Addition-curable organopolysiloxane composition

Abstract

Provided is a composition which contains (A) a polysiloxane resin (1) [where R1 is an aliphatic unsaturated bond-free monovalent hydrocarbon group, R2 is an alkenyl group or the like, R3 is an alkyl group or the like, 0 ≤ a ≤ 0.6, 0.2 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.8, 0 ≤ f ≤ 0.6, 0 ≤ g ≤ 0.8, 0.1 ≤ (c + e + g) ≤ 0.8, a + b + c + d + e + f + g = 1, 0 ≤ h ≤ 1], (B) a straight-chain polysiloxane (2) (where R4 is an aliphatic unsaturated bond-free monovalent hydrocarbon group, R5 is an alkenyl group or the like, R6 is a monovalent hydrocarbon group, and n is an integer of 0 to 1,200), (C) an aliphatic unsaturated bond-free hydrogen polysiloxane having three or more hydrogen atoms bonded to Si in one molecule, and (D) a platinum group metal catalyst, and in which the number of hydrogen atoms bonded to Si per alkenyl group is 0.7 to 2.3. Said composition has an organosilsesquioxane unit and is excellent in flexibility and moldability.

Description

Addition-curable organopolysiloxane composition

[0001] The present invention relates to an addition-curable organopolysiloxane composition.

[0002] Conventionally, polysiloxanes that can be crosslinked by hydrosilylation are known. However, our research has revealed that polysiloxanes that can be crosslinked by hydrosilylation containing alkylsilsesquioxane units are difficult to synthesize because the hydrolysis condensation reaction of their monomer alkyltrialkoxysilane compounds is very rapid, leading to gelation.

[0003] Patent Document 1 discloses a method for hydrolyzing an alkoxysilane mixture containing methyltrimethoxysilane, in which the hydrolysis is performed using a silanol group produced by the hydrolysis of an alkoxysilyl group as a catalyst to slow down the rate of hydrolysis condensation. This document also discloses a method for synthesizing organopolysiloxanes without gelation by adding a carboxylic acid or carboxylate salt after hydrolysis condensation and distilling off methanol. However, although the method in Patent Document 1 is suitable for synthesizing low molecular weight organopolysiloxanes, the polymerization is slow, so strict reaction conditions are required to obtain relatively high molecular weight organopolysiloxanes, making reaction control difficult and leading to problems such as gelation, reduced reproducibility, and reduced workability due to microgel formation.

[0004] To address these issues, Patent Document 2 discloses a method for efficiently producing an addition-crosslinkable polysiloxane having alkylsilsesquioxane units. However, the organopolysiloxane obtained by the formulation in Patent Document 2 has the problem of lacking flexibility and pliability, and having poor moldability, although a hardened film with high hardness can be obtained.

[0005] Japanese Patent Publication No. 2712817, Japanese Unexamined Patent Publication No. 2020-111657

[0006] The present invention has been made in view of the above circumstances, and aims to provide an addition-curing silicone composition having organosilsesquioxane units and exhibiting excellent flexibility and moldability.

[0007] As a result of diligent research to achieve the above objective, the present inventors have found that a certain polysiloxane having organosilsesquioxane units that can be crosslinked is suitable for use as a binder component or coating material in heat-resistant paints, etc., because heating yields a cured product with excellent heat resistance and hardening properties. Furthermore, they have found that by incorporating a certain linear organopolysiloxane, flexibility and pliability can be imparted to the polysiloxane, allowing for easy molding, thus completing the present invention.

[0008] In other words, the present invention comprises: 1. (A) Polysiloxane resin represented by the following formula (1): 100 parts by mass [In the formula, R 1 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond, R 2 Each of these independently represents a hydrogen atom or an alkenyl group having 2 to 12 carbon atoms (however, R 2 The proportion of hydrogen atoms in the total number of atoms is 10-90 mol%, R 3 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and a, b, c, d, e, f, and g are numbers satisfying 0 ≤ a ≤ 0.6, 0.2 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.8, 0 ≤ f ≤ 0.6, 0 ≤ g ≤ 0.8, and 0.1 ≤ (c + e + g) ≤ 0.8 and a + b + c + d + e + f + g = 1, and h is a number satisfying 0 ≤ h ≤ 1. ] (B) Linear polysiloxane represented by the following formula (2): 50 to 300 parts by mass, (In the formula, R 4 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond, R 5 Each of these independently represents a hydrogen atom or an alkenyl group with 2 to 12 carbon atoms, R 6Each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, and n is an integer of 0 to 1,200. (C) An organohydrogenpolysiloxane having 3 or more hydrogen atoms bonded to silicon atoms in one molecule and not containing an aliphatic unsaturated bond: 1 to 500 parts by mass, and (D) containing a platinum group metal catalyst, the number of hydrogen atoms bonded to silicon atoms in the composition is 0.7 to 2.3 per alkenyl group bonded to silicon atoms in the composition. An addition-curable silicone composition, 2. The R 1 is a methyl group, and the alkenyl group in the R 2 is a vinyl group. An addition-curable silicone composition of 1, 3. An addition-curable silicone composition of 1 in which a is 0, 4. An addition-curable silicone composition of 1 in which g is 0, 5. The c, e and g are numbers satisfying 0 ≦ c ≦ 0.4, 0.1 ≦ e ≦ 0.5, 0 ≦ g ≦ 0.4, and 0.2 ≦ (c + e) ≦ 0.8. An addition-curable silicone composition of 1, 6. An addition-curable silicone composition of 1 in which the alkenyl group content in the component (A) is 0.05 to 0.6 mol / 100 g, 7. The polystyrene-reduced weight average molecular weight (Mw) in the gel permeation chromatography of the component (A) is 1,000 to 50,000. An addition-curable silicone composition of 1, 8. The component (C) is one or more selected from an organohydrogenpolysiloxane represented by the following formula (3) and an organohydrogenpolysiloxane represented by the following formula (4). (In the formula, R 7 each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond, p is an integer of 1 to 100, q is an integer of 0 to 100, r is 0 or 1, and s is 0 or 1. However, p + r + s is 3 or more. The arrangement order of the siloxane units in the parentheses with p and q is arbitrary.) (In the formula, R 8Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond, where t is an integer from 3 to 6, and u is an integer from 0 to 3. However, t + u is an integer from 3 to 6. The order of the siloxane units in parentheses is arbitrary.) 9. The above R 7 and R 8 The present invention provides: 10. An addition-curable silicone composition having 8 methyl groups; 11. An addition-curable silicone composition having 0.9 to 2.1 hydrogen atoms bonded to silicon atoms in the composition per alkenyl group bonded to silicon atoms in the composition; and a cured product of any of the addition-curable silicone compositions 1 to 10.

