Curable silicone composition

Abstract

The present disclosure provides a curable silicone composition having a refractive index of 1.42 to 1.50 measured by an Abbe refractometer at a wavelength of 589 nm at 25 DEG C, the composition comprising: (A) an organopolysiloxane having on average in a molecule at least one alkenyl group bearing 2 to 12 carbon atoms and at least one aryl group bearing 6 to 12 carbon atoms; (B) an organohydrogenpolysiloxane having on average in the molecule at least one silicon-bonded hydrogen atom and at least one aryl group bearing 6 to 12 carbon atoms; (C) fumed silica; (D) a surfactant selected from the group consisting of polyether-modified organopolysiloxanes and silicon-free polyethers; and (E) a hydrosilylation reaction catalyst. The composition has good film-forming properties on a fluorine film, and is cured to form a cured product having transparency and printability, and is capable of preventing a component such as an MQ resin from migrating from Si-OCA to the cured product even if the cured product is in contact with Si-OCA.

Description

[0001] Cross - reference to related applications

[0002] This patent application claims the priority and all advantages of U.S. Provisional Patent Application No. 63 / 435,631, filed on December 28, 2022, the content of which is incorporated herein by reference. Technical field

[0003] The present invention relates to a curable silicone composition. Background art

[0004] The optical display of a foldable mobile phone is generally composed of ultra - thin glass (UTG), a transparent silicone adhesive (Si - OCA), and thermoplastic polyurethane (TPU), where Si - OCA is used to improve the visibility of the optical display. However, TPU has problems such as water absorption and susceptibility to ultraviolet (UV) light irradiation. The water - absorbing TPU is mechanically weakened, and the TPU exposed to UV turns yellow.

[0005] Recently, silicone - based materials are considered to replace TPU. Curable silicone compositions can be used for silicone - based materials. For example, Patent Document 1 discloses a curable silicone composition for an optical device, which contains: a first siloxane compound having a polyether residue, a second siloxane compound having 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, which contains: a first siloxane compound having a silicon - bonded alkenyl group at its terminal, a second siloxane compound having silicon - bonded hydrogen at its terminal, a hydrophilic polyoxyalkylene compound in an amount of 0.05 wt% to 3 wt% based on the total weight of the first siloxane compound and the second siloxane compound, and a hydrosilylation reaction catalyst; and Patent Documents 3 and 4 disclose a curable silicone composition, which contains: 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 reaction catalyst.

[0006] The silicone - based materials are required to have transparency, printability, and film - forming characteristics on a fluorine film. However, the silicone - based materials have the following problems: their adhesion characteristics tend to decrease due to the migration of components such as MQ resin from Si - OCA to the silicone - based materials.

[0007] Prior art documents

[0008] Patent Document

[0009] Patent Document 1: US Patent Application Publication No. 2015 / 0353688 A1

[0010] Patent Document 2: International Patent Application Publication No. WO 2016 / 006773 A1

[0011] Patent Document 3: US Patent Application Publication No. 2020 / 0385579 A1

[0012] Patent Document 4: US Patent Application Publication No. 2020 / 0385580 A1 Summary of the Invention

[0013] Technical Problem

[0014] An object of the present invention is to provide a curable silicone composition which has good film-forming properties on a fluorine film, cures to form a cured product having transparency and printability, and can prevent components such as MQ resin from migrating from Si - OCA to the cured product even when the cured product is in contact with Si - OCA.

[0015] Solution to the Problem

[0016] The curable silicone composition of the present invention has a refractive index measured at a wavelength of 589 nm by an Abbe refractometer at 25°C in the range of 1.42 to 1.50, and the composition comprises:

[0017] (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 in its molecule;

[0018] (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 in its molecule, the amount of the organohydrogenpolysiloxane being such that relative to one mole of alkenyl groups in component (A),

[0019] the silicon - bonded hydrogen atoms in this component are in the range of 0.1 mole to 10 moles;

[0020] (C) a silica filler in the range of 0.1% by mass to 5% by mass of the total mass of the composition;

[0021] (D) a surfactant selected from polyether - modified organopolysiloxanes and silicon - free polyethers in the range of 0.01% by mass to 5% by mass of the total mass of the composition;

[0022] and

[0023] (E) A catalytic amount of a hydrosilylation catalyst.

[0024] In various embodiments, the content of the aryl group in components (A) and (B) is in the range of 10% by mass to 40% by mass of the total mass of components (A) and (B).

[0025] In various embodiments, component (C) is a gas-phase or precipitated silica filler having a BET surface area of at least 50 m 2 / g.

