Curable silicone composition

Abstract

The present disclosure provides a curable silicone composition having a refractive index of 1.42 to 1.50 at 25°C, as measured using an Abbe refractometer at a wavelength of 589 nm. The composition comprises: (A) an organopolysiloxane having, on average, at least one alkenyl group having 2 to 12 carbon atoms and at least one aryl group having 6 to 12 carbon atoms per molecule; (B) an organohydrogenpolysiloxane having, on average, at least one silicon-bonded hydrogen atom and at least one aryl group having 6 to 12 carbon atoms per molecule; (C) fumed silica; (D) a surfactant selected from polyether-modified organopolysiloxanes and silicon-free polyethers; and (E) a hydrosilylation reaction catalyst. The composition exhibits excellent film-forming properties on fluorine films and cures to form a transparent, printable cured product. Even when the cured product comes into contact with Si-OCA, it is capable of preventing migration of components such as MQ resin from the Si-OCA to the cured product.

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 / 435,631, filed December 28, 2022, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a curable silicone composition. [Background technology]

[0003] The optical display of a flip phone is generally composed of ultra-thin glass (UTG), transparent silicone adhesive (Si-OCA), and thermoplastic polyurethane (TPU). Si-OCA is used to improve the visibility of the optical display. However, TPU has problems such as water absorption and vulnerability to ultraviolet (UV) light. Water-absorbed TPU becomes mechanically weak, and UV-exposed TPU turns yellow.

[0004] Recently, TPU is expected to be replaced by silicone-based materials. As the silicone-based material, a curable silicone composition is available. For example, Patent Document 1 discloses a curable silicone composition for optical devices, which comprises a first siloxane compound having a polyether residue, a second siloxane compound having a silicon-bonded hydrogen at its terminal, a third siloxane compound having a silicon-bonded alkenyl group at its terminal, and a hydrosilylation reaction catalyst. Patent Document 2 discloses a curable polysiloxane composition comprising a first siloxane compound having a silicon-bonded alkenyl group at its terminal, a second siloxane compound having a silicon-bonded hydrogen atom at its terminal, 0.05 to 3 wt % of a hydrophilic polyalkylene oxide compound based on the total weight of the first and second siloxane compounds, and a hydrosilylation catalyst. Patent Documents 3 and 4 disclose curable silicone compositions comprising an organopolysiloxane having at least two alkenyl groups in the molecule, an organopolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule, a polyether-modified silicone, and a hydrosilylation catalyst.

[0005] Silicone-based materials are required to be transparent, printable, and able to form films on fluorine films. However, there is a problem in that the adhesion is easily reduced due to the migration of components such as MQ resin from Si-OCA to the silicone-based material.

[0006] Prior art documents Patent documents Patent Document 1: U.S. Patent Application Publication No. 2015 / 0353688(A1) Patent Document 2: International Patent Application Publication No. 2016 / 006773(A1) Patent Document 3: U.S. Patent Application Publication No. 2020 / 0385579(A1) Patent Document 4: U.S. Patent Application Publication No. 2020 / 0385580(A1) Summary of the Invention

[0007] technical challenges The object of the present invention is to provide a curable silicone composition that has good film-forming properties on a fluorine film, cures to form a cured product that is transparent and suitable for printing, and prevents the migration of components such as MQ resin from Si-OCA to the cured product when the cured product comes into contact with Si-OCA. [Means for solving the problem]

[0008] The curable silicone composition of the present invention has a refractive index of 1.42 to 1.50 at 25°C as measured at a wavelength of 589 nm using an Abbe refractometer, and the composition is (A) an organopolysiloxane having at least one alkenyl group having an average of 2 to 12 carbon atoms and at least one aryl group having an average of 6 to 12 carbon atoms in the molecule; (B) an organohydrogenpolysiloxane having, on average, at least one silicon-bonded hydrogen atom and at least one aryl group having from 6 to 12 carbon atoms in the molecule, wherein the amount of silicon-bonded hydrogen atoms in this component is in the range of 0.1 to 10 moles per mole of alkenyl groups in component (A); (C) a silica filler in the range of 0.1 to 5% by weight of the total weight of the composition; (D) a surfactant selected from polyether-modified organopolysiloxanes and silicon-free polyethers in an amount ranging from 0.01 to 5% by mass of the total mass of the composition; and (E) a catalytic amount of a hydrosilylation reaction catalyst.

[0009] In various embodiments, the content of aryl groups in components (A) and (B) ranges from 10 to 40 weight percent of the total weight of components (A) and (B).

[0010] In various embodiments, component (C) is at least 50 ml 2 / g BET surface area.

