Curable silicone composition

Abstract

A curable silicone composition is provided. The composition includes (A) an epoxy-functional organopolysiloxane resin having a monovalent aromatic hydrocarbon group, (B) an epoxy-functional organosiloxane oligomer, (C) a photoacid generator and / or a thermal acid generator, and (D) a black azo dye. The composition exhibits good to excellent storage stability and cures to form a cured product that exhibits good to excellent light blocking properties without shrinkage and "mura" defects.

Description

[Technical Field]

[0001] The present invention relates to a curable silicone composition. [Background technology]

[0002] Recently, black gap-filling materials have been used in LED display applications to improve color and clarity. For example, black gap-filling materials are typically used to fill pixel pitch gaps and gaps between LED chips, flush with the LED chips and providing a smooth overall display surface. The primary purpose of black gap-filling materials is to absorb light that is not emitted perpendicularly from the display panel. Side-directed light can interfere with each other and reduce clarity and brightness in display applications. This light absorption performance, or light blocking performance, is expressed as an average optical density (OD) value from the visible wavelength range (360 nm to 740 nm). Generally, this application requires an average OD value of 2 or higher, meaning that at least 99% of the light is absorbed.

[0003] Silicone gap-filling materials are used in conventional LED / LCD chips, which typically have a height of 0.4 mm to 1.6 mm. Due to the sufficient height of the LED / LCD chip package, these silicone gap-filling materials were able to meet the target OD value by using carbon black as a colorant. Patent Document 1 describes a curable silicone composition containing an organopolysiloxane having at least two alkenyl groups per molecule, an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule, a carbon black pigment, and a platinum-based catalyst.

[0004] However, as LEDs become smaller and thinner, these silicone gap-filling materials have become unusable as black gap-filling materials for micro / mini LED applications. The height of micro LED packages has been reduced to 0.1 mm, meaning that black gap-filling materials must have an OD value of 2 or greater at a thickness of 0.1 mm. To further meet optical observation performance (OD value > 2), additional carbon black was introduced into the formulation during testing. However, excessive amounts of carbon black caused serious settling and separation issues during storage and clogging during use. The settling / separation resulted in an uneven black appearance and variations in light transmittance within the sample. The clogging phenomenon also led to processability issues in the distribution line.

[0005] Patent Document 1 describes a curable silicone composition containing an organopolysiloxane having at least two alkenyl groups per molecule, an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule, an azo dye, and a platinum-based catalyst. When black gap-filling materials require OD at thin material thicknesses, black dyes are used to prevent settling problems. However, most dyes are hydrophilic and incompatible with organic and inorganic polymers. While there are hydrophobic azo dyes that are compatible with organic polymers, they are incompatible with the silicone matrix. Many prior art techniques utilize solvents to dissolve black dyes in silicone formulations. Solvents are widely used to dissolve azo dyes in silicone polymers. However, solvents cause shrinkage of the material during the curing process, which can lead to uneven thickness and warping of the material. Drying of the solvent also causes a "bumpy" effect, creating a smeared surface around the cured area.

[0006] Furthermore, Patent Document 3 describes a curable silicone composition having good transparency, which contains an epoxy-functional organopolysiloxane resin, an epoxy-functional organosiloxane oligomer, and a cationic photoinitiator, and which can be cured by irradiation with ultraviolet light. However, Patent Document 3 does not describe the addition of a black azo dye, which results in poor transparency. [Prior art documents] [Patent documents]

[0007] Patent Document 1: U.S. Patent Application Publication No. 2007 / 0287771(A1) Patent Document 2: U.S. Patent Application Publication No. 2010 / 0103507(A1) Patent Document 3: U.S. Patent Application Publication No. 2014 / 0154626(A1) Summary of the Invention

[0008] technical issues It is an object of the present invention to provide a curable silicone composition that has excellent storage stability and cures to form a cured product that exhibits good to excellent light blocking properties without shrinkage and "mura" defects.