[0026] In various embodiments, the polyether-modified organopolysiloxane for component (D) is an organopolysiloxane grafted with at least one polyether residue in the molecule.

[0027] In various embodiments, the composition further comprises: (F) a hydrosilylation inhibitor in the range of 0.01% by mass to 3% by mass of the total mass of the composition.

[0028] In various embodiments, the composition further comprises: (G) an organic solvent in the range of 0.01% by mass to 3% by mass of the total mass of the composition.

[0029] In various embodiments, the composition is a composition for sealing, coating, or adhering optical elements.

[0030] The display device of the present invention includes: 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 described above.

[0031] Inventive Effect

[0032] The curable silicone composition of the present invention has good film-forming properties on a fluorine film, and cures to form a cured product having transparency and printability, and even when the cured product is in contact with Si-OCA, it can prevent components such as MQ resin from migrating from Si-OCA to the cured product. Description of the Drawings

[0033] Figure 1 is a photograph of the cured product in Example IE1.

[0034] Figure 2 is a photograph of the cured product in Comparative Example CE1, in which aggregation of fumed silica is observed.

[0035] Figure 3 is a photograph of the cured product in Comparative Example CE2 or CE7, in which Benard cells phenomenon is observed.

[0036] Figure 4It is a photograph of the cured product in Comparative Example CE2, in which shrinkage was observed.

[0037] Figure 5 It is a photograph of the cured product in Comparative Example CE4 or CE6, in which fumed silica was observed due to refractive index mismatch.

[0038] Figure 6 It is a photograph of the cured product in Comparative Example CE9, in which shrinkage was observed.

[0039] Figure 7 It is a photograph of the printability test in Example IE1 (right figure) and Comparative Example CE4 (left figure).

[0040] Definitions

[0041] The terms "comprising" or "containing" are used herein in their broadest sense, meaning and encompassing the concepts of "including", "consisting essentially of", and "consisting of". The use of "for example", "for instance", "such as", and "including" to list exemplary examples does not mean being limited to the listed examples. 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" is used to reasonably cover or describe minor variations in a numerical value measured by instrumental analysis or as a result of sample handling. Such minor variations can be about ±0 - 25%, ±0 - 10%, ±0 - 5%, or ±0 - 2.5% of the numerical value. Additionally, the term "about" applies to both numerical values when associated with a range of values. Further, the term "about" applies to a numerical value even when not explicitly stated.

[0042] It should be understood that the appended claims are not limited to the specific and particular compounds, compositions, or methods described in the specific embodiments, which may vary between 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, special, and / or unexpected results can be obtained from each member of the corresponding Markush group independent of all other Markush members. Each member of the Markush group can be relied upon individually and / or in combination and provides sufficient support for specific embodiments within the scope of the appended claims.

[0043] It should also be understood that any ranges and sub-ranges relied upon in describing various embodiments of the present invention independently and collectively fall within the scope of the appended claims, and it should be understood that all ranges described and contemplated include all integral and / or fractional values therewithin, even if such values are not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and sub-ranges fully describe and enable the various embodiments of the present invention, and such ranges and sub-ranges can be further delineated into related one-half, one-third, one-fourth, one-fifth, etc. By way of example only, the range of "0.1 to 0.9" can be further delineated into the lower one-third (i.e., 0.1 to 0.3), the middle one-third (i.e., 0.4 to 0.6), and the upper one-third (i.e., 0.7 to 0.9), which independently and collectively fall within the scope of the appended claims and can be individually and / or collectively relied upon and provide adequate support for specific embodiments within the scope of the appended claims. Additionally, with respect to language that defines or modifies a range such as "at least," "greater than," "less than," and "not exceeding," it should be understood that such language includes sub-ranges and / or upper or lower limits. As another example, the range of "at least 10" inherently includes sub-ranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., and each sub-range can be individually and / or collectively relied upon and provide adequate support for specific embodiments within the scope of the appended claims. Finally, the individual numbers within the disclosed ranges can be relied upon and provide adequate support for specific embodiments within the scope of the appended claims. For example, the range of "1 to 9" includes each individual integer such as 3, as well as individual numbers including a decimal point (or fraction) such as 4.1, which can be relied upon and provide adequate support for specific embodiments within the scope of the appended claims. Detailed Description of the Invention

[0044] The curable organosilicon composition of the present invention will be described in detail.

