Addition-curable organically modified silicone composition and cured product

Abstract

To provide an addition-curable organically modified silicone composition that exhibits adhesive properties and yields a low-hardness cured product.SOLUTION: An addition-curable organically modified silicone composition comprises: (A) a silicon polymer having a structure represented by the following formula as a terminal group or a connecting group, (B) an organosilicon compound having two hydrogen atoms bonded to terminal silicon atoms in each molecule, (C) an organosilicon compound having three or more hydrogen atoms bonded to terminal silicon atoms in each molecule, and (D) a platinum group metal catalyst.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an addition-curable organically modified silicone composition and a cured product thereof. [Background technology]

[0002] Organomodified silicones such as alkylene-modified silicones and arylene-modified silicones have characteristics such as higher hardness, higher toughness, and higher gas barrier properties than dimethyl silicones. Due to these characteristics, organomodified silicones are used as coating materials for electronic components and sealing materials for light-emitting diodes.

[0003] It has been known that a composition containing an addition polymer of vinylnorbornene and bis(dimethylsilyl)benzene and an organohydrogenpolysiloxane can be used as an ultraviolet-activated addition curing material (Patent Documents 1 and 2).

[0004] However, these compositions are intended to provide a cured product with high hardness, and there has been a demand for organic modified silicone compositions that give cured products with low hardness that can be used for applications such as pressure sensitive adhesives. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-108471 A [Patent Document 2] Patent Publication No. 2022-53875 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide an addition-curable organically modified silicone composition that gives a cured product that has adhesive properties and low hardness. [Means for solving the problem]

[0007] Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems and have found that the following composition gives a cured product having adhesiveness and low hardness, thereby completing the present invention.

[0008] That is, the present invention provides 1. (A) A polymer represented by the following general formula (1): [ka] [In the formula, X is each independently a divalent group represented by the following structural formula (2), Y is each independently a monovalent group represented by any one of the following structural formulas (3) to (5), Y' is each independently a divalent group represented by the following structural formula (6) or (7), and Me represents a methyl group. m is an integer of 0 to 12. [ka] (In the formula, an asterisk (*) indicates a bonding site with a silicon atom.) [ka] (In formulas (3) to (7), an asterisk (*) indicates a bonding site with a silicon atom, and the configuration at each asymmetric carbon may be either cis (exo) or trans (endo).) (B) An organosilicon compound having two hydrogen atoms bonded to terminal silicon atoms in one molecule. (C) Organosilicon compounds having three or more hydrogen atoms bonded to terminal silicon atoms in one molecule (D) Platinum group metal catalyst Contains an addition-curable organically modified silicone composition in which components (B) and (C) are blended in amounts such that, per addition-reactive carbon-carbon double bond in component (A), there are 0.40 to 0.60 hydrogen atoms bonded to silicon atoms in component (B), and there are 0.05 to 0.10 hydrogen atoms bonded to silicon atoms in component (C); 2. A cured product of the addition-curable organically modified silicone composition described in 1. to provide. Effect of the Invention

[0009] According to the present invention, it is possible to obtain an organically modified silicone resin cured product that has adhesiveness and low hardness, thereby resolving the technical problems associated with conventional materials. Therefore, the addition-curable organically modified silicone composition of the present invention is useful as a material for optical devices or optical components, and as a pressure-sensitive adhesive or adhesive for electronic device applications. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be specifically described below. [1] Component (A) Component (A) in the addition-curable silicone composition of the present invention is a polymer represented by the following structural formula (1).

[0011] [ka]

[0012] In formula (1), X is each independently a divalent group represented by the following structural formula (2), Y is each independently a monovalent group represented by any one of the following structural formulas (3) to (5), Y' is each independently a divalent group represented by the following structural formula (6) or (7), and Me represents a methyl group.

[0013] [ka] (In the formula, an asterisk (*) indicates a bonding site with a silicon atom.)

[0014] [ka] (In formulas (3) to (7), an asterisk (*) indicates a bonding site with a silicon atom, and the configuration at each asymmetric carbon may be either cis (exo) or trans (endo).)

