Ultraviolet curable silicone composition

Abstract

Provided is an ultraviolet-curable silicone composition having excellent curability in portions that are not irradiated by light and in the thickness direction. Provided is an ultraviolet-curable silicone composition comprising (A) a polyorganosiloxane having at least two alkenyl groups in one molecule; (B) a polyorganosiloxane having, in one molecule, at least two hydrogen atoms or mercaptoalkyl groups bonded to a silicon atom; (C) an ultraviolet diffusion material; and (D) a platinum-based catalyst or a photoreaction initiator that is activated by ultraviolet light, the amount of component (C) blended per 100 parts by mass of component (A) being 0.05-15.0 parts by mass, and the transmission percentage of the composition before curing being 33-95% as measured at a wavelength of 365 nm in accordance with JIS K 0115.

Description

Technical Field

[0001] The present invention relates to a UV-curable silicone composition, and particularly to a UV-curable silicone composition whose cured product can be suitably used as a sealing material for electrical components, electronic components, etc. Background Art

[0002] As elastic adhesives, sealing materials, coating materials, electrical insulation sealing materials, etc. in semiconductor elements such as ICs and LSIs, and electrical / electronic components equipped with these semiconductor elements, capacitors, resistors, etc., and optical components such as lenses, mirrors, filters, prisms, etc., silicone compositions are used from the viewpoints of excellent heat resistance and obtaining good adhesion and bonding properties to these components. In particular, a UV-curable addition reaction type silicone composition utilizing hydrosilylation is widely used because it cures by short-time UV irradiation, has excellent productivity, and can bond well between components.

[0003] As such a UV-curable silicone composition, Patent Document 1 discloses a UV-curable organopolysiloxane gel composition for a damping material of an objective lens driving device, which contains, in a given ratio: (A) an organopolysiloxane having an average of 0.1 or more alkenyl groups bonded to silicon atoms in one molecule; (B) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule; and (C) a photoactive platinum complex curing catalyst, showing that a composition having both the advantages of a given polymer design and rapid curability based on UV irradiation can be prepared.

[0004] In addition, Patent Document 2 discloses a UV-curable liquid silicone composition for an image display device, which contains, in a given ratio: (A) an organopolysiloxane having a viscosity of 50 to 100,000 mPa·s at 25°C and containing at least two alkenyl groups in one molecule; (B) an organohydrogenpolysiloxane such as a linear organohydrogenpolysiloxane having hydrogen atoms (Si-H groups) directly bonded to silicon atoms only at the terminals on both sides of the molecular chain; and (C) one or more photoactive hydrosilylation reaction catalysts selected from a specific compound group, has a given viscosity, and can cure in several minutes to several tens of minutes under mild temperature conditions of 100°C or lower, showing that a cured product having good mechanical properties and optical properties can be provided.

[0005] On the other hand, a UV-curable silicone composition using a mercapto-functionalized polyorganosiloxane, a photoinitiator, and various fillers is also known. For example, Patent Document 3 discloses a UV-curable silicone composition containing: (A) having a unit formula [(CH3)3SiO 1 / 2 x ​[[(CH3)2SiO]] y [R(CH3)SiO] z (R is independently a mercapto group (C 1～30 ) hydrocarbyl) mercapto-functional polyorganosiloxane; a polyorganosiloxane containing at least 2 aliphatic unsaturated carbon-carbon bonds and at least 1 in an organic molecule; a filler such as silica powder, ceramic glass powder; and a photoinitiator.

[0006] In Patent Document 4, there is disclosed an ultraviolet curable silicone composition comprising: (A) an alkenyl-functional, linear triorganosiloxy-terminated polydiorganosiloxane having at least 2 vinyl groups or the like bonded to silicon atoms in each molecule, (B) represented by the general formula: R’’R’2SiO(R’’’R’SiO) x (R’RSiO) y SiR’2R’’ (each R is selected from mercaptoalkyl groups having 2 to 6 carbon atoms / groups, and each R’’ is selected from groups of R and R’), a mercapto-functional crosslinking agent having at least 2 mercapto groups in each molecule; (C) a photosensitizer; (D) a storage stabilizer and optionally an enhancer such as pyrogenic silica.

[0007] Such an ultraviolet curable silicone composition starts to cure upon irradiation with ultraviolet light, and thus there is a problem that the composition flows during the period until complete curing and the curing of the portion not irradiated with ultraviolet light is insufficient. To solve such a problem, various curing methods for ultraviolet curable silicone compositions have been proposed. For example, in Patent Document 5, for the purpose of curing while maintaining the shape at the initial stage of heating, there is disclosed a curing method including a step of heating after irradiating the composition with light having a specific emission spectrum. Further, in Patent Document 6, for the purpose of uniformly curing even a portion where light does not reach and a thick molded article, there is disclosed a curing method of a composition, which is composed of a first step and a second step. In the first step, the composition is irradiated with ultraviolet light to increase the catalytic activity of a photoactive platinum complex curing catalyst, and in the second step, the composition obtained in the first step is applied to a desired site and cured.

[0008] On the other hand, it is also known to incorporate a light diffusing agent, an inorganic ultraviolet absorber, etc. into silicone compositions such as thermosetting type and moisture-curing type. For example, in Patent Document 7, a silicone rubber composition is disclosed which contains, in a given proportion: (A) a thermosetting silicone rubber mixture, and (B) a diffusing agent composed of inorganic particles containing calcium carbonate having a given particle size and refractive index, and is shown to be usable as a manufacturing material for the outer cover of lighting fixtures etc. which require light diffusibility. In Patent Documents 8 and 9, a light diffusing dimethyl silicone rubber composition is disclosed which disperses, in a given proportion, a light diffusing agent composed of silicone elastomer particles or fine glass beads having a given average particle size in an uncured dimethyl silicone rubber complex, and is shown to be usable in members etc. for the purpose of scattering LED light.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-213132

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2019-210351

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2017-502102

[0014] Patent Document 4: Japanese Patent Application Laid-Open No. 60-110752

[0015] Patent Document 5: Japanese Patent Application Laid-Open No. 2012-121960

[0016] Patent Document 6: Japanese Patent Application Laid-Open No. 2013-87199

[0017] Patent Document 7: Japanese Patent Application Laid-Open No. 2013-185123

[0018] Patent Document 8: Japanese Patent Application Laid-Open No. 2011-184625

[0019] Patent Document 9: Japanese Patent Application Laid-Open No. 2012-33462 Summary of the Invention

[0020] Problems to be Solved by the Invention

[0021] Although the ultraviolet curable silicone compositions disclosed in Patent Documents 1 to 4 are cured by irradiation with ultraviolet rays and exhibit given mechanical properties and optical properties, the curability in the portions not irradiated with light and in the thickness direction is insufficient, and there is a problem that the quality of the cured product is unstable. In addition, since the curing methods such as those disclosed in Patent Documents 5 and 6 require additional equipment and the operations become complicated, an ultraviolet curable silicone composition that can provide a cured product with stable quality without using these methods is required. Further, the compositions of Patent Documents 7 to 9 are intended for use in light diffusing members such as outer covers for lighting fixtures, which are formed by thermally curing the compositions, and are not intentionally cured by ultraviolet irradiation, and are not compositions cured by ultraviolet rays.

[0022] An object of the present invention is to provide an ultraviolet curable silicone composition having excellent curability in portions not irradiated with light and in the thickness direction.

[0023] Means for Solving the Problem

[0024] The present inventors repeatedly conducted in-depth studies to solve the above problems, and as a result, found that by blending a given amount of an ultraviolet diffusing material in an ultraviolet curable silicone composition and adjusting the transmittance of the composition to a given range, the curability of the composition can be improved, thereby achieving the present invention.

[0025] The present invention relates to the following [1] to

[17] .

[0026] [1] An ultraviolet curable silicone composition comprising: (A) a polyorganosiloxane having at least two alkenyl groups in one molecule; (B) a polyorganosiloxane having at least two hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule; (C) an ultraviolet diffusing material; and (D) a platinum-based catalyst or a photoreaction initiator activated by ultraviolet rays, wherein the blending amount of the (C) component is 0.05 to 15.0 parts by mass with respect to 100 parts by mass of the (A) component, and the transmittance percentage before curing of the above composition measured at a wavelength of 365 nm in accordance with JIS K 0115 is 33 to 95%.

[0027] [2] The ultraviolet curable silicone composition according to [1], wherein the absorbance at a wavelength of 365 nm obtained by measuring, in accordance with JIS K 0115, a sample prepared by using a spacer and two glass plates so that the thickness of the above mixture is 200 μm instead of a glass cell for a mixture of 100 parts by mass of the (A) component and 0.25 parts by mass of the (C) component is in the range of 0.005 to 0.5.

[0028] [3] The ultraviolet curable silicone composition according to [1] or [2], wherein the composition is irradiated with ultraviolet light having a diameter of 7.0 mm and an illuminance of 100 mW / cm 2 at a wavelength of 365 nm for 45 seconds in a yellow light room, and then stored at 23 °C for 16 hours to obtain a cured product. In the obtained cured product, the cured diameter at a depth of 5.8 mm is 18 mm or more.

[0029] [4] The ultraviolet curable silicone composition according to any one of [1] to [3], wherein the average particle diameter of the component (C) is 0.01 to 25 μm.

[0030] [5] The ultraviolet curable silicone composition according to any one of [1] to [4], wherein the component (C) is selected from calcium carbonate, silica, and alumina.

[0031] [6] The ultraviolet curable silicone composition according to any one of [1] to [5], wherein the component (A) contains linear polyorganosiloxane, and the average alkenyl content of the component (A) is 0.03 to 1.0 mmol / g.

[0032] [7] The ultraviolet curable silicone composition according to any one of [1] to [6], wherein the component (B) is a polyorganohydrogensiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule, and the component (D) is a platinum-based catalyst activated by ultraviolet light.

[0033] [8] The ultraviolet curable silicone composition according to [7], wherein the component (B-1) contains (b1) containing R c1 2HSiO 1 / 2 units (wherein R c1 is independently a C1-C6 alkyl group or a C6-C 20 aryl group) and SiO 4 / 2 units of polyorganohydrogensiloxane.

[0034] [9] The ultraviolet curable silicone composition according to [7] or [8], wherein the component (D-1) is a platinum-based catalyst having a cyclic diene compound as a ligand, and the compounding amount of the component (D-1) in the composition is 1 to 50 ppm in terms of the mass of platinum metal.

