Curable silicone composition and cured product thereof

Abstract

The present disclosure relates to an organopolysiloxane resin having (A) an alkenyl group in the molecule, (B) an organosiloxane oligomer having a viscosity of 1,000 mPa s or less at 25°C, having at least one silicon-bonded alkenyl group or silicon-bonded hydrogen atom in the molecule, and having at least one silicon-bonded aryl group, and (C) (C1) an organosiloxane oligomer having at least one alkenyl group in the molecule, and having at least one silicon-bonded aryl group and SiO 4 / 2 The present invention relates to a curable silicone composition comprising an organosilicon compound selected from (C1) an organopolysiloxane having no silicon-bonded aryl group, (C2) an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and no silicon-bonded aryl group, (C3) a disilylbenzene, and mixtures thereof, and (D) a hydrosilylation reaction catalyst. This composition is easy to handle at room temperature without the use of a solvent, and cures by heating to form a cured product that is non-tacky at room temperature and has excellent melt viscosity.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and all benefits of U.S. Provisional Patent Application No. 63 / 313,392, filed February 24, 2022, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a curable silicone composition and a cured product thereof. [Background technology]

[0003] Curable silicone compositions cure to form cured products that have excellent heat resistance, electrical insulation properties, and weather resistance, and are therefore widely used as protective coatings, encapsulants, or sealants for electrical / electronic devices.

[0004] For example, Patent Document 1 discloses CH2=CH(CH3)2SiO 1 / 2 The unit, (CH3)3SiO 1 / 2 unit, and SiO 4 / 2 The present invention discloses that a curable silicone composition comprising an organopolysiloxane resin consisting of N-(2-methyl-2-phenylene)-2-sulfonyl units, an organopolysiloxane having at least two alkenyl groups in the molecule, an organopolysiloxane having at least two alkenyl groups in the molecule, an organopolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule, and a hydrosilylation reaction catalyst cures to a cured product having hot melt properties.

[0005] However, such curable silicone compositions are typically solvent-based compositions.The solvent is mainly used to reduce the viscosity of the curable silicone composition, and is removed after the composition is applied.As with all solvent-based curable silicone compositions, special precautions must be taken to avoid the inclusion and exposure of solvent to the environment, and to avoid flammable and explosive conditions, since many of the solvents are flammable.

[0006] Prior art documents Patent Literature Patent Document 1: Korean Patent Application Publication No. 10-2021-0084572(A) Summary of the Invention

[0007] Problem to be solved by the invention An object of the present invention is to provide a curable silicone composition that does not require the use of a solvent and has excellent handleability at room temperature, and that cures upon heating to form a cured product that is non-tacky and has excellent melt viscosity at room temperature.

[0008] Means for solving the problem The curable silicone composition of the present invention comprises: (A) The average unit formula: (R 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (SiO 4 / 2 ) c (HO 1 / 2 ) d (In the formula, each R 1 are independently alkyl groups, R 2 is an alkenyl group, and "a", "b", "c" and "d" are numbers that satisfy the conditions: a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a+b+c=1; and (B) an organosiloxane oligomer having a viscosity at 25°C of 1,000 mPa s or less, selected from (B1) an organosiloxane oligomer having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group in the molecule, (B2) an organosiloxane oligomer having at least one silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and a mixture of components (B1) and (B2); (C) (C1) has at least one alkenyl group in the molecule, and has a silicon-bonded aryl group and SiO 4 / 2(C2) an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and having no silicon-bonded aryl groups; (C3) an organopolysiloxane having the following general formula: HR 1 2Si-C6H4-SiR 1 2H (In the formula, each R 1 is as defined above), and mixtures thereof; (D) a catalytic amount of a hydrosilylation reaction catalyst; Here, based on the total mass of components (A) to (C), the amount of component (A) is in the range of 60 to 75 mass%, the amount of component (B) is in the range of 5 to 35 mass%, and the amount of component (C) is in the range of 0 to 30 mass%, with the proviso that the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) is greater than 0.30 and less than or equal to 0.90.

[0009] In various embodiments, component (B1) is 11 ) the following general formula: R 2 R 3 2SiO(R 3 2SiO) m SiR 3 2R 2 (In the formula, each R 2 are independently an alkenyl group, and each R 3 are independently an alkyl group or an aryl group, provided that at least one R 3 is an aryl group, and “m” is an integer of 0 to 10).

