtained from a high-pressure or ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a carbon arc lamp, a fluorescent lamp, a semiconductor solid-state laser, an argon laser, a He-Cd laser, a KrF excimer laser, an ArF excimer laser, a F2 laser, etc. It is preferred to use a radiation light source with a strong light hardness in the range of 200nm to 400nm. Furthermore, electron beams, X-rays, etc. with high energy radiation can also be used. The irradiation time of the radiation energy is usually sufficient for about 0.1 seconds to 10 seconds at room temperature, but in the case of low transmittance of the energy line or thick film thickness of the curable composition, it is sometimes preferred to spend more time than it. If necessary, it can also be heated at room temperature to 150°C for a few seconds to a few hours after irradiating the energy line for post-curing (after cure).

[0085] The radiation-curable organopolysiloxane composition of the present invention may be diluted in an organic solvent for use as needed. The type of organic solvent is not particularly limited as long as it is a conventionally known solvent used in a stripping agent composition. Examples thereof include aromatic hydrocarbon compounds such as toluene and xylene; aliphatic hydrocarbon compounds such as hexane, heptane, octane, and nonane; alcohols such as methanol, ethanol, isopropanol, and butanol; ester compounds such as ethyl acetate and butyl acetate; ketone compounds such as acetone and methyl ethyl ketone, and the like.

[0086] The radiation-curable organopolysiloxane composition of the present invention can be cured by radiation irradiation even in air, but in order to improve the curability, it is preferably cured by reducing the oxygen concentration. The lower the oxygen concentration, the more the curability is improved, so the lower the oxygen concentration, the more preferred. For example, the oxygen concentration is 1% by volume, preferably 0.1% by volume, and more preferably 0.01% by volume.

[0087] Example

[0088] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0089] In the following, the physical properties in the table are measured by the following test methods. The viscosity is a value measured at 25° C. using a BM type rotational viscometer. In the structural formula, Me represents a methyl group, and AO represents an acryloyloxy group.

[0090] In the embodiment, the (meth)acryloyl-containing organopolysiloxane is 1 H-NMR (nuclear magnetic resonance, NMR) and 29 The structural analysis was performed by Si-NMR analysis. The ratio of the hydroxyl-containing organic group to the total number of the (meth)acryloyl-containing organic group and the hydroxyl-containing organic group bonded to the silicon atom of the (meth)acryloyl-containing organopolysiloxane (described as "hydroxyl ratio" in the following examples and comparative examples) was calculated as follows.

[0091] For example, in the case of Synthesis Example 3, 1 H-NMR and 29 The number of hydroxyl-containing organic groups determined by Si-NMR analysis was 0.1, and the number of (meth)acryloyl-containing organic groups was 1.9. Therefore, the ratio of hydroxyl-containing organic groups to the total was calculated as 0.1 / (0.1+1.9)=0.05.

[0092] [Synthesis example 1]

[0093] In a 300 mL three-necked flask equipped with a stirrer and a thermometer, 4.4 g of 1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl)oxy]pentanetrisiloxane, 182.3 g of octamethylcyclotetrasiloxane, 42.3 g of an organopolysiloxane represented by the following formula (8), 0.15 g of 2,6-di-tert-butyl-4-methylphenol, and 0.005 g of N,N'-diphenyl-p-phenylenediamine were added, and stirred at room temperature for 5 minutes. Subsequently, 2.7 g of methanesulfonic acid was added, and the mixture was heated and stirred at 90°C for 8 hours. After the reaction solution was cooled to room temperature, 7.05 g of sodium bicarbonate was added, and the mixture was heated and stirred at 105°C for 2 hours. The reaction solution was filtered under pressure and then distilled off under reduced pressure at 115°C and 20 mmHg for 6 hours to obtain an acryl group-containing organopolysiloxane represented by the following average composition formula (A-1). The viscosity at 25°C was 400 mPa·s. The hydroxyl ratio in the acryl group-containing organopolysiloxane was less than 0.001.

