Addition curing-type organically modified silicone composition and cured product

Abstract

Provided is an addition curing-type organically modified silicone composition that contains: (A) a polymer represented by formula (1) [X is a divalent group represented by formula (2), Y is a group represented by any one of formulae (3) to (5), Y' is a group represented by formula (6) or formula (7), and m is an integer between 0 and 12.]; (B) an organosilicon compound having two terminal silicon atom-bonded hydrogen atoms per molecule; (C) an organosilicon compound having three or more terminal silicon atom-bonded hydrogen atoms per molecule; and (D) a platinum group metal catalyst. The blending quantities of components (B) and (C) are such that the number of silicon atom-bonded hydrogen atoms in component (B) is 0.40-0.60 and the number of silicon atom-bonded hydrogen atoms in component (C) is 0.05-0.10 per addition reactive carbon-carbon double bond in component (A).

Description

Addition-curable organically modified silicone composition and cured product

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

[0002] Organo-modified 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, organo-modified silicones are used as coating materials for electronic components and as encapsulants for light-emitting diodes.

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

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

[0005] JP 2019-108471 A JP 2022-53875 A

[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 is adhesive and has low hardness.

[0007] As a result of extensive research aimed at solving the above problems, the present inventors have found that the following composition provides a cured product that is adhesive and has low hardness, and have thus completed the present invention.

[0008] That is, the present invention provides: 1. (A) a polymer represented by the following general formula (1): [In the formula, each X is independently a divalent group represented by the following structural formula (2), each Y is independently a monovalent group represented by any of the following structural formulas (3) to (5), each Y' is independently a divalent group represented by the following structural formula (6) or (7), and Me represents a methyl group. m is an integer from 0 to 12.] (In the formula, an asterisk (*) indicates a bonding site with a silicon atom.) (In formulas (3) to (7), an asterisk (*) indicates the bonding site to the silicon atom, and the configuration at each asymmetric carbon may be either cis (exo) or trans (endo).) An addition-curable organo-modified silicone composition comprising: (B) an organosilicon compound having two hydrogen atoms bonded to terminal silicon atoms per molecule; (C) an organosilicon compound having three or more hydrogen atoms bonded to terminal silicon atoms per molecule; and (D) a platinum group metal catalyst, wherein the amounts of components (B) and (C) are 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; and 2. a cured product of the addition-curable organo-modified silicone composition according to 1.

[0009] According to the present invention, it is possible to obtain a cured organic-modified silicone resin that has adhesive properties and low hardness, thereby resolving the technical problems associated with conventional materials. Therefore, the addition-curable organic-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.

[0010] The present invention will be described in detail 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]

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

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

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

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

[0016] Furthermore, m is an integer of 0 to 12, 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 kinematic viscosity of component (A) is not particularly limited, but is preferably 1,000 to 100,000 mm 2 / s is preferred, 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 (the same applies hereinafter).

[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 (e.g., 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 isomers may be used.

[0020] (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]

[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 reaction catalyst is not particularly limited, and known catalysts can be used. Examples include platinum-based catalysts such as platinum metal-supported carbon powder, platinum black, platinic chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, and platinum bisacetoacetate; and platinum group metal catalysts such as palladium-based catalysts and rhodium-based catalysts. In addition, the addition reaction conditions, the use of solvents, etc. are not particularly limited, and the reaction can be carried out under known conditions.

[0025] As described above, when preparing component (A), component (b) is used in an excess molar amount relative to component (a), and therefore 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) relative to all addition-reactive carbon-carbon double bonds in the composition of the present invention is preferably 20 to 100 mol %, and more preferably 40 to 100 mol %.

[0027] The component (A) may be used alone or in combination of two or more.

[0028] [2] Component (B) 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 an organosilicon compound having a structure similar to that of HRSiO 2 / 2 (wherein R represents an organic group), HPreferably, component (B) is an organosilicon compound that does not have a C-type unit), and more preferably, component (B) is, for example, a linear organohydrogenpolysiloxane represented by the following general formula (10). (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 siloxane units in parentheses may be arranged in any order.)

[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), those represented by the following formula are more preferred. (In the formula, Me represents a methyl group, and Ph represents a phenyl group.)

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

[0032] The amount of component (B) to be blended 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 number is less than 0.40, the resulting polymer will be insufficiently crosslinked and will be liquid. If the number is more than 0.60, the polymer will cure too quickly, causing the cured product to lose its adhesiveness.

[0033] The component (B) may be used alone or in combination of two or more.

[0034] [3] Component (C) Component (C) of the present invention is an organosilicon compound having at least three hydrogen atoms (hydrosilyl groups) bonded to terminal silicon atoms per molecule. Such terminal hydrosilyl groups are highly reactive in the hydrosilylation reaction, and therefore rapidly undergo crosslinking to give a rubbery 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. Of these, the top two are preferred:

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

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

[0038] The component (C) may be used alone or in combination of two or more.

[0039] [4] Component (D) 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). There are no particular restrictions on the platinum group metal catalyst, and any known catalyst used in 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, and rhodium; platinum compounds such as platinic chloride, chloroplatinic acid, alcohol-modified chloroplatinic acid, coordination compounds of chloroplatinic acid with olefins, vinylsiloxanes, or acetylene compounds, and complexes of platinum and vinylsiloxane; and platinum group metal compounds such as tetrakis(triphenylphosphine)palladium and chlorotris(triphenylphosphine)rhodium.

