UV-curable liquid silicone composition and silicone cured product

Abstract

To provide a UV-curable liquid silicone composition which cures quickly under gentle temperature conditions at or below 100°C, while maintaining superior storage stability.SOLUTION: A UV-curable liquid silicone composition comprises (A) a linear organopolysiloxane having in one molecule at least two alkenyl groups directly bonded to silicon atoms, (B) an organohydrogenpolysiloxane having in one molecule at least two hydrogen atoms directly bonded to silicon atoms, (C) a photoactive hydrosilylation reaction catalyst, and (D) at least one of compounds represented by formula (1) or formula (2), wherein the amount of component (D) is adjusted such that the molar ratio of component (D) / component (C) is 0.1 to 50.0.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] As an adhesive used when bonding another member such as a touch panel, a cover glass, or a cover film to a flat panel display (FPD) such as a liquid crystal display (LCD), an organic EL display (OLED), a plasma display (PDP), or a flexible display, or a member such as a liquid crystal module (LCM) or a flexible printed wiring board (FPC) such as a touch panel type FPD, a 3D display, or an e-book, an acrylic resin, a urethane resin, or further a silicone-based adhesive is used. In recent years, in particular, a silicone rubber adhesive that is optically highly transparent, excellent in light resistance and heat resistance, and further has a low elastic modulus has attracted attention.

[0003] In a touch panel device, there is a light-shielding portion derived from a support, and in some cases, poor curing of the adhesive applied under the light-shielding portion becomes a problem. As a method for solving this problem, the development of an addition-curable adhesive for an image display device, particularly an addition-curable material whose addition reaction trigger is ultraviolet irradiation instead of heating, has been actively carried out (Patent Document 1). In an ultraviolet addition-curable material, since it remains liquid for a while even after ultraviolet irradiation activates the catalyst, ultraviolet irradiation can be performed before bonding even to a portion that becomes a light-shielding portion, so that the portion under the light-shielding portion can be uniformly cured and adhered.

[0004] However, in the case of ultraviolet radiation-curable materials, when bonding image display device members, particularly polarizing plates, touch panels, display panels, etc., curing inhibition of the addition curing reaction may occur due to ultraviolet radiation, and phenomena such as delayed curing or non-curing of the material have been observed. When image display device members such as polarizing plates and liquid crystal modules are irradiated with ultraviolet rays, substances such as benzyl acrylate and benzyl aldehyde derived from the protective coating of the image display device members may be generated. It is considered that curing inhibition occurs in the addition reaction using a platinum catalyst due to these substances (Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to overcome the above problems, for example, a method of applying a composition with improved curability can be considered. However, as a trade-off, the storage stability of the ultraviolet radiation-curable material deteriorates, and a significant increase in viscosity may occur during long-term storage.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultraviolet curable liquid silicone composition that can be cured in a short time under mild temperature conditions of 100°C or lower and has excellent storage stability, an adhesive using the same, and an electric and electronic component using the cured product thereof.

Means for Solving the Problems

[0008] In order to solve the above problems, in the present invention, (A) A linear organopolysiloxane having a viscosity at 25 °C of 50 to 100,000 mPa·s and having at least two alkenyl groups directly bonded to silicon atoms in one molecule, (B) An organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule (C) A photoactive hydrosilylation reaction catalyst, and (D) It contains at least one of the compounds represented by the following formulas (1) and (2), and the blending amount of the component (D) is such that the molar ratio of the component (D) / the component (C) is 0.1 to 50.0, and there is provided an ultraviolet curable liquid silicone composition. [Chemical formula] [In formulas (1) and (2), R 1 ~R 7 are each independently a hydrogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, or a substituent represented by the following formula (3).] -Si(R 8 )3(3) (In the formula, R 8 are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms.)

[0009] The ultraviolet curable liquid silicone composition of the present invention is excellent in curability and storage stability.

[0010] Moreover, in the ultraviolet curable liquid silicone composition of the present invention, it is preferable that the blending amount of the component (B) is such that the ratio of the number of hydrogen atoms directly bonded to silicon atoms (Si-H groups) / the number of aliphatic unsaturated bonds contained in the groups directly bonded to silicon atoms is 0.3 to 2.5.