[0094] [Chemistry 11]

[0095]

[0096] [Chemistry 12]

[0097]

[0098] (In the above formulas, Me is methyl, AO- is acryloyloxy; the same applies below; the bonding order of the siloxane units shown in brackets is not limited to the above)

[0099] [Synthesis example 2]

[0100] In a 300 mL three-necked flask equipped with a stirring device and a thermometer, 7.4 g of 1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl)oxy]pentanetrisiloxane, 200.7 g of octamethylcyclotetrasiloxane, 24.8 g of the organopolysiloxane represented by the formula (8), 0.12 g of 2,6-di-tert-butyl-4-methylphenol, and 0.005 g of N,N'-diphenyl-p-phenylenediamine were added and stirred at room temperature for 5 minutes. Thereafter, 2.7 g of methanesulfonic acid was added and heated and stirred at 90°C for 8 hours. After the reaction solution was cooled to room temperature, 7.05 g of sodium bicarbonate was added and heated and stirred at 105°C for 2 hours. After the reaction solution was filtered under pressure, it was removed by vacuum distillation at 115°C and 20 mmHg for 6 hours to obtain an acryl-containing organopolysiloxane represented by the following average composition formula (A-2). The viscosity at 25° C. is 180 mPa·s. The ratio of hydroxyl groups in the acryl group-containing organopolysiloxane is less than 0.001.

[0101] [Chemistry 13]

[0102]

[0103] [Synthesis example 3]

[0104] In a 300 mL three-necked flask equipped with a stirring device, a thermometer, and a Dean-Stark device, 79.70 g of an organopolysiloxane represented by the following formula (9) with a viscosity of 35 mPa·s at 25°C, 34.32 g of ethyl acrylate, 4.179 g of zirconium acetylacetonate, 0.58 g of diethylhydroxylamine, 0.059 g of 2,6-di-tert-butyl 4-methylphenol, and 92.81 g of toluene were added, and the mixture was heated and stirred at 85°C for 24 hours while removing the ethanol produced as a by-product. After filtering the reaction solution, it was removed by vacuum distillation at 85°C and 20 mmHg for 2 hours to obtain an acryl-containing organopolysiloxane represented by the following average composition formula (A-3). The viscosity at 25°C was 18 mPa·s. The hydroxyl ratio in the acryl-containing organopolysiloxane was 0.05.

[0105] [Chemistry 14]

[0106]

[0107] [Chemistry 15]

[0108]

[0109] [Synthesis Example 4]

[0110] In a 300 mL three-necked flask equipped with a stirring device, a thermometer, and a Dean-Stark device, 110.74 g of an organopolysiloxane represented by the following formula (10) with a viscosity of 500 mPa·s at 25°C, 72.40 g of ethyl acrylate, 5.88 g of zirconium acetylacetonate, 0.82 g of diethylhydroxylamine, 0.097 g of 2,6-di-tert-butyl 4-methylphenol, and 18.31 g of toluene were added, and the mixture was heated and stirred at 85°C for 24 hours while removing the ethanol produced as a by-product. After filtering the reaction solution, it was removed by vacuum distillation at 85°C and 20 mmHg for 2 hours to obtain an acryl-containing organopolysiloxane represented by the following average composition formula (A-4). The viscosity at 25°C was 200 mPa·s. The hydroxyl ratio in the obtained acryl-containing organopolysiloxane was 0.10.

[0111] [Chemistry 16]

[0112]

[0113] [Chemistry 17]

[0114]

[0115] [Synthesis example 5]

[0116] In Synthesis Example 4, 132.34 g of the organopolysiloxane represented by the formula (10), 86.53 g of ethyl acrylate, 0.70 g of zirconium acetylacetonate, 0.10 g of diethylhydroxylamine, and 0.328 g of 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate were used instead of 2,6-di-tert-butyl-4-methylphenol, and toluene was not contained. Synthesis Example 4 was repeated to obtain an acryl-containing organopolysiloxane represented by the following average composition formula (A-5). The viscosity at 25°C was 220 mPa·s. The hydroxyl ratio in the acryl-containing organopolysiloxane was 0.20.

[0117] [Chemistry 18]

[0118]

[0119] [Comparative Synthesis Example 1]

[0120] In Synthesis Example 4, 70.76 g of the organopolysiloxane represented by the formula (10), 45.70 g of ethyl acrylate, 1.45 g of p-toluenesulfonic acid monohydrate instead of zirconium acetylacetonate and diethylhydroxylamine, 0.060 g of 2,6-di-tert-butyl 4-methylphenol and 94.80 g of toluene were used. Synthesis Example 4 was repeated to obtain an acryl-containing organopolysiloxane represented by the following average composition formula (D-1). The viscosity at 25° C. was 26 mPa·s. The hydroxyl ratio in the acryl-containing organopolysiloxane was 0.45.

