Curable silicone composition

Abstract

A curable silicone composition is provided. The composition comprises: (A) an epoxy-functional organopolysiloxane resin having monovalent aromatic hydrocarbon groups; (B) an epoxy-functional organosiloxane oligomer; (C) a photo-acid 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 hiding properties without causing shrinkage and "MURA" defects.

Description

Technical Field

[0001] This invention relates to a curable organosilicon composition. Background Technology

[0002] Recently, black gap filler materials have been used in LED display applications to improve tone and sharpness. For example, black gap filler materials are typically used to fill the gaps between pixel pitches and LED chips, having the same height as the LED chips to provide a smooth overall display surface. The primary purpose of black gap filler materials is to absorb light that is not emitted vertically from the display panel. Side light can interfere with each other and reduce the sharpness and brightness of the display application. This light absorption performance, or shading characteristic, is expressed as the average optical density (OD) value in the visible wavelength range (360nm-740nm). Typically, this application requires an average OD value greater than or equal to 2, meaning that at least 99% or more of the light will be absorbed.

[0003] In conventional LED / LCD chips, silicone interstitial materials are used, typically with a height between 0.4 mm and 1.6 mm. Due to the sufficient height of LED / LCD chip packages, these silicone interstitial materials can meet target OD values ​​by using carbon black as a colorant. Patent Document 1 describes a curable silicone composition comprising: an organopolysiloxane having at least two alkenyl groups per molecule, an organohydrogen polysiloxane having at least two silicon atoms bonded to hydrogen atoms per molecule, carbon black pigment, and a platinum catalyst.

[0004] However, as LEDs become smaller and thinner, these silicone interstitial materials cannot be used as black interstitial materials for micro / mini LED applications. The height of micro LED packages has decreased to 0.1 mm thickness, meaning the black interstitial material needs an OD value greater than or equal to 2 at a thickness of 0.1 mm. Furthermore, to meet the light observation performance requirements (OD value > 2), additional carbon black was introduced into the formulation during testing. However, excessive carbon black caused severe sedimentation and separation problems during storage and clogging problems during use. Sedimentation / separation resulted in an uneven black appearance, leading to variations in light transmittance within the sample. Clogging caused processability issues at the dispensing lines.

[0005] Patent document 2 describes a curable silicone composition comprising: an organopolysiloxane having at least two alkenyl groups per molecule, an organohydrogen polysiloxane having at least two silicon atoms bonded to hydrogen atoms per molecule, an azo dye, and a platinum catalyst. Black dyes are used to prevent sedimentation problems when black interstitial filling materials need to achieve open-dip condensation (OD) at thin material thicknesses. However, most dyes are hydrophilic and incompatible with both organic and inorganic polymers. Hydrophobic azo dyes compatible with organic polymers exist, but they are incompatible with silicone matrices. Many prior art techniques utilize solvents to dissolve black dyes in silicone formulations. Solvents are widely used to dissolve azo dyes containing silicone polymers. However, solvents cause material shrinkage during curing, which can lead to uneven material thickness and warping. Solvent drying also results in a “Mura” effect, causing the surface around the cured area to become contaminated.

[0006] Meanwhile, Patent Document 3 describes a curable silicone composition with good transparency and comprising: an epoxy-functionalized organopolysiloxane resin; an epoxy-functionalized organosiloxane oligomer; and a cationic photoinitiator, wherein the composition can be cured by UV radiation. However, Patent Document 3 does not teach the addition of a black azo dye because of its poor transparency.

[0007] [Existing Technical Documents]

[0008] [Patent Literature]

[0009] Patent Document 1: U.S. Patent Application Publication No. 2007 / 0287771 A1

[0010] Patent Document 2: U.S. Patent Application Publication No. 2010 / 0103507 A1

[0011] Patent Document 3: U.S. Patent Application Publication No. 2014 / 0154626 A1 Summary of the Invention

[0012] Technical issues

[0013] One object of the present invention is to provide a curable silicone composition having excellent storage stability and curing to form a cured product exhibiting good to excellent shielding properties without causing shrinkage and “MURA” defects.