[0045] Component (A) is the matrix compound of the composition of the present invention and is 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 in the molecule. Examples of the alkenyl group include vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, and dodecenyl group, among which the vinyl group is preferred. Examples of the aryl group include phenyl group, tolyl group, xylyl group, and naphthyl group, among which the phenyl group is preferred. In addition, examples of the group bonded to the silicon atom other than the alkenyl group and the aryl group in component (A) include alkyl groups having 1 to 12 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group; and groups in which some or all of the hydrogen atoms in the alkyl group are substituted by halogen atoms such as fluorine atom, chlorine atom, or bromine atom. In addition, the silicon atom in component (A) may also have a small amount of hydroxyl groups or alkoxy groups, such as methoxy group or ethoxy group, within the range that does not impair the object of the present invention.

[0046] Examples of the molecular structure of component (A) include linear structure, partially branched linear structure, branched structure, and three-dimensional network structure. Component (A) may be a type of organopolysiloxane having these molecular structures, or may be a mixture of two or more types of organopolysiloxanes having these molecular structures.

[0047] The branched organopolysiloxane for component (A) is generally represented by the following average unit formula:

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

[0049] 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 its examples include the same groups as described above. However, at least one R 1 in the molecule is an alkenyl group, preferably a vinyl group.

[0050] 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 in the molecule 2 is an aryl group, preferably a phenyl group.

[0051] 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, if "a", "b", "c" and "d" are numbers within the above ranges, the cured product obtained by curing the composition of the present invention will have appropriate hardness and mechanical strength.

[0052] The linear organopolysiloxane for component (A) is usually represented by the following general formula:

[0053] R 3 3SiO(R 3 2SiO) m SiR 3 3

[0054] 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 same groups as R 1 described above. However, at least two Rs in the molecule 3 are alkenyl groups and at least one R in the molecule 3 is an aryl group, or optionally at least two Rs in the molecule 3 are vinyl groups and at least one R in the molecule 3 is a phenyl group.

[0055] In the above formula, "m" is an integer from 10 to 1,000, or optionally an integer from 10 to 500.

[0056] The viscosity of the linear organopolysiloxane at 25 °C is not limited, but it is usually not more than 100,000 mPa·s, optionally not more than 50,000 mPa·s, or optionally not more than 20,000 mPa·s. It should be noted that in this specification, the viscosity is the value measured using a B-type viscometer according to ASTM D 1084 at 23 °C ± 2 °C.

[0057] The linear organopolysiloxane for component (A) is usually at least one selected from the organopolysiloxanes represented by the following formulas:

[0058] (CH2=CH)(CH3)2SiO[(C6H5)2SiO] m Si(CH3)2(CH=CH2)

[0059] (CH2=CH)(CH3)2SiO[(C6H5)2SiO] m1 [(CH3)2SiO] m2 Si(CH3)2(CH=CH2)

[0060] (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] m1 [(CH3)2SiO] m2 Si(CH3)2(CH=CH2)

[0061] (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] m Si(CH3)2(CH=CH2)

[0062] (CH2=CH)(CH3)(C6H5)SiO[(C6H5)(CH3)SiO] m1 [(CH3)2SiO] m2 Si(CH3)(C6H5)2(CH=CH2)

[0063] In the above formulas, "m" is as described above, and "m1" and "m2" are integers satisfying the following conditions: 10 ≤ (m1 + m2) ≤ 1,000, or optionally 10 ≤ (m1 + m2) ≤ 500.

[0064] The amount of component (A) is not limited, but based on the total mass of components (A) to (C) respectively, this component is usually used in an amount of 60% to 90% by mass, optionally in an amount of 65% to 90% by mass, or optionally in an amount of 70% to 90% by mass. This is because if the amount is equal to or higher than the lower limit of the above range, the cured product obtained by curing the composition of the present invention will have appropriate hardness and mechanical strength, and if the amount is equal to or lower than the upper limit of the above range, the composition will have a suitable viscosity at 25°C.

[0065] Component (B) is an organosiloxane having on average at least one silicon-bonded hydrogen atom and at least one aryl group having 6 to 12 carbon atoms in the molecule, and is used as a crosslinking agent for the composition. Examples of the aryl group include the same groups as described above, and a phenyl group is preferred. Examples of the groups bonded to the silicon atom and the aryl group other than the hydrogen atom include alkyl groups having 1 to 12 carbon atoms, such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group; and groups in which some or all of the hydrogen atoms in these alkyl groups are substituted with halogen atoms such as fluorine atom, chlorine atom, or bromine atom. In addition, the silicon atom in component (B) may also have a small amount of hydroxyl groups or alkoxy groups such as methoxy group or ethoxy group within the range not impairing the object of the present invention.

[0066] The viscosity of component (B) at 25 °C is not limited, but is usually not more than 1,000 mPa·s, optionally not more than 500 mPa·s, or optionally not more than 100 mPa·s. It should be noted that in this specification, the viscosity is the value measured at 23 °C ± 2 °C using a B-type viscometer according to ASTM D 1084.