[0009] The present invention provides a composition containing an addition-crosslinkable polysiloxane having organosilsesquioxane units, which, upon heating, yields a heat-resistant cured product. Therefore, it is suitable for use as a binder component in heat-resistant paints and resins, as well as for coatings on building materials and molded articles, and as a coating and sealing material for electronic components. Furthermore, the polysiloxane of the present invention exhibits excellent flexibility and pliability, making it easy to mold and process, and enabling its application in a wide range of uses.

[0010] The present invention will be described in detail below. [1] Addition-curable organopolysiloxane composition The addition-curable organopolysiloxane composition in the present invention contains (A) organopolysiloxane resin, (B) linear organopolysiloxane, (C) organohydrogenpolysiloxane, and (D) platinum group metal catalyst, and from the viewpoint of the reactivity of the composition, the number of hydrogen atoms bonded to silicon atoms in the composition is 0.7 to 2.3, preferably 0.8 to 2.2, and more preferably 0.9 to 2.1 per alkenyl group bonded to silicon atoms in the composition. The ratio of the number of hydrogen atoms bonded to silicon atoms in the composition to the number of alkenyl groups bonded to silicon atoms can be determined, for example, by the method used in the later examples.

[0011] [Component (A)] Component (A) is a polysiloxane resin represented by the following formula (1), and has an alkenyl group bonded to a silicon atom and a hydrogen atom (Si-H group) bonded to a silicon atom. It is a component that imparts hardness to the resulting cured product by forming crosslinks with other components (A) and / or with component (B), which will be described later, through a hydrosilylation reaction.

[0012]

[0013] In equation (1), R 1 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 6 carbon atoms, that does not contain an aliphatic unsaturated bond. 1 The monovalent hydrocarbon group having 1 to 12 carbon atoms can be linear, branched, or cyclic. Specific examples include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, tert-butyl, neopentyl, n-hexyl, n-heptyl, and n-octyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups; unsubstituted aryl groups such as phenyl and naphthyl groups; alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, and butylphenyl groups; and aralkyl groups such as benzyl and phenylethyl groups. Among these, R 1 The group is preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

[0014] R 2 Each of these is independently a hydrogen atom or an alkenyl group having 2 to 12 carbon atoms. 2 The alkenyl group having 2 to 12 carbon atoms may be linear, branched, or cyclic. Specific examples include vinyl, 1-propenyl, allyl(2-propenyl), hexenyl, octenyl, cyclopentenyl, and cyclohexenyl groups, with vinyl being preferred among these. 2 The proportion of hydrogen atoms in the total number of atoms is 10 to 90 mol%, preferably 30 to 70 mol%. If the proportion of hydrogen atoms is less than 10 mol% or more than 90 mol%, curing failure may occur, and the hardness of the cured product may decrease significantly.

[0015] R 3 Each of these is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 3 The alkyl group having 1 to 4 carbon atoms can be linear, branched, or cyclic, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, tert-butyl, and among them R 3 Hydrogen atoms, methyl groups, and ethyl groups are preferred as the elements.