[0011] If it is within such a range, the mechanical properties of the cured product are more excellent.

[0012] Furthermore, in the ultraviolet curable liquid silicone composition of the present invention, R 1 ~R 7are preferably, independently of each other, a hydrogen atom or a methyl group.

[0013] Such an ultraviolet-curable liquid silicone composition is surely excellent in curability and storage stability.

[0014] In the ultraviolet-curable liquid silicone composition of the present invention, the blending amount of the component (D) is preferably an amount such that the molar ratio of the component (D) / the component (C) is 1.0 to 25.0.

[0015] Within such a range, the ultraviolet-curable liquid silicone composition of the present invention becomes more excellent in curability and storage stability.

[0016] Furthermore, the ultraviolet-curable liquid silicone composition of the present invention preferably contains, as the component (E), a silane compound containing one or more selected from the group consisting of a (meth)acrylic group, an epoxy group, an alkenyl group, and an alkoxysilyl group.

[0017] By containing such a component (E), the ultraviolet-curable liquid silicone composition of the present invention is imparted with adhesiveness to a substrate.

[0018] The present invention provides an adhesive comprising the above ultraviolet-curable liquid silicone composition.

[0019] Such an adhesive is excellent in curability and storage stability and has good handleability.

[0020] Furthermore, the present invention provides a silicone cured product which is a cured product of the above ultraviolet-curable liquid silicone composition.

[0021] Such a silicone cured product can be suitably used for sealing, fixing, or adhering of electric and electronic parts.

[0022] Furthermore, the present invention provides an electric and electronic part sealed, fixed, or adhered with the above silicone cured product.

[0023] Such electrical and electronic components are excellent in reliability.

Advantages of the Invention

[0024] As described above, the ultraviolet-curable liquid silicone composition of the present invention can be cured in a short time under mild temperature conditions of 100°C or lower and has excellent storage stability. Therefore, the ultraviolet-curable liquid silicone composition of the present invention can provide an adhesive with good handleability, and the cured product thereof is suitably used for sealing, fixing, or adhering electrical and electronic components.

Embodiments for Carrying Out the Invention

[0025] As described above, there has been a demand for the development of an ultraviolet-curable liquid silicone composition that can be cured in a short time under mild temperature conditions of 100°C or lower and has excellent storage stability.

[0026] As a result of intensive studies on the above problems, the present inventors have found that an ultraviolet-curable liquid silicone composition containing the following components (A) to (D) and having a molar ratio of the component (D) / the component (C) within a specific range can solve the above problems, and thus completed the present invention.

[0027] That is, the present invention is (A) A linear organopolysiloxane having a viscosity at 25°C of 50 to 100,000 mPa·s and having at least two alkenyl groups directly bonded to silicon atoms in one molecule, (B) An organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule (C) A photoactive hydrosilylation reaction catalyst, and (D) A composition containing at least one of the compounds represented by the following formulas (1) and (2), and having a blending amount of the component (D) such that the molar ratio of the component (D) / the component (C) is 0.1 to 50.0, which is an ultraviolet-curable liquid silicone composition.

Chemical formula

[0028] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0029] [UV curable liquid silicone composition] The UV curable liquid silicone composition of the present invention contains the following components (A) to (D), and may contain component (E) and other components as necessary. Hereinafter, each component will be described in detail.

[0030] [Component (A)] Component (A) is a linear organopolysiloxane having a viscosity at 25°C of 50 to 100,000 mPa·s and having at least 2, preferably 2 to 6, alkenyl groups (hereinafter referred to as "silicon atom-bonded alkenyl groups") directly bonded (bonded) to silicon atoms in one molecule.

[0031] The above silicon atom-bonded alkenyl group preferably has 2 to 8, more preferably 2 to 4 carbon atoms. Specific examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, etc., and a vinyl group is particularly preferred.