[0067] Examples of the molecular structure of component (B) include linear, partially branched linear, branched, cyclic, and three-dimensional network structures.

[0068] The linear organosiloxane for component (B) is usually represented by the following general formula:

[0069] HR 4 2SiO(R 4 2SiO) n SiR 4 2H.

[0070] 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, and examples thereof include the same groups as R 2 described above. However, at least one R 4 is an aryl group, usually a phenyl group.

[0071] In this 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 0 or 1.

[0072] The linear organosiloxane for component (B) is usually at least one selected from organosiloxane oligomers represented by the following formula:

[0073] H(CH3)2SiO(C6H5)2SiOSi(CH3)2H

[0074] H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H

[0075] The branched organosiloxane for component (B) is generally represented by the following average unit formula:

[0076] (R 4 2HSiO 1 / 2 ) e (R 4 SiO 3 / 2 ) f

[0077] In the above formula, each R 4 is an alkyl group or an aryl group, and examples thereof include the same groups as those described above. However, at least one R 4 is an aryl group, usually a phenyl group.

[0078] In the above formula, "e" and "f" are numbers that satisfy the following conditions:

[0079] e > 0, f > 0, and e + f = 1.

[0080] The branched organosiloxane for component (B) is generally represented by the following average unit formula:

[0081] [(CH3)2HSiO 1 / 2 e [C6H5SiO 3 / 2 f

[0082] where "e" and "f" are as described above.

[0083] The amount of component (B) used is such that the hydrogen atoms bonded to silicon in component (B) are each in the range of 0.1 mole to 10 moles, optionally in the range of 0.5 mole to 1.5 moles, or optionally in the range of 0.8 mole to 1.5 moles, relative to one (1) mole of alkenyl groups in component (A). This is because if the molar ratio is equal to or higher than the lower limit of the above range, the composition can be sufficiently cured, and the cured product obtained by curing the composition of the present invention will have appropriate hardness and mechanical strength, while if the molar ratio is equal to or lower than the upper limit of the above range, the cured product has good thermal stability.

[0084] Component (C) is a silica filler, and because it prevents the composition from shrinking during curing, it improves the film-forming properties on the fluorine film. In addition, it can simultaneously increase the strength of the cured product. Component (C) generally has a BET surface area of at least 50 m​​2 / g, optionally 80 m 2 / g to 400 m 2 / g or optionally 100 m 2 / g to 400 m 2 / g of fumed or precipitated silica filler. The surface of the silica filler may be untreated or treated with treating agents (such as organochlorosilanes, organoalkoxysilanes, organosilazanes, and organosiloxane oligomers).

[0085] The silica filler for component (C) is commercially available. Examples of the silica filler include fumed silica under the trade name AEROSIL TM such as AEROSIL TM R8200, R9200, R812, R812S, R972, R974, R805, R202 from Degussa Corporation; fumed silica under the trade name CAB-O-SIL TM ND-TS, TS610 or TS710 from Cabot Corporation; and fumed silica under the trade name REOLOSIL TM such as DM-10, DM-20S, DM-30, HM-30S, MT-10, PM-20L, QS-10, QS-20A and QS-25C from Tokuyama Corporation.

[0086] The amount of component (C) is in the range of 0.1% by mass to 5% by mass, or preferably in the range of 0.3% by mass to 2% by mass, of the composition of the present invention. This is because if the amount is equal to or higher than the lower limit of the above range, the cured product obtained by curing the composition of the present invention has appropriate hardness and mechanical strength, while if the amount is equal to or lower than the upper limit of the above range, the composition of the present invention has good transparency.

[0087] Component (D) is a surfactant selected from polyether-modified organopolysiloxanes and silicon-free polyethers, and improves the film-forming properties of the composition on a fluorine film. During the coating and curing process of the composition, as the polymer chains aggregate, heat convection occurs, resulting in the Benard cell phenomenon. Therefore, the problem that the surface of the cured product becomes uneven occurs. This phenomenon can be solved by adding component (D), and this component helps to obtain a uniform film.

[0088] The polyether-modified organopolysiloxanes for component (D) are not limited, but are organopolysiloxanes having at least one polyether block or residue in the molecule. That is, the polyether-modified organopolysiloxanes are block copolymers of polyether blocks and organopolysiloxane blocks, or organopolysiloxanes grafted with at least one polyether residue in the molecule. Among them, organopolysiloxanes grafted with at least one polyether residue in the molecule are preferred. These polyether-modified organopolysiloxanes are commercially available under the trade names DOWSIL TM 57 Additive, DOWSIL TM 67 Additive, DOWSIL TM 500W Additive, DOWSIL TM 501W Additive and DOWSIL TM 502W Additive are commercially available from The Dow Chemical Company, Midland, Michigan.