[0014] Solution to the problem

[0015] The curable silicone composition of the present invention comprises:

[0016] (A) Epoxy-functional organopolysiloxane resins represented by the following average unit formula:

[0017] (R , 1 , , 1-6 , 1 , , m , 2 ,

[0022] , 6-10 ,

[0023] , 2 , 2 ,

[0021] 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 )[[ID=]] c (SiO 4 / 2 ) d

[0018] where each R 1 is the same or different organic group, and the organic group is selected from C 1-6 monovalent aliphatic hydrocarbon group, C 6-10 monovalent aromatic hydrocarbon group, and monovalent epoxy-substituted organic group, provided that at least about 15 mol% of the total R 1 is the C 6-10 monovalent aromatic hydrocarbon group; and "a", "b", "c", and "d" are numbers satisfying the following 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 about 2 mol% to about 30 mol% of the total siloxane units have monovalent epoxy-substituted organic groups;

[0019] (B) An epoxy-functional organosiloxane oligomer represented by the following general formula:

[0020] X 1 -R 2 2SiO(SiR 2 2O) m SiR 2 2-X 1

[0021] where each R 2 is the same or different organic group, and the organic group is selected from C 1-6 monovalent aliphatic hydrocarbon group and C 6-10 monovalent aromatic hydrocarbon group; each X 1 is the same or different monovalent epoxy-substituted organic group; and "m" is a number from about 0 to about 100, and its amount is about 5% to about 80% by mass of the total mass of components (A), (B), (C), and (D);

[0022] (C) A photoacid generator and / or a thermal acid generator, and its amount is about 0.01% to about 5% by mass of the total mass of components (A), (B), (C), and (D); and

[0023] (D) A black azo dye, in an amount of about 0.1% by mass to about 5% by mass of the total mass of components (A), (B), (C) and (D).

[0024] In various embodiments, the monovalent epoxy-substituted organic group in component (A) is selected from the following groups: glycidyloxyalkyl group, 3,4-epoxycyclohexylalkyl group and epoxyalkyl group.

[0025] In various embodiments, the monovalent epoxy-substituted organic group in component (B) is selected from the following groups: glycidyloxyalkyl group, 3,4-epoxycyclohexylalkyl group and epoxyalkyl group.

[0026] In various embodiments, component (B) is an epoxy-functionalized organosiloxane oligomer represented by the following general formula:

[0027] X 1 -R 2 2SiOSiR 2 2-X 1

[0028] Where R 2 and X 1 As stated above.

[0029] 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.

[0030] Beneficial effects of the present invention

[0031] The curable silicone compositions of the present invention exhibit good to excellent storage stability and, upon curing, form cured products that exhibit good to excellent shielding properties without causing shrinkage and “MURA” defects. Detailed Implementation

[0032] The terms “comprising” or “containing” are used in their broadest sense herein to mean and encompass the concepts of “including,” “comprising,” “substantially consisting of,” and “consisting of.” The use of “for example,” “for instance,” “such as,” and “including” to list exemplary examples does not imply limitation to the listed examples. Therefore, “for example” or “such as” means “for example, but not limited to” or “such as, but not limited to” and covers other similar or equivalent examples. As used herein, the term “about” is used to reasonably encompass or describe minute variations in numerical values ​​measured by instrumental analysis or as a result of sample processing. Such minute variations can be approximately ±0-25, ±0-10, ±0-5, or ±0-2.5% of the numerical value. Additionally, the term “about” applies to two numerical values ​​when associated with a range of values. Furthermore, the term “about” applies to numerical values ​​even when not explicitly stated. Generally, as used in this article, ">" means "higher than" or "greater than"; "≥" means "at least" or "greater than or equal to"; "<" means "lower than" or "less than"; and "≤" means "at most" or "less than or equal to".