[0016] In equation (1), a is a number satisfying 0 ≤ a ≤ 0.6, but from the viewpoint of crack suppression effect, a number satisfying 0 ≤ a ≤ 0.3 is preferred, and 0 is more preferred. b is a number satisfying 0.2 ≤ b ≤ 0.9, but from the viewpoint of scratch resistance of the resulting cured product, a number satisfying 0.2 ≤ b ≤ 0.7 is preferred, and a number satisfying 0.3 ≤ b ≤ 0.6 is preferred. c is a number satisfying 0 ≤ c ≤ 0.7, but from the viewpoint of hardness and flexibility of the resulting cured product, a number satisfying 0.1 ≤ c ≤ 0.4 is preferred, and 0 is more preferred. d is a number satisfying 0 ≤ d ≤ 0.6, but from the viewpoint of hardness of the resulting cured product, a number satisfying 0 ≤ d ≤ 0.5 is preferred, and a number satisfying 0 ≤ d ≤ 0.4 is more preferred. e is a number satisfying 0 ≤ e ≤ 0.7, but from the viewpoint of hardness of the resulting cured product, a number satisfying 0.1 ≤ e ≤ 0.5 is preferred, and a number satisfying 0.1 ≤ e ≤ 0.3 is more preferred. f is a number that satisfies 0 ≤ f ≤ 0.6, but from the viewpoint of the heat stability and crack resistance of the resulting cured product, a number that satisfies 0.1 ≤ f ≤ 0.4 is preferred, and a number that satisfies 0.1 ≤ f ≤ 0.2 is more preferred. g is a number that satisfies 0 ≤ g ≤ 0.7, but from the viewpoint of the hardness of the resulting cured product and the stability of the composition, a number that satisfies 0 ≤ g ≤ 0.4 is preferred, and 0 is more preferred. a, b, c, d, e, f, and g are numbers that satisfy a + b + c + d + e + f + g = 1. Also, c + e + g is a number that satisfies 0.1 ≤ (c + e + g) ≤ 0.8, but a number that satisfies 0.1 ≤ (c + e + g) ≤ 0.5 is preferred, and a number that satisfies 0.1 ≤ (c + e + g) ≤ 0.3 is more preferred. h is a number satisfying 0 ≤ h ≤ 1, but from the viewpoint of the curability of the composition and the crack resistance of the resulting cured product, a number satisfying 0 ≤ h ≤ 0.2 is preferred, and a number satisfying 0 ≤ h ≤ 0.1 is more preferred.

[0017] (A) Specific examples of components include, but are not limited to, those listed below. Note that Me represents a methyl group, Ph represents a phenyl group, and Vi represents a vinyl group (the same applies below). (MeSiO 3 / 2 ) 0.5 (MeViSIO) 2 / 2 ) 0.15 (MeHSio 2 / 2 ) 0.15 (Me3SiO 1 / 2 )0.2 (HO 1 / 2 ) 0.02 (PhSiO 3 / 2 ) 0.5 (MeViSIO) 2 / 2 ) 0.15 (MeHSio 2 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.2 (HO 1 / 2 ) 0.02 (SiO 4 / 2 ) 0.1 (MeSiO 3 / 2 ) 0.43 (MeViSIO) 2 / 2 ) 0.15 (MeHSio 2 / 2 ) 0.15 (Me3SiO 1 / 2 ) 0.17 (HO 1 / 2 ) 0.02

[0018] (A) The alkenyl group content in component (A) is preferably 0.05 to 0.6 mol / 100g, and more preferably 0.1 to 0.3 mol / 100g, from the viewpoint of the curability of the composition. For example, the method used in the later examples can be used as the measurement conditions for the alkenyl group content.

[0019] The weight-average molecular weight (Mw) of the above organopolysiloxane in gel permeation chromatography (GPC), calculated in terms of polystyrene, is preferably 1,000 to 50,000, and more preferably 5,000 to 20,000. If the weight-average molecular weight is 1,000 or higher, it exhibits excellent film formation, storage stability, and coating properties, and if it is 50,000 or lower, there is no risk of unevenness or uneven coating during painting. For example, the measurement conditions for GPC can be the method used in the later examples.

[0020] Note that component (A) may be a single composition or a mixture of multiple polysiloxane resins with different compositions.

[0021] Component (A) can be produced by known methods. For example, it can be synthesized according to the procedure described in Japanese Patent Application Publication No. 2020-111657, and is obtained by hydrolyzing and condensing a chlorosilane and / or alkoxysilane, or a partially hydrolyzed condensate thereof, which can form siloxane units constituting the polysiloxane resin represented by formula (1) above by hydrolysis and condensation, in an organic solvent capable of dissolving the raw material silane compound and the resulting polysiloxane resin under acidic conditions. To obtain a polysiloxane with a desired weight-average molecular weight, this can be done by adjusting the monomer mixing ratio, reaction temperature and time, and the amounts of water and organic solvent used. The polysiloxane resin thus produced is then subjected to removal of organic solvents as needed, and precipitates are removed by filtration.

[0022] [Component (B)] Component (B) is a linear polysiloxane represented by the following formula (2), and is a component that forms crosslinks with the alkenyl groups and / or Si-H groups bonded to the silicon atoms of component (A) through a hydrosilylation reaction, thereby imparting flexibility to the cured product.

[0023]

[0024] In equation (2), R 4 Each of these is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms, that does not contain an aliphatic unsaturated bond. 4 The monovalent hydrocarbon group having 1 to 12 carbon atoms can be linear, branched, or cyclic. Specific examples include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, tert-butyl, neopentyl, n-hexyl, n-heptyl, and n-octyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups; aryl groups such as phenyl and naphthyl groups; alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, and butylphenyl groups; and aralkyl groups such as benzyl and phenylethyl groups. Preferably, the alkyl group has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, with the methyl group being particularly preferred.

[0025] R 5 Each of these is independently a hydrogen atom or an alkenyl group having 2 to 12 carbon atoms. 5 The alkenyl group having 2 to 12 carbon atoms can be linear, branched, or cyclic, and specific examples include vinyl, 1-propenyl, allyl(2-propenyl), hexenyl, octenyl, cyclopentenyl, and cyclohexenyl groups. Among these, R 5 A hydrogen atom or a vinyl group is preferred.