[0089] Examples of the silicon-free polyethers for component (D) include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters. The silicon-free polyethers are commercially available. Examples of the silicon-free polyethers include 2,6,8-trimethyl-4-nonyl polyoxyethylene ether sold by The Dow Chemical Company, Midland, Michigan under the trade names TERGITOL TM TMN-6 and TERGITOL TM TMN-10, and secondary alkyl polyoxyethylene ethers sold under the trade names TERGITOL TM 15-S-3, TERGITOL TM 15-S-7, TERGITOL TM 15-S-9, TERGITOL TM 15-S-15, TERGITOL TM 15-S-30 and TERGITOL TM 15-S-40 sold C 11-15 secondary alkyl polyoxyethylene ethers.

[0090] The amount of component (D) is in the range of 0.01% to 5% by mass of the composition, or preferably in the range of 0.1% to 2% by mass. This is because when the content of component (D) is greater than or equal to the lower limit of the above range, because if the amount is equal to or higher than the lower limit of the above range, the cured product obtained by curing the composition of the present invention has appropriate hardness and mechanical strength, and if the amount is equal to or lower than the upper limit of the above range, the composition of the present invention has good transparency.

[0091] Component (E) is a hydrosilylation reaction catalyst for accelerating the curing of the composition of the present invention. 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 types thereof. In particular, platinum-based catalysts are preferred because they can significantly accelerate the curing of the composition of the present invention. Examples of component (E) include finely powdered platinum; platinum black; chloroplatinic acid, alcohol-modified chloroplatinic acid; chloroplatinic acid / diene complexes; platinum / olefin complexes; platinum / carbonyl complexes such as platinum bis(acetoacetate) and platinum bis(acetylacetone); chloroplatinic acid / vinylsiloxane complexes such as chloroplatinic acid / divinyltetramethyldisiloxane complex and chloroplatinic acid / tetravinyltetramethylcyclotetrasiloxane complex; platinum / vinylsiloxane complexes such as platinum / divinyltetramethyldisiloxane complex and platinum / tetravinyltetramethylcyclotetrasiloxane complex; complexes of chloroplatinic acid and acetylene alcohol; and mixtures of two or more types thereof. Specifically, platinum-vinylsiloxane complexes are preferred because they produce excellent acceleration effects.

[0092] Examples of the vinylsiloxane used in the platinum-vinylsiloxane complex include 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, vinylsiloxane oligomers in which some methyl groups of the vinylsiloxane are substituted with ethyl groups, phenyl groups, etc., and vinylsiloxane oligomers in which the vinyl groups of the vinylsiloxane are substituted with allyl groups, hexenyl groups, etc. Specifically, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is preferred because the resulting platinum-vinylsiloxane complex has good stability.

[0093] To improve the stability of the platinum-vinylsiloxane complex, it is preferred to dissolve these platinum-vinylsiloxane complexes in: vinylsiloxane oligomers 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 organosiloxane oligomers such as dimethylsiloxane oligomers, and particularly preferably, to dissolve these complexes in vinylsiloxane oligomers.

[0094] The amount of component (E) is not limited, but generally, the amount is such that the platinum atom content in component (E) is in the range of 0.01 ppm to 500 ppm, optionally in the range of 0.01 ppm to 100 ppm, or optionally in the range of 0.1 ppm to 50 ppm (in mass units) with respect to the composition of the present invention. This is because when the amount is greater than or equal to the lower limit of the above range, the curability of the obtained composition is good, and when the amount is less than or equal to the upper limit of the above range, the coloring of the obtained cured product is suppressed.

[0095] The composition of the present invention may contain (F) a hydrosilylation reaction inhibitor for extending the pot life at room temperature and improving the storage stability. Examples of component (F) include: alkynols such as 1-ethynylcyclohex-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; unsaturated carboxylic acid esters such as diallyl maleate, dimethyl maleate, diethyl fumarate, diallyl fumarate, and bis(2-methoxy-1-methylethyl) maleate, monooctyl maleate, monoisooctyl maleate, monoallyl maleate, monomethyl maleate, monoethyl fumarate, monoallyl fumarate, and 2-methoxy-1-methylethyl maleate; alkoxysilanes 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 types thereof. In particular, a mixture of an alkynol and an unsaturated carboxylic acid ester is preferred to prevent surface wrinkles from forming in the cured product.

[0096] The amount of component (F) is not limited, but generally it is in the range of 0.0001% by mass to 5% by mass of the composition, or optionally in the range of 0.005% by mass to 3% by mass.