[0035]

[10] The ultraviolet curable silicone composition according to any one of [7] to [9], wherein the ratio of the number of moles of hydrogen atoms bonded to silicon atoms of the component (B-1), H B to the number of moles of alkenyl groups of the component (A), Vi A i.e., H B / Vi AThe ratio is 0.3 to 2.0.

[0036]

[11] The ultraviolet curable silicone composition according to any one of [1] to [6], wherein the component (B) is a polyorganosiloxane (B-2) having at least two mercaptoalkyl groups bonded to a silicon atom in one molecule, and the component (D) is a photoreaction initiator (D-2).

[0037]

[12] The ultraviolet curable silicone composition according to

[11] , wherein the component (B-2) contains (b2) a polyorganosiloxane containing at least two R d1 SiO 3 / 2 units (wherein R d1 is a mercaptoalkyl group having 1 to 6 carbon atoms).

[0038]

[13] A potting material comprising the ultraviolet curable silicone composition according to any one of [1] to

[12] .

[0039]

[14] The potting material according to

[13] , which is used for connector pins.

[0040]

[15] A sealing material comprising a cured product of the ultraviolet curable silicone composition according to any one of [1] to

[12] .

[0041]

[16] The sealing material according to

[15] , which is used for electrical components or electronic components.

[0042]

[17] The sealing material according to

[16] , wherein the electrical component or electronic component is a connector having connector pins.

[0043] Advantages of the Invention

[0044] According to the present invention, it is possible to provide an ultraviolet curable silicone composition having excellent curability in a portion not irradiated with light and in the thickness direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a photograph taken in a yellow light room of a sample for measuring the absorbance at a wavelength of 365 nm of a mixed solution of 100 parts by mass of the component (A) and 0.25 parts by mass of the component (C) and the ultraviolet curable silicone composition.

[0046] Figure 2 is a photograph taken from above in a yellow light room of a device for measuring the curing diameter.

[0047] Figure 3 is a schematic view when observing the Figure 2 device from above.

[0048] Figure 4 is Figure 3 a sectional view taken along line A-A' of

[0049] Figure 5 is a schematic diagram showing the cured area and cured diameter after ultraviolet irradiation in Figure 3 and 4 It is a schematic diagram showing the cured area and cured diameter after ultraviolet irradiation in

[0050] Figure 6 is a graph showing the relationship between the parts by mass of untreated calcium carbonate (average particle diameter 2.0 μm) as component (C) relative to 100 parts by mass of component (A) and the cured diameters at the upper part (depth 0 mm), middle part (depth 2.9 mm), and lower part (depth 5.8 mm) based on Examples 1 to 6 and Comparative Examples 1 to 2.

[0051] Figure 7 is a graph showing the relationship between the average particle diameter of calcium carbonate in a composition in which 0.25 part by mass of calcium carbonate is blended relative to 100 parts by mass of component (A) and the cured diameters at the upper part (depth 0 mm), middle part (depth 2.9 mm), and lower part (depth 5.8 mm) based on Examples 2 and 22 to 30. Detailed Description

[0052] The ultraviolet curable silicone composition contains: (A) a polyorganosiloxane having at least 2 alkenyl groups in one molecule; (B) a polyorganosiloxane having at least 2 hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule; (C) an ultraviolet diffusing material; and (D) a platinum-based catalyst or a photoreaction initiator activated by ultraviolet rays. The blending amount of component (C) relative to 100 parts by mass of component (A) is 0.05 to 15.0 parts by mass, and the transmission percentage of the above composition before curing measured at a wavelength of 365 nm in accordance with JIS K 0115 is 33 to 95%. By blending a given amount of component (C) and setting the transmission percentage of the composition before curing to 33 to 95%, an ultraviolet curable silicone composition excellent in curability in the portions not irradiated with light and in the thickness direction can be produced.

[0053] From the viewpoint of the curability of the composition, it is preferable that component (B) is a combination of (B-1) a polyorganohydrosiloxane having at least 2 hydrogen atoms bonded to silicon atoms in one molecule and component (D) is a combination of (D-1) a platinum-based catalyst activated by ultraviolet rays; or component (B) is a combination of (B-2) a polyorganosiloxane having at least 2 mercaptoalkyl groups bonded to silicon atoms in one molecule and component (D) is a combination of (D-2) a photoreaction initiator.

[0054] For the purposes of this specification, the term "organic group" means a group containing carbon. The valence of an organic group is denoted as "n-valent" by setting n as an arbitrary natural number. Thus, for example, a "monovalent organic group" means a carbon-containing group having only one bonding end. Elements other than carbon may also have bonding ends. Even without specifically indicating the valence, those skilled in the art can determine the appropriate valence based on the context.

[0055] For the purposes of this specification, the term "hydrocarbyl group" means a group containing carbon and hydrogen and having at least one hydrogen atom removed from the molecule. The hydrocarbyl group is not particularly limited and may be substituted by one or more substituents. Examples of the hydrocarbyl group include hydrocarbyl groups having 1 to 20 carbon atoms, such as aliphatic hydrocarbyl groups and aromatic hydrocarbyl groups. The above-mentioned "aliphatic hydrocarbyl group" may be linear, branched, or cyclic, and may be saturated or unsaturated. In addition, the hydrocarbyl group may contain one or more ring structures. It should be noted that the hydrocarbyl group may have one or more nitrogen atoms (N), oxygen atoms (O), sulfur atoms (S), silicon atoms (Si), amide bonds, sulfonyl bonds, siloxane bonds, carbonyl groups, carbonyloxy groups, etc. or structures containing heteroatoms at its terminal or in the molecular chain.

[0056] For the purposes of this specification, the substituents of the "hydrocarbyl group" are not particularly limited. For example, they may include halogen atoms; groups selected from C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-10 cycloalkyl, C 3-10 unsaturated cycloalkyl, 5- to 10-membered heterocyclic groups, 5- to 10-membered unsaturated heterocyclic groups, C 6-10 aryl, and 5- to 10-membered heteroaryl groups that may be substituted by one or more halogen atoms.

[0057] In this specification, unless otherwise specified, alkyl and phenyl groups may be unsubstituted or substituted. The substituents of these groups are not particularly limited. For example, they may include groups selected from halogen atoms, C 1-6 alkyl, C 2-6 alkenyl, and C 2-6 alkynyl, one or more of which.

[0058] In this specification, when describing the structure of a siloxane compound, the structure units of the siloxane compound are sometimes recorded using the following abbreviated symbols. Hereinafter, these structure units may be referred to as "M units", "D units", etc.

[0059] M: (CH3)3SiO 1 / 2

[0060] M H : H(CH3)2SiO 1 / 2

[0061] M Vi : CH2=CH(CH3)2SiO 1 / 2

[0062] D: (CH3)2SiO 2 / 2

[0063] D H : H(CH3)SiO 2 / 2

[0064] D Vi : CH2=CH(CH3)SiO 2 / 2

[0065] T: CH3SiO 3 / 2

[0066] T SH : HS(CH2)3SiO 3 / 2

[0067] Q: SiO 4 / 2 (tetrafunctional)

[0068] The silicone compound is a compound constructed by combining the above structural units, and may at least partially contain substances in which methyl groups of the above structural units are replaced by other groups such as halogens such as fluorine and hydrocarbon groups such as phenyl groups. In addition, for example, when denoted as D H 20 D 20 it does not mean 20 consecutive D units followed by 20 consecutive D units, but is understood that the respective units can be arranged arbitrarily. The silicone compound can three-dimensionally obtain various structures by using T units or Q units. H

[0069] <Physical properties of the ultraviolet curable silicone composition>

[0070] [Transmission percentage before curing of the composition]

[0071] In the ultraviolet curable silicone composition, the percentage of light transmittance of the composition before curing measured at a wavelength of 365 nm in accordance with JIS K 0115 is 33 to 95%. By setting the percentage of light transmittance within the above range, an ultraviolet curable silicone composition excellent in curability in the portion not irradiated with light and in the thickness direction can be produced. If the percentage of light transmittance is less than 33%, the curability of the composition is significantly reduced. If the percentage of light transmittance is greater than 95%, although the composition is cured by ultraviolet light, the effect of improving the curability in the portion not irradiated with light and in the thickness direction is small. The above percentage of light transmittance is preferably 33 to 90%, more preferably 33 to 88%, further preferably 34 to 88%, further preferably 40 to 85%, further preferably 48 to 77%, still further preferably 48 to 72%, and particularly preferably 50 to 67%.

[0072] By appropriately selecting the type and blending amount of the (C) ultraviolet diffusing material, the percentage of light transmittance can be adjusted to the above range.

[0073] In the present invention, the percentage of light transmittance of the composition before curing is measured as follows in accordance with JIS K 0115. Using a cell with a thickness of 10 mm, the composition before curing is added to the sample cell, and ion-exchanged water is added to the reference cell, and the transmittance of the composition at a wavelength of 365 nm is measured. Then, in accordance with the Lambert-Beer law, the obtained measured value is converted from a thickness of 10 mm to a thickness of 1 mm to obtain the percentage of light transmittance of the composition.

[0074] [Absorbance of the mixture of 100 parts by mass of the (A) component and 0.25 part by mass of the (C) component]

[0075] From the viewpoint of improving the curability in the portion not irradiated with light and in the thickness direction, for the mixture of 100 parts by mass of the (A) component and 0.25 part by mass of the (C) component, the absorbance at a wavelength of 365 nm measured by replacing the glass cell with a sample prepared using a spacer and two glass plates so that the thickness of the above mixture is 200 μm in accordance with JIS K 0115 is preferably in the range of 0.005 to 0.5, more preferably 0.02 to 0.5, further preferably 0.02 to 0.4, still further preferably 0.03 to 0.3, and particularly preferably 0.05 to 0.2.

[0076] [Absorbance of the composition before curing]

[0077] From the viewpoint of improving the curability in the portions not irradiated with light and in the thickness direction, for the ultraviolet curable silicone composition before curing, the absorbance at a wavelength of 365 nm measured using a specimen made of a spacer and two glass plates in such a manner that the thickness of the above composition is 200 μm instead of a glass cell in accordance with JIS K 0115 is preferably in the range of 0.005 to 3.0, more preferably in the range of 0.015 to 2.7, still more preferably in the range of 0.02 to 2.6, and particularly preferably in the range of 0.02 to 1.0.