[0011] In various embodiments, the polyether-modified organopolysiloxane for component (D) is an organopolysiloxane having at least one polyether residue grafted into the molecule.

[0012] In various embodiments, the composition further comprises (F) a hydrosilylation reaction inhibitor in the range of 0.01 to 3 wt % of the total weight of the composition.

[0013] In various embodiments, the composition further comprises (G) an organic solvent in the range of 0.01 to 3% by weight of the total weight of the composition.

[0014] In various embodiments, the composition is a composition for sealing, coating, or adhering an optical element.

[0015] The display device of the present invention comprises ultra-thin glass (UTG), a transparent silicone adhesive (Si-OCA), and a silicone film, the silicone film being produced by curing the above-described curable silicone composition. [Effects of the Invention]

[0016] The curable silicone composition of the present invention has good film-forming properties on fluorine films, and upon curing forms a cured product that is transparent and suitable for printing. Furthermore, even when the cured product comes into contact with Si-OCA, it is possible to prevent the migration of components such as MQ resin from Si-OCA to the cured product. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a photograph of the cured product of Example IE1. [Figure 2] 1 is a photograph of the cured product of Comparative Example CE1, in which aggregation of fumed silica was observed. [Figure 3] 1 is a photograph of the cured product of Comparative Example CE2 or CE7, in which the Bernard cell phenomenon was observed. [Figure 4] 1 is a photograph of the cured product of Comparative Example CE2, in which shrinkage was observed. [Figure 5]Photographs of the cured products of Comparative Examples CE4 and CE6, showing fumed silica observed due to refractive index mismatch. [Figure 6] 1 is a photograph of the cured product of Comparative Example CE9, in which shrinkage was observed. [Figure 7] 1 is a photograph of a printability test for Example IE1 (right) and Comparative Example CE4 (left).

[0018] definition The terms "comprising" or "comprise" are used herein in their broadest sense to refer to and encompass the concepts of "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "e.g.," "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 a numerical value determined by instrumental analysis or resulting from handling of a sample. Such slight variations may be as little 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.

[0019] It is understood that the appended claims are not limited to the explicit and specific compounds, compositions, or methods described in the detailed description, which may vary among specific embodiments falling within the scope of the appended claims. With respect to any Markush group relied upon herein to describe specific features or aspects of various embodiments, it should be understood that different, extraordinary, and / or unexpected results can be obtained from each element of the respective Markush group, independently of all other Markush elements. Each element of a 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.

[0020] 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 delineated into related halves, thirds, fourths, fifths, etc. As merely an example, a range "from 0.1 to 0.9" may be further delineated 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 within which specific embodiments may be relied upon and provide sufficient support, individually and / or inclusively. Additionally, with respect to terms defining or modifying a range, such as "at least," "greater than," "less than," "less than or equal to," etc., such terms should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" inherently 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 collectively to provide sufficient support for specific embodiments within the appended claims. Finally, individual numbers within disclosed ranges may be relied upon to provide sufficient support for specific embodiments within the appended claims. For example, the range "from 1 to 9" includes various individual integers, such as 3, as well as 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 appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0021] The curable silicone composition of the present invention will now be described in detail.

[0022] Component (A) is the base compound of the composition and is an organopolysiloxane containing at least one alkenyl group having an average of 2 to 12 carbon atoms per molecule and at least one aryl group having an average of 6 to 12 carbon atoms per molecule. Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups, with vinyl being preferred. Examples of aryl groups include phenyl, tolyl, xylyl, and naphthyl groups, with phenyl being preferred. In addition, examples of groups bonded to silicon atoms in component (A) other than alkenyl and aryl groups 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, as well as groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms, such as fluorine, chlorine, or bromine. Furthermore, the silicon atoms in component (A) may contain small amounts of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, as long as the object of the present invention is not impaired.

[0023] Examples of the molecular structure of component (A) include a linear structure, a partially branched linear structure, a branched structure, and a three-dimensional network structure. Component (A) may be one of organopolysiloxanes having these molecular structures, or may be a mixture of two or more organopolysiloxanes having these molecular structures.

[0024] The branched organopolysiloxane of component (A) is typically represented by the following average unit formula: (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c (HO 1 / 2 )d .

[0025] In the above formula, each R 1 is, independently, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and examples thereof include the same groups as described above. However, at least one R 1 in the molecule is an alkenyl group, preferably a vinyl group.

[0026] In the above formula, R 2 is an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and examples thereof include the same groups as described above. However, at least one R 2 in the molecule is an aryl group, preferably a phenyl group.