[0033] As used herein, the terms "epoxy-functional" or "epoxy-substituted" refer to a functional group in which an oxygen atom or an epoxy substituent is directly attached 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 groups; (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 groups; and epoxyalkyl groups, such as 2,3-epoxypropyl, 3,4-epoxybutyl, and 4,5-epoxypentyl groups.

[0034] As used herein, the term "MURA" or "MURA defect" refers to a contrast-related defect where one or more pixels are brighter or darker than their surrounding pixels when they should have uniform brightness. For example, various imperfections in the display components can cause undesirable brightness adjustment when displaying intended flat color areas. Mura defects are typically characterized by uneven distortion. Generally, such contrast-related defects can be identified as "spots," "bands," "streaks," etc.

[0035] As used herein, the term “OD” or “optical density” is intended to indicate shading characteristics. The value of “OD” is expressed by the following equation:

[0036] OD = -log(I T / I0)

[0037] Where I0 is the intensity of the light incident on the light density changing element; and I T It represents the intensity of transmitted light. In other words, a larger "OD" value indicates better shading properties.

[0038] <Cureable Organosilicon Composition>

[0039] Component (A) is an epoxy-functionalized organopolysiloxane resin represented by the following average siloxane unit formula:

[0040] (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d .

[0041] In this formula, each R 1 These are the same or different organic groups, and the organic groups are selected from C. 1-6 Monovalent aliphatic hydrocarbon groups, C 6-10 Monovalent aromatic hydrocarbon groups and monovalent epoxy-substituted organic groups.

[0042] C in component (A) 1-6 Examples of monovalent aliphatic hydrocarbon groups include C 1-6 Alkyl groups, such as methyl, ethyl, propyl, butyl, and hexyl groups; C 2-6 Alkenyl groups, such as vinyl groups, allyl groups, and hexenyl groups; and C 1-6 Halogenated alkyl groups, such as 3-chloropropyl groups and 3,3,3-trifluoropropyl groups. Among them, methyl groups are generally preferred.

[0043] C in component (A) 6-10 Examples of monovalent aromatic hydrocarbon groups include phenyl groups, tolyl groups, xylyl groups, and naphthyl groups. Among these, phenyl groups are generally preferred.

[0044] Examples of the monovalent epoxy-substituted organic groups in component (A) include glycidyloxyalkyl groups such as 3-glycidyloxypropyl group, 4-glycidyloxybutyl group, and 5-glycidyloxypentyl group; 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 group, 3,4-epoxybutyl group, and 4,5-epoxypentyl group. Among them, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0045] In component (A), at least about 15 mol%, optionally at least about 20 mol%, or optionally at least about 25 mol% of the total R 1 is a C 6-10 monovalent aromatic hydrocarbon group. If the content of the monovalent aromatic hydrocarbon group is greater than or equal to the lower limit described above, the mechanical properties of the cured product will increase.

[0046] In this formula, "a", "b", "c", and "d" are mole fractions and numbers that satisfy the following 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. 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 because when there are too many (R 1 3SiO 1 / 2 ), the molecular weight of the epoxy-containing organopolysiloxane resin (A) decreases, while when introducing (SiO 4 / 2 ), the hardness of the cured product of the epoxy-functional organopolysiloxane resin (A) increases significantly and the product may be prone to being brittle. For this reason, "d" is 0 ≤ d < 0.4, optionally 0 ≤ d < 0.2, or optionally d = 0. In addition, (R 1 2SiO 2 / 2 ) units and (R 1 SiO 3 / 2The molar ratio "b / c" of the epoxy-functionalized silicone resin (A) can be not less than about 0.1 and not more than about 0.6. In some examples, deviations from this range in the manufacture of the epoxy-functionalized silicone resin (A) may result in the formation of insoluble byproducts, making the product more prone to cracking due to reduced toughness, or causing a decrease in the product's strength and elasticity, making it more scratch-resistant. In some examples, the range of molar ratio "b / c" exceeds about 0.1 and does not exceed about 0.6. The epoxy-functionalized silicone resin (A) contains (R 1 2SiO 2 / 2 )siloxane unit and (R 1 SiO 3 / 2 The siloxane unit, and its molecular structure is in most cases a network structure or a three-dimensional structure, because the molar ratio "b / c" exceeds about 0.1 and does not exceed about 0.6. Therefore, in epoxy-functionalized organopolysiloxane resin (A), there is (R) 1 2SiO 2 / 2 )siloxane unit and (R 1 SiO 3 / 2 )siloxane unit, while (R 1 3SiO 1 / 2 )siloxane units and (SiO 4 / 2 The siloxane unit is an optional constituent unit. That is, epoxy-functionalized organopolysiloxane resins containing the following average unit formulas can exist:

