Hardening silicone composition and its hardening product

Abstract

The curable silicone composition contains (A) a diorganopolysiloxane having two alkenyl groups bonded to silicon atoms at both ends of the molecular chain, (B) an organopolysiloxane resin having an alkenyl group bonded to a silicon atom, (C) an organopolysiloxane essentially composed of (c1) a diorganopolysiloxane having a hydrogen atom bonded to a silicon atom at both ends of the molecular chain and (c2) an organopolysiloxane resin having a hydrogen atom bonded to a silicon atom, and (D) a hydrosilylation reaction catalyst. By curing the composition, a cured product can be formed that exhibits excellent adhesion properties to various base materials used in optical devices.

Description

Technical Field

[0001] The present invention relates to a curable silicone composition and a cured product thereof.

Background Art

[0002] Since a curable silicone composition can be cured to form a cured product having high transparency and high elongation, it is used as an adhesive or a pressure-sensitive adhesive for improving the visibility of an optical display.

[0003] For example, Patent Document 1 discloses a curable silicone composition containing at least one organopolysiloxane having at least two alkenyl groups in one molecule, at least one organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in one molecule, and a hydrosilylation reaction catalyst.

[0004] Further, Patent Document 2 discloses a curable silicone composition containing a linear or partially branched organopolysiloxane having an alkenyl group in one molecule, a resinous organopolysiloxane having an alkenyl group in one molecule, a linear or partially branched organohydrogenpolysiloxane having a silicon atom-bonded hydrogen atom at the molecular chain end, a resinous organohydrogenpolysiloxane having a silicon atom-bonded hydrogen atom in one molecule, and a hydrosilylation reaction catalyst.

[0005] However, these curable silicone compositions have a problem that they form a cured product having poor adhesion characteristics to various substrates used for optical displays.

Prior Art Documents

Patent Documents

[0006] Patent Document 1: US Patent Application Publication No. 2014 / 0150972 (A1) Patent Document 2: US Patent Application Publication No. 2022 / 0002493 (A1)

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a curable silicone composition capable of forming a cured product exhibiting excellent adhesion properties to various base materials used in optical displays, and further to provide a cured product exhibiting excellent adhesion properties.

Means for Solving the Problems

[0008] The curable silicone composition of the present invention comprises: (A) The following general formula: R 1 2R 2 SiO(R 1 2SiO) m SiR 1 2R 2 A diorganopolysiloxane represented by (In the formula, each R 1 is independently an alkyl group having 1 to 12 carbon atoms, each R 2 is independently an alkenyl group having 2 to 12 carbon atoms, and "m" is an integer of 100 to 1000), and (B) The following average unit formula: (R 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (SiO 4 / 2 ) c (HO 1 / 2 ) d A resinous organopolysiloxane represented by (In the formula, R 1 and R 2 are as described above, and "a", "b", "c", and "d" are numbers satisfying a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a + b + c = 1, and are in an amount of 1.0 to 5.0 parts by mass with respect to 100 parts by mass of component (A)), and (C) An organopolysiloxane having a silicon atom-bonded hydrogen atom, in an amount such that the molar ratio of the silicon atom-bonded hydrogen atom provided by component (C) to the alkenyl group provided by components (A) and (B) is in the range of 0.5 to 2, and (D) An effective amount of a hydrosilylation reaction catalyst, and Component (C) is the following component (c1) and component (c2): (c1) A diorganopolysiloxane having silicon atom-bonded hydrogen atoms at both ends of the molecular chain, and (c2) The following average unit formula: (R 1 3SiO 1 / 2 ) e (HR 1 2SiO 1 / 2 ) f (SiO 4 / 2 ) g (HO 1 / 2 ) h An organopolysiloxane resin represented by (wherein R 1 is as described above, and "e", "f", "g", and "h" are numbers satisfying e≥0, f>0, 0.3≤g≤0.7, 0≤h≤0.05, and e + f + g = 1), and The molar ratio of the silicon-bonded hydrogen atom provided by component (c1) to the silicon-bonded hydrogen atom provided by component (c2) is in the range of 10 to 60.

[0009] In various embodiments, the curable silicone composition may further contain (E) a hydrosilylation reaction inhibitor in an amount of about 0.00001 to about 0.5 parts by mass based on 100 parts by mass of the total mass of components (A) to (C).

[0010] The cured product of the present invention is obtained by curing the above curable silicone composition. [Advantages of the Invention]

[0011] By curing the curable silicone composition of the present invention, a cured product can be formed that exhibits excellent adhesion characteristics to various base materials used in optical devices. The cured product of the present invention exhibits excellent adhesion characteristics.