[0009] Solutions to the problem The curable silicone composition of the present invention comprises: (A) an epoxy-functional organopolysiloxane resin represented by the average unit formula: [ka] In the formula, each R 1 is C 1~6 Monovalent aliphatic hydrocarbon radical, C 6~10 are the same or different organic groups selected from monovalent aromatic hydrocarbon groups and monovalent epoxy-substituted organic groups, provided that all R 1 At least about 15 mol % of 6~10It is a monovalent aromatic hydrocarbon group, and "a", "b", "c", and "d" are numbers satisfying the conditions of 0 ≦ a < 0.4, 0 < b < 0.5, 0 < c < 1, 0 ≦ d < 0.4, 0.1 ≦ b / c ≦ 0.6, and a + b + c + d = 1. About 2 to about 30 mol% of all siloxane units have the monovalent epoxy-substituted organic group, an epoxy-functional silicone resin, and (B) An epoxy-functional organosiloxane oligomer represented by the following general formula: [Chemical formula] In the formula, each R 2 is the same or different organic group selected from a monovalent aliphatic hydrocarbon group and a monovalent aromatic hydrocarbon group, and each X 1~6 6~10 is the same or different monovalent epoxy-substituted organic group, a number from about 0 to about 5, "m" is a number from about 0 to about 100, and about 5% to about 80% by mass of the total mass of components (A), (B), (C), and (D) is an epoxy-functional organosiloxane oligomer, and (C) A photoacid generator and / or a thermal acid generator in an amount of about 0.01% to about 5% by mass of the total mass of components (A), (B), (C), and (D), and (D) A black azo dye in an amount of about 0.1% to about 5% by mass of the total mass of components (A), (B), (C), and (D). (C) A photoacid generator and / or a thermal acid generator in an amount of about 0.01% to about 5% by mass of the total mass of components (A), (B), (C), and (D), and (D) A black azo dye in an amount of about 0.1% to about 5% by mass of the total mass of components (A), (B), (C), and (D).

[0010] In various embodiments, the monovalent epoxy-substituted organic group in component (A) is a group selected from a glycidoxyalkyl group, a 3,4-epoxycyclohexylalkyl group, and an epoxyalkyl group. [[ID=id="27"]]

[0011] In various embodiments, the monovalent epoxy-substituted organic group in component (B) is a group selected from a glycidoxyalkyl group, a 3,4-epoxycyclohexylalkyl group, and an epoxyalkyl group.

[0012] In various embodiments, component (B) is an epoxy-functional organosiloxane oligomer represented by the following general formula. [ka] (In the formula, R 2 and X 1 is as above).

[0013] In various embodiments, component (D) is selected from Solvent Black 3, Solvent Black 27, Solvent Black 28, Solvent Black 29, Solvent Black 34, Solvent Black 43, and Solvent Black 46.

[0014] Advantageous Effects of the Invention The curable silicone compositions of the present invention exhibit good to excellent storage stability and cure to form cured products that exhibit good to excellent light-blocking properties without shrinkage or "mura" defects.

[0015] Mode of Invention The term "comprising" or "comprise" is used broadly herein to mean and encompass "including," "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 account for slight variations in a numerical value as determined by instrumental analysis or as a result of sample handling. Such minor variations may be as little as ±0 to 25%, ±0 to 10%, ±0 to 5%, or ±0 to 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 apply to a numerical value even if not expressly stated. Generally, as used herein, ">" means "greater than" or "over," "≧" means "at least" or "greater-than or equal to," "<" means "below" or "less-than," and "≦" means "at most" or "less-than or equal to."

[0016] As used herein, the term "epoxy-functional" or "epoxy-substituted" refers to a functional group in which the oxygen atoms of the epoxy substituent are directly bonded to two adjacent carbon atoms in a carbon chain or ring system. Examples of epoxy-substituted functional groups include, but are not limited to, glycidoxyalkyl groups such as 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl; (3,4-epoxycycloalkyl)alkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl; and epoxyalkyl groups such as 2,3-epoxypropyl, 3,4-epoxybutyl, and 4,5-epoxypentyl.