[0078] Figure 1 shows a photograph taken of a specimen for measuring the absorbance at a wavelength of 365 nm of the above mixture and the above composition in accordance with JIS K 0115. As Figure 1 shown, a specimen is made of a spacer and two glass plates in such a manner that the thickness of the above mixture or the above composition is 200 μm, and it is used as a specimen cell by replacing a glass cell. As the glass plates, micro slides S9112 (manufactured by Matsunami Glass Industry Co., Ltd., 76 mm × 52 mm × 1.0 to 1.2 mm thick) are used. Figure 1 In, the white part is the part where two glass plates are overlapped, and the above mixture or the above composition with a thickness of 200 μm exists in the transparently cut part in the glass plate. As the reference cell, one of the above micro slides S9112 is used.

[0079] <(A) Polyorganosiloxane having at least two alkenyl groups in one molecule>

[0080] The component (A) is a polyorganosiloxane having at least two alkenyl groups in one molecule. The component (A) functions as a base polymer of the ultraviolet curable silicone composition. The alkenyl group may be bonded to the molecular chain end of the molecular main chain, may be bonded to the side chain in the middle of the molecular chain, or may be bonded to both. In this specification, the so-called molecular main chain means the relatively longest bonded chain in the molecule. As long as the molecular structure of the component (A) is a structure having a siloxane bond as the main skeleton, there is no particular limitation, and it may be any of linear, branched, cyclic, or three-dimensional network-like, and the siloxane skeleton may be interrupted by a divalent organic group. The component (A) may be used alone or in combination of two or more.

[0081] Component (A) has at least two alkenyl groups in one molecule. Component (A) may be a mixture of a plurality of polyorganosiloxanes having at least two alkenyl groups in one molecule. Among them, from the viewpoint of forming a stable three-dimensional structure based on a crosslinking reaction during curing and imparting appropriate hardness to the cured product, component (A) preferably contains linear polyorganosiloxane, and more preferably contains linear polyorganosiloxane having one alkenyl group at each of the two ends of the molecular main chain. In this case, component (A) preferably contains 30% by mass or more of linear polyorganosiloxane based on 100% by mass of component (A), more preferably contains 50% by mass or more, and further preferably contains 80% by mass or more. The upper limit of the content of linear polyorganosiloxane based on 100% by mass of component (A) is 100% by mass.

[0082] The alkenyl group is not particularly limited as long as it has a carbon-carbon double bond and can undergo an addition reaction. The carbon number of the alkenyl group is preferably 2 to 20, more preferably 2 to 8, and further preferably 2 to 6. The alkenyl group may also have a branched structure or a ring structure. The position of the carbon-carbon double bond in the hydrocarbon constituting the alkenyl group can be any position. From the aspect of reactivity, the carbon-carbon double bond is preferably located at the end of the group. As a preferred example of the alkenyl group, vinyl can be cited from the aspect of easy synthesis of polyorganosiloxane.

[0083] The alkenyl content of component (A) is not particularly limited and can be 0.02 mmol / g or more on average. The alkenyl content of component (A) is preferably 0.02 to 2.0 mmol / g on average, more preferably 0.03 to 1.0 mmol / g, further preferably 0.03 to 0.5 mmol / g, still further preferably 0.04 to 0.5 mmol / g, and particularly preferably 0.10 to 0.50 mmol / g. By setting the alkenyl content within the above range, an ultraviolet curable silicone composition excellent in curability and storage stability in a portion not irradiated with light and in the thickness direction can be prepared. Here, when component (A) is a mixture of a plurality of polyorganosiloxanes, the alkenyl content of component (A) is the average value of the mixture.

[0084] The alkenyl content of component (A) can be determined by a spectrophotometer based on the absorbance (near 2150 nm) of the CH2=CH- group.

[0085] In one embodiment of the present invention, component (A) has at least two alkenyl groups bonded to silicon atoms in one molecule. Component (A) forms a network structure through an addition reaction with the hydrosilyl group (Si-H group) of component (B-1) or the mercapto group of component (B-2) described later. Component (A) typically has at least two alkenyl-containing siloxane units represented by the general formula (1) in the molecule:

[0086] R1 m R 2 n SiO （4-m-n） / 2 (1)

[0087] (wherein,

[0088] R 1 is an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond;

[0089] R 2 is an alkenyl group;

[0090] m is an integer of 0 to 2;

[0091] n is an integer of 1 to 3, where m + n is 1 to 3.).

[0092] R 1 is an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond. Specifically, R 1 may be an alkyl group, such as a C1-C6 alkyl group (such as methyl, ethyl, propyl, etc.); a cycloalkyl group, such as a C3-C 10 cycloalkyl group (such as cyclohexyl, etc.); an aryl group, such as a C6-C 20 aryl group (such as phenyl, tolyl, xylyl, naphthyl, anthryl, etc.); an aralkyl group, such as a C7-C 13 aralkyl group (such as 2-phenylethyl, 2-phenylpropyl, etc.); a substituted hydrocarbon group, such as a halogen-substituted hydrocarbon group (such as chloromethyl, chlorophenyl, 3,3,3-trifluoropropyl, etc.). From the viewpoint of ease of synthesis and the like, an alkyl group is preferred, among which methyl, ethyl and propyl are preferred, and methyl is more preferred. In order to adjust the refractive index, an aryl group may be used in combination, and among them, phenyl is preferred from the viewpoint of ease of synthesis and the like.

[0093] From the viewpoint of obtaining an ultraviolet-curable silicone composition having excellent curability and storage stability, the component (A) preferably contains a linear polyorganosiloxane having one alkenyl group at each of the two ends of the molecular main chain. In one embodiment of the present invention, the linear polyorganosiloxane can be represented by the formula (I), for example:

[0094] [Chemical formula 1]

[0095]

[0096] (wherein,

[0097] R a1 is independently a C2-C6 alkenyl group,

[0098] R b1 is independently a C1-C6 alkyl group or a C6-C 20 aryl group,

[0099] n1 is a number obtained by averaging the alkenyl content of the linear polyorganosiloxane to 0.02 mmol / g or more).

[0100] Examples of the C2-C6 alkenyl group include vinyl, allyl, 3-butenyl, and 5-hexenyl groups. Examples of the C1-C6 alkyl group include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups. C6-C 20 Examples of the aryl group include phenyl, naphthyl, and anthryl groups.

[0101] Regarding R a1 , from the viewpoints of ease of synthesis and not impairing the fluidity of the composition before curing and the heat resistance of the cured product, vinyl is preferred. Regarding R b1 , from the viewpoints of ease of synthesis and excellent balance of the fluidity of the composition, mechanical strength of the cured product, etc., a C1-C6 alkyl group is preferred, and methyl is particularly preferred. Therefore, the component (A) is preferably a polymethylvinylsiloxane in which both ends are blocked by dimethylvinylsiloxane units and the intermediate units contain dimethylsiloxane units.

[0102] The content of the polymethylvinylsiloxane in which both ends are blocked by dimethylvinylsiloxane units and the intermediate units contain dimethylsiloxane units in 100% by mass of the component (A) is preferably 30% by mass or more, more preferably 50% by mass or more, and still more preferably 80% by mass or more. The upper limit of the above content is 100% by mass.

[0103] Regarding n1, from the viewpoints of ensuring stable liquid properties of the composition and curability in portions not irradiated with light and in the thickness direction, it is preferably a number obtained by averaging the alkenyl content of the linear polyorganosiloxane to 0.02 mmol / g or more, more preferably a number in the range of 0.02 to 2.0 mmol / g, still more preferably a number in the range of 0.03 to 1.0 mmol / g, still more preferably a number in the range of 0.03 to 0.5 mmol / g, even more preferably a number in the range of 0.04 to 0.5 mmol / g, and particularly preferably a number in the range of 0.10 to 0.50 mmol / g.

[0104] The viscosity of the component (A) at 23°C is preferably 10 to 100,000 mPa·s, more preferably 100 to 50,000 mPa·s, and still more preferably 100 to 10,000 mPa·s.

[0105] In this specification, the viscosity of each component and the ultraviolet curable silicone composition is a value measured using a rotational viscometer in accordance with JIS K 6249 under the conditions of a No. 1, 2, 3, or 4 rotor, 0.3 to 60 rpm, and 23°C.

[0106] The component (A) may also be a mixture of a polymethylvinylsiloxane having dimethylvinylsiloxane units at both ends and dimethylsiloxane units in the middle units and other linear, branched or cyclic polyorganosiloxanes containing alkenyl groups.

[0107] Commercially available products can be used for the component (A). In addition, polyorganosiloxanes having alkenyl groups introduced by known reactions can also be used. As the component (A), depending on the position or type of substituents, degree of polymerization, etc., only one compound can be used, or two or more compounds can be used in combination. Since the component (A) is a polyorganosiloxane, it can be a mixture of polyorganosiloxanes having various degrees of polymerization.

[0108] From the viewpoint of the balance of workability, curability and storage stability, the blending amount of the component (A) is preferably 70.0 to 99.8% by mass, more preferably 80.0 to 99.7% by mass, and still more preferably 90.0 to 99.7% by mass based on 100% by mass of the ultraviolet curable silicone composition.

[0109] <(B) Polyorganosiloxane having at least two hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule>

[0110] The component (B) is a polyorganosiloxane having at least two hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule. The component (B) functions as a crosslinking agent and forms a network structure through an addition reaction with the alkenyl group of the component (A). The component (B) can be used alone or in combination of two or more. Hereinafter, a polyorganohydrosiloxane (B-1) having at least two hydrogen atoms bonded to silicon atoms in one molecule and a polyorganosiloxane (B-2) having at least two mercaptoalkyl groups bonded to silicon atoms in one molecule will be specifically described.

[0111] [(B-1) Polyorganohydrosiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule]

[0112] The hydrogen atoms of the component (B-1) can be bonded to the silicon atoms at the ends of the molecular chain, can be bonded to the silicon atoms in the middle of the molecular chain, or can be bonded to both. As long as the molecular structure of the component (B-1) is a structure with a siloxane bond as the main skeleton, there is no particular limitation, and it can be any of linear, branched, cyclic or three-dimensional network-like, and the siloxane skeleton can also be interrupted by divalent organic groups. In addition, the component (B-1) can have hydroxyl groups or alkoxy groups such as methoxy and ethoxy bonded to silicon atoms. The component (B-1) can be used alone or in combination of two or more.

[0113] In a typical case, the component (B-1) has at least two siloxane units represented by the general formula (2) containing a hydrogen atom bonded to a silicon atom in the molecule:

[0114] R 3 p H q SiO （4-p-q） / 2 (2)

[0115] (In the formula,

[0116] R 3 is an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond;

[0117] p is an integer from 0 to 2;

[0118] q is an integer from 1 to 3, where p + q is from 1 to 3.).