[0047] (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c

[0048] (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c

[0049] (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d

[0050] (R 1 3SiO 1 / 2 ) a (R1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d

[0051] In component (A), all siloxane units in the molecule, optionally from about 10 mol% to about 30 mol%, or optionally from about 15 mol% to about 30 mol%, have epoxy-substituted organic groups. If the amount is greater than or equal to the lower limit of the above-described range for such siloxane units, the crosslinking density during curing can be increased. On the other hand, it may be suitable if the amount is less than or equal to the upper limit of the above-described range, as this may result in an increase in the heat resistance of the cured product. In the epoxy-functional monovalent hydrocarbon groups, the epoxy groups can be bonded to silicon atoms via alkylene groups so that these epoxy groups are not directly bonded to silicon atoms. The epoxy-functionalized organopolysiloxane resin (A) can be produced by well-known conventional manufacturing methods.

[0052] While there are no particular restrictions on the weight-average molecular weight of the epoxy-functionalized organopolysiloxane resin (A), in some embodiments, a molecular weight of not less than about 10 is preferred, taking into account the toughness of the cured product and its solubility in organic solvents. 3 And no more than approximately 10 6 In one embodiment, the epoxy-functionalized organopolysiloxane resin (A) comprises a combination of two or more such epoxy-functionalized organopolysiloxane resins having different contents and types of epoxy organic groups and monovalent hydrocarbon groups or having different molecular weights.

[0053] Component (B) is an epoxy-functionalized organosiloxane oligomer represented by the following general formula:

[0054] X 1 -R 2 2SiO(SiR 2 2O) m SiR 2 2-X 1 .

[0055] In this formula, each R 2 These are the same or different organic groups, and the organic groups are selected from C. 1-6 Monovalent aliphatic hydrocarbon groups and C 6-10 Monovalent aromatic hydrocarbon groups.

[0056] C in component (B) 1-6 Examples of monovalent aliphatic hydrocarbon groups include C 1-6Alkyl groups, such as methyl, ethyl, propyl, butyl, and hexyl groups; C 2-6 Alkenyl groups, such as vinyl groups, allyl groups, and hexenyl groups; and C 1-6 Halogenated alkyl groups, such as 3-chloropropyl groups and 3,3,3-trifluoropropyl groups. Among them, methyl groups are generally preferred.

[0057] C in component (B) 6-10 Examples of monovalent aromatic hydrocarbon groups include phenyl groups, tolyl groups, xylyl groups, and naphthyl groups. Among these, phenyl groups are generally preferred.

[0058] In component (B), 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 total R 2 C 6-10 Monovalent aromatic hydrocarbon groups. If the content of monovalent aromatic hydrocarbon groups is greater than or equal to the lower limit mentioned above, the masking properties of the cured product can be increased and the mechanical properties of the cured product can be increased.

[0059] In this formula, each X 1 Organic groups that are the same or different monovalent epoxy-substituted groups. X 1 Examples of monovalent epoxy-substituted organic groups include glycidyloxyalkyl groups, such as 3-glycidyloxypropyl, 4-glycidyloxybutyl, and 5-glycidyloxypentyl; 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. Generally, 3,4-epoxycycloalkylalkyl groups are preferred.

[0060] In the above general formula, "m" is a number from about 0 to about 100, optionally from about 0 to about 20, or optionally from about 0 to about 10. If "m" is less than or equal to the upper limit of the above range, the masking properties of the cured product can be increased.