[0010] In various embodiments, component (B 11 ) is expressed by the following formula: (CH2=CH)(CH3)2SiO(C6H5)2SiOSi(CH3)2(CH=CH2) (CH2=CH)(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2(CH=CH2) (CH2=CH)(CH3)(C6H5)SiOSi(CH3)(C6H5)(CH=CH2) The organosiloxane oligomer is at least one selected from the organosiloxane oligomers represented by the following formula:

[0011] In various embodiments, component (B2) is 21 ) the following general formula: HR 3 2SiO(R 3 2SiO) m SiR 3 2H (In the formula, each R 3 are independently an alkyl group or an aryl group, provided that at least one R 3 is an aryl group, and “m” is an integer of 0 to 10).

[0012] In various embodiments, component (B 21 ) is expressed by the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H The organosiloxane oligomer is at least one selected from the organosiloxane oligomers represented by the following formula:

[0013] In various embodiments, the curable silicone composition further comprises a hydrosilylation reaction inhibitor in an amount, calculated in units of mass for the (E) composition, of 0.1 to 10,000 ppm of this component.

[0014] In various embodiments, the curable silicone composition further comprises (F) an adhesion promoter in an amount of up to 10 parts by weight per 100 parts by weight of the combined weight of components (A)-(C).

[0015] The cured product of the present invention can be obtained by curing the above-described curable silicone composition.

[0016] Effect of the Invention The curable silicone composition of the present invention has excellent handleability at room temperature without using a solvent, and cures upon heating to form a cured product that is non-tacky at room temperature and has excellent melt viscosity.

[0017] definition The terms "comprising" or "comprise" are used herein in their broadest sense to mean and encompass the ideas of "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "eg," "such as," and "including" to list examples does not limit the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and encompasses other similar or equivalent examples. As used herein, the term "about" serves to reasonably encompass or describe slight variations in values ​​measured by instrumental analysis or as a result of handling samples. Such slight variations may be as much as ±0-25, ±0-10, ±0-5, or ±0-2.5% of the numerical value. Furthermore, the term "about" applies to both numerical values ​​when relating to a range of values. Furthermore, the term "about" may be applied to numerical values ​​even if not expressly stated.

[0018] It should be understood that the appended claims are not limited to the express and specific compounds, compositions, or methods described in the Detailed Description, which may vary among specific embodiments within the scope of the appended claims. With respect to any Markush group on which recitation of specific features or aspects of various embodiments is made herein, it should be understood that different, special, and / or unexpected results may be obtained from each element of the respective Markush group, independently of all other Markush elements. Each element of the Markush group may be relied upon individually and / or in combination to provide sufficient support for specific embodiments within the scope of the appended claims.

[0019] Any ranges and subranges relied upon in describing various embodiments of the present invention should also be understood to be within the scope of the appended claims, both individually and inclusively, and all ranges including integer and / or fractional values ​​are understood to be described and contemplated therein, even if not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and subranges fully describe and enable various embodiments of the present invention, and that such ranges and subranges may be further described into relevant halves, thirds, fourths, fifths, etc. As merely an example, a range "from 0.1 to 0.9" may be further described into a lower third, i.e., 0.1 to 0.3, a middle third, i.e., 0.4 to 0.6, and an upper third, i.e., 0.7 to 0.9, which are individually and inclusively within the scope of the appended claims, and may be relied upon and provide sufficient support for specific embodiments within the scope of the appended claims, individually and / or inclusively. In addition, with respect to words defining or modifying a range, such as "at least," "greater than," "less than," "less than," etc., such words should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" essentially includes subranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., each of which may be relied upon individually and / or inclusively to provide sufficient support for specific embodiments within the scope of the appended claims. Finally, individual numbers within the disclosed ranges may be relied upon to provide sufficient support for specific embodiments within the scope of the appended claims. For example, the range "from 1 to 9" includes various individual integers, such as 3, and individual numbers including decimal points (or fractions), such as 4.1, which may be relied upon to provide sufficient support for specific embodiments within the scope of the appended claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The curable silicone composition of the present invention will now be described in detail.

[0021] Component (A) has the following average unit formula: (R 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (SiO 4 / 2 ) c (HO 1 / 2 ) d The organopolysiloxane resin is represented by the formula:

[0022] In the formula, each R 1 are independently an alkyl group. The alkyl group is exemplified by an alkyl group having 1 to 12 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a undecyl group, and a dodecyl group. Among these, a methyl group is preferred.

[0023] In the formula, R 2 is an alkenyl group. The alkenyl group is exemplified by alkenyl groups having 2 to 12 carbon atoms, such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, and a dodecenyl group. Among these, a vinyl group is preferred.

[0024] In the formula, "a", "b", "c" and "d" are numbers that satisfy the conditions of a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a+b+c=1, and may be 0.1≦a≦0.5, 0.01≦b≦0.2, 0.4≦c≦0.7, 0≦d≦0.05, and a+b+c=1, or may be 0.2≦a≦0.5, 0.01≦b≦0.2, 0.4≦c≦0.7, 0≦d≦0.05, and a+b+c=1. This is because, when "a", "b", "c" and "d" are numbers within the above-mentioned ranges, the cured product obtained by curing the present composition has appropriate hardness and mechanical strength.