[0119] As R 3 , the same groups as R 1 in the general formula (1) can be cited, and the preferred modes are the same. In the component (B-1), the number of hydrogen atoms bonded to the silicon atom is preferably 3 to 100, more preferably 5 to 50, in one molecule.

[0120] The component (B-1) preferably contains (b1) a polyorganohydrogensiloxane containing R c1 2HSiO 1 / 2 units (in the formula, R c1 is independently a C1-C6 alkyl group or a C6-C 20 aryl group) and SiO 4 / 2 units. The inventors have found that when the composition is irradiated with ultraviolet light, the component (b1) not only has a high ability to cure the composition in the irradiated range but also has a high ability to cure the composition by three-dimensionally expanding the range. By making the component (B-1) contain the component (b1), a composition with more excellent curability in the part where light cannot reach around the irradiated part and in the thickness direction can be prepared.

[0121] The component (b1) can be any of a branched, cyclic, and three-dimensional network structure (a structure formed by densification of SiO 4 / 2 units). Regarding R c1 , a C1-C6 alkyl group is preferred from the viewpoints of ease of synthesis and the like, and a methyl group is particularly preferred.

[0122] Among them, the component (b1) is preferably a polyorganohydrogensiloxane bonded with 3 to 6 SiO 4 / 2 units and 6 to 12 R c1 2HSiO 1 / 2 units; particularly preferred is [R c1 2HSiO1 / 2 6[SiO 4 / 2 3, [R c1 2HSiO 1 / 2 8[SiO 4 / 2 4, [R c1 2HSiO 1 / 2 10 [SiO 4 / 2 5, [R c1 2HSiO 1 / 2 12 [SiO 4 / 2 6 such that 3 to 6 SiO 4 / 2 units form a cyclic siloxane skeleton, and 2 R 4 / 2 units are bonded to each SiO c1 2HSiO 1 / 2 unit of the cyclic polyorganohydrogensiloxane.

[0123] The viscosity of the component (B-1) at 23 °C is preferably 1 to 100 mPa·s, more preferably 1 to 50 mPa·s.

[0124] The component (B-1) can use commercially available products. In addition, the component (B-1) can also be synthesized by known reactions. As the component (B-1), depending on the position or type of substituents, degree of polymerization, etc., one compound can be used alone, or two or more compounds can be used in combination. Since the component (B-1) is a polyorganohydrogensiloxane, it can be a mixture of polyorganohydrogensiloxanes having various degrees of polymerization.

[0125] From the viewpoints of operability, curability, and expandability of the curing range, the molar ratio H B of the hydrogen atoms bonded to silicon atoms in the component (B-1) to the molar ratio Vi A of the alkenyl groups in the component (A), that is, the ratio H B / Vi A is preferably 0.3 to 2.0, more preferably 0.4 to 1.5, and particularly preferably 0.5 to 1.1.

[0126] [(B-2) A polyorganosiloxane having at least two mercaptoalkyl groups bonded to silicon atoms in one molecule]

[0127] ​​The mercaptoalkyl group of the component (B-2) can be bonded to the silicon atom at the end of the molecular chain, can be bonded to the silicon atom in the middle of the molecular chain, or can be bonded to both. As long as the molecular structure of the component (B-2) is a structure with a siloxane bond as the main skeleton, there is no particular limitation, and it can be any of linear, branched, cyclic, or three-dimensional network-like, and the siloxane skeleton can also be interrupted by a divalent organic group. In addition, the component (B-2) can have a hydroxyl group or an alkoxy group such as a methoxy group or an ethoxy group bonded to the silicon atom. The component (B-2) can be used alone or in combination of two or more.

[0128] In a representative case, the component (B-2) has at least two siloxane units represented by the general formula (3) containing a mercaptoalkyl group bonded to a silicon atom in the molecule:

[0129] R 3 r R 4 s SiO （4-r-s） / 2 (3)

[0130] (In the formula,

[0131] R 3 is an unsubstituted or substituted monovalent hydrocarbon group without an aliphatic unsaturated bond;

[0132] R 4 is a mercaptoalkyl group having 1 to 6 carbon atoms;

[0133] r is an integer of 0 to 2;

[0134] s is an integer of 1 to 3, where r + s is 1 to 3.).

[0135] From the aspect of ensuring a stable structure based on the crosslinking reaction while suppressing excessive curing shrinkage, the number of mercaptoalkyl groups bonded to the silicon atom is preferably 2 to 20, more preferably 3 to 10, and further preferably 3 to 7 in one molecule.

[0136] As R 4 , examples include mercaptomethyl, 2-mercaptoethyl, 3-mercaptopropyl, 4-mercaptobutyl, 6-mercaptohexyl, etc. However, from the aspect of ease of synthesis, etc., mercaptomethyl and 3-mercaptopropyl are preferred, and 3-mercaptopropyl is more preferred. As R 3 , examples include the same groups as R 1 in the general formula (1), and the preferred modes are also the same.

[0137] From the viewpoint of crosslinking reactivity, the component (B-2) preferably contains (b2) at least two R d1 SiO 3 / 2 units in one molecule (in the formula, Rd1 a polyorganosiloxane having a mercaptoalkyl group with 1 to 6 carbon atoms. Among them, the component (b2) more preferably contains at least 2 Rs in one molecule d1 SiO 3 / 2 units, and R 3 3SiO 1 / 2 units and R 3 2SiO 2 / 2 units.

[0138] From the viewpoints of workability and crosslinking reactivity, a compound in which the ratio of the number of R d1 SiO 3 / 2 units to the number of siloxane units not containing a mercaptoalkyl group is 1:60 to 1:5 is preferred, but it is not limited thereto.

[0139] From the viewpoint of ensuring curability and mechanical properties of the cured product, the content of the component (b2) relative to 100% by mass of the component (B-2) is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more. The upper limit of the content of the component (b2) relative to 100% by mass of the component (B-2) is 100% by mass.

[0140] The viscosity of the component (B-2) at 23°C is preferably 20 to 25000 mPa·s, more preferably 50 to 10000 mPa·s, and further preferably 100 to 1000 mPa·s.

[0141] The method for preparing the component (B-2) is not particularly limited. For example, it can be produced by hydrolyzing, polycondensing, or re-equilibrating a mercaptoalkylalkoxysilane such as mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptopropylmethyldimethoxysilane, mercaptopropylmethyldiethoxysilane, mercaptopropyldimethylmethoxysilane, mercaptopropyldimethylethoxysilane, etc. with a desired alkylchlorosilane, alkylalkoxysilane, or siloxane containing silanol.

[0142] The component (B-2) can use commercially available products. In addition, the component (B-2) can also be synthesized by known reactions. As the component (B-2), depending on the position or type of substituents, degree of polymerization, etc., only one compound can be used, or two or more compounds can be used in combination. Since the component (B-2) is a polyorganosiloxane, it can be a mixture of polyorganosiloxanes having various degrees of polymerization.

[0143] The number of mercapto groups in the component (B-2) can be measured by iodine-based colorimetric titration. This measurement is a method using the reaction of the following formula:

[0144] 2RSH + I2 → RSSR + 2HI

[0145] In the titration, the phenomenon that the titrant turns slightly yellow due to a trace amount of excessive iodine is utilized.

[0146] From the viewpoints of operability, curability, and expandability of the curing range, the number of moles of mercaptoalkyl bonded to a silicon atom, SH, of the component (B-2) B relative to the number of moles of vinyl group, Vi, of the component (A) A The ratio, that is, SH B / Vi A is preferably from 0.3 to 2.0, more preferably from 0.4 to 1.5, and particularly preferably from 0.5 to 1.1.

[0147] <(C) Ultraviolet Diffusion Material>

[0148] The component (C) is a component that significantly improves the curability in the portion where light does not reach and in the thickness direction when the composition is irradiated with ultraviolet rays. The component (C) can be used alone or in combination of two or more.

[0149] In the ultraviolet curable silicone composition, the transmission percentage before curing of the above composition measured at a wavelength of 365 nm in accordance with JIS K 0115 is 33 to 95%. The component (C) is not particularly limited as long as it is a substance that makes the transmission percentage before curing of the composition within the above range. The component (C) can also be surface-treated with a hydrophobizing agent such as fatty acid.

[0150] Examples of the component (C) include calcium carbonate, silica, alumina, magnesia, calcium oxide, glass beads, glass hollow spheres, etc. Among them, from the viewpoint of improving the curability in the portion where light does not reach and in the thickness direction, those selected from calcium carbonate, silica, and alumina are preferred, and calcium carbonate is more preferred.

[0151] From the viewpoint of improving the curability in the portion where light does not reach and in the thickness direction, the average particle diameter of the component (C) is preferably from 0.01 to 25 μm, more preferably from 0.01 to 15 μm, further preferably from 0.01 to 10 μm, still further preferably from 0.01 to 3.0 μm, and particularly preferably from 0.01 to 2.0 μm. In addition, from the viewpoint of operability, the lower limit of the average particle diameter of the component (C) is preferably set to 0.1 μm or more. The average particle diameter is the median diameter d50 of the primary particle diameter measured by the laser diffraction / scattering method. When the component (C) is aggregated, using an optical microscope, 50 aggregated primary particles are observed, and the average value of their maximum diameters is set as the average particle diameter.

[0152] From the viewpoints of improving the curability in the portions not irradiated with light and in the thickness direction, the blending amount of the component (C) is 0.05 to 15.0 parts by mass, preferably 0.10 to 10.0 parts by mass, more preferably 0.10 to 5.0 parts by mass, further preferably 0.10 to 2.0 parts by mass, still further preferably 0.10 to 1.0 parts by mass, and particularly preferably 0.10 to 0.25 parts by mass, based on 100 parts by mass of the component (A). If the blending amount of the component (C) is less than 0.05 parts by mass, the effect of improving the curability in the portions not irradiated with light cannot be obtained. If it is more than 15.0 parts by mass, the curability in the portions not irradiated with light and in the thickness direction is rather decreased.

[0153] <(D) Platinum-based catalyst or photoinitiator activated by ultraviolet rays>

[0154] The component (D) is a platinum-based catalyst or a photoinitiator activated by ultraviolet rays. From the viewpoint of crosslinking reactivity, when the component (B) is the component (B-1), the component (D) is preferably the platinum-based catalyst (D-1) activated by ultraviolet rays. Further, from the viewpoint of crosslinking reactivity, when the component (B) is the component (B-2), the component (D) is preferably the photoinitiator (D-2).