[0017] As used herein, the term "mura" or "mura defect" refers to a contrast-type defect in which one or more pixels are brighter or darker than surrounding pixels when they should have uniform brightness. For example, when a flat area of ​​an intended color is displayed, various imperfections in the display components can result in undesirable modulation of brightness. A mura defect is generally a non-uniform distortion. Generally, such contrast-type defects can be identified as "stains," "bands," "streaks," etc.

[0018] The term "OD" or "optical density" as used herein is meant to indicate light blocking properties. The value of "OD" is expressed by the following formula: OD=-log(I T / I0) Here, I0 is the intensity of the light incident on the optical density change element, and I T is the intensity of transmitted light. In other words, the larger the "OD" value, the better the light blocking properties.

[0019] <Curable Silicone Composition> Component (A) is an epoxy-functional organopolysiloxane resin represented by the average siloxane unit formula: [ka] In the formula, each R 1 is C 1~6 Monovalent aliphatic hydrocarbon radical, C 6~10 They are the same or different organic groups selected from monovalent aromatic hydrocarbon groups and monovalent epoxy-substituted organic groups.

[0020] C in component (A) 1~6 Examples of monovalent aliphatic hydrocarbon groups include C groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6 alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0021] C in component (A) 6~10 Examples of monovalent aromatic hydrocarbon groups include phenyl, tolyl, xylyl, and naphthyl groups, of which phenyl groups are generally preferred.

[0022] Examples of the monovalent epoxy-substituted organic group in component (A) include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 3,4-epoxycycloalkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl; and epoxyalkyl groups such as 2,3-epoxypropyl, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0023] In component (A), at least about 15 mol%, optionally at least about 20 mol%, or optionally at least about 25 mol% of all R 1 is a monovalent aromatic hydrocarbon group. If the content of the monovalent aromatic hydrocarbon group is at least the above lower limit, the light transmittance of the cured product can be improved, and the mechanical properties of the cured product are also improved. 6~10 In the formula, "a", "b", "c", and "d" are mole fractions and numbers that satisfy the conditions of 0 ≤ a < 0.4, 0 < b < 0.5, 0 < c < 1, 0 ≤ d < 0.4, 0.1 ≤ b / c ≤ 0.6, and a + b + c + d = 1, optionally a = 0, 0 < b < 0.5, 0 < c < 1, 0 ≤ d < 0.2, 0.1 < b / c ≤ 0.6, and b + c + d = 1, or optionally a = 0, 0 < b < 0.5, 0 < c < 1, d = 0, 0.1 < b / c ≤ 0.6, and b + c = 1. "a" is 0 ≤ a < 0.4, optionally 0 ≤ a < 0.2, or optionally a = 0, which is because if the (R

[0024] 3SiO 1 3SiO 1 / 2 ) siloxane units are too many, the molecular weight of the epoxy-containing organopolysiloxane resin (A) decreases, and when (SiO 4 / 2 ) siloxane units are introduced, the hardness of the cured product of the epoxy-functional organopolysiloxane resin (A) increases significantly, and the cured product may become brittle. For this reason, "d" is 0 ≤ d < 0.4, optionally 0 ≤ d < 0.2, or optionally d = 0. In addition, the molar ratio "b / c" of the (R 1 2SiO 2 / 2 ) unit and the (R 1 SiO 3 / 2 ) unit can be about 0.1 or more and about 0.6 or less. In some examples, in the production of the epoxy-functional silicone resin (A), if it is outside this range, insoluble by-products may be generated, the toughness decreases and the product is likely to crack, or the strength and elasticity of the product are low and it is likely to be scratched. In some examples, the range of the molar ratio "b / c" is greater than about 0.1 and less than or equal to about 0.6. The epoxy-functional organopolysiloxane resin (A) is (R 1 2SiO2 / 2 ) siloxane units and (R 1 SiO 3 / 2 ) siloxane units, and its molecular structure is in most cases a network structure or a three-dimensional structure, because the "b / c" molar ratio is greater than about 0.1 and less than or equal to about 0.6. Therefore, in the epoxy-functional organopolysiloxane resin (A), (R 1 2SiO 2 / 2 ) siloxane units and (R 1 SiO 3 / 2 ) siloxane units are present, but (R 1 3SiO 1 / 2 ) siloxane units and (SiO 4 / 2 The siloxane unit is an optional building block. That is, there may be an epoxy-functional organopolysiloxane resin comprising the average unit formula: [ka]