[0026] R 6 Each of these is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. 6 The monovalent hydrocarbon group having 1 to 12 carbon atoms can be linear, branched, or cyclic. Specific examples include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, tert-butyl, neopentyl, n-hexyl, n-heptyl, and n-octyl groups; cycloalkyl groups such as cyclopentyl and cyclohexyl groups; aryl groups such as phenyl and naphthyl groups; alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, and butylphenyl groups; aralkyl groups such as benzyl and phenylethyl groups; vinyl, 1-propenyl, allyl(2-propenyl), hexenyl, octenyl, cyclopentenyl, and cyclohexenyl groups. Among these, R 6 A methyl group or a vinyl group is preferred.

[0027] n is an integer between 0 and 1,200, and is preferably an integer between 10 and 1,000, considering the balance between the hardness and flexibility of the cured product.

[0028] (B) Specific examples of component include, but are not limited to, those listed below. HMe2SiO-(Me2SiO) 10 -SiMe2H HMe2SiO- (Me2SiO) 20 -SiMe2H HMe2SiO- (Me2SiO) 40 -SiMe2H HMe2SiO- (Me2SiO) 400-SiMe2H HMe2SiO- (Me2SiO) 1000 -SiMe2H ViMe2SiO- (Me2SiO) 10 -SiMe2Vi ViMe2SiO- (Me2SiO) 20 -SiMe2Vi ViMe2SiO- (Me2SiO) 40 -SiMe2Vi ViMe2SiO- (Me2SiO) 400 -SiMe2Vi ViMe2SiO- (Me2SiO) 1000 -SiMe2Vi Vi3SiO- (Me2SiO) 10 -SiVi3 Vi3SiO- (Me2SiO) 20 -SiVi3 Vi3SiO- (Me2SiO) 40 -SiVi3 Vi3SiO- (Me2SiO) 400 -SiVi3 Vi3SiO- (Me2SiO) 1000 -SiVi3

[0029] The amount of component (B) is 50 to 300 parts by mass, preferably 70 to 250 parts by mass, and more preferably 80 to 200 parts by mass, per 100 parts by mass of component (A). If the amount of component (B) is less than the lower limit, the flexibility may be poor, and if it exceeds the upper limit, the hardness may be insufficient. Component (B) may be used alone or in combination of two or more types.

[0030] [Component (C)] Component (C) is an organohydrogenpolysiloxane having three or more hydrogen atoms bonded to silicon atoms in one molecule, preferably 3 to 100, and not containing aliphatic unsaturated bonds. It is a component that increases the crosslinking points through hydrosilylation reactions with alkenyl groups bonded to silicon atoms of components (A) and (B) above, thereby improving the curability of the composition and giving hardness to the cured product.

[0031] Component (C) is preferably one or more selected from the organohydrogenpolysiloxane represented by the following formula (3), the organohydrogenpolysiloxane represented by the following formula (4), and the organohydrogenpolysiloxane represented by the following formula (5).

[0032] (In equation (3), the order of the siloxane units in parentheses labeled p and q is arbitrary, and in equation (4), the order of the siloxane units in parentheses is arbitrary.)

[0033] In formula (3), R 7 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond. 7 The monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, and n-hexyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and naphthyl; alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, and butylphenyl; and aralkyl groups such as benzyl and phenylethyl. Alkyl groups having 1 to 3 carbon atoms are preferred, and methyl groups are more preferred.

[0034] p is an integer between 1 and 100, preferably between 10 and 80. q is an integer between 0 and 100, preferably between 0 and 50. r is 0 or 1, preferably 0. s is 0 or 1, preferably 0. p + r + s is 3 or greater, preferably in the range of 4 to 100.

[0035] In formula (4), R 8 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond. 8 The monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, and n-hexyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and naphthyl; alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, and butylphenyl; and aralkyl groups such as benzyl and phenylethyl. Alkyl groups having 1 to 3 carbon atoms are preferred, and methyl groups are more preferred.

[0036] t is an integer between 3 and 6, preferably between 4 and 6. u is an integer between 0 and 3, preferably between 0 and 2. t + u is an integer between 3 and 6, preferably 4.

[0037] In formula (5), R 9 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond. 8 The monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, and n-hexyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and naphthyl; alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, and butylphenyl; and aralkyl groups such as benzyl and phenylethyl. Alkyl groups having 1 to 3 carbon atoms are preferred, and methyl groups are more preferred.

[0038] R 10 Each of these is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 10 The alkyl group having 1 to 4 carbon atoms can be linear, branched, or cyclic, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, tert-butyl, and among them R 10 Hydrogen atoms, methyl groups, and ethyl groups are preferred as the elements.