[0025] The molecular weight of the organopolysiloxane resin of component (A) is not limited, but its number average molecular weight (Mn), measured by gel permeation chromatography (GPC) in terms of standard polystyrene, is preferably at least 1,500 g / mol, alternatively at least 2,000 g / mol, or alternatively at least 3,000 g / mol, while Mn is preferably not more than 6,000 g / mol, alternatively not more than 5,500 g / mol. The Mn of component (A) can be any range combining the upper and lower limits described above. It should be noted that when component (A) is in a solid state at 25°C and it is difficult to uniformly mix other components in the composition, this problem can be solved by preparing an organic solution of component (A) in advance, mixing it with some or all of components (B) and (C), and then removing the organic solvent used from this mixture. It should be noted that any organic solvent that can be used to prepare the organic solution of component (A) can be used as long as it can dissolve component (A) and can be easily removed. Specific examples include, but are not limited to, aromatic hydrocarbons such as toluene and xylene, and aliphatic hydrocarbons such as hexane and heptane.

[0026] Component (A) is used in an amount of 60 to 75% by mass based on the total mass of components (A) to (C), because when the amount is equal to or greater than the lower limit of the above range, the cured product obtained by curing the composition has appropriate hardness and mechanical strength, whereas when the amount is equal to or less than the upper limit of the above range, the composition has an appropriate viscosity at 25°C.

[0027] Component (B) is an organosiloxane oligomer for imparting flow properties to the curable silicone composition and hot melt properties to the cured product obtained by curing the composition. The molecular structure of the organosiloxane oligomer of component (B) is not limited, but is exemplified by linear and partially branched linear. The molecular weight of the organosiloxane oligomer of component (B) is not limited, but is preferably 2,000 g / mol or less, alternatively 1,500 g / mol or less. Such organosiloxane oligomers typically have a viscosity at 25°C of 1,000 mPa·s or less, alternatively 500 mPa·s or less, or alternatively 100 mPa·s or less. It should be noted that in this specification, viscosity is measured at 23±2°C using a Brookfield viscometer according to ASTM D1084.

[0028] The organosiloxane oligomer of component (B) also acts as a chain extender or crosslinker for the composition and is selected from (B1) an organosiloxane oligomer having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group in the molecule, (B2) an organosiloxane oligomer having at least one silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and a mixture of components (B1) and (B2).

[0029] The organosiloxane oligomer of component (B1) typically has the following general formula: R 2 R 3 2SiO(R 3 2SiO) m SiR 3 2R 2 It is an organosiloxane oligomer represented by the formula:

[0030] In the formula, each R 2 are each independently an alkenyl group, examples of which include the same groups as those mentioned above. Among these, a vinyl group is preferred.

[0031] In the formula, each R 3R is independently an alkyl group or an aryl group. 3 Examples of the alkyl group of R 1 The alkyl groups are the same as those shown in R 3 Examples of the aryl group include aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl groups. However, at least one R 3 is an aryl group, typically a phenyl group.

[0032] In the formula, "m" is an integer from 0 to 10, alternatively an integer from 0 to 5, alternatively an integer from 0 to 3, or alternatively an integer of 0 or 1.

[0033] Component (B1) typically has the following formula: (CH2=CH)(CH3)2SiO(C6H5)2SiOSi(CH3)2(CH=CH2) (CH2=CH)(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2(CH=CH2) (CH2=CH)(CH3)(C6H5)SiOSi(CH3)(C6H5)2(CH=CH2) The organosiloxane oligomer is at least one selected from the organosiloxane oligomers represented by the following formula:

[0034] The organosiloxane oligomer of component (B2) typically has the following general formula: HR 3 2SiO(R 3 2SiO) m SiR 3 2H It is an organosiloxane oligomer represented by the formula:

[0035] In the formula, each R 3 is an alkyl or aryl group, examples of which include the same groups as above. However, at least one R 3 is an aryl group, typically a phenyl group.

[0036] In the formula, "m" is an integer from 0 to 10, alternatively an integer from 0 to 5, alternatively an integer from 0 to 3, or alternatively an integer of 0 or 1.

[0037] Component (B2) typically has the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H The organosiloxane oligomer is at least one selected from the organosiloxane oligomers represented by the following formula:

[0038] Component (B) is used in an amount of 5 to 35% by weight, alternatively 5 to 30% by weight, based on the total weight of components (A) to (C). This is because, if the amount is equal to or greater than the lower limit of the above range, the composition has good handleability, while if the amount is equal to or less than the upper limit of the above range, the resulting cured product has good transparency. The organosiloxane oligomer of component (B) may be a mixture of components (B1) and (B2). However, the amounts of components (B1) and (B2) are not limited, but the amount of component (B) should be such that the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) is in the range of 0.3 to 0.9.