[0121] [Chemistry 19]

[0122]

[0123] [Comparative Synthesis Example 2]

[0124] Into a 300 mL separable flask equipped with a stirring device, a thermometer, a dropping funnel, and a reflux cooling tube, 80.86 g of epoxy-modified organopolysiloxane represented by the following formula (11), 0.95 g of 1,4-diazabicyclo[2.2.2]octane, 0.059 g of 2,6-di-tert-butyl-4-methylphenol, and 95.40 g of toluene were added and heated to 50° C. When 50° C. was reached, a mixture of 36.55 g of acrylic acid and 6.40 g of acrylic anhydride was dropped from the dropping funnel, and the temperature was raised after the dropwise addition was completed, and the mixture was heated and stirred at 90° C. to 100° C. for 40 hours. Thereafter, the mixture was removed by reduced pressure distillation at 120° C. and 20 mmHg for 3 hours, and then filtered to obtain an acryl-containing organopolysiloxane represented by the following average composition formula (D-2). The viscosity at 25° C. was 600 mPa·s. The ratio of hydroxyl groups in the acryl group-containing organopolysiloxane is 0.50.

[0125] [Chemistry 20]

[0126]

[0127] [Chemistry 21]

[0128]

[0129] Hereinafter, each component used in the following Examples and Comparative Examples will be described.

[0130] (B) Multifunctional acrylate

[0131] (B-1) Trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0132] (B-2) Di-trimethylolpropane tetraacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0133] (B-3) Pentafunctional acrylic silane compound represented by the following general formula (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0134] [Chemistry 22]

[0135]

[0136] (C) Radical polymerization initiator

[0137] (C-1) 2-Hydroxy-2-methyl-1-phenyl-propane-1-one

[0138] [Example 1]

[0139] A radiation-curable organopolysiloxane composition was obtained by uniformly mixing 100 parts by mass of the (meth)acryloyl group-containing organopolysiloxane (A-1) obtained in Synthesis Example 1, 10 parts by mass of (B) trimethylolpropane triacrylate (B-1), and 5.0 parts by mass of (C) a radical polymerization initiator: 2-hydroxy-2-methyl-1-phenyl-propane-1-one (C-1).

[0140] [Example 2 to Example 10, Comparative Example 1 to Comparative Example 10]

[0141] In Examples 2 to 10 and Comparative Examples 1 to 10, similarly to Example 1, each component was uniformly mixed in accordance with the composition shown in Table 1 below to obtain a radiation-curable organopolysiloxane composition.

[0142] The radiation-curable organopolysiloxane compositions obtained in Examples 1 to 10 and Comparative Examples 1 to 10 and release sheets formed using the compositions were evaluated for releasability by the following method.

[0143] [Peeling force measurement test of release sheet]

[0144] On a PET film with a thickness of 38 μm, the 2 The radiation-curable organopolysiloxane composition was roll-coated in an amount of 1000 mJ / cm2 using two 80 W / cm2 high-pressure mercury lamps set at an oxygen concentration of 150 ppm. 2The obtained peeling sheet was stored at 25°C for 20 hours, and then a 25mm wide acrylic adhesive tape TESA7475 (trade name) was attached to the surface of the hardened film. A 2kg roller was used to press the film back and forth once to prepare a sample for peeling force measurement. A 70g / cm 2 The adhesive tape was then stretched and peeled off at a peeling speed of 0.3 m / min at an angle of 180° using a tensile tester, and the force required at this time (N / 25 mm) was measured. The results are recorded in Table 1.

[0145] [Residual adhesion rate of adhesive tape]

[0146] The sample for peeling force measurement was prepared by the same method as above. 2 The tape was then peeled off at a peeling speed of 0.3 m / min at an angle of 180° using a tensile testing machine, and the tape was attached to a stainless steel (Steel Use Stainless, SUS) plate. A 2 kg roller was pressed back and forth once, and the tape was peeled off after being placed at 25°C for 30 minutes, and the force (Y) required at this time was measured. For comparison, the force (Z) required to peel off the acrylic adhesive tape TESA7475 that was not attached to the peeling sheet from the SUS plate was measured. The value obtained by dividing (Y) by (Z) is the residual adhesion rate. The results are recorded in Table 1.

[0147] [Adhesion test of release sheet]

[0148] The peeling sheet was prepared by the same method as described above. After the peeling sheet was stored in a wet heat dryer at 60°C and 90% RH for 7 days, the hardened film was rubbed 10 times with fingers to confirm the adhesion to the substrate. The hardened film was evaluated by setting ○ when no blurring or peeling was observed, △ when slightly blurring and peeling were observed, and × when peeling from the substrate was observed. The results are recorded in Table 1.