[0097] In addition, the composition of the present invention may contain (G) a solvent in order to reduce its viscosity and improve the coating processability or wettability. Examples of component (G) include: hydrocarbon-based solvents, such as aromatic hydrocarbon-based solvents, such as toluene and xylene; aliphatic hydrocarbon-based solvents, such as hexane, heptane, octane, isooctane, decane, cyclohexane, methylcyclohexane, and isoparaffin; industrial gasoline (rubber solvents, etc.); petroleum benzene; and solvent naphtha; ketone-based solvents, such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, methyl isobutyl ketone, diisobutyl ketone, acetylacetone, and cyclohexanone; ester-based solvents, such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, and isobutyl acetate; ether-based solvents, such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl 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; silicone-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 types thereof.

[0098] The amount of component (G) is not limited, but it is generally an amount in the range of about 1% by mass to 10% by mass of the composition.

[0099] To improve the adhesion of the cured product to the substrate material contacted during curing, the compositions of the present invention may contain an adhesion promoter. In certain embodiments, the adhesion promoter is generally a silicone compound having at least one alkoxy group bonded to a silicon atom in the molecule. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group; and the methoxy group is the most typical. In addition, examples of the non-alkoxy groups bonded to the silicon atom of the silicone compound are: substituted or unsubstituted monovalent hydrocarbon groups such as an alkyl group, an alkenyl group, an aryl group, an aralkyl group, and a haloalkyl group; monovalent organic groups containing an epoxy group such as a 3-glycidoxypropyl group, a 4-glycidoxybutyl group, or a similar glycidoxyalkyl group; a 2-(3,4-epoxycyclohexyl)ethyl group, a 3-(3,4-epoxycyclohexyl)propyl group, or a similar epoxycycloalkyl group; and a 4-oxetanyl group, an 8-oxetanyloctyl group, or a similar oxetanyl group; monovalent organic groups containing an acrylic group such as a 3-methacryloxypropyl group; and a hydrogen atom. The silicone compound generally has a silicon-bonded alkenyl group or a silicon-bonded hydrogen atom. In addition, due to the ability to impart good adhesion to various types of substrate materials, the silicone compound generally has at least one monovalent organic group containing an epoxy group in the molecule. Examples of this type of silicone compound are silane compounds, silicone oligomers, and alkyl silicates. Examples of the molecular structures of the silicone oligomers or alkyl silicates are a linear structure, a partially branched linear structure, a branched structure, a cyclic structure, and a network structure. Linear structures, branched structures, and network structures are typical. Examples of this type of silicone compound are silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, etc.; silicone compounds having at least one silicon-bonded alkenyl group or a silicon-bonded hydrogen atom and at least one silicon-bonded alkoxy group in the molecule; mixtures of silane compounds or silicone compounds having at least one silicon-bonded alkoxy group and silicone 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 ethyl polysilicate containing an epoxy group.

[0100] The amount of the adhesion promoter is not particularly limited, but in order to achieve good adhesion to the substrate material contacted during curing, it is generally at most 10% by mass of the composition.

[0101] The refractive index (RI) at 25 °C of the composition of the present invention, measured by 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 if the RI of the composition of the present invention is lower than the lower limit of the above range, the composition can be well coated on the fluorine film without any problems; however, the cured product obtained by curing the composition has poor printability, and there is migration of MQ resin from the Si-OCA, so its adhesiveness tends to decrease. If the RI exceeds the upper limit of the above range, the composition can solve the problem of printability and prevent the decrease in adhesiveness to Si-OCA; however, the composition has poor film-forming properties and shrinkage may occur. These problems can be solved by adding component (C), however, there is a mismatch between component (C) and the composition. Without being bound or limited by any particular theory, to solve such problems, it is believed that the key point is that the composition of the present invention has the above RI. To control the RI of the composition, the content of the total aryl groups in components (A) and (B) is generally in the range of 10% by mass to 40% by mass of the total mass of components (A) and (B), or optionally in the range of 15% by mass to 30% by mass.

[0102] The composition of the present invention is cured by standing at room temperature or heating, but preferably, the composition is heated to achieve rapid curing. The heating temperature is preferably in the range of 50 °C to 200 °C.

[0103] The composition of the present invention preferably forms a cured product having a Shore A hardness of 15 to 99 or optionally 30 to 95 measured by a Shore A hardness tester at the time of curing. This is because when the hardness of the cured product of the curable silicone composition is greater than or equal to the lower limit of the above range, the cured product is strong and exhibits sufficient protection, and when the hardness is less than or equal to the upper limit of the above range, the cured product becomes flexible and has sufficient durability.