[0032] Examples of the organic group bonded to the silicon atom other than the alkenyl group described above include monovalent hydrocarbon groups having no aliphatic unsaturated bond and having 1 to 10 carbon atoms, which may be unsubstituted or substituted. Specifically, linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, aralkyl groups, halogenated alkyl groups, etc. are exemplified. Preferred examples of the linear alkyl group include those having 1 to 10 carbon atoms such as methyl group, ethyl group, propyl group, hexyl group, octyl group, decyl group, etc., and more preferably those having 1 to 6 carbon atoms. Preferred examples of the branched alkyl group include those having 1 to 10 carbon atoms such as isopropyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group, etc., and more preferably those having 1 to 6 carbon atoms. Preferred examples of the cyclic alkyl group include those having 3 to 10 carbon atoms such as cyclopentyl group, cyclohexyl group, etc. Preferred examples of the aryl group include those having 6 to 10 carbon atoms such as phenyl group, tolyl group, etc. Preferred examples of the aralkyl group include those having 7 to 10 carbon atoms such as 2-phenylethyl group, 2-methyl-2-phenylethyl group, etc. Preferred examples of the halogenated alkyl group include those having 1 to 10 carbon atoms such as 3,3,3-trifluoropropyl group, 2-(nonafluorobutyl)ethyl group, 2-(heptadecafluorooctyl)ethyl group, etc., and more preferably those having 1 to 6 carbon atoms.

[0033] Among these, linear alkyl groups and aryl groups are preferred, linear alkyl groups and aryl groups having 1 to 6 carbon atoms are more preferred, and methyl group and phenyl group are particularly preferred.

[0034] (A) The viscosity of the component at 25 ° C is in the range of 50 to 100,000 mPa·s, preferably in the range of 1000 to 100,000 mPa·s. When the viscosity is less than 50 mPa·s or exceeds 100,000 mPa·s, the ultraviolet curable liquid silicone composition of the present invention lacks handling workability, and the cured product of the silicone composition cannot ensure good physical properties.

[0035] In this specification, the viscosity is the measured value at 25°C using a rotational viscometer.

[0036] Examples of the component (A) include dimethylvinylsiloxy group-terminated dimethylpolysiloxane at both ends of the molecular chain, methylphenylvinylsiloxy group-terminated dimethylpolysiloxane at both ends of the molecular chain, dimethylvinylsiloxy group-terminated dimethylsiloxane-methylphenylsiloxane copolymer at both ends of the molecular chain, dimethylvinylsiloxy group-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both ends of the molecular chain, trivinylsiloxy group-terminated dimethylpolysiloxane at both ends of the molecular chain, silanol group-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both ends of the molecular chain, silanol group-terminated dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer at both ends of the molecular chain, trimethylsiloxy group-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both ends of the molecular chain, and dimethylvinylsiloxy group-terminated methyl(3,3,3-trifluoropropyl)polysiloxane at both ends of the molecular chain, etc.

[0037] The organopolysiloxane of the component (A) may be used alone or in combination of two or more.

[0038] [Component (B)] The component (B) is an organohydrogenpolysiloxane having at least 2, usually 2 to 200, preferably 2 to 100, more preferably 2 to 50 hydrogen atoms directly bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane may be any of linear, branched, cyclic, or three-dimensional network-structured resinous substances.

[0039] Examples of such organohydrogenpolysiloxane include the organohydrogenpolysiloxane represented by the following formula (4). R 9 a H b SiO (4-a-b) / 2 (4)

[0040] In the above formula (4), R9 represents a non-substituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, a is 0.7 to 2.1, b is 0.001 to 1.0, and a + b is a positive number satisfying 0.8 to 3.0.

[0041] In the above formula (4), R 9 Specific examples of the monovalent hydrocarbon group include the same as those exemplified as the silicon atom-bonded organic group other than the silicon atom-bonded alkenyl group in the description of the component (A), etc., and preferably a methyl group and a phenyl group.