[0027] In the above formula, "a", "b", "c", and "d" are numbers satisfying the following conditions: 0 < a ≤ 0.3, 0 ≤ b ≤ 0.2, 0.5 ≤ c ≤ 0.9, 0 ≤ d ≤ 0.05, and a + b + c = 1, or optionally, 0.1 ≤ a ≤ 0.3, b = 0, 0.7 ≤ c ≤ 0.9, 0 ≤ d ≤ 0.05, and a + b + c = 1. This is because when "a", "b", "c", and "d" are numbers within the above ranges, the cured product obtained by curing this composition has appropriate hardness and mechanical strength.

[0028] The linear organopolysiloxane of component (A) is usually represented by the following general formula. R 3 3SiO(R 3 2SiO) m SiR 3 3

[0029] In the above formula, each R 3 is, independently, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and examples thereof include the above R 1However, at least two R 3 is an alkenyl group, and at least one R 3 is an aryl group, or optionally, at least two R 3 is a vinyl group, and at least one R 3 is a phenyl group.

[0030] In the above formula, "m" is an integer between 10 and 1000, optionally an integer between 10 and 500.

[0031] The viscosity of the linear organopolysiloxane at 25°C is not limited, but is typically 100,000 mPa·s or less, and may optionally be 50,000 mPa·s or less, or optionally 20,000 mPa·s or less. Note that in this specification, viscosity is a value measured at 23±2°C using a Brookfield viscometer in accordance with ASTM D1084.

[0032] The linear organopolysiloxane of component (A) is usually at least one selected from organopolysiloxanes represented by the following formula: (CH2=CH)(CH3)2SiO[(C6H5)2SiO] m Si(CH3)2(CH=CH2) (CH2=CH)(CH3)2SiO[(C6H5)2SiO] m1 [(CH3)2SiO] m2 Si(CH3)2(CH=CH2) (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] m1 [(CH3)2SiO] m2 Si(CH3)2(CH=CH2) (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] m Si(CH3)2(CH=CH2) (CH2=CH)(CH3)(C6H5)SiO[(C6H5)(CH3)SiO] m1 [(CH3)2SiO] m2Si(CH3)(C6H5)2(CH=CH2)

[0033] In the above formula, "m" is as defined above, and "m1" and "m2" are integers that satisfy 10≦(m1+m2)≦1,000, optionally 10≦(m1+m2)≦500.

[0034] The amount of component (A) is not limited, but is typically 60 to 90 mass %, optionally 65 to 90 mass %, or optionally 70 to 90 mass %, based on the total mass 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 cured product obtained by curing the composition has appropriate hardness and mechanical strength, while, when the amount is equal to or less than the upper limit of the above range, the composition has a suitable viscosity at 25°C.

[0035] Component (B) is an organosiloxane containing, on average, at least one silicon-bonded hydrogen atom and at least one aryl group having 6 to 12 carbon atoms per molecule, and is used as a crosslinking agent for the composition. Examples of the aryl group include the same groups as those listed above, with phenyl being preferred. Examples of silicon-bonded groups other than hydrogen atoms and aryl groups 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, as well as groups in which some or all of the hydrogen atoms of these alkyl groups have been substituted with halogen atoms, such as fluorine, chlorine, or bromine. Furthermore, the silicon atoms in component (B) may contain small amounts of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, as long as the objectives of the present invention are not impaired.

[0036] The viscosity of component (B) at 25°C is not limited, but is typically 1,000 mPa·s or less, optionally 500 mPa·s or less, or optionally 100 mPa·s or less. Note that in this specification, viscosity is a value measured at 23±2°C using a Brookfield viscometer in accordance with ASTM D1084.

[0037] Examples of the molecular structure of component (B) include a linear structure, a partially branched linear structure, a branched structure, a cyclic structure, and a three-dimensional network structure.

[0038] The linear organosiloxane of component (B) is typically represented by the following general formula: HR 4 2SiO(R 4 2SiO) n SiR 4 2H.

[0039] In the above formula, each R 4 is an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, examples of which include the above-mentioned R 2 However, at least one R 4 is an aryl group, usually a phenyl group.

[0040] In the above formula, "n" is an integer from 0 to 10, optionally an integer from 0 to 5, optionally an integer from 0 to 3, or optionally an integer of 0 or 1.

[0041] The linear organosiloxane of component (B) is usually at least one selected from organosiloxane oligomers represented by the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H.

[0042] The branched organosiloxane of component (B) is represented by the following general formula: R 4 2HSiO1 / 2 ) e (R 4 SiO 3 / 2 ) f

[0043] In the above formula, each R 4 is an alkyl group or an aryl group, examples of which include the same groups as those described above. However, at least one R 4 is an aryl group, usually a phenyl group.

[0044] In the above formula, "e" and "f" are numbers that satisfy the following conditions: e>0, f>0, e+f=1.