[0015] In addition, the bonding direction of the divalent group represented by the structural formula (6) or (7) is not limited to the above-described one, and also includes structures obtained by rotating each structure by 180° on the paper.

[0016] Furthermore, m is an integer of 0 to 12, and preferably an integer of 1 to 5. If m exceeds 12, the composition becomes a highly viscous liquid at room temperature, making it difficult to handle.

[0017] The kinetic viscosity of component (A) is not particularly limited, but is preferably 1,000 to 100,000 mm 2 / s is preferable, and 5,000 to 30,000 mm 2 In the present invention, the kinematic viscosity is a value measured at 23° C. using a Cannon-Fenske viscometer (hereinafter the same).

[0018] The component (A) can be prepared, for example, as an addition reaction product of (a): bis(dimethylsilyl)benzene and (b): vinylnorbornene according to known methods (such as those described in JP-A-2005-133073).

[0019] The component (a) is an ortho-, meta-, or para-substituted bis(dimethylsilyl)benzene represented by the following structural formula (8), and a single structure or a mixture of two or more types of isomers may be used.

[0020] [ka] (In the formula, Me represents a methyl group.)

[0021] The component (b) is 5-vinylbicyclo[2.2.1]hept-2-ene represented by the following structural formula (9), and may be a single structure or a mixture of two or more isomers.

[0022] [ka]

[0023] The component (A) of the present invention can be obtained, for example, by subjecting 1 mole of component (a) having two SiH groups per molecule to an addition reaction of more than 1 mole but not more than 10 moles, preferably more than 1 mole but not more than 5 moles, of component (b) having two addition-reactive carbon-carbon double bonds per molecule, in the presence of a hydrosilylation reaction catalyst.

[0024] The hydrosilylation catalyst is not particularly limited, and known catalysts can be used. For example, platinum-based catalysts such as carbon powder carrying platinum metal, platinum black, platinic chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, platinum bisacetoacetate, etc.; platinum group metal catalysts such as palladium catalysts and rhodium catalysts. The addition reaction conditions, the use of a solvent, and the like are not particularly limited, and the reaction may be carried out under known conditions.

[0025] As described above, when preparing component (A), a molar excess of component (b) is used relative to component (a), so component (A) has two addition-reactive carbon-carbon double bonds per molecule that are derived from the structure of component (b).

[0026] Furthermore, when a component having addition reactive carbon-carbon double bonds other than component (A) is used, the proportion of addition reactive carbon-carbon double bonds derived from component (A) in the total addition reactive carbon-carbon double bonds in the composition of the present invention is preferably 20 to 100 mol %, more preferably 40 to 100 mol %.

[0027] The component (A) may use one type alone, or two or more types in combination.

[0028] [2](B) Component The component (B) of the present invention is an organosilicon compound having two hydrogen atoms (hydrosilyl groups) bonded to terminal silicon atoms in one molecule. Such terminal hydrosilyl groups are highly reactive, and therefore the hydrosilylation reaction proceeds quickly. In addition, component (B) is HRSiO 2 / 2 (wherein R represents an organic group) H As the component (B), for example, a linear organohydrogenpolysiloxane represented by the following general formula (10) is more preferred. [ka] (In the formula, Me is a methyl group, Ph is a phenyl group, j is an integer of 0 or more, and k is an integer of 1 or more. The order of the parenthesized siloxane units may be arbitrary.)

[0029] j is preferably an integer of 0 to 10, and more preferably 0. k is preferably an integer of 1 to 100, and more preferably 1.

[0030] As the component (B), one represented by the following formula is more preferable. [ka] (In the formula, Me represents a methyl group, and Ph represents a phenyl group.)

[0031] The kinetic viscosity of component (B) is not particularly limited, but is preferably 0.1 to 100,000 mm 2 / s is preferable, and 0.5 to 500 mm 2 / s, and more preferably 1 to 10 mm 2 / s.

[0032] The amount of component (B) is such that the number of hydrogen atoms bonded to silicon atoms in component (B) is 0.40 to 0.60, preferably 0.40 to 0.55, and more preferably 0.45 to 0.55 per addition reactive carbon-carbon double bond in component (A). If the amount is less than 0.40, the crosslinking of the resulting polymer is insufficient and the polymer becomes liquid. If the amount is more than 0.60, the polymer cures too quickly, causing the cured product to lose its adhesiveness.