[0061] In particular, due to the storage stability of the compositions of the present invention and the masking properties of the cured products, component (B) is preferably an epoxy-functional organosiloxane oligomer represented by the following general formula:

[0062] X 1 -R 2 2SiOSiR 2 2-X 1

[0063] Where R 2 and X 1 As stated above.

[0064] The state of component (B) at 25°C is unrestricted, but it is typically a liquid. The viscosity of component (B) at 25°C is unrestricted; however, the viscosity is typically in the range of about 5 mPa·s to about 100 mPa·s. Note that in this specification, the viscosity is the value measured at 23°C ± 2°C using a Type B viscometer according to ASTM D 1084.

[0065] The content of component (B) is from about 5% to about 80% by mass, optionally from about 10% to about 80% by mass, optionally from about 10% to about 70% by mass, or optionally from about 20% to about 70% by mass, of the total mass of components (A), (B), (C), and (D). If the content of component (B) is greater than or equal to the lower limit of the above range, the flexibility and impact strength of the cured product can be increased. On the other hand, if the content is less than or equal to the upper limit of the above range, the toughness and tensile strength of the cured product can be increased.

[0066] Component (C) is a photoacid generator and / or a thermal acid generator used to cure the compositions of the present invention. Any acid generator known to those skilled in the art can be used, such as sulfonium salts, iodonium salts, selenium salts, phosphonium salts, diazonium salts, p-toluenesulfonate, trichloromethyl-substituted triazines, and trichloromethyl-substituted benzenes.

[0067] Examples of matte salts may include those derived from the formula: R c 3S + X - The salt represented. In this formula, R c It can represent methyl, ethyl, propyl, butyl, and other C. 1-6 Alkyl groups; phenyl, naphthyl, biphenyl, tolyl, propylphenyl, decylphenyl, dodecylphenyl and other C 1-24 An aryl group or a substituted aryl group, and X in the formula - It can represent SbF6 - AsF6 - PF6 - BF4 - B(C6F5)4 - HSO4 - ClO4 - CF3SO3 - And other non-nucleophilic, non-basic anions.

[0068] Examples of iodonium salts may include those derived from the formula: R c 2I + X- The salts represented; examples of selenium salts may include those derived from the formula: R c 3Se + X - The salt represented; examples of phosphonium salts may include those derived from the formula: R c 4P + X - The salts represented; examples of diazonium salts may include those derived from the formula: R c N2 + X - The salt represented by the formula; where R in the formula c and X - Compared with the R discussed in this article c 3S + X - The same as described above.

[0069] Examples of p-toluenesulfonates may include those derived from the formula: CH3C6H4SO3R c1 The compound represented, wherein R in the formula c1 This refers to organic groups that contain electron-withdrawing groups, such as benzoylphenylmethyl group, phthalimide group, etc.

[0070] Examples of trichloromethyl-substituted triazines may include those derived from [CC13]2C3N3R. c2 The compound represented, wherein R in the formula c2 Represents phenyl, substituted or unsubstituted phenylethyl, substituted or unsubstituted furanylethynyl and other electron-withdrawing groups.

[0071] Examples of trichloromethyl-substituted benzene may include CCl3C6H3R c R c3 The compound represented, wherein R in the formula c Compared with the R discussed in this article c 3S + X - The same as described, and R c3 Represents halogen groups, halogen-substituted alkyl groups, and other halogen-containing groups.

[0072] Examples of acid generators may include, for example, triphenylsulfonium tetrafluoroborate, di(p-tert-butylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodonium hexafluoroantimonate, 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate and p-chlorophenyldiazotetrafluoroborate.

[0073] The content of component (C) is from about 0.01% to about 5% by mass, optionally from about 0.01% to about 2% by mass, or optionally from about 0.02% to about 0.8% by mass, or optionally from 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 greater than or equal to the lower limit of the above range, the curable silicone composition can be completely cured. On the other hand, if the content is less than or equal to the upper limit of the above range, the mechanical properties of the cured product can be increased.