[0012] Definition The term "comprising" or "comprise" is used in the broadest sense in this specification and means "including", "include", "consist(ing) essentially of", and "consist(ing) of", encompassing those concepts. The use of "for example", "e.g.,", "such as", and "including" for listing examples is not limited to the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to", including other similar or equivalent examples. The term "about" as used in this specification serves to reasonably encompass or describe slight variations in numerical values measured by instrumental analysis or as a result of handling samples. Such slight variations can be on the order of ±0 to 25, ±0 to 10, ±0 to 5, or ±0 to 2.5% of the numerical value. Further, the term "about" applies to both numerical values when related to a range of values. Moreover, the term "about" may apply to numerical values even when not explicitly stated.

[0013] Generally, as used herein, a hyphen "-" or a tilde "~" in a range of values means "to" or "through", ">" means "above" or "greater-than", "≧" means "at least" or "greater-than or equal to", "<" means "below" or "less-than", and "≦" means "at most" or "less-than or equal to". Each of the aforementioned patent applications, patents, and / or patent publications is hereby expressly incorporated by reference in its entirety into this specification, on an individual basis, for reference in one or more non-limiting embodiments.

Best Mode for Carrying Out the Invention

[0014] <Curable silicone composition> First, the curable silicone composition of the present invention will be described in detail.

[0015] <Component (A)> Component (A) is a diorganopolysiloxane represented by the following general formula: R 1 2R 2 SiO(R 1 2SiO) m SiR 1 2R 2 is a diorganopolysiloxane represented by the formula.

[0016] In the above formula, each R 1 is, independently, an alkyl group having 1 to 12 carbon atoms. Examples of alkyl groups include methyl group, ethyl group, propyl group, butyl group, and octyl group, among which the methyl group is preferred.

[0017] In the above formula, each R 2is, independently, an alkenyl group having 2 to 12 carbon atoms. Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, and a dodecenyl group, among which the vinyl group is preferred.

[0018] In the above formula, "m" is an integer from 100 to 1000, or an integer from 100 to 800. This is because when "m" is equal to or greater than the lower limit of the above range, the mechanical properties of the obtained cured product are sufficient, while when "m" is equal to or less than the upper limit of the above range, the obtained composition has a viscosity suitable for processing and handling.

[0019] The viscosity of component (A) at 25 °C is not limited, but typically it is in the range of about 100 mPa·s to about 100,000 mPa·s, or in the range of about 200 mPa·s to about 50,000 mPa·s, or in the range of about 300 mPa·s to about 50,000 mPa·s. It should be noted that in this specification, the viscosity is the value measured at 23 ± 2 °C using a B-type viscometer in accordance with ASTM D1084.

[0020] Component (B) is an organopolysiloxane resin represented by the following average unit formula: (R 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (SiO 4 / 2 ) c (HO 1 / 2 ) d

[0021] In the above formula, R 1 and R 2 are as described above. Examples thereof include the same groups as those described above.

[0022] ​In the above formula, "a", "b", "c", and "d" are such that a ≥ 0, b > 0, 0.3 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1. Optionally, 0.1 ≤ a ≤ 0.5, 0.01 ≤ b ≤ 0.2, 0.4 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1, or optionally, 0.2 ≤ a ≤ 0.5, 0.01 ≤ b ≤ 0.2, 0.4 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1. These are numbers that satisfy the given conditions because if "a", "b", "c", and "d" are within the above ranges, the cured product obtained by curing this composition has appropriate hardness and mechanical strength.

[0023] The amount of component (B) is in the range of 1.0 to 5.0 parts by mass, or in the range of 1.0 to 3.0 parts by mass with respect to 100 parts by mass of component (A). This is because when the amount is equal to or greater than the lower limit of the above range, the mechanical properties of the obtained cured product are sufficient, while when the amount is equal to or less than the upper limit of the above range, the obtained composition has a viscosity suitable for processing and handling.

[0024] <Component (C)> Component (C) is a crosslinking agent for components (A) and (B) in this composition, has a silicon atom-bonded hydrogen atom, and consists of the following components (c1) and (c2): (c1) A diorganopolysiloxane having silicon atom-bonded hydrogen atoms at both ends of the molecular chain, and (c2) The following average unit formula: (R 1 3SiO 1 / 2 ) e (HR 1 2SiO 1 / 2 ) f (SiO 4 / 2 ) g (HO 1 / 2 ) h An organopolysiloxane resin represented by (wherein R 1 is as described above, and "e", "f", "g", and "h" are numbers that satisfy e ≥ 0, f > 0, 0.3 ≤ g ≤ 0.7, 0 ≤ h ≤ 0.05, and e + f + g = 1), and is an organopolysiloxane consisting essentially of these.