[0033] The component (B) may use one type alone, or two or more types in combination.

[0034] [3](C) component The component (C) of the present invention is an organosilicon compound having at least three hydrogen atoms (hydrosilyl groups) bonded to terminal silicon atoms in one molecule. Such terminal hydrosilyl groups are highly reactive in the hydrosilylation reaction, and therefore crosslinking proceeds rapidly to give a rubber-like cured product.

[0035] Specific examples of component (C) include, but are not limited to, the following organosilicon compounds containing terminal hydrosilyl groups. In the following formula, Me is a methyl group, and Ph is a phenyl group. Among these, the top two are preferred. [ka]

[0036] The kinetic viscosity of component (C) is not particularly limited, but is preferably 0.1 to 100,000 mm 2 / s is preferable, and 0.5 to 500 mm 2 / s, and more preferably 1 to 50 mm 2 / s.

[0037] The amount of component (C) is such that the number of hydrogen atoms bonded to silicon atoms in component (C) is 0.05 to 0.10, preferably 0.05 to 0.09, and more preferably 0.05 to 0.08 per addition reactive carbon-carbon double bond in component (A). If the amount is less than 0.05, the crosslinking of the resulting polymer is insufficient and the polymer becomes liquid. If the amount is more than 0.10, the polymer cures too quickly, causing the cured product to lose its adhesiveness.

[0038] The component (C) may use either a single type alone, or a combination of two or more types.

[0039] [4](D) component The platinum group metal catalyst of component (D) is a component that promotes the hydrosilylation reaction between the addition-reactive carbon-carbon double bonds in component (A) and the hydrosilyl groups in components (B) and (C). The platinum group metal catalyst is not particularly limited, and any known catalyst for hydrosilylation reactions can be used, including those used in heat-curable silicone compositions and those used in silicone compositions that are cured by irradiation with light.

[0040] Specific examples of materials used in heat-curable silicone compositions include carbon powder supporting platinum metal; platinum group metal elements such as platinum (including platinum black), palladium, rhodium, etc.; platinum compounds such as platinic chloride, chloroplatinic acid, alcohol-modified chloroplatinic acid, coordination compounds of chloroplatinic acid with olefins, vinylsiloxane or acetylene compounds, complexes of platinum and vinylsiloxane, etc.; and platinum group metal compounds such as tetrakis(triphenylphosphine)palladium, chlorotris(triphenylphosphine)rhodium, etc.

[0041] For silicone compositions that are cured by irradiation with light, ultraviolet-activated platinum group metal catalysts are preferred, which are inactive in the dark and convert to active platinum catalysts when irradiated with light having a wavelength of 200 to 500 nm, thereby promoting the hydrosilylation reaction. Specific examples of such catalysts include, for example, (η5 -cyclopentadienyl)trialiphatic platinum compounds, and UV-activated platinum complexes such as bis(acetylacetonato)platinum compounds. Among these, preferred for use in heat-curable compositions are platinum compounds such as a coordination compound of chloroplatinic acid with vinylsiloxane or acetylene compound, and a complex of platinum with vinylsiloxane. Preferred for use in UV-activated compositions are (η 5 -cyclopentadienyl)trialiphatic platinum compounds or bis(acetylacetonato)platinum compounds are preferred.

[0042] There are no limitations on the amount of component (D) that may be added, so long as it is an amount that promotes the curing (hydrosilylation reaction) of the composition, and an amount such that the platinum group metal atoms in component (D) are in a range from 0.01 to 500 ppm by mass, and more preferably from 0.05 to 100 ppm, based on the combined mass of components (A), (B), and (C).

[0043] The component (D) may use either a single type alone, or a combination of two or more types.

[0044] [5](E) component If necessary, a reaction inhibitor (E) may be added to the composition of the present invention to prevent thickening or gelation before heat curing when the composition is formulated or applied to a substrate. Specific examples thereof include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, ethynylmethyldecylcarbinol, 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynoxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane. Of these, 1-ethynylcyclohexanol, ethynylmethyldecylcarbinol, and 3-methyl-1-butyn-3-ol are preferred.