[0149]

[0150] As shown in Table 1, the release sheet obtained using the composition containing the organopolysiloxane having a high hydroxyl content has poor light peelability, and also has poor storage stability due to decreased adhesion to the substrate during storage under hot and humid conditions. In contrast, the release sheet having a cured layer containing the radiation-curable organopolysiloxane composition of the present invention has a small force required to peel from the adhesive layer, has excellent light peelability, has high adhesion to the substrate, and has long-term stability without decreasing adhesion even after hot and humid storage.

[0151] Industrial Applicability

[0152] The cured product comprising the radiation-curable organopolysiloxane composition of the present invention requires little force to be peeled off from the adhesive layer, is easily peeled off, has high substrate adhesion, and is also excellent in storage stability. Therefore, it is useful as a release sheet composition such as release paper and release film for various adhesive materials.

Claims

1. A radiation-curable organopolysiloxane composition comprising the following components (A), (B) and (C); (A) an organopolysiloxane represented by the following formula (1), In the formula, R 1 are independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, an organic group containing a hydroxyl group, or an organic group containing a (meth)acryloyl group, R 1 At least one of them is an organic group containing a (meth)acryloyl group, a is an integer greater than 2, b is an integer greater than 0, c is an integer greater than 0, d is an integer greater than 0, 2≦a+b+c+d≦1,000, and the R 1 at least one of the groups is a hydroxyl group or an organic group containing a hydroxyl group, and the ratio of the number of the hydroxyl group and the organic group containing a hydroxyl group to the total number of the organic group containing a (meth)acryloyl group, the hydroxyl group and the organic group containing a hydroxyl group is 0.0001 or more and 0.4 or less, (B) a compound having two or more acrylic groups in one molecule: 0.1 to 50 parts by mass based on 100 parts by mass of the component (A); and (C) Radical polymerization initiator: 0.1 to 15 parts by mass based on 100 parts by mass of the component (A), wherein the radiation-curable organopolysiloxane composition does not contain a compound represented by the formula (1) corresponding to R 1 An organopolysiloxane having a ratio of the number of hydroxyl groups and hydroxyl-containing organic groups to the total number of (meth)acryloyl group-containing organic groups, hydroxyl groups and hydroxyl-containing organic groups exceeding 0.

4. 2 . The radiation-curable organopolysiloxane composition according to claim 1 , wherein the component (B) is an organosilane having three or more acrylic groups in one molecule or a hydrolysis-condensate thereof. 3 . The radiation-curable organopolysiloxane composition according to claim 1 , wherein the component (B) is a hydrocarbon compound having three or more acrylic groups in one molecule and no hetero atom, or a hydrocarbon compound having three or more acrylic groups in one molecule and having a hetero atom.

4. The radiation-curable organopolysiloxane composition according to any one of claims 1 to 3, wherein in the formula (1), the (meth)acryloyl group-containing organic group is represented by the following formula (a) or (b) and has one or more (meth)acryloyl groups, In the formulas (a) and (b), R 2 is a hydrogen atom or a methyl group, a1 is 0 or 1, a2 is 1 or 2, k is an integer of 1 to 5, f is an integer of 0 to 10, g is an integer of 0 to 10, f+g is 0 to 10, one or more hydrogen atoms bonded to the carbon atoms of the alkylene group are substituted with a hydroxyl group or an alkyl group having 1 to 5 carbon atoms and having a hydroxyl group, or none of the hydrogen atoms bonded to the carbon atoms of the alkylene group are substituted with a hydroxyl group or an alkyl group having 1 to 5 carbon atoms and having a hydroxyl group, and in the above formulae, the ethylene oxide and propylene oxide shown in brackets are randomly arranged or form a block structure.

5. The radiation-curable organopolysiloxane composition according to any one of claims 1 to 3, wherein in the formula (1), R 1 At least one of them is a hydroxyl group or an organic group containing a hydroxyl group, and the ratio of the number of the hydroxyl group and the organic group containing a hydroxyl group to the total number of the organic group containing a (meth)acryloyl group, the hydroxyl group and the organic group containing a hydroxyl group is 0.001 to 0.

3. 6 . A cured product obtained by curing the radiation-curable organopolysiloxane composition according to claim 1 . 7 . A release sheet comprising a substrate and a layer laminated on at least one surface of the substrate, wherein the layer includes the cured product according to claim 6 .

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