[0025] In component (A), about 2 to about 30 mol%, optionally about 10 mol% to about 30 mol%, or optionally about 15 mol% to about 30 mol% of the siloxane units in the molecule contain epoxy-substituted organic groups. The presence of such siloxane units at or above the lower limit of the above range can improve crosslink density during curing. On the other hand, an amount below the upper limit of the above range can be advantageous because it can improve the light transmittance and heat resistance of the cured product. In the epoxy-functional monovalent hydrocarbon group, the epoxy group can be bonded to the silicon atom via an alkylene group, thereby preventing the epoxy group from being directly bonded to the silicon atom. The epoxy-functional organopolysiloxane resin (A) can be produced by well-known conventional manufacturing methods.

[0026] There is no particular limitation on the weight average molecular weight of the epoxy-functional organopolysiloxane resin (A). However, in consideration of the toughness of the cured product and its solubility in organic solvents, in some embodiments, the molecular weight is about 10 3 More than or equal to approximately 10 6In one embodiment, the epoxy-functional organopolysiloxane resin (A) comprises a combination of two or more such epoxy-functional silicone resins having different amounts and types of epoxy-containing organic groups and monovalent hydrocarbon groups, or having different molecular weights.

[0027] Component (B) is an epoxy-functional organosiloxane oligomer represented by the general formula: [ka] In the formula, each R 2 is C 1~6 Monovalent aliphatic hydrocarbon groups and C 6~10 are the same or different organic groups selected from monovalent aromatic hydrocarbon groups.

[0028] C in component (B) 1~6 Examples of monovalent aliphatic hydrocarbon groups include C groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6 alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0029] C in component (B) 6~10 Examples of monovalent aromatic hydrocarbon groups include phenyl, tolyl, xylyl, and naphthyl groups, of which phenyl groups are generally preferred.

[0030] In component (B), all R 2 at least about 10 mol %, optionally at least about 20 mol %, optionally at least about 30 mol %, or optionally at least about 40 mol % of 6~10 When the content of the monovalent aromatic hydrocarbon group is equal to or greater than the above lower limit, not only can the light-blocking properties of the cured product be improved, but also the mechanical properties of the cured product can be improved.

[0031] In the formula, each 1 are the same or different monovalent epoxy-substituted organic groups. 1 Examples of monovalent epoxy-substituted organic groups include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 3,4-epoxycycloalkylalkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl; and epoxyalkyl groups such as 2,3-epoxypropyl, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0032] In the above general formula, "m" is a number of about 0 to about 100, optionally about 0 to about 20, or optionally about 0 to about 10. When "m" is equal to or less than the upper limit of the above range, the light-blocking properties of the cured product can be improved.

[0033] In particular, from the viewpoint of the storage stability of the composition and the light-blocking properties of the cured product, component (B) is preferably an epoxy-functional organosiloxane oligomer represented by the following general formula: [ka] (In the formula, R 2 and X 1 is as above).

[0034] The state of component (B) at 25°C is not limited, but is generally a liquid. The viscosity of component (B) at 25°C is not limited, but is generally within the range of about 5 to about 100 mPa·s. In this specification, viscosity is a value measured at 23±2°C using a Brookfield viscometer in accordance with ASTM D 1084.

[0035] The content of component (B) is about 5% to about 80% by mass of the total mass of components (A), (B), (C), and (D), optionally about 10% to about 80% by mass, optionally about 10% to about 70% by mass, or optionally about 20% to about 70% by mass. If the content of component (B) is at or above the lower limit of the above range, the flexibility and impact strength of the cured product can be improved. On the other hand, if the content is at or below the upper limit of the above range, the toughness and tensile strength of the cured product can be improved.