[0039] Component (C) is an optional component, which has at least one alkenyl group in the (C1) molecule, and has silicon-bonded aryl groups and SiO 4 / 2 (C2) an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and having no silicon-bonded aryl groups; (C3) an organopolysiloxane having the following general formula: HR 1 2Si-C6H4-SiR 1 2H and mixtures thereof.

[0040] When the mixture of components (A) and (B) can be completely cured, the addition of component (C) is optional. However, when the mixture cannot be cured due to a lack of silicon-bonded alkenyl groups, component (C1) should be added, and when the mixture cannot be cured due to a lack of silicon-bonded hydrogen atoms, component (C2) and / or (C3) should be added. Furthermore, when the cured product obtained by curing the composition is hard, component (C) should be added as a chain extender, and when the cured product obtained by curing the composition is soft, component (C) should be added as a crosslinker.

[0041] Component (C1) has at least one alkenyl group in the molecule, and has silicon-bonded aryl groups and SiO 4 / 2 It is an organopolysiloxane having no unit. Examples of the alkenyl group include alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl. Among these, vinyl is preferred. Examples of groups bonded to silicon atoms other than alkenyl groups in component (C1) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl.

[0042] The molecular structure of component (C1) is not limited, but is typically a linear structure, a partially branched linear structure, a branched structure, or a cyclic structure. Component (C1) may be one organopolysiloxane having these molecular structures, or may be a mixture of two or more organopolysiloxanes having these molecular structures.

[0043] Examples of such component (C1) include dimethylpolysiloxanes whose molecular chain ends are capped with dimethylvinylsiloxy groups, copolymers of dimethylsiloxanes whose molecular chain ends are capped with dimethylvinylsiloxy groups and methylvinylsiloxanes, copolymers of dimethylsiloxanes whose molecular chain ends are capped with trimethylsiloxy groups and methylvinylsiloxanes, and mixtures of two or more of these.

[0044] Component (C2) is an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and no silicon-bonded aryl group. Examples of the group bonded to the silicon atom in component (C2) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups.

[0045] The molecular structure of component (C2) is not limited, but typically includes a linear structure, a partially branched linear structure, a branched structure, a cyclic structure, and a three-dimensional network structure. Component (C2) may be one organopolysiloxane having these molecular structures, or may be a mixture of two or more organopolysiloxanes having these molecular structures.

[0046] Examples of such component (C2) include methylhydrogenpolysiloxane capped at both molecular chain ends with trimethylsiloxy groups, a copolymer of dimethylsiloxane and methylhydrogensiloxane capped at both molecular chain ends with trimethylsiloxy groups, dimethylpolysiloxane capped at both molecular chain ends with dimethylhydrogensiloxy groups, a copolymer of dimethylsiloxane and methylhydrogensiloxane capped at both molecular chain ends with dimethylhydrogensiloxy groups, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2A copolymer consisting of the unit (CH3)2HSiO 1 / 2 The unit, (CH3)3HSiO 1 / 2 Unit and SiO 4 / 2 Copolymers of these units, as well as mixtures of two or more of these, are included.

[0047] Component (C3) has the following general formula: HR 1 2Si-C6H4-SiR 1 2H (In the formula, each R 1 is as above).

[0048] An example of such a component (C3) is the following disilylbenzene: H(CH3)2Si-C6H4-Si(CH3)2H H(CH3)(C2H5)Si-C6H4-Si(CH3)(C2H5)H

[0049] The organosilicon compound of component (C) may be a mixture of components (C1) and (C2). However, component (C) typically has a viscosity of 1,000 mPa·s or less, alternatively 500 mPa·s or less, or alternatively 100 mPa·s or less at 25° C. It should be noted that viscosity herein is measured at 23±2° C. using a Brookfield viscometer according to ASTM D1084.

[0050] Component (C) is used in an amount of 0 to 30% by weight, alternatively 2 to 30% by weight, based on the total weight of components (A) to (C). This is because when the amount is equal to or greater than the lower limit of the above range, the composition has good handleability, while when the amount is equal to or less than the upper limit of the above range, the composition has good transparency. The organosilicon compound of component (C) may be a mixture of components (C1) to (C3). However, the amounts of components (C1) to (C3) are not limited, but the amount of component (C) should be such that the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) is in the range of 0.3 to 0.9.