[0039] In equation (5), a1 is a number satisfying 0 ≤ a1 ≤ 0.6, but from the viewpoint of crack suppression effect, a number satisfying 0 ≤ a1 ≤ 0.3 is preferred, and 0 is more preferred. b1 is a number satisfying 0.2 ≤ b1 ≤ 0.9, but from the viewpoint of scratch resistance of the resulting cured product, a number satisfying 0.4 ≤ b1 ≤ 0.9 is preferred, and a number satisfying 0.6 ≤ b1 ≤ 0.9 is more preferred. c1 is a number satisfying 0 ≤ c1 ≤ 0.8, but from the viewpoint of hardness and flexibility of the resulting cured product, a number satisfying 0 ≤ c1 ≤ 0.4 is preferred, and 0 is more preferred. d1 is a number satisfying 0 ≤ d1 ≤ 0.6, but from the viewpoint of hardness of the resulting cured product, a number satisfying 0 ≤ d ≤ 0.4 is preferred, and 0 is more preferred. e1 is a number satisfying 0 ≤ e1 ≤ 0.8, but from the viewpoint of hardness of the resulting cured product, a number satisfying 0.1 ≤ e1 ≤ 0.6 is preferred, and a number satisfying 0.1 ≤ e1 ≤ 0.4 is more preferred. f1 is a number satisfying 0 ≤ f1 ≤ 0.6, but from the viewpoint of the heat resistance stability and crack resistance of the resulting cured product, a number satisfying 0 ≤ f1 ≤ 0.5 is preferred, and a number satisfying 0 ≤ f1 ≤ 0.4 is more preferred. g1 is a number satisfying 0 ≤ g1 ≤ 0.8, but from the viewpoint of the hardness of the resulting cured product and the stability of the composition, a number satisfying 0.1 ≤ g1 ≤ 0.6 is preferred, and a number satisfying 0.1 ≤ g1 ≤ 0.4 is more preferred. Note that a1, b1, c1, d1, e1, f1 and g1 are numbers satisfying a1 + b1 + c1 + d1 + e1 + f1 + g1 = 1. Also, c1 + e1 + g1 is a number satisfying 0.1 ≤ (c1 + e1 + g1) ≤ 0.8, but a number satisfying 0.1 ≤ (c1 + e1 + g1) ≤ 0.5 is preferred. h1 is a number satisfying 0 ≤ h1 ≤ 1, but from the viewpoint of the curability of the composition and the crack resistance of the resulting cured product, a number satisfying 0 ≤ h1 ≤ 0.2 is preferred, and a number satisfying 0 ≤ h1 ≤ 0.1 is more preferred.

[0040] The weight-average molecular weight (Mw) of the organohydrogenpolysiloxane represented by formula (5) in terms of polystyrene in the GPC is preferably 1,000 to 50,000, and more preferably 3,000 to 20,000. If the weight-average molecular weight is 1,000 or more, it has excellent film-forming properties, storage stability, and coating properties, and if it is 50,000 or less, there is no risk of unevenness or uneven coating during painting.

[0041] (C) Specific examples of component (C) include, but are not limited to, those listed below.

[0042] (The order of the siloxane units in parentheses in the formula is arbitrary.)

[0043] The amount of component (C) is in the range of 1 to 500 parts by mass, preferably 3 to 150 parts by mass, and more preferably 5 to 20 parts by mass, per 100 parts by mass of component (A). If the amount of component (C) is less than the lower limit, the hardness may decrease, and if it exceeds the upper limit, the flexibility may be poor. Component (C) can be used alone or in combination of two or more types.

[0044] [Component (D)] Component (D) is a platinum group metal catalyst, and any platinum group metal catalyst that promotes the addition reaction (hydrosilylation reaction) of organopolysiloxanes is acceptable. Conventional known platinum group metal catalysts used in hydrosilylation reactions can be used. Examples include platinum-based, palladium-based, and rhodium-based catalysts, but platinum-based catalysts, which are relatively easy to obtain, are preferred. Examples include elemental platinum, platinum black, chloroplatinic acid, chloroplatinic acid-olefin complex, chloroplatinic acid-divinyltetramethyldisiloxane complex, chloroplatinic acid-alcohol coordination compound, platinum diketone complex, platinum-olefin complex, platinum-alcohol complex, platinum coordination compound, etc. Note that a single platinum group metal catalyst may be used, or two or more may be used in combination.

[0045] The amount of component (D) should be an effective amount as a catalyst, that is, an effective amount necessary to promote the hydrosilylation reaction and cure the composition of the present invention. Preferably, it is 0.1 to 500 ppm, more preferably 1 to 200 ppm, on a mass basis converted to platinum group metal atoms, relative to the mass of component (A). If the amount of catalyst is above the lower limit, the catalytic effect is reliably obtained, and if it is below the upper limit, the catalytic effect increases in proportion to the amount added, making it economical.

[0046] [Other Components] In addition to the components (A) to (D) above, the addition-curable silicone composition of the present invention may contain any other components as long as they do not impair the effects of the present invention. For example, the addition-curable silicone composition of the present invention may contain a reaction control agent that suppresses the progress of the hydrosilylation reaction in order to extend the shelf life and pot life. The reaction control agent may be a conventionally known reaction control agent used in addition-curable silicone compositions, and examples include acetylene compounds such as ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, and 3,5-dimethyl-1-hexyne-3-ol; various nitrogen compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; organophosphorus compounds such as triphenylphosphine; oxime compounds; and organochloro compounds.

[0047] When using a reaction control agent, the amount to be added is preferably 0.01 to 2.0 parts by mass, more preferably 0.01 to 0.1 parts by mass, per 100 parts by mass of component (A). Within this range, the reaction control effect is sufficiently exhibited. The reaction control agent may be diluted with organopolysiloxane, toluene, or the like to improve its dispersibility in the addition-curable silicone composition.

[0048] The addition-curable silicone composition of the present invention may contain a heat-resistant additive to improve heat resistance. Examples of heat-resistant additives include cerium oxide, iron oxide, halogen compounds, and hindered amine compounds. When a heat-resistant additive is used, the amount added is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of component (A).