[0036] Component (C) is a photoacid generator and / or thermal acid generator that cures the composition. Any acid generator known to those skilled in the art can be used, such as sulfonium salts, iodonium salts, selenonium salts, phosphonium salts, diazonium salts, paratoluenesulfonates, trichloromethyl-substituted triazines, and trichloromethyl-substituted benzenes.

[0037] Examples of sulfonium salts include those of formula R c 3S + X - In the formula, R c are methyl, ethyl, propyl, butyl, and other C 1~6 Alkyl groups: phenyl, naphthyl, biphenyl, tolyl, propylphenyl, decylphenyl, dodecylphenyl, and other C 1~24 may represent an aryl group or a substituted aryl group, wherein X - is SbF6 - , AsF6 - , PF6 - , BF4 - , B(C6F5)4 - , HSO4 - , ClO4 - , CF3SO3 - , and other non-nucleophilic non-basic anions.

[0038] Examples of iodonium salts include those of formula R c 2I + X - Examples of selenonium salts include salts represented by the formula R c 3Se+ X - Examples of phosphonium salts include salts represented by the formula R c 4P + X - Examples of diazonium salts include salts represented by the formula R c N2 + X - In the formula, R c and X - is R c 3S + X - is the same as that described herein with respect to

[0039] Examples of paratoluenesulfonates include those of the formula CH3C6H4SO3R c1 In the formula, R c1 represents an organic group containing an electron-withdrawing group such as a benzoylphenylmethyl group, a phthalimido group, and the like.

[0040] Examples of trichloromethyl-substituted triazines include [CC13]2C3N3R c2 In the formula, R c2 represents phenyl, substituted or unsubstituted phenylethyl, substituted or unsubstituted furanylethynyl, and other electron-withdrawing groups.

[0041] An example of a trichloromethyl-substituted benzene is CCl3C6H3R c R c3 In the formula, R c is R c 3S + X - is the same as described herein for R c3 represents halogen groups, halogen-substituted alkyl groups, and other halogen-containing groups.

[0042] Examples of the acid generator include triphenylsulfonium tetrafluoroborate, di(p-tert-butylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodonium hexafluoroantimonate, 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, and p-chlorophenyldiazonium tetrafluoroborate.

[0043] The content of component (C) is about 0.01% to about 5% by mass, optionally about 0.01% to about 2% by mass, optionally about 0.02% to about 0.8% by mass, or optionally about 0.02% to about 0.5% by mass, of the total mass of components (A), (B), (C), and (D). If the content of component (C) is at or above the lower limit of the above range, the curable silicone composition will be sufficiently cured. On the other hand, if the content is at or below the upper limit of the above range, the mechanical properties of the cured product will be improved.

[0044] Component (D) is a black azo dye that improves the light-blocking properties of the cured product. The black azo dye significantly reduces the occurrence of fine particles, voids, pinholes, and striations in the composition, thereby extending the storage stability of the composition. Black azo dyes are generally identified by a color index of Solvent Black 3 to 47. Examples of black azo dyes include Solvent Black 3, Solvent Black 27, Solvent Black 28, Solvent Black 29, Solvent Black 34, Solvent Black 43, and Solvent Black 46. Among these, Solvent Black 27 is most preferred because it not only improves storage stability but also improves the light-blocking properties of the thin film of the cured product.

[0045] These black azo dyes are commercially available. A preferred black azo dye is Orasol Black RLI, a 1:2 pigment-chrome mixture available from Ciba-Geigy. Other dyes identified by Solvent Black 3 through Solvent Black 47 include, in particular, Solvent Black 35 (Nitrocellulose Varnish Black X50, BASF), Solvent Black 27 (Nitrocellulose Varnish Black X51, BASF), Solvent Black 3 (Neptunium Black X60, BASF), Solvent Black 5 (Aniline Black X12, BASF), Solvent Black 7 (Neptunium Black NB X14, BASF), Solvent Black 46 (Neptunium Black A Black X17, BASF), Solvent Black 47 (Neopin Black X58, BASF), Solvent Black 28 (Orasol Black CN, Ciba-Geigy), Solvent Black 29 (Orasol Black RL, Ciba-Geigy), and Solvent Black 45 (Savinyl Black RLS, Sandoz Corporation).