[0051] The molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) ("SiH / Vi ratio") is greater than 0.30 and less than or equal to 0.90, alternatively in the range of 0.31 to 0.80, or alternatively in the range of 0.34 to 0.70. This is because, when the molar ratio is equal to or greater than the lower limit of the above range, the composition can be completely cured, and the cured product obtained by curing the composition has appropriate hardness and a non-tacky surface, while when the molar ratio is equal to or less than the upper limit of the above range, the cured product has good hot melt properties.

[0052] Component (D) is a hydrosilylation catalyst used to accelerate the curing of the composition. Component (D) hydrosilylation catalysts are well known in the art and commercially available. Suitable hydrosilylation catalysts include, but are not limited to, platinum group metals, including platinum, rhodium, ruthenium, palladium, osmium or iridium metals, or organometallic compounds thereof, and combinations of any two or more thereof. Component (D) is typically a platinum-based catalyst that can dramatically accelerate the curing of the composition. Examples of platinum-based catalysts include platinum fine powder, chloroplatinic acid, alcoholic solutions of chloroplatinic acid, platinum-alkenylsiloxane complexes, platinum-olefin complexes, and platinum-carbonyl complexes, with platinum-alkenylsiloxane complexes being the most typical.

[0053] In various embodiments, component (D) is a hydrosilylation catalyst comprising a complex of platinum with a low molecular weight organopolysiloxane, including a complex of platinum with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane. These complexes may be microencapsulated in a resin matrix. In a specific embodiment, the catalyst includes a complex of platinum with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane.

[0054] Examples of hydrosilylation catalysts suitable for component (D) are described in, for example, U.S. Patent Nos. 3,159,601, 3,220,972, 3,296,291, 3,419,593, 3,516,946, 3,814,730, 3,989,668, 4,784,879, 5,036,117 and 5,175,325, and European Patent No. 0347895(B). Microencapsulated hydrosilylation catalysts and their preparation methods are exemplified in U.S. Patent Nos. 4,766,176 and 5,017,654.

[0055] The amount of component (D) in the composition is an amount effective to promote the curing of the composition. Specifically, in order to sufficiently cure the composition, the content of component (D) is typically an amount such that the content of the catalytic metal in component (D) relative to the composition is about 0.01 to about 500 ppm, alternatively about 0.01 to about 100 ppm, alternatively about 0.01 to about 50 ppm, alternatively about 0.1 to about 10 ppm, calculated as a mass unit.

[0056] In various embodiments, the curable silicone composition includes (E) a hydrosilylation reaction inhibitor to control the cure rate of the curable silicone composition. In certain embodiments, component (E) includes, but is not limited to, an alkyne alcohol such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, or 2-phenyl-3-butyn-2-ol, 1-ethynyl-cyclohexan-1-ol; an ene-yne ​​compound such as 3-methyl-3-penten-1-yne, or 3,5-dimethyl-3-hexen-1-yne; or 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, tris[(1,1-dimethyl-2-propynyl)oxy]methylsilane, diallylmaleate, or benzotriazole, which may be incorporated into the composition as an optional component.

[0057] The amount of component (E) in the composition is not particularly limited, but when contained, it is typically about 1 to about 10,000 ppm, alternatively about 10 to about 5,000 ppm, in terms of mass units for the composition. This is because, when the amount of component (E) is equal to or greater than the lower limit of the above range, the storage stability of the composition is good, whereas, when the amount of component (E) is equal to or less than the upper limit of the above range, the curability of the composition at low temperatures is good.

[0058] The curable silicone composition of the present invention optionally comprises (F) a silicone having an average unit formula: (R 1 3SiO 1 / 2 ) e (SiO 4 / 2 ) f The composition may further comprise a non-functional organopolysiloxane resin represented by the formula:

[0059] In the formula, each R 1 are independently alkenyl groups, examples of which are the same as those mentioned above.

[0060] In the formula, "e" and "f" are numbers that satisfy the conditions of 0.3≦e≦0.7, 0.3≦f≦0.7, and e+f=1, and may also satisfy the conditions of 0.4≦e≦0.6, 0.4≦f≦0.6, and e+f=1. This is because, when "e" and "f" are numbers within the above-mentioned ranges, the cured product obtained by curing the present composition has appropriate hardness and mechanical strength.

[0061] The amount of component (F) in the composition is not particularly limited, but when it is contained, it is typically 0 to 30 parts by weight per 100 parts by weight of the total of components (A) to (C). This is because the handleability of the composition is good when the amount of component (F) is equal to or less than the upper limit of the above range.

[0062] The viscosity of the composition at 25° C. is not limited, but is typically in the range of 100 to 100,000 mPa·s.

[0063] Next, the cured product of the present invention will be described in detail.