[0042] Specific examples of the component (B) include siloxane oligomers such as 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyltetracyclosiloxane, 1,3,5,7,8-pentamethylpentacyclosiloxane, methylhydrogencyclopolysiloxane, methylhydrogen siloxane·dimethylsiloxane cyclic copolymer, tris(dimethylhydrogensiloxy)methylsilane, etc.; methylhydrogenpolysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain, dimethylsiloxane·methylhydrogen siloxane copolymer blocked with trimethylsiloxy groups at both ends of the molecular chain, methylhydrogenpolysiloxane blocked with silanol groups at both ends of the molecular chain, dimethylsiloxane·methylhydrogen siloxane copolymer blocked with silanol groups at both ends of the molecular chain, dimethylpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, methylhydrogenpolysiloxane blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, dimethylsiloxane·methylhydrogen siloxane copolymer blocked with dimethylhydrogensiloxy groups at both ends of the molecular chain, etc.; R 9 2(H)SiO 1 / 2 units and SiO 4 / 2 units, and optionally R 9 3SiO 1 / 2 units, R 9 2SiO 2 / 2 units, R 9 (H)SiO 2 / 2 units, (H)SiO 3 / 2 units or R 9 3SiO 3 / 2In addition to silicone resins containing units, those in which some or all of these methyl groups are replaced by other alkyl groups such as ethyl groups and n-propyl groups can be mentioned.

[0043] In addition, examples of organohydrogenpolysiloxanes containing phenyl groups include tris(dimethylhydrogensiloxy)phenylsilane, a copolymer of methylhydrogensiloxane and diphenylsiloxane blocked at both ends with trimethylsiloxy groups, a copolymer of methylhydrogensiloxane and methylphenylsiloxane blocked at both ends with trimethylsiloxy groups, a copolymer of dimethylsiloxane, methylhydrogensiloxane and diphenylsiloxane blocked at both ends with trimethylsiloxy groups, a copolymer of dimethylsiloxane, methylhydrogensiloxane and methylphenylsiloxane blocked at both ends with trimethylsiloxy groups, a diphenylsiloxane copolymer blocked at both ends with dimethylhydrogensiloxy groups, a copolymer of methylhydrogensiloxane and diphenylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, a copolymer of methylhydrogensiloxane and methylphenylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, a copolymer of dimethylsiloxane and diphenylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, a copolymer of dimethylsiloxane and methylphenylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, a copolymer of dimethylsiloxane, methylhydrogensiloxane and diphenylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, a copolymer of dimethylsiloxane, methylhydrogensiloxane and methylphenylsiloxane blocked at both ends with dimethylhydrogensiloxy groups, a cyclic copolymer of methylhydrogensiloxane and diphenylsiloxane, a cyclic copolymer of methylhydrogensiloxane and methylphenylsiloxane, a cyclic copolymer of dimethylsiloxane, methylhydrogensiloxane and diphenylsiloxane, a cyclic copolymer of dimethylsiloxane, methylhydrogensiloxane and methylphenylsiloxane, (CH3)2HSiO 1 / 2 units and SiO 4 / 2 units and (C6H5)SiO 3 / 2 units and a copolymer composed of, (CH3)2HSiO1 / 2 Unit and SiO 4 / 2 Unit and (C6H5)2SiO 2 / 2 Copolymer composed of units, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 Unit and (C6H5)3SiO 1 / 2 Copolymer composed of units, (CH3)3SiO 1 / 2 Unit and (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 Unit and (C6H5)SiO 3 / 2 Copolymer composed of units, (CH3)3SiO 1 / 2 Unit and (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 Unit and (C6H5)2SiO 2 / 2 Copolymer composed of units, (CH3)3SiO 1 / 2 Unit and (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 Unit and (C6H5)3SiO 1 / 2 Examples include copolymers composed of units, etc.

[0044] (B) The organohydrogenpolysiloxane of the component may be used alone or in combination of two or more.

[0045] (B) The blending amount of the component is preferably an amount such that the ratio of the number of hydrogen atoms directly bonded to silicon atoms (Si-H groups) in the composition / the number of aliphatic unsaturated bonds contained in the groups directly bonded to silicon atoms is 0.3 to 2.5, more preferably 0.5 to 1.2. Within such a range, the mechanical properties of the cured product are more excellent.

[0046] Also, from the viewpoint of the mechanical properties of the cured product, the blending amount of (B) component is preferably 1 to 20 parts by mass, more preferably 3 to 10 parts by mass with respect to 100 parts by mass of (A) component.

[0047] [Component (C)] (C) component is a photoactive hydrosilylation reaction catalyst. When activated by irradiation with ultraviolet rays, it has a catalytic effect of promoting the hydrosilylation reaction between the silicon atom-bonded alkenyl group in the (A) component, such as aliphatic unsaturated hydrocarbon groups like methacryloyloxyalkyl, and the Si-H group in the (B) component.