[0155] [(D-1) Platinum-based catalyst activated by ultraviolet rays]

[0156] The component (D-1) is a catalyst that is activated by ultraviolet rays and is used to promote the addition reaction between the alkenyl group of the component (A) and the hydrosilyl group (Si-H group) of the component (B), particularly the component (B-1). From the viewpoint of good catalytic activity, the component (D-1) is preferably a platinum-based catalyst having a cyclic diene compound as a ligand. The component (D-1) can be used alone or in combination of two or more.

[0157] Examples of the platinum-based catalyst having a cyclic diene compound as a ligand 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)ethyl dimethylplatinum complex, (cyclopentadienyl)acetyldimethylplatinum complex, (methylcyclopentadienyl)trimethylplatinum complex, (methylcyclopentadienyl)trihexylplatinum complex, (trimethylsilylcyclopentadienyl)trimethylplatinum complex, (dimethylphenylsilylcyclopentadienyl)triphenylplatinum complex, (cyclopentadienyl)dimethyltrimethylsilylmethylplatinum complex, and the like.

[0158] From the viewpoint of the curability of the composition, the compounding amount of the component (D-1) in the ultraviolet curable silicone composition is preferably an amount of 1 to 50 ppm in terms of the mass of platinum metal, more preferably 4 to 50 ppm, and still more preferably 10 to 50 ppm.

[0159] Similarly, the compounding amount of the component (D-1) relative to the total mass of the components (A) and (B) is preferably an amount of 1 to 50 ppm in terms of the mass of platinum metal, more preferably 4 to 50 ppm, and still more preferably 10 to 50 ppm.

[0160] [(D-2) Photoinitiator]

[0161] The component (D-2) is a component that acts as a radical initiator when the alkenyl group of the component (A) and the mercapto group of the component (B), particularly the component (B-2), are photocrosslinked, or acts as a sensitizer. Regarding the component (D-2), from the viewpoint of reactivity, aromatic hydrocarbons, acetophenone and its derivatives, benzophenone and its derivatives, o-benzoylbenzoate, benzoin and benzoin ethers and their derivatives, xanthone and its derivatives, disulfide compounds, quinone compounds, halogenated hydrocarbons and amines, organic peroxides, etc. can be exemplified. From the viewpoints of compatibility and stability with the components (A) and (B-2), compounds or organic peroxides containing a substituted or unsubstituted benzoyl group are more preferably contained. The component (D-2) can be used alone or in combination of two or more.

[0162] As the component (D-2), examples thereof include acetophenone, propiophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE (registered trademark) 651: manufactured by IGM Resins B.V.), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Irgacure (registered trademark) 1173: manufactured by IGM Resins B.V.), 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE (registered trademark) 184: manufactured by IGM Resins B.V.), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-1-one (IRGACURE (registered trademark) 2959: manufactured by IGM Resins B.V.), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (IRGACURE (registered trademark) 127: manufactured by IGM Resins B.V.), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (IRGACURE (registered trademark) 907: manufactured by IGM Resins B.V.), 2-benzyl-2-dimethylamino-(4-morpholinophenyl)-butan-1-one (IRGACURE (registered trademark) 369: manufactured by IGM Resins B.V.), 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (IRGACURE (registered trademark) 379: manufactured by IGM Resins B.V.); 2,4,6-trimethylbenzoyl-diphenyl-oxide phosphine (LUCIRIN TPO: manufactured by IGM Resins B.V.), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE (registered trademark) 819: manufactured by IGM Resins B.V.); 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyl oxime)] (IRGACURE (registered trademark) OXE 01: manufactured by IGM Resins B.V.), acetophenone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime) (IRGACURE (registered trademark) OXE 02: manufactured by IGM Resins B.V.); a mixture of 2-[2-oxo-2-phenylacetoxyethoxy]ethyl ester and 2-(2-hydroxyethoxy)ethyl ester (IRGACURE (registered trademark) 754: manufactured by IGM Resins B.V.), methyl benzoylformate (DAROCUR (registered trademark) MBF: IGM Resins B.V.ethyl-4-dimethylaminobenzoate (DAROCUR® EDB: manufactured by IGM Resins B.V.), 2-ethylhexyl-4-dimethylaminobenzoate (DAROCUR® EHA: manufactured by IGM Resins B.V.), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide (CGI 403: manufactured by IGM Resins B.V.), benzoyl peroxide, cumene hydroperoxide, etc.

[0163] From the viewpoint of the curability of the composition, the blending amount of the component (D-2) in the ultraviolet curable silicone composition is preferably an amount of 0.05 to 10% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0.1 to 5% by mass.

[0164] Similarly, the blending amount of the component (D-2) relative to the total mass of the components (A) and (B) is preferably an amount of 0.05 to 10% by mass, more preferably 0.1 to 10% by mass, and still more preferably 0.1 to 5% by mass.

[0165] <Other components>

[0166] The ultraviolet curable silicone composition may also contain other components as long as its object and effects are not impaired. As other components, flame retardants, tackifiers, heat resistance imparting agents, diluents, inhibitors of addition reaction curing catalysts, resins other than polyorganosiloxanes, etc. can be appropriately blended. In addition, the ultraviolet curable silicone composition may contain polyorganosiloxanes other than the component (A), for example, polyorganosiloxanes having 1 or less alkenyl groups in one molecule; polyorganohydrogensiloxanes other than the component (B-1), for example, polyorganohydrogensiloxanes having 1 hydrogen atom bonded to a silicon atom in one molecule; polyorganosiloxanes other than the component (B-2), for example, polyorganosiloxanes having 1 mercaptoalkyl group bonded to a silicon atom in one molecule; inorganic or organic pigments other than the component (C), etc. The other components can be used alone or in combination of two or more.

[0167] <Method for producing ultraviolet curable silicone composition>

[0168] The ultraviolet curable silicone composition can be obtained by mixing the components (A) to (D) and other components used as required using a mixer such as a planetary mixer. At the time of mixing, heating can be carried out in the range of 50 to 150 °C as required while mixing. In order to perform uniform finishing, a kneading operation is preferably carried out under high shear force. As the kneading device, there are a three-roll mill, a colloid mill, a sand mill, etc., and among them, the method using a three-roll mill is preferred.

[0169] In consideration of the storage stability of the composition, the ultraviolet-curable silicone composition can also be made into a two-component composition. In the case of making a two-component composition, it is preferred that the first agent contains components (A), (C) and (D) and does not contain component (B); the second agent contains components (A) and (B) and optionally used component (C) and does not contain component (D). In the two-component ultraviolet-curable silicone composition, the first agent and the second agent are prepared separately. The first agent and the second agent can be manufactured by the same method as the one-component composition.

[0170] From the viewpoints of workability, the curability in the portion where light does not reach around the portion irradiated with ultraviolet rays and in the thickness direction, the viscosity of the ultraviolet-curable silicone composition at 23 °C is preferably 10 to 100,000 mPa·s, more preferably 100 to 60,000 mPa·s, and still more preferably 100 to 20,000 mPa·s.

[0171] In the case where the ultraviolet-curable silicone composition is a two-component composition formed by the first agent and the second agent, the viscosities of the first agent and the second agent are preferably 10 to 100,000 mPa·s, more preferably 100 to 60,000 mPa·s, and still more preferably 100 to 20,000 mPa·s. The ultraviolet-curable silicone composition is preferably stored in the dark at a temperature below normal temperature.

[0172] <Method for curing ultraviolet-curable silicone composition>

[0173] The ultraviolet-curable silicone composition can be cured by irradiation with ultraviolet rays. The irradiation amount is preferably 100 to 10,000 mJ / cm 2 , more preferably 300 to 6,000 mJ / cm 2 , still more preferably 500 to 5,000 mJ / cm 2Note that the irradiation dose is the measured value of UVA. Here, UVA refers to ultraviolet rays in the wavelength range of 315 to 400 nm. The composition has good curability when irradiated with ultraviolet rays having a wavelength in the range of, for example, 250 to 450 nm. As a light source for emitting ultraviolet rays of such a wavelength, for example, a high-pressure mercury lamp (UV-7000) manufactured by USHIO Electric, Inc., a metal halide lamp (UVL-4001M3-N1), a metal halide lamp (JM-MTL 2KW) manufactured by JM tech of Korea, an ultraviolet irradiation lamp (OSBL360) manufactured by Mitsubishi Electric Corporation, an ultraviolet irradiation machine (UD-20-2) manufactured by GS YUASA Corporation, a fluorescent lamp (FL-20BLB) manufactured by Toshiba Corporation), H tubes, H+ tubes, V tubes, D tubes, Q tubes, and M tubes manufactured by Heraeus, an LED lamp (HLDL-155UV) manufactured by CCS Corporation, etc. can be mentioned.

[0174] Although the curing time of the composition also depends on the irradiation dose of ultraviolet rays, it is generally 30 minutes or less, preferably 10 minutes or less. Although the progress of curing of the composition can be judged visually, it can also be quantitatively evaluated based on the time until the storage modulus G' and the loss modulus G" become equal, the time until the storage modulus G' reaches a given value, etc. For example, under the condition of 23°C after ultraviolet irradiation, if the time until the storage modulus G' becomes equal to the loss modulus G" is within 30 minutes, preferably within 10 minutes, it can be said that the curing time is short and the operability is excellent, so it is preferred.

[0175] <Curing Property of Ultraviolet-Curable Organosilicon Composition>

[0176] The ultraviolet-curable organosilicon composition has excellent curability in the parts not irradiated with light and in the thickness direction. Specifically, after irradiating the ultraviolet-curable organosilicon composition with ultraviolet rays having a diameter of 7.0 mm, an illuminance of 100 mW / cm 2 , and a wavelength of 365 nm for 45 seconds in a yellow light room and storing it at 23°C for 16 hours to obtain a cured product, in the obtained cured product, the cured diameter at a depth of 5.8 mm is preferably 18 mm or more, more preferably 20 mm or more, and further preferably 23 mm or more.

[0177] In addition, after irradiating the ultraviolet-curable organosilicon composition with ultraviolet rays having a diameter of 7.0 mm, an illuminance of 100 mW / cm 2, after irradiating with ultraviolet light having a wavelength of 365 nm for 45 seconds and storing at 23°C for 16 hours to obtain a cured product, in the obtained cured product, the cured diameter at a depth of 2.9 mm is preferably 14 mm or more, more preferably 15 mm or more, and further preferably 16 mm or more. In addition, when irradiating the ultraviolet curable silicone composition in a yellow light room with a diameter of 7.0 mm and an illuminance of 100 mW / cm 2 , after irradiating with ultraviolet light having a wavelength of 365 nm for 45 seconds and storing at 23°C for 16 hours to obtain a cured product, in the obtained cured product, the cured diameter at a depth of 0 mm is preferably 7 mm or more, more preferably 11 mm or more, and further preferably 12 mm or more.