[0045] The branched organosiloxane of component (B) is typically represented by the following average unit formula: [(CH3)2HSiO 1 / 2 ] e [C6H5SiO 3 / 2 ] f (where "e" and "f" are as defined above).

[0046] Component (B) is used in an amount such that the silicon-bonded hydrogen atoms in component (B) are each in the range of 0.1 to 10 moles, optionally in the range of 0.5 to 1.5 moles, or optionally in the range of 0.8 to 1.5 moles per mole of alkenyl groups in component (A), because when the molar ratio is at or above 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 mechanical strength, while when the molar ratio is at or below the upper limit of the above range, the cured product has good thermal stability.

[0047] Component (C) is a silica filler that prevents shrinkage of the composition during curing and improves film-forming properties on the fluorine film. At the same time, it can improve the strength of the cured product. Component (C) is usually present in a range of at least 50 m. 2 / g, optional 80~400m 2 / g, or optionally 100-400m2 The silica filler is a fumed or precipitated silica filler having a BET surface area of ​​1 / g. The surface of the silica filler may be untreated or may be treated with a treating agent such as an organochlorosilane, an organoalkoxysilane, an organosilazane, or an organosiloxane oligomer.

[0048] The silica filler of component (C) is commercially available. Examples of silica fillers include fumed silicas manufactured by Degussa under the trade name AEROSIL®, such as AEROSIL® R8200, R9200, R812, R812S, R972, R974, R805, and R202; fumed silicas manufactured by Cabot under the trade name CAB-O-SIL® ND-TS, TS610, or TS710; and fumed silicas manufactured by Tokuyama under the trade name REOLOSIL®, such as DM-10, DM-20S, DM-30, HM-30S, MT-10, PM-20L, QS-10, QS-20A, and QS-25C.

[0049] The amount of component (C) is in the range of 0.1 to 5% by weight of the composition, or optionally in the range of 0.3 to 2% by weight, because if the amount is equal to or greater than the lower limit of the range, the cured product obtained by curing the composition has appropriate hardness and mechanical strength, while if the amount is equal to or less than the upper limit of the range, the composition has good transparency.

[0050] Component (D) is a surfactant selected from polyether-modified organopolysiloxanes and silicon-free polyethers, and it improves the film-forming properties of the composition on fluorine films. During the coating and curing process of the composition, polymer chains aggregate and thermal convection occurs, resulting in the Bernard cell phenomenon. This causes the problem of uneven surfaces on the cured product. Adding component (D) can resolve this phenomenon, helping to obtain a uniform film.

[0051] The polyether-modified organopolysiloxane of component (D) is not particularly limited, but is an organopolysiloxane having at least one polyether block or residue in the molecule. That is, the polyether-modified organopolysiloxane is a block copolymer of a polyether block and an organopolysiloxane block, or an organopolysiloxane having at least one polyether residue grafted into the molecule. Among these, organopolysiloxanes having at least one polyether residue grafted into the molecule are preferred. These polyether-modified organopolysiloxanes are commercially available from Dow Chemical Company in Midland, Michigan, under the trade names DOWSIL™ 57 Additive, DOWSIL™ 67 Additive, DOWSIL™ 500W Additive, DOWSIL™ 501W Additive, and DOWSIL™ 502W Additive, respectively.

[0052] Examples of silicon-free polyethers of component (D) include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters.Silicon-free polyethers are commercially available.Examples of silicon-free polyethers include 2,6,8-trimethyl-4-nonyl polyoxyethylene ethers, under the trade names TERGITOL™ TMN-6 and TERGITOL™ TMN-10, and under the trade names TERGITOL™ 15-S-3, TERGITOL™ 15-S-7, TERGITOL™ 15-S-9, TERGITOL™ 15-S-15, TERGITOL™ 15-S-30, and TERGITOL™ 15-S-40, both from Dow Chemical Company, Midland, Michigan. 11-15 Contains secondary alkyl polyoxyethylene ethers.

[0053] The amount of component (D) is in the range of 0.01 to 5% by weight of the composition, or optionally in the range of 0.1 to 2% by weight, because when the content of component (D) is equal to or greater than the lower limit of the range, the cured product obtained by curing the composition has appropriate hardness and mechanical strength, while when the amount is equal to or less than the upper limit of the range, the composition has good transparency.