[0048] As the photoactive hydrosilylation reaction catalyst, a platinum complex having a cyclic diene compound as a ligand is preferable. Specific examples include (1,5-cyclooctadienyl)diphenylplatinum complex, (1,5-cyclooctadienyl)dipropylplatinum complex, (2,5-norbornadiene)dimethylplatinum complex, (2,5-norbornadiene)diphenylplatinum complex, (cyclopentadienyl)dimethylplatinum complex, (methylcyclopentadienyl)diethylplatinum complex, (trimethylsilylcyclopentadienyl)diphenylplatinum complex, (methylcycloocta-1,5-dienyl)diethylplatinum complex, (cyclopentadienyl)trimethylplatinum complex, (cyclopentadienyl)ethyldimethylplatinum complex, (cyclopentadienyl)acetyldimethylplatinum complex, (methylcyclopentadienyl)trimethylplatinum complex, (methylcyclopentadienyl)trihexylplatinum complex, (trimethylsilylcyclopentadienyl)trimethylplatinum complex, (dimethylphenylsilylcyclopentadienyl)triphenylplatinum complex, and (cyclopentadienyl)dimethyltrimethylsilylmethylplatinum complex, etc.

[0049] The content of the (C) component is preferably an amount of 0.1 to 1,000 ppm, more preferably an amount of 5 to 500 ppm, as the mass of platinum metal, based on the total mass of the (A) component and the (B) component. If the blending amount is 0.1 ppm or more, the addition reaction by ultraviolet irradiation is promoted and sufficient curing proceeds. If the blending amount is 1,000 ppm or less, the workable time and the storage stability of the ultraviolet curable liquid silicone composition can be ensured.

[0050] [(D) component] (D) component contains at least one of the compounds represented by the following formulas (1) and (2). [Chemical formula] In the above formulas (1) and (2), R 1 ~R 7 are, independently of each other, a hydrogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, or a substituent represented by the following formula (3). -Si(R 8 )3(3) (In the formula, R 8 are, independently of each other, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms.) The above component (D) is a compound that controls the reactivity of the photoactive hydrosilylation reaction catalyst.

[0051] As the monovalent hydrocarbon group having 1 to 12 carbon atoms of the above R 1 ~R 7 , those having no aliphatic unsaturated bond such as an alkenyl group are preferred, and alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl groups; cycloalkyl groups such as cyclohexyl group; aryl groups such as phenyl, tolyl, xylyl, naphthyl groups; aralkyl groups such as benzyl, phenethyl groups, and halogenated alkyl groups such as chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl groups in which a part or all of the hydrogen atoms of these groups are substituted with halogen atoms are preferred. Among these, alkyl groups and aryl groups are preferred, and methyl group and phenyl group are more preferred. As R 1 ~R 7 , in particular, hydrogen or methyl groups are more preferred, independently of each other.

[0052] Specific examples of the component (D) include, but are not limited to, those shown below. [Chemical formula]

[0053] The component (D) may be used alone or in combination of two or more.

[0054] The blending amount of component (D) is an amount such that the molar ratio of component (D) / component (C) is 0.1 to 50.0, and more preferably 1.0 to 25.0.

[0055] When the molar ratio is less than 0.1, the control effect on the photoactive platinum complex curing catalyst becomes insufficient, and the storage stability of the ultraviolet curable liquid silicone composition of the present invention decreases. Further, when the molar ratio exceeds 50.0, the curability of the silicone composition is insufficient.

[0056] Also, from the viewpoints of the storage stability and curability of the ultraviolet curable liquid silicone composition of the present invention, the blending amount of component (D) is preferably 0.0001 to 0.03 parts by mass, and more preferably 0.0005 to 0.02 parts by mass with respect to 100 parts by mass of component (A).

[0057] [Component (E)] Component (E) is a silane compound containing one or more selected from the group consisting of (meth)acrylic group, epoxy group, alkenyl group, and alkoxysilyl group. The ultraviolet curable liquid silicone composition of the present invention may contain the component (E) as an adhesion aid for imparting adhesiveness to a substrate.