[0178] Use Figures 2 - 5 to explain the method for measuring the above-mentioned cured diameter. Figure 2 is a photograph taken from above of the device used to measure the cured diameter in a yellow light room, Figure 3 is a schematic view when observing the device from above. Figure 4 is Figure 3 A cross-sectional view taken along the line A-A' of Figure 5 is in Figure 3 and 4 is a schematic view for explaining the cured area and the cured diameter after ultraviolet irradiation in

[0179] A yellow light room refers to an environment that shields light with wavelengths of 500 nm or less including ultraviolet light. Specifically, it means an environment that cuts off 98% or more of the wavelengths of 500 nm or less from the light of fluorescent lamps. For example, a yellow light room is usually set up when processing photosensitive substances in a clean room of a semiconductor factory. For example, by using a windowless room and using commercially available yellow fluorescent lamps as lighting, a yellow light room can be made. As commercially available yellow fluorescent lamps, for example, yellow straight tube LED lamps manufactured by Toshiba Corporation can be cited.

[0180] As Figure 3 and 4 shown, prepare a metal mold 6 having a rectangular parallelepiped recess 1 (inside the dotted lines of Figure 3 and Figure 4 ) with a length of 60 mm, a width of 25 mm, and a depth of 6.0 mm. In order to prevent reflection of ultraviolet light, a black tape 4 for the bottom (thickness 0.2 mm) is pasted on the entire bottom surface of the recess 1. Thereafter, in a yellow light room, the sample 7 (the compositions of the examples and comparative examples) is filled into the recess 1, and an upper black tape 5 (thickness 0.2 mm) having a hole 2 with a diameter of 7.0 mm is pasted in a manner covering the upper part of the composition. Subsequently, on the upper black tape 5, a transparent glass 3 with a thickness of 1 mm and one size larger than the size of the recess 1 is placed.

[0181] The specimen 7 set like this was irradiated with ultraviolet rays having an illuminance of 100 mW / cm 2 and a wavelength of 365 nm for 45 seconds (exposure dose: 4500 mJ / cm 2 ) using a UV-LED irradiator manufactured by CCS, Inc. through the hole 2, and then stored at 23°C for 16 hours. As shown in Figure 5 , the specimen 7 was cured within the range of the cured area 8. The upper black tape 5 was removed, the metal mold 6 was erected to remove the uncured portion, and the maximum diameters of the cured upper part (depth 0 mm), middle part (depth 2.9 mm), and lower part (depth 5.8 mm) were measured using a vernier caliper, which were defined as the cured diameters of the upper part, middle part, and lower part, respectively.

[0182] <Use of the UV-curable silicone composition>

[0183] Since the UV-curable silicone composition has excellent workability and crosslinking curability, it can be suitably used as a potting material. Specifically, the UV-curable silicone composition can be suitably used for materials having portions where light is difficult to irradiate, particularly potting materials for connector pins.

[0184] In another aspect of the present invention, the cured product of the UV-curable silicone composition can be suitably used as a sealing material. An article using the cured product of the UV-curable silicone composition as a sealant has excellent water resistance and durability at the bonding surface and the sealed portion, so the cured product can be suitably used as a sealing material for electrical components or electronic components. In addition, since the portions around the UV-irradiated portion of the UV-curable silicone composition where light does not reach and the curability in the thickness direction are excellent, the quality of the cured product is stable. Therefore, for example, it can be used as: an adhesive for bonding of image display devices such as liquid crystal, plasma, and organic EL; or a sealant for sealing LED elements or OLED elements. In particular, the sealing material containing the cured product of the UV-curable silicone composition can be suitably used for electrical component or electronic component applications, particularly suitable for connector applications having connector pins.

[0185] Examples

[0186] Hereinafter, examples and comparative examples will be given to further illustrate the present invention in detail. However, the present invention is not limited by these examples. Unless otherwise specified, the units are in parts by mass or mass%.

[0187] <Measurement method>

[0188] [Refractive index]

[0189] The refractive indices of the components (A) and (A') were measured at 25°C in accordance with JIS K 0062.

[0190] [Average particle size]

[0191] For the components (C) and (C'), an optical microscope (Keyence Corporation's digital microscope, VHX-500F) was used to observe and confirm the presence or absence of aggregation. When no aggregation was observed in the components (C) and (C'), for their average particle size (median diameter d50), the primary particle diameter was measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by Beckman Coulter, Inc., LS13320). When aggregation occurred in the components (C) and (C'), 50 aggregated primary particles were observed using the above optical microscope, and the average value of their maximum diameters was set as the average particle size.

[0192] [Viscosity]

[0193] For the component (A) and the compositions of the examples and comparative examples, in accordance with JIS K 6249, a rotational viscometer (Vismetron VDA2 type, manufactured by Shibaura Systems Co., Ltd.) was used, and the viscosity at 23°C was measured at 60 rpm using a No. 2 rotor. The viscosity was measured immediately after the preparation of the composition and after storing it at 23°C in a yellow light-free environment for 24 hours, respectively.

[0194] [Transmission percentage]

[0195] For the pre-cured compositions of the examples and comparative examples, the transmission percentage was measured in accordance with JIS K 0115. Using a 10 mm thick cell, the pre-cured composition was added to the sample cell, and ion-exchanged water was added to the reference cell. The transmittance of the composition at a wavelength of 365 nm was measured. Then, in accordance with the Lambert-Beer law, the obtained measured value was converted from a 10 mm thickness to a 1 mm thickness to obtain the transmission percentage of the composition.

[0196] [Absorbance]

[0197] (1) Preparation of a mixed solution of 100 parts by mass of the component (A) and 0.25 parts by mass of the component (C) or (C')

[0198] For the (A) component and the (C) or (C') component that constitute the compositions of the examples and comparative examples, a mixed solution of 100 parts by mass of the (A) component and 0.25 parts by mass of the (C) or (C') component was prepared. 25 parts by mass of the (C) or (C') component was added to 25 parts by mass of the (A) component, and it was stirred for 2 minutes using a rotation / revolution mixer (manufactured by THINKY CORPORATION, ARE-501). Thereafter, 50 parts by mass of the (A) component was added in 10-parts-by-mass portions without forming lumps, and each time it was added, it was stirred for 2 minutes using the above rotation / revolution mixer to prepare a base liquid. The (A) component was added little by little without forming lumps to the base liquid thus obtained, and each time it was added, it was stirred for 2 minutes using the above rotation / revolution mixer to obtain a mixed solution of 100 parts by mass of the (A) component and 0.25 parts by mass of the (C) or (C') component.

[0199] (2) Measurement of absorbance

[0200] For the mixed solution obtained as described above and the compositions of the examples and comparative examples, the absorbance at a wavelength of 365 nm was measured in accordance with JIS K 0115.

[0201] Figure 1 The photograph shows a photograph taken of a specimen for measuring the absorbance at a wavelength of 365 nm of the above mixed solution and the above composition in accordance with JIS K 0115. As Figure 1 shown, a specimen was prepared using a spacer and two glass plates such that the thickness of the above mixed solution or the above composition was 200 μm, and this specimen was used as a sample cell instead of a glass cell. The glass plates used were micro slides S9112 (manufactured by Matsunami Glass Industry Co., Ltd., 76 mm × 52 mm × 1.0 to 1.2 mm thick). In Figure 1 it, the white part is the part where two glass plates are overlapped, and in the transparently cut part in the glass plate, there is the above mixed solution or the above composition with a thickness of 200 μm. A reference cell used one of the above micro slides S9112.

[0202] [Shore 00 hardness]

[0203] The compositions of the examples and comparative examples were poured into a mold of 60 mm in length × 25 mm in width × 6 mm in depth, and using HLDL-155UV manufactured by CCS Co., Ltd., the irradiation illuminance was 100 mW / cm 2After being cured by ultraviolet rays for 45 seconds, it was further stored at 23°C and 50% RH for 16 hours. For the cured product obtained as described above, the Shore 00 hardness was measured in accordance with ASTM D 2240. It should be noted that when the composition was not completely cured by ultraviolet irradiation, it was designated as "uncured". In addition, when the ultraviolet irradiation surface was cured but the opposite side was not cured, it was designated as "bottom surface uncured".

[0204] [Penetration]

[0205] For the composition of Example 14 with a Shore 00 hardness of 0, the penetration was measured using a penetrometer in accordance with JIS K 6249. The penetration of Example 14 was 25.

[0206] [Gelation time]

[0207] For the compositions of the examples and comparative examples, using a viscoelasticity measuring device MCR301 (manufactured by Anton Paar), the storage modulus G' was measured over time from the start of ultraviolet irradiation. Using the above-mentioned viscoelasticity measuring device, with a Φ12 mm parallel plate, at a gap of 0.5 mm, a frequency of 1 Hz, and a strain of 1%, the measurement of the storage modulus G' of the ultraviolet curable silicone composition at 23°C was started. The ultraviolet curable silicone composition was irradiated with ultraviolet rays of 100 mW / cm 2 for 45 seconds (irradiation dose 4500 mJ / cm 2 ). The time from the start of irradiation until the storage modulus G' was equal to the loss modulus G" was defined as the gelation time. The shorter the gelation time, the faster the curing, and it was judged that the curability was excellent. It should be noted that the measurement of the gelation time was carried out until 60 minutes after the start of ultraviolet irradiation. When the storage modulus G' was less than the loss modulus G", it was designated as "uncured".

[0208] [Curing diameter]

[0209] When irradiating ultraviolet rays, as an index of the extent to which the composition can be cured not only in the irradiated area but also extended to, the curing diameter was measured. Figure 2 is a photograph taken from above of the device used for the above measurement in a yellow light room, Figure 3 is a schematic diagram when observing the device from above. Figure 4 is Figure 3 the A-A' line cross-sectional view of. Figure 5 is in Figure 3 and 4 is a schematic diagram explaining the cured area and curing diameter after ultraviolet irradiation.