[0049] The addition-curable silicone composition of the present invention may contain a diluent to reduce viscosity. The diluent is not particularly limited as long as it can dissolve or disperse the organopolysiloxane of the present invention, and specific examples include aromatic hydrocarbons such as toluene and xylene; hydrocarbons such as hexane and octane; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and isobutyl acetate; and alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, and t-butanol.

[0050] The addition-curable silicone composition of the present invention may contain an adhesion aid to impart adhesion to a substrate. Examples of adhesion aids include organosilicon compounds such as silanes and siloxanes containing functional groups that impart adhesion, and non-silicone organic compounds. Specific examples of functional groups that impart adhesion include vinyl groups bonded to silicon atoms, alkenyl groups such as allyl groups, epoxy groups bonded to silicon atoms via hydrogen atoms or carbon atoms (e.g., γ-glycidoxypropyl group, β-(3,4-epoxycyclohexyl)ethyl group, acryloxy groups (e.g., γ-acryloxypropyl group), methacryloxy groups (e.g., γ-methacryloxypropyl group), and alkoxysilyl groups (e.g., trimethoxysilyl groups, triethoxysilyl groups, methyldimethoxysilyl groups, and other alkoxysilyl groups bonded to silicon atoms via alkylene groups that may contain one or two ester, urethane, or ether structures).

[0051] Examples of organosilicon compounds containing functional groups that impart adhesion include silane coupling agents, siloxanes having alkoxysilyl groups and organic functional groups, and compounds obtained by introducing alkoxysilyl groups into organic compounds having reactive organic groups. Examples of non-silicone organic compounds include allyl esters of organic acids such as triallyl isocyanurate, epoxy ring-opening catalysts, organotitanium compounds, organozirconium compounds, and organoaluminum compounds. The adhesive aid may be used alone or in combination of two or more types.

[0052] When using an adhesive aid, the amount to be added is preferably 0.05 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of component (A).

[0053] The addition-curable silicone composition of the present invention may contain inorganic fillers to improve its reinforcing properties. Examples of inorganic fillers include fuzzy silica (dry silica), precipitated silica (wet silica), crystalline silica, polysilsesquioxane, titanium dioxide, alumina, and fillers obtained by surface hydrophobizing these fillers with organosilicon compounds such as organoalkoxysilane compounds, organochlorosilane compounds, organosilazane compounds, and low molecular weight siloxane compounds. When using inorganic fillers, the amount added is preferably 0.1 to 30 parts by mass, more preferably 1 to 15 parts by mass, per 100 parts by mass of component (A).

[0054] The addition-curable silicone composition of the present invention may contain organopolysiloxane raw rubber to improve its strength. Raw rubber refers to a high polymer that is either a very viscous liquid or a non-liquid (paste or solid) substance with no self-flow properties at room temperature (25°C). The average degree of polymerization of the organopolysiloxane raw rubber is preferably 2,000 to 50,000, and more preferably 2,500 to 30,000. Examples of organopolysiloxane raw rubber include dimethylpolysiloxane, methylphenylpolysiloxane, methylvinylpolysiloxane, methylphenylsiloxane / dimethylsiloxane copolymer, methylvinylsiloxane / dimethylsiloxane copolymer, and methylphenylsiloxane / methylvinylsiloxane / dimethylsiloxane copolymer, in which both ends of the molecular chain are sealed with trimethylsiloxy groups, dimethylphenylsiloxane groups, vinyldimethylsiloxane groups, divinylmethylsiloxane groups, trivinylsiloxy groups, methylphenylvinylsiloxane groups, etc. When using organopolysiloxane raw rubber, the amount blended is preferably 0.1 to 30 parts by mass, more preferably 1 to 15 parts by mass, per 100 parts by mass of component (A).

[0055] There are no particular limitations on the method for preparing the addition-curable silicone composition of the present invention; the components (A) to (D) described above and any other components as needed can be mixed by appropriate means.

[0056] [2] Cured Products The addition-curable silicone composition of the present invention can be cured to form a cured product. The curing conditions are not particularly limited, but it is preferable to use a temperature of 100 to 250°C for 30 to 300 minutes. The cured products of the present invention have an excellent balance of heat resistance, hardness, and flexibility, and can therefore be suitably used as binder components for heat-resistant paints and heat-resistant resins, as well as for coatings on building materials and molded articles, and as coating and sealing materials for electronic components.

[0057] The present invention will be described in more detail below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The average composition of organopolysiloxanes was determined using an NMR measuring device manufactured by JEOL Ltd. 1 H-NMR and 29 These values ​​are calculated from the integrated values ​​of the Si-NMR spectrum, and similarly, the amount of alkenyl groups in the composition and the ratio of the number of hydrogen atoms bonded to silicon atoms to the alkenyl groups bonded to silicon atoms in the composition are also calculated. 1 The weight-average molecular weight (Mw) was calculated from 1H-NMR. The weight-average molecular weight is the polystyrene equivalent value obtained by GPC (gel permeation chromatography) measurement under the following conditions. [GPC conditions] Apparatus: HLC-8220 (manufactured by Tosoh Corporation) Columns: TSKgel GMHXL-L, TSKgel G4000HXL, TSKgel G2000HXL ×2 Developing solvent: Tetrahydrofuran (THF) Flow rate: 1 mL / min Detector: RI Column oven temperature: 40°C Standard substance: Polystyrene