[0054] Component (E) is a hydrosilylation catalyst used to accelerate the curing of the present composition. Examples of component (E) include platinum group element catalysts and platinum group element compound catalysts, and specific examples include platinum-based catalysts, rhodium-based catalysts, palladium-based catalysts, and combinations of at least two of them. In particular, platinum-based catalysts are preferred because they can dramatically accelerate the curing of the present composition. Examples of component (E) include finely powdered platinum, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid / diolefin complex, platinum / olefin complex, platinum / carbonyl complexes such as platinum bis(acetoacetate) and platinum bis(acetylacetonate), chloroplatinic acid / alkenylsiloxane complexes such as chloroplatinic acid / divinyltetramethyldisiloxane complex and chloroplatinic acid / tetravinyltetramethylcyclotetrasiloxane complex, platinum / alkenylsiloxane complexes such as platinum / divinyltetramethyldisiloxane complex and platinum / tetravinyltetramethylcyclotetrasiloxane complex, complexes of chloroplatinic acid and acetylene alcohol, and mixtures of two or more of these. In particular, platinum-alkenylsiloxane complexes are preferred because of their excellent accelerating effect.

[0055] Examples of alkenylsiloxanes used in platinum-alkenylsiloxane complexes include 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, alkenylsiloxane oligomers in which some of the methyl groups of these alkenylsiloxanes have been substituted with ethyl groups, phenyl groups, etc., and alkenylsiloxane oligomers in which the vinyl groups of these alkenylsiloxanes have been substituted with allyl groups, hexenyl groups, etc. 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is particularly preferred because the resulting platinum-alkenylsiloxane complexes have good stability.

[0056] To improve the stability of the platinum-alkenylsiloxane complexes, it is preferable to dissolve these platinum-alkenylsiloxane complexes in an organosiloxane oligomer such as an alkenylsiloxane oligomer, such as 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3-diallyl-1,1,3,3-tetramethyldisiloxane, 1,3-divinyl-1,3-dimethyl-1,3-diphenyldisiloxane, 1,3-divinyl-1,1,3,3-tetraphenyldisiloxane, or 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, or a dimethylsiloxane oligomer, and it is particularly preferable to dissolve the complexes in an alkenylsiloxane oligomer.

[0057] The amount of component (E) is not limited, but is usually such that the content of platinum atoms in component (E) is in the range of 0.01 to 500 ppm, optionally 0.01 to 100 ppm, or optionally 0.1 to 50 ppm by mass of the composition. This is because, when the amount is equal to or greater than the lower limit of the above range, the curability of the resulting composition is good, while, when the amount is equal to or less than the upper limit of the above range, discoloration of the resulting cured product is suppressed.

[0058] The present composition may contain (F) a hydrosilylation reaction inhibitor to extend the working life at ambient temperature and improve storage stability. Examples of component (F) include alkyne alcohols such as 1-ethynylcyclohexan-1-ol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyn-2-ol; ene-yne ​​compounds such as 3-methyl-3-penten-1-yne, 3-methyl-3-hexen-1-yne, 1-ethynylcyclohexene, 3-ethyl-3-buten-1-yne, 3-phenyl-3-buten-1-yne, and 3,5-dimethyl-3-hexen-1-yne; diallyl maleate, dimethyl maleate, diethyl fumarate, and diallyl fumarate. Examples of suitable silanes include unsaturated carboxylic acid esters such as maleate, bis(2-methoxy-1-methylethyl)maleate, monooctyl maleate, monoisooctyl maleate, monoallyl maleate, monomethyl maleate, monoethyl fumarate, monoallyl fumarate, and 2-methoxy-1-methylethyl maleate, alkyne oxysilanes such as dimethylbis(3-methyl-1-butyn-3-oxy)silane and methylvinylbis(3-methyl-1-butyn-3-oxy)silane, triallyl isocyanurate compounds, and mixtures of two or more thereof. In particular, a mixture of an alkyne alcohol and an unsaturated carboxylic acid ester is preferred to prevent the cured product from developing wrinkles on the surface.

[0059] The amount of component (F) is not limited, but is typically in the range of 0.0001 to 5% by weight, or optionally in the range of 0.005 to 3% by weight, of the composition.

[0060] In addition, the present composition may contain a solvent (G) to reduce its viscosity and improve application workability and wetting. Examples of component (G) include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane, decane, cyclohexane, methylcyclohexane, and isoparaffin, hydrocarbon solvents such as industrial gasoline (e.g., rubber solvent), petroleum benzine, and solvent naphtha, ketone solvents such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, methyl isobutyl ketone, diisobutyl ketone, acetonylacetone, and cyclohexanone, ester solvents such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, and isobutyl acetate, diethyl ether, dipropyl ether, diisopropyl ether, and dibutyl ether. Examples of suitable solvents include ether-based solvents such as methyl methyl ether, 1,2-dimethoxyethane, and 1,4-dioxane; solvents having ester and ether components such as 2-methoxyethyl acetate, 2-ethoxyethyl acetate, propylene glycol monoether acetate, and 2-butoxyethyl acetate; siloxane-based solvents such as hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tris(trimethylsiloxy)methylsilane, and tetrakis(trimethylsiloxy)silane; fluorine-based solvents such as trifluorotoluene, hexafluoroxylene, methyl nonafluorobutyl ether, and ethyl nonafluorobutyl ether; and mixed solvents of two or more of these.