[0074] Component (D) is a black azo dye to improve the masking properties of the cured product. The black azo dye significantly reduces the appearance of particles, voids, pinholes, and streaks in the compositions of this invention and prolongs the storage stability of the compositions. Black azo dyes are generally designated 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. Solvent Black 27 is the most preferred choice as it not only improves storage stability but also enhances the masking properties of the cured product film.

[0075] These black azo dyes are commercially available. A preferred black azo dye is Orasol Black RLI, a 1:2 mixture of pigment and chromium, available from Ciba-Geigy. This includes other dyes specified by Solvent Black 3 through Solvent Black 47, particularly Solvent Black 35 (Nitrocellulose Lacquer Black X50, BASF), Solvent Black 27 (Nitrocellulose Lacquer 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 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).

[0076] The content of component (D) is from about 0.1% by mass to about 5% by mass of the total mass of components (A), (B), (C), and (D), or optionally from about 0.5% by mass to about 5% by mass. If the content of component (D) is greater than or equal to the lower limit of the above range, the masking properties of the cured product can be increased. On the other hand, if the content is less than or equal to the upper limit of the above range, the curability of the composition can be increased and the mechanical properties of the cured product can be increased.

[0077] The compositions of the present invention comprise components (A) to (D) described above; however, in order to impart better mechanical strength to the cured products of the compositions of the present invention, they may contain photosensitizers, and / or tackifiers other than component (C), and / or alcohols, and / or inorganic fillers.

[0078] Examples of photosensitizers include isopropyl-9H-thioxanth-9-one, anthrone, 1-hydroxycyclohexylphenyl ketone, 2,4-diethyl-9H-thioxanth-9-one, 2-isopropylthioxanthone, 2-hydroxy-2-methyl-1-phenylpropion-1-one, 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT), pentaerythritol tetratetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) [3,5-bis(1,1-di-tert-butyl-4-hydroxyphenyl)methyl]phosphonate, 33',3”,5,5',5”-hexane-tert-butyl-4-a,a',a”-(trimethylbenzene-2,4,6-tolyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] and hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0079] The content of the photosensitizer is not limited, but it is generally in the range of about 0.001% by mass to about 1% by mass of the total mass of components (A), (B), (C), (D) and the photosensitizer, optionally in the range of about 0.005% by mass to about 0.5% by mass, or optionally in the range of about 0.005% by mass to about 0.1% by mass. If the content of the photosensitizer is greater than or equal to the lower limit of the above range, the curability of the cured product can be increased. On the other hand, if the content is less than or equal to the upper limit of the above range, the mechanical properties of the cured product can be increased.

[0080] Examples of tackifiers include epoxy-functionalized alkoxysilanes, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldiethoxysilane, and combinations thereof; and unsaturated alkoxysilanes, such as vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecenyltrimethoxysilane, and 3-methylpropene. Acyloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and combinations thereof; epoxy-functionalized siloxanes having silicon-bonded alkoxy groups, such as reaction products of hydroxyl-terminated polyorganosiloxanes with epoxy-functionalized alkoxysilanes (e.g., one of the alkoxysilanes described above), or physical blends of hydroxyl-terminated polyorganosiloxanes with epoxy-functionalized alkoxysilanes. Tackifiers may comprise epoxy-functionalized alkoxysilanes and combinations thereof. Examples of tackifiers include mixtures of the reaction products of 3-glycidoxypropyltrimethoxysilane and hydroxyl-terminated methyl vinyl siloxane with 3-glycidoxypropyltrimethoxysilane, or mixtures of 3-glycidoxypropyltrimethoxysilane with hydroxyl-terminated methyl vinyl siloxane, or mixtures of 3-glycidoxypropyltrimethoxysilane with hydroxyl-terminated methyl vinyl / dimethyl siloxane copolymer.

[0081] The content of the tackifier is not limited, but its amount is generally from about 0.01% to about 5% by mass of the total mass of components (A), (B), (C), (D) and the tackifier, or optionally from about 0.1% to about 2% by mass.