[0210] As Figure 3 and4 As shown, a metal mold 6 with a rectangular depression 1 having a length of 60 mm, a width of 25 mm, and a depth of 6.0 mm ( Figure 3 and Figure 4 within the dashed line) is prepared. To prevent ultraviolet reflection, a black tape 4 for the bottom (thickness 0.2 mm) is pasted on the entire bottom surface of the depression 1. Subsequently, in a yellow light room, a sample 7 (the compositions of the examples and comparative examples) is filled into the depression 1, and a black tape 5 for the upper part with a hole 2 having a diameter of 7.0 mm is pasted in a manner covering the upper part of the composition. In addition, on the black tape 5 for the upper part, a transparent glass 3 with a thickness of 1 mm and having a size one circle larger than that of the depression 1 is placed.

[0211] For the sample 7 set up like this, ultraviolet rays with an illuminance of 100 mW / cm 2 and a wavelength of 365 nm are irradiated through the hole 2 using a UV-LED irradiator manufactured by CCS, Inc. for 45 seconds (exposure dose 4500 mJ / cm 2 ), and then stored at 23°C for 16 hours. The sample 7 is cured within the range of the curing area 8 as Figure 5 shown. The black tape 5 for the upper part is removed, the metal mold 6 is erected to remove the uncured part, and the maximum diameters of the cured upper part (depth 0 mm), middle part (depth 2.9 mm), and lower part (depth 5.8 mm) are measured respectively using a vernier caliper, which are set as the curing diameters of the upper part, middle part, and lower part. Regarding the curing diameter, when it is 7.0 mm or more for the upper part, 14 mm or more for the middle part, and 18 mm or more for the lower part, it is judged that the part where light cannot reach around the part irradiated with ultraviolet rays and the curability in the thickness direction are excellent. It should be noted that when the composition is not cured by ultraviolet irradiation, it is set as "uncured".

[0212] <Usage Components>

[0213] The respective components used are as follows. Here, the notations mean the following meanings.

[0214] M: (CH3)3SiO 1 / 2

[0215] M H : H(CH3)2SiO 1 / 2

[0216] M Vi : CH2=CH(CH3)2SiO 1 / 2

[0217] D: (CH3)2SiO 2 / 2

[0218] D H : H(CH3)SiO2 / 2

[0219] D Vi : CH2=CH(CH3)SiO 2 / 2

[0220] T SH : HS(CH2)3SiO 3 / 2

[0221] Q: SiO 4 / 2 (tetrafunctional)

[0222] Component (A): a polyorganosiloxane having at least two alkenyl groups in one molecule

[0223] Use a polymethylvinylsiloxane with both ends blocked by M Vi units and the middle units containing D units.

[0224] (A-1) M Vi D m1 M Vi (1): The average vinyl content is 0.180 mmol / g, the viscosity at 23 °C: 450 mPa·s, the refractive index: 1.403

[0225] (A-2) M Vi D m2 M Vi (2): The average vinyl content is 0.047 mmol / g, the viscosity at 23 °C: 12,800 mPa·s, the refractive index: 1.403

[0226] (A-3) M Vi D m3 M Vi (3): The average vinyl content is 0.029 mmol / g, the viscosity at 23 °C: 78,800 mPa·s, the refractive index: 1.404

[0227] (A-4) M Vi D m4 M Vi (4): The average vinyl content is 0.145 mmol / g (composed of 5 mol% of diphenylsiloxane and 95 mol% of dimethylsiloxane), the viscosity at 23 °C: 1300 mPa·s, the refractive index: 1.428

[0228] The alkenyl content of component (A) is determined by a spectrophotometer based on the absorbance of the CH2=CH- group (near 2150 nm).

[0229] Component (A'): a methacrylic-functional silicone oligomer with both ends methyl

[0230] (A'-1) 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane (TSL9706, manufactured by Momentive Performance Materials Japan Co., Ltd., refractive index: 1.450)

[0231] Component (B): A polyorganosiloxane having at least two hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule

[0232] (B-1) Crosslinkable polymethylhydrogensiloxane represented by the average unit formula M H 8Q4 (SiH content: 10.16 mmol / g)

[0233] (B-2) Crosslinkable polymethylhydrogensiloxane represented by the average unit formula M H D H 9D 11 M H (SiH content: 8.27 mmol / g)

[0234] (B-3) Crosslinkable polymethylhydrogensiloxane represented by the average unit formula MD H 23 D 16 M (SiH content: 8.60 mmol / g)

[0235] (B-4) A polymethylsiloxane having at least two HS(CH2)3SiO units in one molecule, represented by M(T SH )5D 60 (SH content: 0.94 mmol / g) 3 / 2

[0236] Synthesis example of (B-4)

[0237] To 1549.2 g (12 mol) of dimethyldichlorosilane, 21.7 g (0.2 mol) of trimethylchlorosilane, 196.4 g (1.0 mol) of 3-mercaptopropyltrimethoxysilane and 1500 g of toluene in a 5 L separable flask equipped with a reflux pipe for condensation, a dropping funnel and a three-one motor as a stirring device, a mixture of 1000 g of water and 500 g of toluene was added dropwise from the dropping funnel over about 1 hour. The resulting mixture was hydrolyzed while heating and stirring at 70 °C for 2 hours. After the reaction was completed, the aqueous phase was separated and removed, the oil phase was washed again with water, and then dehydrated by heating at 100 °C to 125 °C. After dehydration was completed, 1.5 g of a 50 mass% potassium hydroxide aqueous solution was added, and the mixture was heated and stirred at 115 to 125 °C for 5 hours to carry out a condensation reaction. After neutralizing the resulting condensation reaction product with chloroethanol, 1200 to 1300 g of toluene was desolvated, and filtration was carried out using Super Celite Floss as a filter aid. Thereafter, the remaining toluene was removed under constant pressure and reduced pressure to obtain 928 g of a mercaptopropyl-containing polymethylsiloxane.

[0238] Average structural formula: { (CH3)3SiO 1 / 2} { HS(CH2)3SiO 3 / 2}5 { (CH3)2SiO 2 / 2} 60

[0239] Component (C): Ultraviolet diffusing agent

[0240] (C-1) Untreated calcium carbonate (CUBE18BH (manufactured by Maruo Calcium Co., Ltd.), average particle size: 2.0 μm (based on laser diffraction / scattering method))

[0241] (C-2) Untreated alumina (AKP-G15 (manufactured by Sumitomo Chemical Co., Ltd.), average particle size: 0.01 μm (based on optical microscope))

[0242] (C-3) Untreated alumina (AKP-G07 (manufactured by Sumitomo Chemical Co., Ltd.), average particle size: 0.02 μm (based on optical microscope))

[0243] (C-4) Untreated alumina (AA-04 (manufactured by Sumitomo Chemical Co., Ltd.), average particle size: 0.4 μm (based on optical microscope))

[0244] (C-5) Untreated alumina (AA-3 (manufactured by Sumitomo Chemical Co., Ltd.), average particle size: 3.0 μm (based on laser diffraction / scattering method))

[0245] (C-6) Untreated ground silica (CRYSTALITE (registered trademark) 5X (manufactured by Ryusen Co., Ltd.), average particle size: 1.0 μm (based on laser diffraction / scattering method))

[0246] (C-7) Untreated ground silica (CRYSTALITE (registered trademark) VX-S (manufactured by Ryusen Co., Ltd.), average particle size: 4.0 μm (based on laser diffraction / scattering method))

[0247] (C-8) Fatty acid-treated calcium carbonate (CALFINE (registered trademark) N-40 (manufactured by Maruo Calcium Co., Ltd.), average particle size: 0.04 μm (based on optical microscope))

[0248] (C-9) Fatty acid-treated calcium carbonate (CALFINE (registered trademark) YM10 (manufactured by Maruo Calcium Co., Ltd.), average particle size: 0.1 μm (based on optical microscope))

[0249] (C-10) Fatty acid-treated calcium carbonate (CALFINE (registered trademark) YM23 (manufactured by Maruo Calcium Co., Ltd.), average particle size: 0.23 μm (based on optical microscope))

[0250] (C-11) Untreated calcium carbonate (KRS1 (manufactured by Maruo Calcium Co., Ltd.), average particle size: 0.4 μm (based on optical microscope))

[0251] (C-12) Untreated calcium carbonate (CUBE-20KA (manufactured by Maruo Calcium Co., Ltd.), average particle size: 2.7 μm (based on laser diffraction / scattering method))

[0252] (C-13) Untreated calcium carbonate (CUBE-50KA (manufactured by Maruo Calcium Co., Ltd.), average particle size: 5.8 μm (based on laser diffraction / scattering method))

[0253] (C-14) Untreated calcium carbonate (CUBE-80KA (manufactured by Maruo Calcium Co., Ltd.), average particle size: 8.9 μm (based on laser diffraction / scattering method))

[0254] (C-15) Untreated calcium carbonate (R-50A (manufactured by Maruo Calcium Co., Ltd.), average particle size: 14.5 μm (based on laser diffraction / scattering method))

[0255] (C-16) Untreated calcium carbonate (R-70H (manufactured by Maruo Calcium Co., Ltd.), average particle size: 24.7 μm (based on laser diffraction / scattering method))

[0256] (C') Component: Filler other than component (C)

[0257] (C'-1) Silazane surface-treated pyrogenic silica (ROX200S (manufactured by Evonik Corporation), average particle size: 0.01 μm (based on optical microscopy))

[0258] (C'-2) Titanium oxide (AEROXIDE (registered trademark) TiO2 P 25 (manufactured by Evonik Corporation), average particle size: 0.03 μm (based on optical microscopy))

[0259] (C'-3) Titanium oxide (TIPAQUE (registered trademark) A-100 (manufactured by Ishihara Sangyo Kaisha, Ltd.), average particle size: 0.15 μm (based on optical microscopy))

[0260] (C'-4) Methyl resin particles (Tospearl (registered trademark) 120 (manufactured by Momentive Performance Materials Japan LLC), average particle size: 2.0 μm (based on laser diffraction / scattering method))

[0261] (D) Component: Platinum-based catalyst or photoinitiator activated by ultraviolet light

[0262] (D-1) Dilute (methylcyclopentadienyl)trimethylplatinum complex (manufactured by Strem Chemicals, Inc. (Germany), platinum content: 61.1 mass%) with M Vi D m1 M Vi Use after diluting to 1.0 mass%.

[0263] (D-2) Use 2-hydroxy-2-methyl-1-phenylpropanone (manufactured by IGM Resins B.V., Irgacure (registered trademark) 1173).