[0061] The amount of component (G) is not particularly limited, but is usually about 1 to 10% by mass of the composition.

[0062] The composition may contain an adhesion promoter to improve adhesion of the cured product to contacting substrates during curing. In certain embodiments, the adhesion promoter is typically an organosilicon compound having at least one alkoxy group bonded to a silicon atom in the molecule. The alkoxy group is exemplified by methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy groups, with methoxy being the most typical. Furthermore, the non-alkoxy groups bonded to the silicon atoms of the organosilicon compounds are exemplified by substituted or unsubstituted monovalent hydrocarbon groups such as alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and halogenated alkyl groups; epoxy-containing monovalent organic groups such as 3-glycidoxypropyl groups, 4-glycidoxybutyl groups, and similar glycidoxyalkyl groups; 2-(3,4-epoxycyclohexyl)ethyl groups, 3-(3,4-epoxycyclohexyl)propyl groups, and similar epoxycyclohexylalkyl groups; and 4-oxiranylbutyl groups, 8-oxiranyloctyl groups, and similar oxiranylalkyl groups, such as 3-methacryloxypropyl groups, and acryl-containing monovalent organic groups, and hydrogen atoms. The organosilicon compounds generally have silicon-bonded alkenyl groups or silicon-bonded hydrogen atoms. Furthermore, due to their ability to impart good adhesion to various types of substrates, the organosilicon compounds generally have at least one epoxy-containing monovalent organic group per molecule. This type of organosilicon compound is exemplified by organosilane compounds, organosiloxane oligomers, and alkyl silicates. The molecular structure of the organosiloxane oligomer or alkyl silicate is exemplified by a linear structure, a partially branched linear structure, a branched structure, a cyclic structure, and a network structure. The linear structure, the branched structure, and the network structure are typical.Organosilicon compounds of this type are exemplified by silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like; siloxane compounds having at least one silicon-bonded alkenyl group or silicon-bonded hydrogen atom and at least one silicon-bonded alkoxy group in the molecule; mixtures of silane compounds or siloxane compounds having at least one silicon-bonded alkoxy group in the molecule with siloxane compounds having at least one silicon-bonded hydroxyl group and at least one silicon-bonded alkenyl group in the molecule; and methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate.

[0063] The amount of adhesion promoter is not particularly limited, but is typically up to 10% by weight of the composition to achieve good adhesion to contacting substrates during cure.

[0064] The refractive index (RI) of the composition at 25°C, as measured using an Abbe refractometer at a wavelength of 589 nm, is in the range of 1.42 to 1.50, optionally in the range of 1.44 to 1.50, or optionally in the range of 1.44 to 1.48. This is because when the RI of the composition is below the lower limit of the above range, the composition can be easily coated on a fluorine film without any problems. However, the cured product obtained by curing this composition has poor printability and tends to have poor adhesion due to migration of the MQ resin from the Si-OCA. On the other hand, when the RI exceeds the upper limit of the above range, the composition can solve the printability problem and prevent the deterioration of adhesion to the Si-OCA. However, this composition has poor film-forming properties and may shrink. These problems can be solved by adding component (C), but there is an inconsistency between component (C) and the composition. Without being bound or limited to any particular theory, it is believed that the key to solving such problems is that the composition has the above-mentioned RI. To control the RI of the composition, the total content of aryl groups in components (A) and (B) is typically in the range of 10 to 40 weight percent, or optionally in the range of 15 to 30 weight percent, of the total weight of components (A) and (B).

[0065] The present composition will cure when left at room temperature or when heated, but to achieve rapid curing, it is preferable to heat the composition. The heating temperature is preferably in the range of 50 to 200°C.

[0066] When cured, the composition preferably forms a cured product having a Shore A hardness, as measured with a Shore A durometer, of 15 to 99, or optionally 30 to 95. This is because, if the hardness of the cured product of the curable silicone composition is at or above the lower limit of the above range, it will be strong and will be able to provide sufficient protection, while if the hardness is at or below the upper limit of the above range, the cured product will be flexible and will be able to provide sufficient durability.

[0067] The composition is preferably a curable silicone composition for sealing, coating, or adhering optical semiconductor elements. [Example]

[0068] The curable silicone composition of the present invention will be described in detail below using examples and comparative examples, but the present invention is not limited to the descriptions of the examples listed below.