[0104] The composition of the present invention is preferably a curable silicone composition for sealing, coating or adhering optical semiconductor elements.

[0105] Examples

[0106] The curable silicone composition of the present invention will be described in detail below using working examples and comparative examples. However, the present invention is not limited by the description of the examples listed below.

[0107] [Refractive Index]

[0108] The refractive index of the curable silicone composition at 25 °C was measured at a wavelength of 589 nm under an atmospheric pressure of 1013 mbar using an Abbe refractometer manufactured by ATAGO Co., Ltd. according to standard DIN 51423.

[0109] [Viscosity]

[0110] The viscosity of the curable silicone composition at 25 °C ± 2 °C was measured according to ASTM D 1084 using a Brookfield cone and plate viscometer (model HB DVIII ULTRA) with a conical rotor CPA - 52Z.

[0111] [Film-Forming Property]

[0112] The curable silicone composition was coated on a fluorine - coated PET film by a bar coater so that the thickness of the composition was 300 μm. Then, the composition was cured at 150 °C for 2 minutes. The film - forming properties of the cured product were observed.

[0113] [Shore A Hardness]

[0114] The curable silicone composition was poured into an aluminum tray to a thickness of 1 cm and cured in an oven at 150 °C for 30 minutes. The cured product was measured with a Shore A durometer.

[0115] [Printability]

[0116] A cured film (sheet) was prepared. A line was drawn on the surface of the cured film using a permanent marker.

[0117] [MQ Migration Problem]

[0118] Liquid PSA was poured onto the cured film, and the PSA was cured at 150 °C for 2 minutes in a film dryer. After curing the PSA for 30 minutes, a 180° peel test with glass was performed to check the adhesion. The adhesion was also checked under 85 °C / 85% RH conditions in the same manner. When the adhesion was different, an MQ migration problem seemed to be observed.

[0119] [Examples IE1 - IE9 and Comparative Examples CE1 - CE9]

[0120] The following components were uniformly mixed according to the compositions (parts by mass) shown in Tables 1 to 3 below to prepare the curable silicone compositions of Examples IE1 - IE9 and Comparative Examples CE1 - CE9. In addition, in Tables 1 to 3, "SiH / Vi" represents the total number of moles of silicon-bonded hydrogen atoms in component (B) relative to 1 mole of the total vinyl groups in component (A) in the curable silicone composition. The measurement results of the curable silicone compositions and the cured products are shown in Tables 1 to 3. The compositions were prepared as follows.

[0121] The curable silicone composition was prepared by blending components (A), (B), (C), (D), (F), and (G) 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.

[0122] The following components were used as component (A).

[0123] (a1): A branched organopolysiloxane represented by the following average unit formula:

[0124] [(CH3)3SiO 1 / 2 0.14 [(CH2=CH)(CH3)2SiO 1 / 2 0.11 (CH3SiO 3 / 2 ) 0.53 (C6H5SiO 3 / 2 ) 0.22

[0125] Having a vinyl group content of about 3.47% by mass and a phenyl group content of about 19.8% by mass.

[0126] (a2): A methylphenylpolysiloxane represented by the following formula:

[0127] (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] 25 Si(CH3)2(CH=CH2)

[0128] And having a vinyl group content of about 1.51% by mass and a phenyl group content of about 53.7% by mass.

[0129] (a3): A copolymer of dimethylsiloxane and diphenylsiloxane represented by the following formula:

[0130] (CH2=CH)(CH3)2SiO[(CH3)2SiO] 210 [(C6H5)2SiO] 51 Si(CH3)2(CH=CH2)​​

[0131] and has a vinyl group content of about 0.21% by mass and a phenyl group content of about 30.4% by mass.

[0132] (a4): A dimethylpolysiloxane represented by the following formula:

[0133] (CH2=CH)(C6H5)(CH3)SiO[(CH3)3SiO] 12 Si(CH2=CH)(C6H5)(CH3)

[0134] and has a vinyl group content of about 4.08% by mass and a phenyl group content of about 23.3% by mass.

[0135] (a5): A dimethylpolysiloxane represented by the following formula:

[0136] (CH2=CH)(CH3)2SiO[(CH3)2SiO] 160 Si(CH3)2(CH=CH2)

[0137] and has a vinyl content of about 0.45% by mass.

[0138] The following components are used as component (B).

[0139] (b1): A trisiloxane represented by the following formula:

[0140] H(CH3)2SiO[(C6H5)2SiO]Si(CH3)2H

[0141] and has a silicon-bonded hydrogen atom content of about 0.61% by mass and about 46.4%

[0142] by mass of phenyl group content.