[0082] Inorganic fillers enhance the mechanical strength of cured products. Examples of fillers include one or more of the following: extremely fine treated or untreated precipitated or pyrolytic silica; precipitated or ground calcium carbonate, zinc carbonate; clays, such as extremely fine kaolin; quartz powder; aluminum hydroxide; zirconium silicate; diatomaceous earth; wollastonite; pyrophylite; and metal oxides, such as pyrolytic or precipitated titanium dioxide, cerium oxide, magnesium oxide powder, zinc oxide, and iron oxide.

[0083] The content of filler is not limited, but is generally in the range of about 1% by mass to about 90% by mass of the total mass of components (A), (B), (C), (D) and filler.

[0084] The compositions of the present invention can be cured by radiation with UV rays (or ultraviolet light) and / or heating. For example, low-pressure, high-pressure or ultra-high-pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps or electrodeless lamps can be used as UV lamps.

[0085] [Example]

[0086] The curable organosilicon compositions of the present invention will now be described in detail using practical and comparative examples. It should be noted that in these formulas, "Me", "Pr", "Ph", and "Ep" respectively indicate a methyl group, a propyl group, a phenyl group, and a 2-(3,4-epoxycyclohexyl)ethyl group. The structure of the epoxy-functionalized organopolysiloxane resins used in the examples is determined by... 13 C NMR and 29 The weight-average molecular weight of the epoxy-functionalized organosiloxane resin was determined by Si NMR measurement. The weight-average molecular weight was calculated using GPC based on a comparison with a polystyrene standard. The viscosity of the epoxy-functionalized organosiloxane oligomers was measured as follows.

[0087] Viscosity

[0088] Viscosity at 23°C ± 2°C was measured using a Type B viscometer (Brookfield HA or HB type rotational viscometer, using a No. 52 spindle, at 5 rpm) in accordance with ASTM D 1084 "Standard Test Methods for Viscosity of Adhesive".

[0089] <Practical Examples 1-7 and Comparative Examples 1-5>

[0090] The curable silicone compositions shown in Table 1 (mass %) were prepared using the following components.

[0091] The following epoxy-functionalized organopolysiloxane resin is used as component (A).

[0092] (a1): Epoxy-functionalized organopolysiloxane resins with a weight-average molecular weight of 2,000 to 6,000 and represented by the following average unit formula:

[0093] (MePhSiO 2 / 2 ) 0.34 (PrSiO 3 / 2 ) 0.50 (EpSiO 3 / 2 ) 0.16

[0094] The following organopolysiloxanes are used as polymers compared with component (A).

[0095] (a2): Methylphenyl polysiloxane, which is capped at both ends of the molecular chain with dimethylvinylsiloxy groups and has a viscosity of 3,500 mPa·s.

[0096] (a3): Dimethyl polysiloxane, which is capped at both ends of the molecular chain with dimethyl vinylsiloxy groups and has a viscosity of 450 mPa·s.

[0097] The following epoxy-functional organosiloxane oligomers are used as component (B).

[0098] (b1): An epoxy-functionalized organosiloxane oligomer with a viscosity of 40 mPa·s, a weight-average molecular weight of 382, ​​and expressed by the following formula:

[0099] Ep-SiMe2OSiMe2-Ep

[0100] The following cationic photoinitiator was used as component (C).

[0101] (c1): 4-Isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate represented by the following formula:

[0102]

[0103] (TR-PAG-30408 ​​obtained from TRONYL)

[0104] The following black azo dye is used as component (D).

[0105] (d1): Solvent Black 27, expressed by the following formula:

[0106]

[0107] (d2): Solvent Black 28

[0108] (d3): Solvent Black 29, expressed by the following formula:

[0109]

[0110] (d4): Solvent Black 34, expressed by the following formula:

[0111]

[0112] (d5): Solvent Black 43

[0113] (d6): Solvent Black 3, expressed by the following formula:

[0114]

[0115] (d7): Solvent Black 46, expressed by the following formula:

[0116]

[0117] The following carbon black pigments are used as colorants compared with component (D).