[0045] When component (E) is used, the amount of component (E) is preferably 0.01 to 2.0 parts by mass, and more preferably 0.01 to 0.3 parts by mass, based on 100 parts by mass of components (A), (B), and (C) combined. If the amount is within this range, the reaction control effect is sufficiently exhibited.

[0046] [6] Other ingredients In addition to the above-mentioned components (A) to (D) and the optional component (E), the composition of the present invention may contain other components as exemplified below, provided that the object of the present invention is not impaired. Examples of such agents include adhesion promoters having at least one of the functional groups consisting of one or more alkenyl groups, (meth)acrylic groups, carbonyl groups, epoxy groups, alkoxysilyl groups, and amide groups in one molecule; thixotropy control agents such as fumed silica; reinforcing agents such as crystalline silica; antioxidants such as hindered phenols and hindered amines; light stabilizers; heat resistance improvers such as metal oxides and metal hydroxides; colorants such as titanium oxide; thermal conductivity-imparting fillers such as alumina and crystalline silica; viscosity adjusters such as non-reactive silicone oils that do not have reactive functional groups; conductivity-imparting agents such as metal powders of silver, gold, etc.; and pigments and dyes for coloring.

[0047] [7] Method for producing silicone composition The method for producing the silicone composition of the present invention is not particularly limited, and may be any method known in the art. That is, the silicone composition of the present invention can be obtained by mixing the components (A) to (D) and the component (E) and other components that are used as needed.

[0048] [8] Silicone cured products The silicone composition of the present invention can be applied to various substrates and used as a laminating material for optical components such as optical devices and optical displays, as a laminating material for electronic devices or electronic components, etc. Substrates that can be used include composite materials, metal members, plastic members, ceramic members, quartz glass, and materials used in the fields of adhesion and bonding for electrical, electronic, and optical applications. The compositions of the present invention can also be used on substrates that have been activated by known pretreatment processes such as primer treatment, plasma treatment, excimer light treatment, and the like.

[0049] The composition of the present invention may be applied to one of two substrates constituting an optical component, an electronic device or an electronic component, etc., and cured, and then the other substrate may be laminated thereto, or the substrates may be laminated together and then cured.

[0050] The silicone composition of the present invention is cured by heating or after irradiation with ultraviolet light at room temperature or under heating. When using a heat-curable platinum complex such as chloroplatinic acid to cure the silicone composition of the present invention, the curing conditions are preferably, for example, 100 to 150°C for 0.5 to 4 hours, and more preferably 100 to 120°C for 0.5 to 1 hour, from the standpoint of curing speed and prevention of discoloration. Also, (η 5 When a UV-activated platinum complex such as a bis(cyclopentadienyl)trialiphatic platinum compound or a bis(acetylacetonato)platinum compound is used, light having a wavelength of preferably 200 to 500 nm, more preferably 200 to 370 nm, is used for photoactivation of the catalyst, and a UV-LED lamp, a metal halide lamp, a mercury lamp, or the like can be used as the light source. The irradiation conditions are, for example, from the viewpoint of the curing speed of the composition and prevention of discoloration, and the irradiation intensity is 30 to 2,000 mW / cm 2 is preferable, and the exposure dose is 1,000 to 100,000 mJ / cm 2 The temperature during irradiation is preferably 10 to 60° C., and more preferably 25 to 40° C. Furthermore, curing may be promoted by heating after UV irradiation, and for example, the heating temperature is preferably 40 to 80° C., and the heating time is preferably 0.5 to 3 hours. The thus obtained cured product of the present invention has adhesive properties and a hardness of preferably 90 or less, more preferably 80 or less, as measured by a Shore 00 type durometer. EXAMPLES

[0051] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following formulas, Me represents a methyl group and Ph represents a phenyl group. The kinetic viscosity is measured using a Cannon-Fenske viscometer.

[0052] [1] Preparation of the composition [Examples 1-1 to 1-5, Comparative Examples 1-1 to 1-4] The following components (A) to (E) were mixed in the amounts (parts by mass) shown in Table 1 to prepare an addition-curable silicone composition.