[0264] Example 1

[0265] Preparation of the mixed solution of components (A) and (C)

[0266] Add 25 parts by mass of (C-1) to 25 parts by mass of (A-1)M Vi D m1 M Vi (1) Stir for 2 minutes using a rotation / revolution mixer (manufactured by THINKY CORPORATION, ARE-501). Then, add 50 parts by mass of (A-1) in 10 parts by mass increments without forming lumps. Each time after addition, stir for 2 minutes using the above rotation / revolution mixer to prepare the base solution.

[0267] To the base liquid obtained as described above, (A-1) was added little by little without forming lumps, and each time it was added, it was stirred for 2 minutes each using the above-mentioned rotation / revolution type stirrer to obtain a mixed liquid of 100.00 parts by mass of (A-1) and 0.10 parts by mass of (C-1).

[0268] Preparation of Ultraviolet-Curable Organosilicon Composition

[0269] To the mixed liquid obtained as described above, 0.17 part by mass of a 1.0 mass% dilution of (D-1) ((D-1): 0.0017 part by mass, M Vi D m1 M Vi (1): 0.1683 part by mass) and 1.78 parts by mass of (B-1) were added and mixed to obtain the ultraviolet-curable organosilicon composition of Example 1.

[0270] Examples 2 to 30

[0271] Except that the components (A) to (D) and their compounding amounts were changed as shown in Tables 1 and 2, the mixed liquid of components (A) and (C) was prepared in the same manner as in Example 1 to obtain the ultraviolet-curable organosilicon compositions of Examples 2 to 30.

[0272] Example 31

[0273] A mixed liquid of 100.00 parts by mass of (A-4) and 0.25 parts by mass of (C-1) was obtained in the same manner as in Example 1. To the mixed liquid obtained as described above, 0.30 part by mass of (D-2) and 15.40 parts by mass of (B-4) were added and mixed in a yellow light room to obtain the ultraviolet-curable organosilicon composition of Example 31.

[0274] Comparative Examples 1 to 6

[0275] Except that the components (A) to (D) and their compounding amounts were changed as shown in Table 3, the mixed liquid of components (A) and (C) or (C') was prepared in the same manner as in Example 1 to obtain the ultraviolet-curable organosilicon compositions of Comparative Examples 1 to 6.

[0276] Comparative Example 7

[0277] A mixed liquid of 100.00 parts by mass of (A'-1) and 0.25 parts by mass of (C-1) was obtained in the same manner as in Example 1. To the mixed liquid obtained as described above, 1.00 part by mass of (D-2) was added and mixed in a yellow light room to obtain the ultraviolet-curable organosilicon composition of Comparative Example 7.

[0278] The compounding and evaluation results of the examples are shown in Tables 1 and 2. The compounding and evaluation results of the comparative examples are shown in Table 3.

[0279]

[0280]

[0281]

[0282] As shown in Tables 1 and 2, the compositions of the examples have a short gelation time, excellent curability, and excellent curability in the portions not irradiated with light and in the thickness direction. The compositions of the above examples are ultraviolet curable silicone compositions containing (A) a polyorganosiloxane having at least two alkenyl groups in one molecule; (B) a polyorganosiloxane having at least two hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule; (C) an ultraviolet diffusing material; and (D) a platinum-based catalyst or a photoinitiator activated by ultraviolet light. Among them, the blending amount of the component (C) relative to 100 parts by mass of the component (A) is 0.05 to 15.0 parts by mass, and the transmission percentage of the above composition before curing measured at a wavelength of 365 nm in accordance with JIS K 0115 is 33 to 95%.

[0283] Figure 6 is a graph showing the relationship between the mass parts of (C-1) untreated calcium carbonate (average particle diameter: 2.0 μm) relative to 100 parts by mass of (A-1) and the curing diameters at the upper part (depth 0 mm), the middle part (depth 2.9 mm), and the lower part (depth 5.8 mm) based on Examples 1 to 6 and Comparative Examples 1 to 2. According to Figure 6 , in Example 1 in which only 0.10 part by mass of (C-1) was blended, the curing diameter increased by 1.6 to 2.0 times compared with Comparative Example 1 in which the component (C) was not blended. It can be seen that by blending a small amount of the component (C), the curing diameter of the composition increases significantly. In addition, it can be seen that the curing diameter becomes extremely large when the blending amount of (C-1) is around 0.25 part by mass, and thereafter, as the blending amount of (C-1) increases, the curing diameter slowly decreases.

[0284] Figure 7 is a graph showing the relationship between the average particle diameter of calcium carbonate in the composition in which 0.25 part of calcium carbonate is blended as the component (C) relative to 100 parts by mass of (A-1) and the curing diameters at the upper part (depth 0 mm), the middle part (depth 2.9 mm), and the lower part (depth 5.8 mm) based on Examples 2 and 22 to 30. According to Figure 7 the following trend was observed: when the average particle diameter of calcium carbonate is 2.0 μm or less, the effect of increasing the curing diameter is large, and if the average particle diameter is greater than 15 μm, the curing diameter decreases.

[0285] According to the comparison of Examples 2, 7, and 8, the component (B) contains M HIn Example 2 of the polyorganohydrogensiloxane of the unit and the Q unit, the curing diameter is more excellent than the case where the component (B) is linear. According to the comparison of Example 2 and Examples 11 to 13, the curing diameter of Example 2 in which the average vinyl group content of the component (A) is 0.10 mmol / g or more is more excellent.

[0286] The curing diameter difference between Comparative Example 1 in which the component (C) was not blended and Comparative Example 2 in which the blending amount of the component (C) was more than 15 parts by mass relative to 100 parts by mass of the component (A). Comparative Examples 3 and 6 in which surface-treated pyrogenic silica and resin particles were respectively blended in place of the component (C) had a transmission percentage before curing of the composition measured at a wavelength of 365 nm greater than 95%, and however, results of curing diameter difference were obtained. Comparative Examples 4 and 5 in which titanium oxide was blended in place of the component (C) and the transmission percentage before curing of the composition measured at a wavelength of 365 nm was less than 33% had significantly poor ultraviolet curability, and the curing diameter could not be evaluated. Comparative Example 7 using a curing system of a dimethacrylate-functional silicone oligomer at both ends and blending the component (C) in place of the components (A) and (B) had a short gelation time and a fast curing speed, however, the curing diameter was significantly poor.

[0287] Industrial applicability

[0288] The cured product of the ultraviolet curable silicone composition is useful as a sealing material for electrical components, electronic components, etc.

[0289] Explanation of reference numerals

[0290] 1 Depression, 2 Hole, 3 Transparent glass, 4 Black tape at the bottom, 5 Black tape at the top, 6 Metal mold, 7 Specimen (ultraviolet curable silicone composition), 8 Curing area, 9 Curing diameter.

Claims

1. An ultraviolet curable silicone composition, comprising: A: a polyorganosiloxane having at least 2 alkenyl groups in one molecule, B: a polyorganosiloxane having at least 2 hydrogen atoms or mercaptoalkyl groups bonded to silicon atoms in one molecule, C: an ultraviolet diffusing material, and D: a platinum-based catalyst or a photoinitiator activated by ultraviolet light, The blending amount of the C component with respect to 100 parts by mass of the A component is 0.05 part by mass to 15.0 parts by mass, The transmission percentage of the composition before curing measured at a wavelength of 365 nm in accordance with JIS K 0115 is 33% to 95%.

2. The ultraviolet curable silicone composition according to claim 1, wherein For a mixture of 100 parts by mass of the A component and 0.25 part by mass of the C component, the absorbance at a wavelength of 365 nm measured in accordance with JIS K 0115 using a sample made of a spacer and two glass plates in such a manner that the thickness of the mixture is 200 μm instead of a glass cell is in the range of 0.005 to 0.

5.

3. The ultraviolet curable silicone composition according to claim 1 or 2, wherein The composition is irradiated with ultraviolet light having a diameter of 7.0 mm, an illuminance of 100 mW / cm 2 , and a wavelength of 365 nm for 45 seconds in a yellow light room and then stored at 23 °C for 16 hours to obtain a cured product. In the obtained cured product, the cured diameter at a depth of 5.8 mm is 18 mm or more.

4. The ultraviolet curable silicone composition according to claim 1 or 2, wherein The average particle size of the C component is 0.01 μm to 25 μm.

5. The ultraviolet curable silicone composition according to claim 1 or 2, wherein The C component is selected from calcium carbonate, silica, and alumina.

6. The ultraviolet curable silicone composition according to claim 1 or 2, wherein The A component contains a linear polyorganosiloxane, and the average alkenyl content of the A component is 0.03 mmol / g to 1.0 mmol / g.

7. The ultraviolet curable silicone composition according to claim 1 or 2, wherein The B component is B-1: a polyorganohydrogensiloxane having at least 2 hydrogen atoms bonded to silicon atoms in one molecule, and the D component is D-1: a platinum-based catalyst activated by ultraviolet light.

8. The ultraviolet curable silicone composition according to claim 7, wherein Component B-1 contains b1: containing R c1 2HSiO 1 / 2 units and SiO 4 / 2 units of polyorganohydrogensiloxane, in R c1 2HSiO 1 / 2 wherein, R c1 is independently a C1-C6 alkyl group or a C6-C 20 aryl group.

9. The ultraviolet curable silicone composition according to claim 7, wherein The D-1 component is a platinum-based catalyst having a cyclic diene compound as a ligand, and the blending amount of the D-1 component in the composition is 1 ppm to 50 ppm in terms of the mass of platinum metal.

10. The ultraviolet curable silicone composition according to claim 7, wherein The number of moles of hydrogen atoms H bonded to silicon atoms in component B-1 B Relative to the number of moles of alkenyl groups Vi in component A A The ratio, that is, H B / Vi A The ratio is 0.3 to 2.

0.

11. The ultraviolet curable silicone composition according to claim 1 or 2, wherein The B component is B-2: a polyorganosiloxane having at least 2 mercaptoalkyl groups bonded to silicon atoms in one molecule, and the D component is D-2: a photoinitiator.

12. The ultraviolet curable silicone composition according to claim 11, wherein The B-2 component contains b2: containing at least two Rs in one molecule d1 SiO 3 / 2 units of polyorganosiloxane, in R d1 SiO 3 / 2 In the formula, R d1 is a mercaptoalkyl group having 1 to 6 carbon atoms.

13. A potting material, comprising the ultraviolet curable silicone composition according to claim 1 or 2.

14. The potting material according to claim 13, which is used for connector pins.

15. A sealing material comprising a cured product of the ultraviolet curable silicone composition according to claim 1 or 2.

16. The sealing material according to claim 15, which is used for an electrical component or an electronic component.

17. The sealing material according to claim 16, wherein The electrical component or the electronic component is a connector having connector pins.

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