[0058] Specific examples of component (E) include vinyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-1003), vinyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-1003), 7-octenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-1083), p-styryltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-1403), γ-(glycidoxypropyl)trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403), γ-(methacryloxypropyl)trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-503), compounds represented by the following structural formula, and hydrolysates thereof, etc.

[0059] [Chemical formula]

[0060] (Component (E) may be used alone or in combination of two or more.)

[0061] (When component (E) is used, the blending amount is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of component (A) from the viewpoints of the adhesiveness of the ultraviolet curable liquid silicone composition of the present invention and the mechanical properties of the cured product.)

[0062] [Other Components] In the ultraviolet curable liquid silicone composition of the present invention, in addition to the above components, other components such as a reaction control agent other than component (D), an adhesion aid other than component (E), an inorganic filler, an organic solvent, and a non-reactive organopolysiloxane may be blended.)

[0063] (The reaction control agent other than component (D) is not particularly limited as long as it is a compound having an action of adjusting the reaction rate of the curing reaction with respect to the photoactive platinum complex curing catalyst of component (C) above and further improving the storage stability of the ultraviolet curable liquid silicone composition of the present invention. Conventionally known ones can also be used. Specifically, 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-trimethylsiloxysiloxycyclohexane, bis[2,2-dimethyl-2-propynyl)oxy]dimethylsilane, 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 can be exemplified.)

[0064] Since the degree of the action of adjusting the reaction rate of the curing reaction possessed by the reaction control agent varies depending on the chemical structure, it is preferable to adjust it to an optimal amount for each reaction control agent used. By blending an optimal amount of the reaction control agent, workability and productivity can be improved.

[0065] As an adhesion aid other than the component (E), it is also possible to add an organic compound that does not contain an organosiloxane skeleton. For example, allyl glycidyl ether, allyl benzoate, bisphenol A diallyl ether, KAYARAD R-604 (Nippon Kayaku Co., Ltd.), etc. can be mentioned.

[0066] Examples of the inorganic filler include inorganic fillers such as crystalline silica, hollow fillers, silsesquioxane, fumed titanium dioxide, magnesium oxide, zinc oxide, aluminum hydroxide, calcium carbonate, zinc carbonate, and glass fibers; inorganic fillers surface-hydrophobized with organosilicon compounds such as organoalkoxysilane compounds, organochlorosilane compounds, organosilazane compounds, and low-molecular-weight siloxane compounds; silicone rubber powder; silicone resin powder, etc.

[0067] The blending of the inorganic filler contributes to the improvement of the mechanical properties of the ultraviolet-curable liquid silicone cured product of the present invention obtained, but also affects the ultraviolet transmittance of the silicone composition. Therefore, it is preferable to adjust it to an optimal amount according to the purpose.

[0068] Furthermore, the ultraviolet-curable liquid silicone composition of the present invention can be suitably used without blending an organic solvent. However, when coating the silicone composition on various substrates, depending on the conditions of coating equipment, etc., the composition of the present invention may be diluted to an arbitrary concentration with an organic solvent such as toluene, xylene, hexane, ethyl acetate, etc.

[0069] Also, as a method for reducing the viscosity of the ultraviolet curable liquid silicone composition of the present invention, a non-reactive organopolysiloxane having no reactive groups such as Si-H group, aliphatic unsaturated bond-containing group, epoxy group, alkoxysilyl group, and silanol group may be used.

[0070] The viscosity of the ultraviolet curable liquid silicone composition of the present invention at 25 °C is preferably 10 to 120,000 mPa·s, more preferably 1,000 to 50,000 mPa·s. Within such a range, the coating property is excellent and it can remain at a constant film thickness on the substrate.

[0071] [Adhesive] The ultraviolet curable liquid silicone composition of the present invention can be used as an adhesive for adhering substrates such as resins. As the substrate, those activated by a pretreatment step added in a well-known process such as primer treatment, plasma treatment, and excimer light treatment can also be used.

[0072] The adhesive composed of the ultraviolet curable liquid silicone composition of the present invention is excellent in curability and storage stability and has good handleability.

[0073] [Silicone cured product] The silicone cured product of the present invention is a cured product of the ultraviolet curable liquid silicone composition of the present invention.