[0064] The cured product of the present invention is obtained by curing the above-mentioned curable silicone composition. The cured product has a non-tacky surface. In particular, the storage modulus G' of the cured product at 20°C is not limited, but is typically in the range of 0.05 to 15 MPa, alternatively in the range of 0.07 to 10 MPa, or alternatively in the range of 0.1 to 5 MPa, under the conditions of frequency = 1 Hz and strain = 1%. The melt viscosity of the cured product at 100°C is not limited, but is typically in the range of 1 to 5000 Pa·s. EXAMPLES

[0065] The curable silicone composition and cured product of the present invention are described in detail below using examples and comparative examples. However, the present invention is not limited to the description of the examples listed below.

[0066] [Gel Permeation Chromatography (GPC)] GPC data for components (a1) and (a2) were collected using a Waters 2695 separation module equipped with a Waters 2414 refractive index detector (RID). Three (7.8 x 300 mm) Styragel HR columns (molecular weight separation range 100-4,000,000) and one Styragel guard column (4.6 x 30 mm) with toluene were used. Samples were prepared as 0.5 wt.% solutions in toluene and filtered through 0.45 micron PTFE syringe filters. A flow rate of 1 milliliter per minute was used, with detector and column temperatures of 45°C, injection volume of 100 microliters, and run time of 60 minutes. Number average molecular weights (Mn) were calculated against linear polystyrene standards covering a molecular weight range of 580-2,610,000.

[0067] [viscosity] The viscosity of each organosiloxane oligomer, organopolysiloxane, and curable silicone composition at 25°C was measured for 1 minute using a HADV III VISCOMETER (Brookfield) with a spindle #CP-25. The viscosity was measured for 2 minutes, and the torque was controlled in the range of 20 to 80%. The final data was collected after the measurement was completed.

[0068] [Melt Viscosity] The melting behavior of the resulting silicone hot melt, obtained by curing the curable silicone composition at 120°C for 30 minutes, could be observed by exposing a solid sample to 100°C. "Melted" means that the shape of the sample collapses and spreads onto the substrate. "Not melted" means that the shape of the sample is maintained. If the sample does not melt at high temperature, the melt viscosity cannot be measured because the sample is fully crosslinked. To measure the melt viscosity, the hot melt sample was prepared in the same manner as above and the sample was placed on a rheometer (ARES-G2, TA Instruments) in parallel plate geometry (25 mm). The melt viscosity was then collected at 100°C at a fixed shear rate of 1 1 / s and a gap of 300 μm.

[0069] [Storage modulus and loss modulus] The curable silicone composition samples were cured, and the shear modulus of the resulting silicone hot melts was evaluated as follows. Each sample prepared as above was poured into a mold (thickness=1 mm) and sandwiched between release films. The assembled samples were cured by heating at 120°C for 30 minutes. After cooling and removing the release films, the samples were placed on a rheometer (ARES-G2, TA Instruments) with parallel plate geometry (25 mm). Dynamic storage modulus (G') was then collected at 20°C and 100°C with a fixed frequency of 1 Hz, using a strain of 0.5%, a gap of 300 μm, and a normal force of 0 N.

[0070] [Examples 1 to 8 and Comparative Examples 1 to 9] The following components were mixed uniformly in the amounts shown in Table 1 to produce a curable silicone composition. When component (A) was solid at 25°C, it was added to the other components using a solvent such as toluene or xylene due to its high viscosity. The solvent was then evaporated and replaced with other components that facilitate mixing to prepare a solventless composition. For example, component (B) was first added to a solution of component (A) dissolved in a solvent. The solvent was then removed under reduced pressure by heating with nitrogen bubbling. After cooling to room temperature, component (C) was added. The mixture was mixed at room temperature. Further, other components were added to the mixture and mixed at room temperature. The resulting composition and cured product were evaluated as described above. These results are shown in Table 1. The "SiH / Vi ratio" in each of Table 1 indicates the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded vinyl groups in components (A) to (C).

[0071] The following organopolysiloxane resins were used as component (A): (a1) The average unit formula: [(CH3)3SiO 1 / 2 ] 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.04 (SiO 4 / 2 ) 0.56 The organopolysiloxane resin has a vinyl group content of about 1.9 mass %, a number average molecular weight (Mn) of about 5,000, and is a solid at 25°C. (a2) The average unit formula: [(CH3)3SiO 1 / 2 ] 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.10 (SiO 4 / 2 ) 0.50 The organopolysiloxane resin has a vinyl group content of about 3.0 mass %, a number average molecular weight (Mn) of about 3,000, and is a solid at 25°C.