[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 into active platinum catalysts when irradiated with light of a wavelength of 200 to 500 nm, thereby accelerating the hydrosilylation reaction. Specific examples of such catalysts include (η 5 and UV-activated platinum complexes such as (η -cyclopentadienyl)trialiphatic platinum compounds and bis(acetylacetonato)platinum compounds. Of these, platinum compounds such as coordination compounds of chloroplatinic acid with vinylsiloxane or acetylene compounds and complexes of platinum with vinylsiloxane are preferred for use in heat-curable compositions. 5 -cyclopentadienyl)trialiphatic platinum compounds or bis(acetylacetonato)platinum compounds are preferred.

[0042] There are no particular restrictions on the amount of component (D) that may be added, provided it is an amount that promotes curing (hydrosilylation reaction) of the composition. Component (D) is preferably added in an amount that results in a platinum group metal atom concentration in component (D) of 0.01 to 500 ppm by mass, and more preferably 0.05 to 100 ppm, relative to the combined mass of components (A), (B), and (C).

[0043] The component (D) may be used alone or in combination of two or more.

[0044] [5] Component (E) A reaction inhibitor as component (E) may be added to the composition of the present invention as needed 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, and among these, 1-ethynylcyclohexanol, ethynylmethyldecylcarbinol, and 3-methyl-1-butyn-3-ol are preferred.

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

[0046] [6] Other Components In addition to the above components (A) to (D) and the optional component (E), the composition of the present invention may contain other components exemplified below, as long as the components do not impair the object of the present invention. Examples include adhesion promoters having at least one selected from the group consisting of one or more alkenyl groups, (meth)acrylic groups, carbonyl groups, epoxy groups, alkoxysilyl groups, and amide groups per 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 fillers such as alumina and crystalline silica; viscosity modifiers such as nonreactive 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 conventionally known method. That is, the silicone composition of the present invention can be obtained by mixing components (A) to (D) and, if necessary, component (E) and other components.

[0048] [8] Silicone Cured Product 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, or as a laminating material for electronic devices or electronic components. 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 composition of the present invention can also be used on substrates that have been activated by known pretreatment processes such as primer treatment, plasma treatment, and excimer light treatment.

[0049] The composition of the present invention may be applied to one of two substrates constituting an optical component, an electronic device / electronic component, or the like, and cured, and then the other substrate may be bonded to the applied composition, or the substrates may be bonded to each other and then cured.

[0050] The silicone composition of the present invention is cured by heating or after ultraviolet irradiation at room temperature or under heating. When a heat-curable platinum complex such as chloroplatinic acid is used 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 viewpoints of curing speed and prevention of discoloration. In addition, (η 5 When a UV-activated platinum complex such as a (-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. Regarding the irradiation conditions, from the viewpoint of the curing speed of the composition and prevention of discoloration, for example, the irradiation intensity is 30 to 2,000 mW / cm. 2 The irradiation dose is preferably 1,000 to 100,000 mJ / cm 2 The temperature during irradiation is preferably 10 to 60°C, more preferably 25 to 40°C. Curing may also be accelerated by heating after UV irradiation; for example, the heating temperature is preferably 40 to 80°C, and the heating time is preferably 0.5 to 3 hours. The cured product of the present invention obtained in this manner has adhesiveness and a hardness measured by a Shore 00 type durometer of preferably 90 or less, more preferably 80 or less.

[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 formula, Me represents a methyl group and Ph represents a phenyl group. The kinematic viscosity is measured using a Cannon-Fenske viscometer.

[0052] [1] Preparation of Compositions [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 addition-curable silicone compositions.

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

[0054] Component (B) 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)

[0055] Component (C) (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)

[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) (In the formula, the arrangement of each siloxane unit in parentheses is random, alternating, or block.)

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

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

[0059] [2] Preparation of Cured Products and Evaluation of Cured State [Examples 2-1, 2-2, and Comparative Examples 2-1, 2-3, 2-4] 8 g of each composition 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 cured product was determined by touch. In addition, the hardness of the cured product 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] 8 g of each of the compositions obtained in Examples 1-3 to 1-5 and Comparative Example 1-2 was irradiated with a UV-LED lamp having a wavelength of 365 nm 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 that the cured product was cured, the product was heated at 80°C for 1 hour to obtain a cured product. The adhesiveness of each cured product was judged by touching with a finger. The hardness of the cured product at 23°C was also evaluated using a Shore 00 type durometer. The results are shown in Table 2.

[0061]

[0062]

[0063] As shown in Table 2, the compositions prepared in Examples 1-1 to 1-5 were found to be adhesive and gave cured products with low hardness, while the compositions prepared in Comparative Examples 1-1 to 1-4 did not exhibit adhesiveness after curing.

Claims

1. (A) A polymer represented by the following general formula (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. (In the formula, an asterisk (*) indicates a bonding site with a silicon atom.) (In formulas (3) to (7), an asterisk (*) indicates the bonding site to the silicon atom, and the configuration at each asymmetric carbon may be either cis (exo) or trans (endo).) An addition-curable organo-modified silicone composition comprising: (B) an organosilicon compound having two hydrogen atoms bonded to a terminal silicon atom per molecule; (C) an organosilicon compound having three or more hydrogen atoms bonded to a terminal silicon atom per molecule; and (D) a platinum group metal catalyst, wherein the amounts of components (B) and (C) are such that, per addition-reactive carbon-carbon double bond in component (A), there is 0.40 to 0.60 hydrogen atoms bonded to silicon atoms in component (B), 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 organically modified silicone composition according to claim 1.

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