[0118] (d8): Carbon black pigment, which has 8m 2 / g BET specific surface area (produced by CARY Company) N990)

[0119] The following components are used as components (E) for comparison.

[0120] (e1): A copolymer of dimethylsiloxane and methylhydrosiloxane, both molecular chains of which are capped with trimethylsiloxy groups and have a viscosity of 5 mPa·s.

[0121] (e2): A complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane

[0122] (e3): Tris[(1,1-dimethyl-2-propynyl)oxy]methylsilane

[0123] (e4): Ethanol

[0124] The curable silicone composition is prepared by the following steps:

[0125] 1. Place all raw materials into a 200mL polyethylene cup;

[0126] 2. Without evacuating the air, mix the raw materials at 1500 rpm for 2 minutes using a mixer (Thinky ARV-310P).

[0127] 3. Scrape the walls and bottom of the polyethylene cup;

[0128] 4. Mix again under the same conditions mentioned above;

[0129] 5. Remove the curable silicone composition.

[0130] The curable silicone composition was cured at 150°C for 1 hour. The curable silicone composition and cured product were evaluated as follows. Their properties are shown in Table 1.

[0131] <Sedimentation / Separation>

[0132] Visually observe the sedimentation / separation of the curable silicone composition.

[0133] <Contraction / Mura>

[0134] Shrinkage of the cured product is evaluated by examining its height (level) after curing the curable silicone composition in vials. The shrinkage of the cured product is visually observed.

[0135] <Average OD>

[0136] A 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) for the visible wavelength range (360 nm–740 nm) was calculated using transmittance measurements (CM-3600A spectrophotometer, Konica Minolta).

[0137] [Table 1]

[0138]

[0139] [Table 1] (continued)

[0140]

[0141]

[0142] Industrial applicability

[0143] The curable silicone compositions of the present invention can be cured to form cured products exhibiting good to excellent shielding properties without causing shrinkage and "MURA" defects. Therefore, the compositions of the present invention can be used as black gap-filling materials for LED display applications.

Claims

1. A curable silicone composition comprising: (A) an epoxy-functional organopolysiloxane resin represented by the following average unit formula: (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d Each R 1 These may be the same or different organic groups, and the organic groups are selected from C. 1-6 Monovalent aliphatic hydrocarbon groups, C 6-10 Monovalent aromatic hydrocarbon groups and monovalent epoxy-substituted organic groups, provided that the total R content is at least 15 mol% 1 For the C 6-10 Monovalent aromatic hydrocarbon groups; and "a", "b", "c" and "d" are numbers that satisfy the following 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 mol% to 30 mol% of the total siloxane units have monovalent epoxy-substituted organic groups; (B) an epoxy-functional organosiloxane oligomer represented by the following general formula: X 1 -R 2 2SiO(SiR 2 2O) m SiR 2 2-X 1 wherein each R 2 is the same or different organic group selected from C 1-6 monovalent aliphatic hydrocarbon group and C 6-10 monovalent aromatic hydrocarbon group; each X 1 is the same or different monovalent epoxy-substituted organic group; and "m" is a number from 0 to 100 in an amount of from 5 mass % to 80 mass % of the total mass of component (A), component (B), component (C), and component (D); (C) a photoacid generator and / or a thermal acid generator in an amount of 0.01 to 5 mass% of the total mass of component (A), component (B), component (C), and component (D); and (D) a black azo dye in an amount of 0.1 to 5 mass% of the total mass of component (A), component (B), component (C), and component (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 the group consisting of a glycidoxyalkyl group, a 3,4-epoxycyclohexylalkyl group, and an epoxyalkyl group.

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

4. The curable silicone composition according to claim 1, wherein component (B) is an epoxy-functional organosiloxane oligomer represented by the following general formula: X 1 -R 2 2SiOSiR 2 2-X 1 wherein R 2 and X 1 As described above.

5. The curable silicone composition according to claim 1, wherein component (D) is a black azo dye selected from the group consisting of 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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