[0143] (b2): A branched organopolysiloxane represented by the following average unit formula:

[0144] [H(CH3)2SiO 1 / 2 0.60 (C6H5SiO 3 / 2 ) 0.40

[0145] has a silicon-bonded hydrogen atom content of about 0.66% by mass and a phenyl group content of about 33.5% by mass.

[0146] (b3): A copolymer of dimethylsiloxane and methylhydrosiloxane represented by the following average formula:

[0147] (CH3)3SiO[(CH3)2SiO] 3.4 ​[H(CH3)SiO] 6.2 Si(CH3)3

[0148] and has a hydrogen atom content bonded to silicon of about 0.79 mass %.

[0149] The following components are used as component (C).

[0150] (c1): Fumed silica with a BET specific surface area of 230 m 2 / g (REOLOSIL DM-30S from Tokuyama Corporation)

[0151] The following components are used as component (D).

[0152] (d1): Polyether-modified organopolysiloxane (DOWSIL TM 57 additive) from Dow Chemical Company

[0153] (d2): C 11-15 Secondary alkyl polyoxyethylene ether (TERGITOL TM 15-S-9 surfactant) from Dow Chemical Company

[0154] (d3): C 11-15 Secondary alkyl polyoxyethylene ether (TERGITOL TM 15-S-3 surfactant) from Dow Chemical Company

[0155] (d4): Perfluorooctane

[0156] The following components are used as component (E).

[0157] (e1): A solution of 11 mass % of a platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane and isopropyl alcohol

[0158] The following components are used as component (F).

[0159] (f1): Bis(methoxymethyl) ethyl maleate

[0160] (f2): Methyl-tris(1,1-dimethyl-2-propynyloxy)silane

[0161] The following components are used as component (G).

[0162] (g1): Toluene

[0163] [Table 1]

[0164]

[0165]

[0166] Based on the photograph of Example IE1 ( Figure 1 ), it was confirmed that the curable silicone composition has good film-forming properties and the cured product has no shrinkage problem. Based on the photograph of Comparative Example CE1 ( Figure 2 ), it was confirmed that due to the observed aggregation of fumed silica, the appearance of the cured product is poor. Based on the photograph of Comparative Example CE2 ( Figure 3 ), it was confirmed that due to the observed Benard cell phenomenon designated by the circle, the appearance of the cured product is poor. Based on the photograph of Comparative Example CE2 ( Figure 4 ), it was confirmed that shrinkage of the cured product designated by the line was observed. Based on the right photograph of Example IE1 ( Figure 7 ), it was confirmed that the cured product has good printability.

[0167] [Table 2]

[0168]

[0169]

[0170] [Table 3]

[0171]

[0172] Based on the photograph of Comparative Example CE4 ( Figure 5 ), it was confirmed that due to the refractive index mismatch, fumed silica in the cured product designated by the circle and square was observed. Based on the photograph of Comparative Example CE9 ( Figure 6 ), it was confirmed that shrinkage of the cured product designated by the line was observed. Based on the left photograph of Comparative Example CE4 ( Figure 7 ), it was confirmed that the cured product has poor printability.

[0173] Industrial Applicability

[0174] The curable silicone composition of the present invention has good film-forming properties on a fluorine film and cures to form a cured product having transparency and printability, and thus it is suitable as a sealant, a coating agent, or an adhesive for an optical display.

Claims

1. A curable silicone composition having a refractive index of 1.42 to 1.50 measured at a wavelength of 589 nm by an Abbe refractometer at 25°C, the composition comprising: (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 in the 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 in the molecule, the amount of the organohydrogenpolysiloxane being such that, relative to one mole of the alkenyl group in component (A), the silicon-bonded hydrogen atoms in this component are in the range of 0.1 mole to 10 moles; (C) a silica filler in the range of 0.1% by mass to 5% by mass of the total mass of the composition; (D) a surfactant selected from polyether-modified organopolysiloxanes and silicon-free polyethers in the range of 0.01% by mass to 5% by mass of the total mass of the composition; and (E) a catalytic amount of a hydrosilylation reaction catalyst.

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

3. The curable organosilicon composition according to claim 1, wherein component (C) is a fumed or precipitated silica filler having a BET surface area of at least 50 m 2 / g.

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

5. The curable silicone composition according to claim 1, the curable silicone composition further comprising: (F) a hydrosilylation reaction inhibitor in the range of 0.01% by mass to 3% by mass of the total mass of the composition.

6. The curable silicone composition according to claim 1, the curable silicone composition further comprising: (G) an organic solvent in the range of 0.01% by mass to 3% by mass of the total mass of the composition.

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

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

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