[0069] [Refractive Index] The refractive index of the curable silicone composition at 25°C was measured using an Abbe refractometer manufactured by ATAGO at a wavelength of 589 nm and an atmospheric pressure of 1013 mbar in accordance with DIN 51423.

[0070] [viscosity] The viscosity of the curable silicone composition at 25±2° C. was measured according to ASTM D 1084 using a Brookfield cone and plate viscometer (Model HB DV III ULTRA) equipped with a cone spindle CPA-52Z.

[0071] [Film forming property] The curable silicone composition was coated onto a fluorine-coated PET film using a bar coater to a thickness of 300 μm. The composition was then cured at 150° C. for 2 minutes. The film-forming properties of the cured product were observed.

[0072] [Shore A hardness] The curable silicone composition is poured into an aluminum dish to a thickness of 1 cm and cured in an oven for 30 minutes at 150° C. The cured product is measured with a Shore A durometer.

[0073] [Printability] A cured film (sheet) is prepared by drawing a line on the surface of the cured film using a permanent marker.

[0074] [MQ migration issue] Liquid PSA is poured onto the cured film and cured in a film dryer at 150°C for 2 minutes. 30 minutes after the PSA has cured, a 180° peel test using glass is performed to check the adhesion. The adhesion is also checked under 85°C / 85%RH conditions. If the adhesion is different, MQ migration problems may be observed.

[0075] [Examples IE1-IE9 and Comparative Examples CE1-CE9] The curable silicone compositions of Examples IE1-IE9 and Comparative Examples CE1-CE9 were prepared by uniformly mixing the following components according to the formulations (parts by mass) shown in Table 1-3 below. In Table 1-3, "SiH / Vi" represents the total moles of silicon-bonded hydrogen atoms in component (B) per mole of all vinyl groups in component (A) in the curable silicone composition. Measurement results for the curable silicone compositions and their cured products are shown in Table 1-3. The compositions were prepared as follows:

[0076] A curable silicone composition was prepared by blending components (A), (B), (C), (D), (F), and (G) together in a 200 mL polyethylene cup. The mixture was mixed at 2000 rpm for 2 minutes. Finally, component (E) was added, and the composition was mixed at 2000 rpm for 2 minutes.

[0077] The following components were used as component (A): (a1) a branched organopolysiloxane having the following average unit formula: [(CH3)3SiO 1 / 2 ] 0.14 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.11 (CH3SiO 3 / 2 ) 0.53 (C6H5SiO 3 / 2 ) 0.22 and having a vinyl group content of about 3.47% by mass and a phenyl group content of about 19.8% by mass. (a2) Methylphenylpolysiloxane having the following formula: (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] 25 Si(CH3)2(CH=CH2) and having a vinyl group content of about 1.51% by mass and a phenyl group content of about 53.7% by mass. (a3) A copolymer of dimethylsiloxane and diphenylsiloxane having the following formula: (CH2=CH)(CH3)2SiO[(CH3)2SiO] 210 [(C6H5)2SiO] 51 Si(CH3)2(CH=CH2) and a copolymer of dimethylsiloxane and diphenylsiloxane, having a vinyl group content of about 0.21% by mass and a phenyl group content of about 30.4% by mass. (a4) Dimethylpolysiloxane having the following formula: (CH2=CH)(C6H5)(CH3)SiO[(CH3)3SiO] 12 Si(CH2=CH)(C6H5)(CH3) and having a vinyl group content of about 4.08% by mass and a phenyl group content of about 23.3% by mass. (a5) Dimethylpolysiloxane having the following formula: (CH2=CH)(CH3)2SiO[(CH3)2SiO] 160 Si(CH3)2(CH=CH2) and having a vinyl content of about 0.45% by weight.

[0078] The following components were used as component (B): (b1) a trisiloxane having the following formula: H(CH3)2SiO[(C6H5)2SiO]Si(CH3)2H and having a silicon-bonded hydrogen atom content of about 0.61% by weight and a phenyl group content of about 46.4% by weight. (b2) a branched organopolysiloxane having the following average unit formula: [H(CH3)2SiO 1 / 2 ]0.60 (C6H5SiO 3 / 2 ) 0.40 and having a silicon-bonded hydrogen atom content of about 0.66 wt. % and a phenyl group content of about 33.5 wt. %. (b3) A copolymer of dimethylsiloxane and methylhydrogensiloxane, having the following average formula: (CH3)3SiO[(CH3)2SiO] 3.4 [H(CH3)SiO] 6.2 Si(CH3)3 and having a silicon-bonded hydrogen atom content of about 0.79% by weight.