[0072] The following organosiloxane oligomers were used as component (B): (b1) the following formula: (CH2=CH)(CH3)2SiO(C6H5)2SiOSi(CH3)2(CH=CH2) It is an organosiloxane oligomer having a viscosity of 8.7 mPa·s and a vinyl group content of approximately 14.06% by mass. (b2) the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H having a viscosity of 4.4 mPa s and a silicon-bonded hydrogen atom content of approximately 0.61 mass%.

[0073] The following organosiloxane oligomers were used as comparisons for component (B): (b3) the following formula: (CH3)3SiO[(C6H5)(CH3)SiO] 16 [(CH3)2SiO] 11 Si(CH3)3 and has a viscosity of 150 mPa·s. (b4) the following formula: (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] 20 Si(CH3)2(CH=CH2) It is an organopolysiloxane oligomer having a viscosity of 2,300 mPa·s and a vinyl group content of approximately 1.43% by mass.

[0074] The following organopolysiloxanes were used as component (C): (c1) the following formula: (CH2=CH)(CH3)2SiO[(CH3)2SiO]7Si(CH3)2(CH=CH2) It is an organopolysiloxane having a viscosity of 7 mPa·s and a vinyl group content of approximately 7.49% by mass. (c2) the following formula: H(CH3)2SiO[(CH3)2SiO] 16 Si(CH3)2H having a viscosity of 15 mPa s and a content of silicon-bonded hydrogen atoms of approximately 0.15 mass%. (c3) 1,4-bis(dimethylsilyl)benzene

[0075] The following hydrosilylation reaction catalyst was used as component (D). (d1) Complex of platinum with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane solution (platinum content = 4% by mass)

[0076] The following hydrosilylation inhibitors were used as component (E): (e1) 1-ethynyl-cyclohexan-1-ol

[0077] The following non-functional organopolysiloxane resins were used as component (F): (f1) The average unit formula: [(CH3)3SiO 1 / 2 ] 0.50 (SiO 4 / 2 ) 0.50 Organopolysiloxane resin represented by the formula:

[0078] [Table 1]

[0079] [Table 2]

[0080] [Table 3]

[0081] [Table 4]

[0082] [Table 5]

[0083] Comparative Examples CE1 and CE2 are representative of conventional silicone hot melt compositions and demonstrate that the use of 70-75% by weight of (A) organopolysiloxane resin provides hot melt properties without components (B) and (D). Comparative Examples CE1 and CE2 provide non-flowable solids at 25°C and even at 20°C have a melt flow rate of 2.79 x 10 4 It gives a tacky surface with a low storage modulus, such as 376 Pa and 376 Pa.

[0084] Comparative Examples CE3 and CE4 illustrate curable silicone compositions that contain component (D) but not component (B). The compositions of Comparative Examples CE3 and CE4 are flowable viscous liquids (89,540 mPa s and 155,000 mPa s, respectively, at 25° C.), while Comparative Example CE3 has a low modulus after curing by hydrosilylation (1.44×10 at 20° C.). 4 Pa) tacky surface (SiH / Vi ratio=0.39). Comparative Example CE4 also does not exhibit hot melt properties at 100° C. (SiH / Vi ratio=0.60). Thus, by using components (A), (C) and (D), it is difficult to obtain a solventless curable composition that exhibits both flowability at room temperature before curing by hydrosilylation and a tack-free surface at room temperature with hot melt properties after curing by hydrosilylation.

[0085] In contrast, Examples IE1-IE8 demonstrate that the curable silicone compositions comprising component (B) described herein are flowable at 25° C. and have a high storage modulus (at least 9×10) after curing by hydrosilylation. 4It is shown that the viscosity of the curable silicone composition is greater than 100 Pa (>100 Pa) and provides a non-tacky surface with hot melt properties. Comparing Comparative Examples CE3 and CE4 and Examples IE2, IE4, IE6, and IE7, it appears that the use of component (B) provides the curable silicone composition with a low viscosity before curing by hydrosilylation, and a high modulus at room temperature (non-tacky) with hot melt properties after curing by hydrosilylation.

[0086] Comparative Examples CE5, CE6, and Examples IE1-IE8 show curable silicone compositions containing component (B) as described herein. Comparing Comparative Examples CE5, CE6, and Examples IE1-IE8, it is believed that the SiH / Vi ratio also imparts surface tackiness (elastic modulus) and hot melt properties. Comparative Example CE5 shows hot melt properties, but has a very tacky surface and a low storage modulus (1,640 Pa) at 20°C after curing by hydrosilylation when the SiH / Vi ratio is 0.30. Furthermore, it does not have hot melt properties when the SiH / Vi ratio is 0.91, as shown in Comparative Example CE6. Without wishing to be bound by theory, it is believed that the curable silicone composition imparts a non-tacky surface and hot melt properties after curing by hydrosilylation when the SiH / Vi ratio is greater than 0.30 and less than or equal to 0.90.