[0053] Component (A) A mixture of polymers in which m in the above structural formula (1) is an integer of 1 to 5 (content of addition reactive carbon-carbon double bonds: 0.47 mol / 100 g)

[0054] (B) Component A compound represented by the following structural formula (kinematic viscosity at 23°C: 4.2 mm 2 / s, silicon-bonded hydrogen atom content: 0.0063 mol / g) [ka]

[0055] (C) Component (C-1) A compound represented by the following structural formula (kinematic viscosity at 23°C: 1.8 mm 2 / s, silicon-bonded hydrogen atom content: 0.0092 mol / g) [ka]

[0056] (C-2) A compound represented by the following structural formula (kinematic viscosity at 23°C: 22.9 mm 2 / s, silicon-bonded hydrogen atom content: 0.0063 mol / g) [ka] (In the formula, the arrangement of each siloxane unit in parentheses is random, alternating, or block.)

[0057] (D) Component (D-1): A toluene solution of platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex having a platinum content of 0.5% by mass. (D-2): A toluene solution of methylcyclopentadienyltrimethylplatinum complex having a platinum content of 0.5% by mass. (D-3): A toluene solution of bis(acetylacetonato)platinum complex having a platinum content of 0.5% by mass.

[0058] (E) Component A compound represented by the following structural formula: [ka]

[0059] [2] Preparation of cured product and evaluation of cured state [Examples 2-1, 2-2, and Comparative Examples 2-1, 2-3, and 2-4] 8 g of each of the compositions obtained in Examples 1-1, 1-2, and Comparative Examples 1-1, 1-3, and 1-4 was cured at 120° C. for 1 hour to obtain a cured product. The tackiness of each of the resulting cured products was judged by touch with a finger. In addition, the hardness of the cured products at 23° C. was evaluated using a Shore 00 type durometer. The results are shown in Table 2.

[0060] [Examples 2-3 to 2-5 and Comparative Example 2-2] For each of the compositions obtained in Examples 1-3 to 1-5 and Comparative Example 1-2 (8 g), a UV-LED lamp with a wavelength of 365 nm was used at room temperature (23°C) with an irradiation intensity of 100 mW / cm. 2 and a dose of 3,000 mJ / cm 2 After irradiating with ultraviolet light so as to obtain a cured product, the product was heated at 80° C. for 1 hour. The tackiness of each of the resulting cured products was judged by touch with a finger. In addition, the hardness of the cured products at 23° C. was evaluated using a Shore 00 type durometer. The results are shown in Table 2.

[0061] [Table 1]

[0062] [Table 2]

[0063] As shown in Table 2, it is apparent that the compositions prepared in Examples 1-1 to 1-5 give cured products that have adhesiveness and low hardness. On the other hand, the compositions prepared in Comparative Examples 1-1 to 1-4 did not exhibit any tackiness after curing.

Claims

1. (A) A polymer represented by the following general formula (1): 【Chemistry 1】 [In the formula, X is each independently a divalent group represented by the following structural formula (2), Y is each independently a monovalent group represented by any one of the following structural formulas (3) to (5), Y' is each independently a divalent group represented by the following structural formula (6) or (7), Me represents a methyl group, and m is an integer from 0 to 12. 【Chemistry 2】 (In the formula, an asterisk (*) indicates a bonding site with a silicon atom.) 【Chemistry 3】 (In formulas (3) to (7), an asterisk (*) indicates a bonding site with a silicon atom, and the configuration at each asymmetric carbon may be either cis (exo) or trans (endo).) (B) An organosilicon compound having two hydrogen atoms bonded to terminal silicon atoms in one molecule. (C) An organosilicon compound having three or more hydrogen atoms bonded to terminal silicon atoms in one molecule. (D) Platinum group metal catalyst Contains An addition-curable organomodified silicone composition in which components (B) and (C) are blended in amounts such that, per addition-reactive carbon-carbon double bond in component (A), the number of hydrogen atoms bonded to silicon atoms in component (B) is 0.40 to 0.60, and the number of hydrogen atoms bonded to silicon atoms in component (C) is 0.05 to 0.

10.

2. A cured product of the addition-curable organomodified silicone composition according to claim 1.

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