[0074] Examples of the ultraviolet light source useful for curing the ultraviolet curable liquid silicone composition of the present invention include ordinary mercury vapor lamps, metal halide lamps, and light emitting diode (LED) elements designed to emit ultraviolet energy in various ultraviolet wavelength bands. For example, the range of useful ultraviolet wavelengths is 220 to 400 nm, preferably 320 to 375 nm. Also, the ultraviolet irradiation amount useful for curing the ultraviolet curable liquid silicone composition of the present invention is not particularly limited as long as it is an irradiation amount sufficient for curing, but is preferably 1,000 to 10,000 mJ / cm 2 and more preferably 1,500 to 7,500 mJ / cm 2 is.

[0075] The ultraviolet-curable liquid silicone composition of the present invention can be cured in a short time of about several minutes at a low temperature of 100°C or lower after ultraviolet irradiation, and has excellent productivity. In addition, since it can be cured in a short time of several minutes to several hours even at room temperature, it can be applied to heat-sensitive members such as resin substrates.

[0076] Such a silicone cured product of the present invention can be suitably used for encapsulating, fixing, or adhering electrical and electronic components.

[0077] [Electrical and Electronic Components] The electrical and electronic components of the present invention are electrical and electronic components encapsulated, fixed, or adhered with the silicone composition of the present invention. Such electrical and electronic components have excellent reliability.

[0078] As a method of using the ultraviolet-curable liquid silicone composition of the present invention, for example, a method of bonding two or more image display device members can be mentioned. The bonding method includes a coating step of applying the ultraviolet-curable liquid silicone composition of the present invention to at least one image display device member, a bonding step of laminating another image display device member through the applied ultraviolet-curable liquid silicone composition having fluidity, and an ultraviolet irradiation step of irradiating the applied ultraviolet-curable liquid silicone composition with ultraviolet light.

[0079] Note that the ultraviolet irradiation step may be performed after the coating step and before the bonding step, or may be performed after the coating step and after the bonding step. Also, in the ultraviolet irradiation step, it is also preferable to irradiate ultraviolet light so as to transmit through the image display device member.

Examples

[0080] Hereinafter, the present invention will be specifically described using examples and comparative examples, but the present invention is not limited thereto.

[0081] [Examples 1 to 3, Comparative Examples 1 to 6] Each of the components shown below was mixed in the compounding amounts (parts by mass) in Table 1 to obtain the ultraviolet-curable liquid silicone compositions of Examples 1 to 3 and Comparative Examples 1 to 6.

[0082] <Component (A)> Dimethylpolysiloxane endblocked with trivinylsiloxy groups at both ends of the molecular chain having a viscosity of 1,500 mPa·s <Component (B)> Tris(dimethylhydrogensiloxy)phenylsilane having a viscosity of 2 mPa·s <Component (C)> 0.5 mass% solution of (methylcyclopentadienyl)trimethylplatinum complex [dimethylpolysiloxane endblocked with dimethylvinylsiloxy groups at both ends of the molecular chain (viscosity 600 mPa·s)]

[0083] <Component (D)> · (D-1): 1,2,3,4,5-Pentamethylcyclopentadiene · (D-2): 6,6-Dimethylfulvene · (D'-1): 1,5-Cyclooctadiene · (D'-2): Dicyclopentadiene

[0084] <Component (E)> 7-Octenyltrimethoxysilane (KBM-1083 manufactured by Shin-Etsu Chemical Co., Ltd.) <Reaction controller> · (F-1): 1,3,5,7-Tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane · (F-2): Dimethylbis(1,1-dimethyl-2-propynyloxy)silane

[0085] [Evaluation method] Regarding the ultraviolet-curable liquid silicone composition obtained above, the viscosity (initial, after standing at 40°C for 1 week), flow stop time, and hardness of the cured product were evaluated as follows. The results are shown in Table 1.

[0086] Viscosity (initial): The viscosity of the obtained ultraviolet-curable liquid silicone composition at 25°C was measured using a BL type rotational viscometer.

[0087] Viscosity (after standing at 40°C for 1 week): The obtained ultraviolet-curable liquid silicone composition was sealed in a container, left standing in a 40°C environment for 1 week, then cooled to 25°C, and the viscosity was measured using a BL type rotational viscometer. When the silicone composition became gel-like and could not be measured, it was described as "gelled".