[0087] Comparative Example CE8 shows that the non-reactive organosiloxane oligomer (b3) having silicone-bonded aryl groups in the molecule is not effective in obtaining the curable silicone composition described herein, and Comparative Example CE9 shows that the high molecular weight organosiloxane polymer (b4) having silicon-bonded aryl groups and silicon-bonded alkenyl groups is not compatible with component (A), thus resulting in a non-homogeneous liquid. [Industrial Applicability]

[0088] The curable silicone composition of the present invention has excellent handleability at room temperature without using a solvent, and cures by heating to form a cured product that is non-tacky and has excellent melt viscosity at room temperature. Therefore, the curable silicone composition is useful as a sealant, adhesive, or coating for optical semiconductor elements in electric / electronic devices.

Claims

1. (A) an average unit formula of: (R １ ３ Yes １／２ ) ａ (R ２ R １ ２ Yes １／２ ) ｂ (Yes) ４／２ ) ｃ (HO １／２ ) ｄ (In the formula, each R １ are independently alkyl groups, and R ２ is an alkenyl group, and "a," "b," "c," and "d" are numbers that satisfy the conditions a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a+b+c=1; and (B) The viscosity at 25°C is 1,000 mPa·s or less, １ ) an organosiloxane oligomer having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group in the molecule; (B ２ ) an organosiloxane oligomer having at least one silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and component (B １ ) and (B ２ and a mixture of (C) (C １ ) having at least one alkenyl group in the molecule, and a silicon-bonded aryl group and SiO ４／２ Organopolysiloxane having no units, (C ２ ) an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and having no silicon-bonded aryl groups; (C ３ ) a compound having the following general formula: HR １ ２ Si-C ６ H ４ -SiR １ ２ H (In the formula, each R １ is as defined above), and mixtures thereof; and (D) a catalytic amount of a hydrosilylation reaction catalyst; A curable silicone composition in which, based on the total mass of components (A), (B), and (C), the amount of component (A) is in the range of 60 to 75 mass%, the amount of component (B) is in the range of 5 to 35 mass%, and the amount of component (C) is in the range of 0 to 30 mass%, respectively, and with the proviso that the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A), (B), and (C) is greater than 0.30 and less than or equal to 0.

90.

2. Ingredients (B １ ) has the following general formula: R ２ R ３ ２ SiO(R ３ ２ SiO) ｍ SiR ３ ２ R ２ (In the formula, each R ２ are independently an alkenyl group, and each R ３ are independently an alkyl group or an aryl group, provided that at least one R ３ 2. The curable silicone composition according to claim 1, wherein the organosiloxane oligomer is represented by the formula:

3. Ingredients (B １ ) has the following formula: (CH ２ =CH)(CH ３ ) ２ SiO(C ６ H ５ ) ２ SiOSi(CH ３ ) ２ (CH=CH ２ ) (CH ２ =CH)(CH ３ ) ２ SiO(C ６ H ５ )(CH ３ )SiOSi(CH ３ ) ２ (CH=CH ２ ) (CH ２ =CH)(CH ３ ) (C ６ H ５ )SiOSi(CH ３ ) (C ６ H ５ ) (CH=CH ２ 3. The curable silicone composition according to claim 2, wherein the organosiloxane oligomer is at least one selected from the group consisting of organosiloxane oligomers represented by the formula:

4. Ingredients (B ２ ) has the following general formula: HR ３ ２ SiO(R ３ ２ SiO) ｍ SiR ３ ２ H (In the formula, each R ３ are independently an alkyl group or an aryl group, provided that at least one R ３ 2. The curable silicone composition according to claim 1, wherein the organosiloxane oligomer is represented by the formula:

5. Ingredients (B ２ ) has the following formula: H(H) ３ ) ２ SiO (C) ６ H ５ ) ２ SiOSi(CH ３ ) ２ H H (CH ３ ) ２ SiO(C ６ H ５ ) (CH ３ )SiOSi(CH ３ ) ２ 5. The curable silicone composition according to claim 4, wherein the organosiloxane oligomer is at least one selected from organosiloxane oligomers represented by H.

6. 2. The curable silicone composition according to claim 1, further comprising: (E) a hydrosilylation reaction inhibitor in an amount of 0.1 to 10,000 ppm in this component, calculated in units of mass for the composition.

7. 2. The curable silicone composition according to claim 1, further comprising (F) an adhesion promoter in an amount of up to 10 parts by weight per 100 parts by weight of the combined weight of components (A) to (C).

8. A cured product obtained by curing the curable silicone composition according to any one of claims 1 to 7.