[0046] The content of component (D) is about 0.1 to about 5 mass% of the total mass of components (A), (B), (C), and (D), or optionally about 0.5 to about 5 mass%. When the content of component (D) is equal to or greater than the lower limit of the above range, the light-blocking properties of the cured product can be improved. On the other hand, when the content is equal to or less than the upper limit of the above range, the curability of the composition can be improved, and the mechanical properties of the cured product can be improved.

[0047] The present composition contains the above-mentioned components (A) to (D), but may also contain a photosensitizer, and / or an adhesion promoter other than component (C), and / or an alcohol, and / or an inorganic filler in order to impart better mechanical strength to a cured product of the present composition.

[0048] Examples of photosensitizers include isopropyl-9H-thioxanthen-9-one, anthrone, 1-hydroxycyclohexyl-phenyl ketone, 2,4-diethyl-9H-thioxanthen-9-one, 2-isopropylthioxanthene, 2-hydroxy-2-methyl-phenylpropan-1-one, 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT), pentaerythritol tetrakis[3-(3,5-di-tert-butyl ether] ... octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[{3,5-bis(1,1-di-tert-butyl-4-hydroxyphenyl)methyl}phosphonate, 3 Examples include 3',3'',5,5',5''-hexane-tert-butyl-4-a,a',a''-(mesitylene-2,4,6-tolyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], and hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0049] The content of the photosensitizer is not limited, but is generally within the range of about 0.001 to about 1 mass %, optionally about 0.005 to about 0.5 mass %, or optionally about 0.005 to about 0.1 mass %, of the total mass of components (A), (B), (C), (D), and the photosensitizer. If the content of the photosensitizer is equal to or greater than the lower limit of the above range, the curability of the cured product can be improved. On the other hand, if the content is equal to or less than the upper limit of the above range, the mechanical properties of the cured product can be improved.

[0050] Examples of adhesion promoters include epoxy-functional alkoxysilanes, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldiethoxysilane, and combinations thereof; unsaturated alkoxysilanes, such as vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecylenyltrimethoxysilane, 3-methacryloyloxysilane, methyltrieth ... Examples of suitable adhesion promoters include hydroxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, and combinations thereof; and epoxy-functional siloxanes having silicon-bonded alkoxy groups, such as the reaction product of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane (e.g., any of those described above), or a physical blend of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane. The adhesion promoter may include a combination of an epoxy-functional alkoxysilane and an epoxy-functional siloxane. For example, the adhesion promoter is exemplified by a mixture of 3-glycidoxypropyltrimethoxysilane with the reaction product of a hydroxy-terminated methylvinylsiloxane and 3-glycidoxypropyltrimethoxysilane, or a mixture of 3-glycidoxypropyltrimethoxysilane with a hydroxy-terminated methylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilane with a hydroxy-terminated methylvinyl / dimethylsiloxane copolymer.

[0051] The content of the adhesion promoter is not limited, but is generally about 0.01 to about 5% by mass, or optionally about 0.1 to about 2% by mass, of the total mass of components (A), (B), (C), (D), and the adhesion promoter.

[0052] Inorganic fillers increase the mechanical strength of the cured product. Examples of fillers include one or more of micronized or untreated precipitated or fumed silica, precipitated or ground calcium carbonate, zinc carbonate, clays such as micronized kaolin, ground quartz, aluminum hydroxide, zirconium silicate, diatomaceous earth, wollastonite, pyrophyllate, and metal oxides such as fumed or precipitated titanium dioxide, cerium oxide, magnesium oxide powder, zinc oxide, and iron oxide.

[0053] The content of the filler is not limited, but is generally about 1 to about 90% by mass of the total mass of components (A), (B), (C), (D) and the filler.