[0088] Flow stop time: In a 25°C environment, the obtained ultraviolet-curable liquid silicone composition was filled in a glass petri dish to a height of 1 cm, and irradiated with ultraviolet light using an LED lamp with a wavelength of 365 nm so that the integrated light quantity was 3,000 mJ / cm 2 at an illuminance of 100 mW / cm 2 Next, the glass petri dish was tilted 90°, and the time (minutes) until the silicone composition no longer deformed was measured.

[0089] Hardness after curing: The obtained ultraviolet-curable liquid silicone composition was applied to an aluminum petri dish to a height of 0.6 cm, and irradiated with ultraviolet light using an LED lamp with a wavelength of 365 nm so that the integrated light quantity was 3,000 mJ / cm 2 at an illuminance of 100 mW / cm 2 Next, the aluminum petri dish was left standing at 25°C for 1 day, and then the hardness of the sample was measured using a durometer Type A hardness tester according to JIS K 6253-3:2012.

[0090]

Table 1

[0091] As shown in Table 1, it was found that the ultraviolet-curable silicone composition of the present invention can be cured in a short time at room temperature after ultraviolet irradiation, and also maintains its liquid state and has excellent storage stability even after standing in a 40°C environment for 1 week. On the other hand, in Comparative Examples 1 and 2 that do not contain the component (D) of the present invention, and Comparative Examples 4 to 6 in which the component (D) is changed to other cyclic unsaturated compounds ((D'-1) component, (D'-2) component), gelation occurred after standing in a 40°C environment for one week, resulting in poor storage stability. Further, the ultraviolet curable silicone composition of Comparative Example 3 containing an excessive amount of the component (D) with respect to the component (C) had good storage stability (viscosity after standing in a 40°C environment for one week), but curing did not occur upon ultraviolet irradiation.

[0092] From the above results, the ultraviolet curable silicone composition of the present invention can be cured in a short time under mild temperature conditions of 100°C or lower, and has excellent storage stability, excellent curability and storage stability, and can provide an adhesive with good handleability. It is clear that the cured product is suitably used for sealing, fixing, or adhering of electric and electronic components.

[0093] Note that the present invention is not limited to the above embodiments. The above embodiments are illustrative, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Claims

1. (A) A linear organopolysiloxane having a viscosity at 25°C of 50 to 100,000 mPa·s and having at least two alkenyl groups directly bonded to silicon atoms in one molecule, (B) An organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule (C) A photoactive hydrosilylation reaction catalyst, and (D) It contains at least one of the compounds represented by the following formulas (1) and (2), and the blending amount of component (D) is such that the molar ratio of the component (D) / the component (C) is 0.1 to 50.

0. An ultraviolet curable liquid silicone composition characterized by this. 【Chemical 1】 〔In formulas (1) and (2), R １ ~R ７ are, independently of one another, a hydrogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, or a substituent represented by the following formula (3).〕 -Si(R ８ ) ３ (3) (wherein, R ８ are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms.)

2. The ultraviolet curable liquid silicone composition according to claim 1, wherein the blending amount of component (B) in the composition is such that the ratio of the number of hydrogen atoms directly bonded to silicon atoms (Si-H groups) / the number of aliphatic unsaturated bonds contained in the groups directly bonded to silicon atoms is 0.3 to 2.

5.

3. In the above formulas (1) and (2), R １ ~R ７ are each independently a hydrogen atom or a methyl group, and the ultraviolet curable liquid silicone composition according to claim 1, characterized in that.

4. The ultraviolet curable liquid silicone composition according to claim 1, wherein the blending amount of component (D) in the composition is such that the molar ratio of the component (D) / the component (C) is 1.0 to 25.

0.

5. Furthermore, it contains (E) a silane compound containing one or more selected from the group consisting of (meth)acrylic groups, epoxy groups, alkenyl groups, and alkoxysilyl groups. The ultraviolet curable liquid silicone composition according to claim 1.

6. An adhesive characterized by being composed of the ultraviolet curable liquid silicone composition according to any one of claims 1 to 5.

7. A silicone cured product characterized by being a cured product of the ultraviolet curable liquid silicone composition according to any one of claims 1 to 5.

8. An electric and electronic component sealed, fixed, or adhered with the silicone cured product according to claim 7.

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