[0079] The following components were used as component (C): (c1) BET specific surface area 230m 2 / g of fumed silica (REOLOSIL DM-30S from TOKUYAMA Corporation).

[0080] The following component was used as component (D): (d1) Polyether-modified organopolysiloxane (DOWSIL™ 57 additive manufactured by Dow Chemical Company) (d2)C 11~15 Secondary alkyl polyoxyethylene ether (TERGITOL™ 15-S-9 surfactant from Dow Chemical Company) (d3)C 11~15 Secondary alkyl polyoxyethylene ether (TERGITOL™ 15-S-3 surfactant from Dow Chemical Company) (d4) Perfluorooctane

[0081] The following components were used as component (E): (e1) Platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of 11% by mass of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane and isopropanol solution

[0082] The following component was used as component (F): (f1) Bis(methoxymethyl)ethyl maleate (f2) Methyl-tris(1,1-dimethyl-2-propynyloxy)silane

[0083] The following component was used as component (G): (g1) Toluene

[0084] [Table 1]

[0085] The photograph of Example IE1 (FIG. 1) confirmed that the curable silicone composition had good film-forming properties and that the cured product did not suffer from shrinkage problems. The photograph of Comparative Example CE1 (FIG. 2) confirmed that aggregation of fumed silica was observed, indicating that the cured product had a poor appearance. The photograph of Comparative Example CE2 (FIG. 3) confirmed that the Bernard cell phenomenon, identified by circles, was observed, indicating that the cured product had a poor appearance. The photograph of Comparative Example CE2 (FIG. 4) confirmed that shrinkage of the cured product, identified by lines, was observed. The photograph on the right of Example IE1 (FIG. 7) confirmed that the cured product had good printability.

[0086] [Table 2]

[0087] [Table 3]

[0088] The photograph of Comparative Example CE4 (FIG. 5) confirmed that the fumed silica in the cured product, identified by circles and squares, was observed due to refractive index mismatch. The photograph of Comparative Example CE9 (FIG. 6) confirmed that shrinkage of the cured product, identified by lines, was observed. The left photograph of Comparative Example CE4 (FIG. 7) confirmed that the printability of the cured product was poor.

[0089] Industrial Applicability The curable silicone composition of the present invention exhibits good film-forming properties on fluorine films and cures to form a cured product that is transparent and suitable for printing, making it suitable for use as a sealant, coating agent, or adhesive for optical displays.

Claims

1. A curable silicone composition having a refractive index of 1.42 to 1.50 at 25°C as measured at a wavelength of 589 nm using an Abbe refractometer, said composition comprising: (A) an organopolysiloxane having at least one alkenyl group having an average of 2 to 12 carbon atoms and at least one aryl group having an average of 6 to 12 carbon atoms in the molecule; (B) an organohydrogenpolysiloxane having, on average, at least one silicon-bonded hydrogen atom and at least one aryl group having from 6 to 12 carbon atoms in the molecule, wherein the amount of silicon-bonded hydrogen atoms in this component is in the range of 0.1 to 10 moles per mole of said alkenyl group in component (A); (C) a silica filler in the range of 0.1 to 5% by weight of the total weight of the composition; (D) a surfactant selected from polyether-modified organopolysiloxanes and silicon-free polyethers in an amount ranging from 0.01 to 5% by weight based on the total weight of the composition; (E) a catalytic amount of a hydrosilylation reaction catalyst.

2. 2. The curable silicone composition according to claim 1, wherein the aryl group content in components (A) and (B) is in the range of 10 to 40 mass %, based on the total mass of components (A) and (B).

3. Component (C) is at least 50 m ２ 10. The curable silicone composition of claim 1, wherein the filler is a fumed or precipitated silica filler having a BET surface area of ​​1000 nm / g.

4. 2. The curable silicone composition according to claim 1, wherein the polyether-modified organopolysiloxane of component (D) is an organopolysiloxane having at least one polyether residue grafted into the molecule.

5. 2. The curable silicone composition according to claim 1, further comprising (F) a hydrosilylation reaction inhibitor in an amount ranging from 0.01 to 3% by weight, based on the total weight of the composition.

6. 2. The curable silicone composition according to claim 1, further comprising (G) an organic solvent in an amount of 0.01 to 3% by weight, based on the total weight of the composition.

7. The curable silicone composition according to any one of claims 1 to 6, which is a composition for sealing, coating, or adhering optical elements.

8. A display device comprising ultra-thin glass (UTG), a transparent silicone adhesive (Si-OCA), and a silicone film, wherein the silicone film is produced by curing the curable silicone composition of any one of claims 1 to 6.

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