[0058] [1] Synthesis of organopolysiloxane resin [Synthesis Example 1] 4,086.6 g of methyltrimethoxysilane was placed in a glass flask equipped with a stirrer, thermometer, condenser, and dropping funnel. While stirring, 486 g of 1N hydrochloric acid was added dropwise over 1 hour, and the mixture was reacted at 67°C for 2 hours. The resulting solution was neutralized with 29.2 g of propylene oxide, and the volatile components and solvent were distilled off to obtain polysilsesquioxane (A-0). 2,252 g of the obtained polysilsesquioxane (A-0), 1,453 g of vinylmethyldimethoxysilane, 1,322 g of dimethyldimethoxysilane, 646 g of hexamethyldisiloxane, and 4,137 g of toluene were stirred, and 60 g of methanesulfonic acid was added. Then, 539 g of water was added dropwise over 1 hour, and the mixture was reacted at 67°C for 2 hours and further at 80 - 90°C for 3 hours. The resulting solution was washed with water until the extracted water became neutral, and then the solvent was distilled off to obtain a product. The ratio of each structural unit in formula (1) calculated from the results of NMR measurement of the obtained organopolysiloxane resin (A-1) was a = 0, b = 0.5, c = 0, d = 0.2, e = 0.2, f = 0.1, g = 0, h = 0.05, where R 1 is a methyl group, and R 2 is a vinyl group, and R 3 is a hydrogen atom. The weight-average molecular weight was 10,000, and the alkenyl group content was 0.2 mol / 100 g.

[0059] [Synthesis Examples 2 - 7] In Synthesis Example 1, the types and amounts of monomers were changed to synthesize organopolysiloxanes (A-2) - (A-7) having the structural units shown in Table 1. Here, Me represents a methyl group, Vi represents a vinyl group, and H represents a hydrogen atom.

[0060]

[0061] [2] Preparation of addition-curable silicone composition [Examples 1-1 to 1-16, Comparative Examples 1-1 to 1-10] Each of the components shown below was mixed at 25°C in the blending amounts (parts by mass) shown in Table 2 to prepare an addition-curable silicone composition. Further, the ratio (H / Vi) of the number of hydrogen atoms bonded to silicon atoms to the number of alkenyl groups (vinyl groups) bonded to silicon atoms in each composition was calculated from the results of NMR measurement.

[0062] Component (A) (A-1): Organopolysiloxane resin obtained in Synthesis Example 1 (A-2): Organopolysiloxane resin obtained in Synthesis Example 2 (A-3): Organopolysiloxane resin obtained in Synthesis Example 3 (A-4): Organopolysiloxane obtained in Synthesis Example 4 (A-5): Organopolysiloxane resin obtained in Synthesis Example 5 (A-6): Organopolysiloxane resin obtained in Synthesis Example 6 (A-7): Organopolysiloxane resin obtained in Synthesis Example 7 Component (B) (B-1): Linear polysiloxane represented by the above formula (2) where R 4 = methyl group, R 5 = hydrogen atom, R 6 = methyl group, n = 20 (B-2): Linear polysiloxane represented by the above formula (2) where R 4 = methyl group, R 5 = hydrogen atom, R 6 = methyl group, n = 60 (B-3): Linear polysiloxane represented by the above formula (2) where R 4 = methyl group, R 5 = hydrogen atom, R 6 = methyl group, n = 400 (B-4): Linear polysiloxane represented by the above formula (2) where R 4 = methyl group, R 5 = vinyl group, R 6 = methyl group, n = 1,000 (B-5): Linear polysiloxane represented by the above formula (2) where R 4 = methyl group, R 5 = vinyl group, R 6 [[ID=and]] = vinyl group, n = 1,000

[0063] Component (C) (C-1): Organohydrogenpolysiloxane represented by the following formula

[0064] (C-2): 1,3,5,7-tetramethylcyclotetrasiloxane (C-3): Organohydrogenpolysiloxane represented by the following formula (The order of the siloxane units in parentheses in the formula is undefined.)

[0065] (C-4): In the above formula (5), R 9 = Methyl group, R 10 = A hydrogen atom, an organohydrogenpolysiloxane having a constituent unit ratio represented by a1=0, b1=0.6, c1=0, d1=0, e1=0.1, f1=0.3, g1=0, h1=0.04 (weight-average molecular weight 5,000, number of hydrogen atoms bonded to silicon atoms per molecule: 8) (C-5): In the above formula (5), R 9 = Methyl group, R 10 = A hydrogen atom, an organohydrogenpolysiloxane having a constituent unit ratio represented by a1=0, b1=0.6, c1=0, d1=0, e1=0.1, f1=0, g1=0.3, h1=0.03 (weight-average molecular weight 6,000, number of hydrogen atoms bonded to silicon atoms per molecule: 35) (C-6): In formula (5), R 9 = Methyl group, R 10 = Hydrogen atom, a1=0, b1=0.6, c1=0, d1=0, e1=0.1, f1=0, g1=0.3, h1=0.03 - Organohydrogenpolysiloxane having a constituent unit ratio (weight-average molecular weight 15,000, number of hydrogen atoms bonded to silicon atoms per molecule: 81) (D) Component (D-1): Toluene solution of platinum-divinyltetramethyldisiloxane complex (platinum concentration 0.5% by mass) Other component control agent: Ethinylmethyldecylcarbinol

[0066]

[0067] [3] Preparation and Evaluation of Cured Products The compositions obtained in Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-10 were added to a Teflon® petri dish, heated at 200°C for 2 hours, and then allowed to cool to 25°C to produce cured products with a thickness of 0.3 mm. The appearance, hardness, and tensile elongation at break of the obtained cured products were measured. The results are shown in Table 3.