[0025] Component (c1) functions as a chain extender in the hydrosilylation reaction with components (A) and (B), improving the flexibility of the cured product. Examples of groups bonded to silicon atoms other than hydrogen atoms in component (c1) include alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, tolyl group, xylyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group; and halogen-substituted alkyl groups having 1 to 12 carbon atoms such as 3-chloropropyl group, 3,3,3-trifluoropropyl group. From the viewpoints of economy and heat resistance, the methyl group is preferred.

[0026] Examples of such component (c1) include dimethylpolysiloxane with dimethylhydrogensiloxy groups protecting both ends of the molecular chain, a copolymer of dimethylsiloxane and methylphenylsiloxane with dimethylhydrogensiloxy groups protecting both ends of the molecular chain, and mixtures of two or more of these types.

[0027] Component (c2) functions as a crosslinking agent in the hydrosilylation reaction with components (A) and (B), improving the mechanical properties of the cured product.

[0028] In the formula of component (c2), each R 1 is independently an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group are as described above. Among them, from the viewpoints of economy and heat resistance, the methyl group is preferred.

[0029] In the formula of component (c2), "e", "f", "g", and "h" are numbers satisfying the conditions: e≧0, f>0, 0.3≦g≦0.7, 0≦h≦0.05, and e + f + g = 1. Optionally, 0≦e≦0.3, 0.1≦f≦0.7, 0.3≦g≦0.6, 0≦h≦0.05, and e + f + g = 1. Or optionally, 0≦e≦0.1, 0.3≦f≦0.7, 0.3≦g≦0.6, 0≦h≦0.01, and e + f + g = 1. This is because if "e", "f", "g", and "h" are numbers within the above ranges, the cured product obtained by curing this composition has appropriate hardness and mechanical strength.

[0030] The molar ratio of the silicon-bonded hydrogen atoms provided by component (c1) to the silicon-bonded hydrogen atoms provided by component (c2) is in the range of 10 to 60. This is because when the molar ratio is equal to or greater than the lower limit of the above range, the elastic modulus of the obtained cured product is sufficient. On the other hand, when the molar ratio is equal to or less than the upper limit of the above range, the mechanical properties of the obtained cured product are sufficient.

[0031] The amount of component (C) is such that the molar ratio of the silicon-bonded hydrogen atoms provided by component (C) to the alkenyl groups provided by components (A) and (B) is in the range of 0.5 to 2, or in the range of 0.8 to 2, or in the range of 0.5 to 1.5. This is to ensure sufficient curing of the obtained composition when the amount is equal to or greater than the lower limit of the above range. However, when it is equal to or less than the upper limit of the above range, the mechanical properties of the obtained cured product are improved.

[0032] <Component (D)> Component (D) is a hydrosilylation reaction catalyst for promoting the curing of this composition. Examples thereof include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts, and platinum-based catalysts are preferred. Examples of platinum-based catalysts include platinum fine powder, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, an alcohol solution of chloroplatinic acid, an olefin complex of platinum, and an alkenylsiloxane complex of platinum.

[0033] The amount of component (D) is an effective amount that promotes the curing of the present composition. Specifically, for the present composition, the amount of platinum atoms in the catalyst is in the range of about 0.1 to about 1000 ppm, or about 1 to about 500 ppm, in terms of mass unit. This is because when the content of component (D) is equal to or higher than the lower limit of the above range, the curing of the obtained composition proceeds, while when the content is equal to or lower than the upper limit of the above range, the obtained cured product is less likely to discolor.

[0034] <Component (E)> The present composition may also contain (E) a hydrosilylation reaction inhibitor in order to control its crosslinking reaction. Examples of component (E) include alkynyl 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; enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne, methylalkenylsiloxane oligomers such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, alkynyloxy silanes such as dimethylbis(3-methyl-1-butyn-3-oxy)silane, and methylvinylbis(3-methyl-1-butyn-3-oxy)silane; alkynyloxy silane compounds such as methyltris(1-methyl-1-phenyl-propynyloxy)silane, dimethylbis(1-methyl-1-phenyl-propynyloxy)silane, methyltris(1,1-dimethyl-propynyloxy)silane, and dimethylbis(1,1-dimethyl-propynyloxy)silane; triazole, phosphine, mercaptan, hydrazine, sulfoxide, phosphate, nitrile, hydroperoxide, amine, ethylenically unsaturated isocyanate, fumarate (e.g., dialkyl fumarate, diallyl fumarate, and / or dialkoxyalkyl fumarate), maleate (e.g., diallyl maleate), alkene, and combinations thereof.