[0054] The composition can be cured by irradiation with UV light (i.e., ultraviolet ("UV") light) and / or heat. For example, low-pressure, high-pressure, or extra-high-pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps, or electrodeless lamps are useful as UV lamps. [Example]

[0055] The curable silicone composition and cured product of the present invention will now be described in detail using examples and comparative examples. Note that in the formulas, "Me," "Pr," "Ph," and "Ep" represent methyl, propyl, vinyl, phenyl, and 2-(3,4-epoxycyclohexyl)ethyl groups, respectively. The structure of the epoxy-functional organopolysiloxane resin used in the examples is: 13 C NMR and 29 The molecular weights of the epoxy-functional organopolysiloxane resins were determined by Si NMR measurements. The weight-average molecular weights of the epoxy-functional organopolysiloxane resins were calculated using GPC based on comparison with polystyrene standards. The viscosity of the epoxy-functional organosiloxane oligomer resins was measured as follows.

[0056] <Viscosity> The viscosity was measured at 23±2° C. using a Brookfield HA or HB type rotational viscometer (using a spindle #52 at 5 rpm) in accordance with ASTM D 1084 "Standard Test Methods for Viscosity of Adhesives."

[0057] <Examples 1 to 7 and Comparative Examples 1 to 5> The curable silicone compositions (% by weight) shown in Table 1 were prepared using the following components.

[0058] The following epoxy-functional organopolysiloxane resin was used as component (A):

[0059] (a1): An epoxy-functional organopolysiloxane resin having a weight average molecular weight of 2,000 to 6,000 and represented by the following average unit formula: [ka]

[0060] The following organopolysiloxanes were used as comparative polymers for component (A):

[0061] (a2): Methylphenylpolysiloxane end-blocked at both molecular chain ends with dimethylvinylsiloxy groups and with a viscosity of 3,500 mPa·s.

[0062] (a3): Dimethylpolysiloxane end-blocked at both molecular chain ends with dimethylvinylsiloxy groups and with a viscosity of 450 mPa·s.

[0063] The following epoxy-functional organosiloxane oligomers were used as component (B):

[0064] (b1): an epoxy-functional organosiloxane oligomer having a viscosity of 40 mPa·s, a weight average molecular weight of 382, ​​and represented by the following formula: Ep-SiMe2OSiMe2-Ep

[0065] The following cationic photoinitiators were used as component (C):

[0066] (c1): 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate represented by the following formula: [ka]

[0067] (TRONYL TR-PAG-30408) The following black azo dye was used as component (D):

[0068] (d1): Solvent Black 27 represented by the following formula: [ka] (d2): Solvent Black 28 (d3): Solvent Black 29 represented by the following formula: [ka] (d4): Solvent Black 34 represented by the following formula: [ka] (d5): Solvent Black 43 (d6): Solvent Black 3 represented by the following formula: [ka] (d7): Solvent Black 46 represented by the following formula [ka]

[0069] The following carbon black pigments were used as comparative colorants for component (D):

[0070] (d8): BET specific surface area is 8m 2 / g of carbon black pigment (CORAX® N990 manufactured by CARY Corporation) The following component was used as component (E) for comparison:

[0071] (e1): A copolymer of dimethylsiloxane and methylhydrogensiloxane, with both ends of the molecular chain capped with trimethylsiloxy groups and a viscosity of 5 mPa·s. (e2): Platinum complex with 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane (e3): Tris[(1,1-dimethyl-2-propynyl)oxy]methylsilane (e4): Ethanol

[0072] A curable silicone composition was prepared by the following steps. 1. Place all ingredients into a 200mL polyethylene cup. 2. The raw materials are mixed for 2 minutes at 1500 rpm using a mixer (Thinky ARV-310P) without vacuuming the air. 3. Scrape off the walls and bottom of the polyethylene cup. 4. Mix again under the same conditions as above. 5. Remove the curable silicone composition.