[0068] (1) Appearance The appearance of the hardened film was visually evaluated in a petri dish. Films without significant oil bleeding or cracking were evaluated as ○, and those with significant oil bleeding or cracking were evaluated as ×. (2) Hardness Hardness was measured using a Type A durometer in accordance with ASTM D2240. Films with a hardness of less than A30 were evaluated as ×, A30 to A50 as △, and those greater than A50 as ○. (3) Tensile elongation at fracture Tensile elongation at fracture was calculated as a percentage of the initial state (100%) by taking a 1cm x 1cm test piece and applying a load diagonally until fracture. Films with a hardness of less than 120% were evaluated as ×, 120% to 150% as △, and those greater than 150% as ○.

[0069]

[0070] As shown in Table 3, the cured products of the silicone compositions in Examples 2-1 to 2-16 exhibit an excellent balance of appearance, hardness, and tensile elongation at fracture. On the other hand, Comparative Example 2-1, which does not contain component (B), shows inferior tensile elongation at fracture, while Comparative Example 2-2, which does not contain component (C), tends to show inferior hardness. Comparative Example 2-3 has a low H / Vi ratio, resulting in insufficient hardness and elongation, while Comparative Example 2-4 has a high H / Vi ratio, leading to a tendency for decreased hardness. Furthermore, Comparative Examples 2-5 to 2-10, in which component (A) was changed to (A-4), (A-5), and (A-6), show significant cracking and oil bleeding in appearance, and also exhibit an inferior balance of hardness and tensile elongation at fracture.

Claims

1. (A) Polysiloxane resin represented by the following formula (1): 100 parts by mass [In the formula, R 1 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond, R 2 Each of these independently represents a hydrogen atom or an alkenyl group having 2 to 12 carbon atoms (however, R 2 The proportion of hydrogen atoms in the total number of atoms is 10-90 mol%, R 3 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and a, b, c, d, e, f, and g are numbers satisfying 0 ≤ a ≤ 0.6, 0.2 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.8, 0 ≤ f ≤ 0.6, 0 ≤ g ≤ 0.8, and 0.1 ≤ (c + e + g) ≤ 0.8 and a + b + c + d + e + f + g = 1, and h is a number satisfying 0 ≤ h ≤ 1. ] (B) Linear polysiloxane represented by the following formula (2): 50 to 300 parts by mass, (In the formula, R 4 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond, R 5 Each of these independently represents a hydrogen atom or an alkenyl group with 2 to 12 carbon atoms, R 6 (C) an organohydrogenpolysiloxane having three or more hydrogen atoms bonded to silicon atoms in one molecule and not containing aliphatic unsaturated bonds: 1 to 500 parts by mass, and (D) an addition-curable silicone composition comprising a platinum group metal catalyst, wherein the number of hydrogen atoms bonded to silicon atoms in the composition is 0.7 to 2.3 per alkenyl group bonded to silicon atoms in the composition.

2. The R 1 is a methyl group, and the alkenyl group in the R 2 is a vinyl group. The addition-curable silicone composition according to claim 1.

3. The addition-curable silicone composition according to claim 1, wherein a is 0.

4. The addition-curable silicone composition according to claim 1, wherein g is 0.

5. The addition-curable silicone composition according to claim 1, wherein c, e, and g are numbers satisfying 0 ≤ c ≤ 0.4, 0.1 ≤ e ≤ 0.5, 0 ≤ g ≤ 0.4, and 0.2 ≤ (c + e) ​​≤ 0.

8.

6. The addition-curable silicone composition according to claim 1, wherein the alkenyl group content in component (A) is 0.05 to 0.6 mol / 100g.

7. The addition-curable silicone composition according to claim 1, wherein the weight-average molecular weight (Mw) of component (A) in terms of polystyrene, as measured by gel permeation chromatography, is 1,000 to 50,000.

8. The addition-curable silicone composition according to claim 1, wherein component (C) is one or more selected from organohydrogenpolysiloxanes represented by the following formula (3) and organohydrogenpolysiloxanes represented by the following formula (4). (In the formula, R 7 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond. p is an integer from 1 to 100, q is an integer from 0 to 100, r is 0 or 1, and s is 0 or 1. However, p + r + s is 3 or greater. The order of the siloxane units in parentheses with p and q is arbitrary. (In the formula, R 8 Each of these independently represents a monovalent hydrocarbon group with 1 to 12 carbon atoms that does not contain an aliphatic unsaturated bond, where t is an integer from 3 to 6 and u is an integer from 0 to 3. However, t + u is an integer from 3 to 6. The order of the siloxane units in parentheses is arbitrary.

9. The aforementioned R 7 and R 8 The addition-curable silicone composition according to claim 8, wherein the group is a methyl group.

10. The addition-curable silicone composition according to claim 1, wherein the number of hydrogen atoms bonded to silicon atoms in the composition is 0.9 to 2.1 per alkenyl group bonded to silicon atoms in the composition.

11. A cured product of an addition-curable silicone composition according to any one of claims 1 to 10.

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