[0035] The amount of component (E) is not limited, but from the viewpoint of imparting sufficient pot life to the composition, it is typically in the range of about 0.00001 to about 0.5 parts by mass, or about 0.0001 to about 0.5 parts by mass, or alternatively about 0.0001 to about 0.1 parts by mass, based on 100 parts by mass of the total mass of components (A) to (C). This is because when the amount of component (E) is equal to or greater than the lower limit of the above range, the pot life of the composition becomes sufficient for use, and when it is equal to or less than the upper limit of the above range, the curability of the composition becomes good for use.

[0036] <Other components> The composition may contain an adhesion promoter, an antioxidant, a reactive diluent, a leveling agent, a filler, an antistatic agent, a defoaming agent, a pigment, etc., as long as the object of the present invention is not impaired.

[0037] <Cured product> Next, the cured product of the present invention will be described in detail.

[0038] The cured product can be obtained by curing the above-described curable silicone composition. The hardness of the cured product is not limited, but typically has a quarter-cone penetration of 20 to 90 when measured using a penetrometer defined in ASTM D1403. This is because when the penetration is equal to or greater than the lower limit of the above range, the cured product can have good peel strength, while when the penetration is equal to or less than the upper limit of the above range, the cured product can have good mechanical properties.

[0039] The shape of the cured product is not limited, and examples thereof include a sheet, a film, a tape, and a mass. Furthermore, integration with various types of substrates is also possible.

Examples

[0040] The curable silicone composition and the cured product of the present invention will be described in more detail below using Examples and Comparative Examples. The present invention is not limited to the following Examples. In the formulas, Me and Vi represent a methyl group and a vinyl group, respectively. The viscosity of the organopolysiloxane was measured as follows.

[0041] <Viscosity> The viscosity at 23 ± 2°C was measured by using a B-type viscometer (Brookfield HADVIII Type rotational viscometer, using RV-03 at 60 rpm for 2 minutes) in accordance with ASTM D 1084, "Standard Test Methods for Viscosity of Adhesive".

[0042] <Penetration> A curable silicone composition with a thickness of 10 mm or more was left to cure in an aluminum dish at 120°C for 40 minutes, and the 1 / 4 cone penetration at 25°C was measured using an Anton Paar penetrometer PNR 12 manufactured by Anton Paar GmbH.

[0043] <180-degree peel strength> A curable silicone composition with a thickness of 1 mm and a width of 25 mm was left to cure between a glass plate and a PET film at 60°C for 30 minutes, and then post-cured at 25°C for 3 days. The 180-degree peel strength was measured at a peel rate of 305 mm / min.

[0044] <Cohesive failure> Cohesive failure of the cured product with respect to the glass plate and the PET film after measuring the 180-degree peel strength.

[0045] <Haze and transmittance> A curable silicone composition with a thickness of 1 mm was left to cure on a glass plate at 70°C for 40 minutes, and then post-cured at 25°C for 3 days. The haze and transmittance of the cured product at 25°C were measured using a spectrophotometer CM-5 manufactured by Konica Minoluta.

[0046] <Haze and transmittance after high-temperature and high-humidity test> The cured product on the glass plate was subjected to the condition of 85°C / 85%RH for 3 days and then cooled. The haze and transmittance of the cured product at 25°C after the high-temperature and high-humidity test were measured using a spectrophotometer CM-5 manufactured by Konica Minoluta.

[0047] <Examples 1 to 6 and Comparative Examples 1 to 3> Using the components described below, curable silicone compositions shown in Table 1 were prepared. First, components (A), (B), and (D) were uniformly mixed. Next, components (C) and (E) were added to produce curable silicone compositions. The obtained cured products were evaluated as described above. These results are shown in Table 1. The "SiH / Vi ratio" in Table 1 indicates the molar ratio of silicon atom-bonded hydrogen atoms provided by component (C) to vinyl groups provided by components (A) and (B). The "SiH ratio" in Table 1 indicates the molar ratio of silicon atom-bonded hydrogen atoms provided by component (c1) to silicon atom-bonded hydrogen atoms provided by component (c2).