[0073] The curable silicone composition was cured for 1 hour at 150° C. The curable silicone composition and the cured product were evaluated as follows. The properties are shown in Table 1.

[0074] <Sedimentation / Separation> The settling / separation of the curable silicone composition was visually observed.

[0075] <Shrinkage / Unevenness> The shrinkage of the cured product was evaluated by checking the height (level) of the curable silicone composition after it had cured in a vial, and the cured product was visually inspected for unevenness.

[0076] <Average OD> The curable silicone composition was sandwiched between two glass structures and cured at 150°C for 1 hour. The thickness of the cured product was 100 μm. The optical density of the cured product with the glass structures was then measured. The average optical density (OD) value from the visible wavelength range (360 nm to 740 nm) was calculated using transmittance measurement (Konica Minolta CM-3600A spectrophotometer). [Table 1] [Table 2]

[0077] Industrial Applicability The curable silicone composition of the present invention can be cured to form a cured product that exhibits good to excellent light blocking properties without shrinkage or "mura" defects, making the composition useful as a black gap fill material for LED display applications.

Claims

1. A curable silicone composition, (A) An epoxy-functional organopolysiloxane resin represented by the following average unit formula, 【Chemistry 1】 In the formula, each R １ C １～６ Monovalent aliphatic hydrocarbon group, C ６～１０ The same or different organic groups selected from monovalent aromatic hydrocarbon groups and monovalent epoxy-substituted organic groups, provided that all R １ At least 15 mol% of C ６～１０ The monovalent aromatic hydrocarbon group is a number satisfying the conditions 0 ≤ a < 0.4, 0 < b < 0.5, 0 < c < 1, 0 ≤ d < 0.4, 0.1 ≤ b / c ≤ 0.6, and a + b + c + d = 1, and 2 to 30 mol% of the total siloxane units is an epoxy-functional organopolysiloxane resin having the monovalent epoxy-substituted organic group. (B) An epoxy-functional organosiloxane oligomer represented by the following general formula, 【Chemistry 2】 In the formula, each R ２ is an organic group which is the same or different and is selected from a monovalent aliphatic hydrocarbon group and a monovalent aromatic hydrocarbon group, and each X １～６ is an organic group which is the same or different and is selected from a monovalent aliphatic hydrocarbon group and a monovalent aromatic hydrocarbon group, and each X ６～１０ is the same or different monovalent epoxy-substituted organic group, and "m" is a number from 0 to 100, １ is the same or different monovalent epoxy-substituted organic group, and "m" is a number from 0 to 100, An epoxy-functional organosiloxane oligomer in an amount of 5% to 80% by mass of the total mass of components (A), (B), (C), and (D), (C) A photoacid generator and / or thermal acid generator in an amount of 0.01% to 5% by mass of the total mass of components (A), (B), (C), and (D), A curable silicone composition comprising (D) a black azo dye in an amount of 0.1% to 5% by mass of the total mass of components (A), (B), (C), and (D).

2. The curable silicone composition according to claim 1, wherein the monovalent epoxy-substituted organic group in component (A) is a group selected from glycidoxyalkyl groups, 3,4-epoxycyclohexylalkyl groups, and epoxyalkyl groups.

3. The curable silicone composition according to claim 1, wherein the monovalent epoxy-substituted organic group in component (B) is a group selected from glycidoxyalkyl groups, 3,4-epoxycyclohexylalkyl groups, and epoxyalkyl groups.

4. The curable silicone composition according to claim 1, wherein component (B) is an epoxy-functional organosiloxane oligomer represented by the following general formula. 【Transformation 3】 (In the formula, each R2 is the same or different organic group selected from C1-6 monovalent aliphatic hydrocarbon groups and C6-10 monovalent aromatic hydrocarbon groups, and each X1 is the same or different monovalent epoxy-substituted organic group.)

5. The curable silicone composition according to claim 1, wherein component (D) is a black azo dye selected from Solvent Black 3, Solvent Black 27, Solvent Black 28, Solvent Black 29, Solvent Black 34, Solvent Black 43, and Solvent Black 46.

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