[0048] The following components were used as component (A). Component (a-1): A vinyl group content of 0.21% by mass and a viscosity of 2400 mPa·s, having the following formula: ViMe2SiO(Me2SiO) 290 SiMe2Vi Dimethylpolysiloxane represented by Component (a-2): A vinyl group content of 0.14% by mass and a viscosity of 9600 mPa·s, having the following formula: ViMe2SiO(Me2SiO) 522 SiMe2Vi Dimethylpolysiloxane represented by

[0049] The following components were used as component (B). Component (b-1): A vinyl group content of 1.8% by mass and having the following average unit formula: (Me3SiO 1 / 2 ) 0.39 (ViMe2SiO 1 / 2 ) 0.05 (SiO 4 / 2 ) 0.56 Organopolysiloxane resin represented by

[0050] The following components were used as component (C). Component (c-1): The content of silicon atom-bonded hydrogen atoms is 0.14% by mass, and the following formula: HMe2SiO(Me2SiO) 20 SiMe2H Dimethylpolysiloxane represented by Component (c-2): The content of silicon atom-bonded hydrogen atoms is 1.0% by mass, and the following average unit formula: (HMe2SiO 1 / 2 ) 0.63 (SiO 4 / 2 ) 0.37 Resinous organopolysiloxane represented by

[0051] The following components were used as component (D). Component (e-1): Solution of Pt-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (Pt content in the solution is 0.9% by mass)

[0052] The following components were used as component (E). Component (e-1): A mixture containing 3% by mass of 1-ethynyl-cyclohexan-1-ol and 97% by mass of dimethylpolysiloxane represented by the following formula, with a vinyl group content of 0.21% by mass and a viscosity of 430 mPa·s: ViMe2SiO(Me2SiO) 179 SiMe2Vi

[0053] [Table 1]

[0054] [Table 2] [Industrial Applicability]

[0055] ​The curable silicone composition of the present invention has excellent curability and cures to form a cured product exhibiting excellent adhesion properties to various substrates used in optical devices. Therefore, the curable silicone composition is useful as an adhesive and a pressure-sensitive adhesive for use in display devices such as optical displays (including touch panels) and optical semiconductor devices (including micro LEDs).

Claims

1. A curable silicone composition comprising: (A)The following general formula: R １ ２ R ２ SiO(R １ ２ SiO) ｍ SiR １ ２ R ２ A diorganopolysiloxane represented by (wherein each R １ is independently an alkyl group having 1 to 12 carbon atoms, and each R ２ is independently an alkenyl group having 2 to 12 carbon atoms, and "m" is an integer of 100 to 1000), and (B)The following average unit formula: (R １ ３ SiO １／２ ) ａ (R ２ R １ ２ SiO １／２ ) ｂ (SiO ４／２ ) ｃ (HO １／２ ) ｄ A resinous organopolysiloxane represented by (wherein R １ and R ２ are as described above, and "a", "b", "c", and "d" are numbers satisfying a ≧ 0, b > 0, 0.3 ≦ c ≦ 0.7, 0 ≦ d ≦ 0.05, and a + b + c = 1, and are in an amount of 1.0 to 5.0 parts by mass based on 100 parts by mass of component (A)), and (C)An organopolysiloxane having a silicon atom-bonded hydrogen atom in an amount such that the molar ratio of the silicon atom-bonded hydrogen atom provided by component (C) to the alkenyl group provided by components (A) and (B) is in the range of 0.5 to 2; (D)An effective amount of a hydrosilylation reaction catalyst, Component (C) comprises the following components (c1) and (c2): (c1)A diorganopolysiloxane having silicon atom-bonded hydrogen atoms at both ends of the molecular chain; (c2)The following average unit formula: (R １ ３ SiO １／２ ) ｅ (HR １ ２ SiO １／２ ) ｆ (SiO ４／２ ) ｇ (HO １／２ ) ｈ An organopolysiloxane resin represented by (wherein R １ is as described above, and "e", "f", "g", and "h" are numbers satisfying e ≧ 0, f > 0, 0.3 ≦ g ≦ 0.7, 0 ≦ h ≦ 0.05, and e + f + g = 1), and is an organopolysiloxane consisting essentially of A curable silicone composition wherein the molar ratio of the silicon-bonded hydrogen atom provided by component (c1) to the silicon-bonded hydrogen atom provided by component (c2) is in the range of 10 to 60.

2. (E)The curable silicone composition according to claim 1, further comprising a hydrosilylation reaction inhibitor in an amount of about 0.00001 to about 0.5 parts by mass based on 100 parts by mass of the total mass of components (A) to (C).

3. A cured product obtained by curing the curable silicone composition according to claim 1 or 2.

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