Ultraviolet-curable composition and use thereof

Abstract

The present invention provides a UV-curable composition containing a silicon atom, which has a cured product with a low refractive index and excellent workability when applied to a substrate. The UV-curable composition of the present invention is characterized by containing one or more organosilicon compounds (A) having an average of one or more UV-reactive functional groups per molecule, having a viscosity of the entire composition of 80 mPa-s or less as measured at 25°C using an E-type viscometer, and being free of an organic solvent, and having a cured product with a refractive index of 1.45 or less as measured at 25°C at a wavelength of 589 nm.

Description

Technical Field

[0001] This invention relates to an ultraviolet (UV) latitude-curable composition that can be cured by actinic rays, such as ultraviolet light or electron beams, and particularly to an UV-curable composition comprising an organosilicon compound, preferably an organosilane and / or a polyorganosiloxane. Specifically, the cured product obtained therefrom has a low refractive index and excellent coatability. The curable composition of this invention has a refractive index as low as 1.45 or below, making it suitable as an insulating material for electronic and electrical equipment, and particularly suitable as a material for use as a coating agent. Furthermore, it exhibits excellent coatability and excellent wettability to substrates, making it useful as an inkjet printing material. Background Technology

[0002] Due to their high heat resistance and excellent chemical stability, silicone resins have been used to date as coating agents, potting compounds, and insulating materials for electronic and electrical equipment. To date, UV-curable silicone compositions have also been reported.

[0003] Touch panels are used in various display devices such as mobile devices, industrial equipment, and car navigation systems. To improve their sensing sensitivity, it is necessary to suppress the noise from light-emitting components such as light-emitting diodes (LEDs) and organic OLEDs (OLEDs). An insulating layer is usually placed between the light-emitting component and the touch screen.

[0004] On the other hand, thin-film display devices such as OLEDs have a structure with multiple functional thin layers stacked together. In recent years, research has begun on improving the overall brightness of the display device by combining layers with high and low refractive indices stacked on the touchscreen layer. Furthermore, inkjet printing is being used as a processing method for organic layers to improve productivity. Therefore, materials that can be processed using inkjet printing are also required for the aforementioned insulating layer.

[0005] Japanese Patent Application Publication No. 2019-73588 discloses a photocurable resin composition consisting of an aromatic compound containing unsaturated bonds and a compound having a thiol group. Japanese Patent Application Publication No. 2020-26515 discloses a photocurable resin composition with a naphthalene compound containing unsaturated bonds as the main component. Both compositions are characterized by being applicable by inkjet printing, and the cured product exhibits a high refractive index of 1.60 or higher.

[0006] On the other hand, Japanese Patent No. 6200591 discloses a sealant for inkjet-coated electronic devices composed of a polysiloxane silicone containing UV-curable functional groups and a specific curable compound. Japanese Patent Application Publication No. 2019-189844 discloses a photocurable resin composition for electronic devices comprising a polyfunctional cationic polymeric compound and a specific monofunctional cationic polymeric compound. While these patent documents do not specify the refractive index of the cured composition, when the refractive index is calculated based on the monomer structure in the cured composition, it is consistently a value of 1.48 or higher in all cases.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2019-73588

[0010] Patent Document 2: Japanese Patent Application Publication No. 2020-26515

[0011] Patent Document 3: Japanese Patent No. 6200591

[0012] Patent Document 4: Japanese Patent Application Publication No. 2019-189844 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] As mentioned above, several UV-curable polysiloxane compositions are known, but there is now a further demand for cured products with a low refractive index of 1.45 or lower, and excellent workability for application to substrates, particularly low-viscosity UV-curable compositions. The object of the present invention is to provide a silicon-containing curable composition, particularly a UV-curable composition, that has a low refractive index after curing and also exhibits excellent workability when applied to substrates.

[0015] Solution for solving the problem

[0016] This invention achieves its purpose by discovering that a UV-curable composition obtained by using one or more organosilicon compounds (A) having an average of one or more UV-reactive functional groups per molecule has low viscosity, excellent workability when applied to a substrate, and its cured product exhibits a low refractive index. The curable composition of this invention can particularly preferably use one or more organosilicon compounds selected from the group consisting of (A1) and (A2): (A1) one or more organosilicon compounds having an average of two or more UV-reactive functional groups per molecule, particularly polyorganosiloxanes; and (A2) organosilicon compounds having one UV-reactive functional group per molecule, particularly organosilanes and polyorganosiloxanes, as component (A). As component (A) of the composition of this invention, one or more organosilicon compounds selected from components (A1) and (A2) can be used at a mass ratio of 100 / 0 to 0 / 100 (A1 / A2). That is, in the curable composition of the present invention, components (A1) and (A2) can be used together as component (A), or components (A1) or (A2) can be used alone as component (A). When only component (A2) is used as component (A), it is preferable that each molecule has one or more, preferably two or more, reactive functional groups that can react with the ultraviolet-reactive functional groups of component (A2), and preferably compounds with ultraviolet-reactive functional groups.

[0017] This invention relates to a UV-curable composition comprising an organosilicon compound, and particularly to a UV-curable polyorganosiloxane composition. This composition can also be cured by forming bonds based on UV-curable functional groups, but the curing method is not limited to UV irradiation. Any method that can use the UV-curable functional groups to induce a curing reaction can also be used, such as using electron beam irradiation to cure the composition of this invention.

[0018] The UV-curable composition of the present invention is characterized in that it contains one or more organosilicon compounds (A) having an average of one or more UV-reactive functional groups per molecule, the overall viscosity of the composition measured at 25°C using an E-type viscometer is 80 mPa·s or less, the composition does not contain organic solvents, and the refractive index of the cured product measured at 25°C and a wavelength of 589 nm is 1.45 or less.

[0019] It should be noted that, unless otherwise specified in this instruction manual, the viscosity of the substance is the value measured using an E-type viscometer at 25°C.

[0020] The ultraviolet-reactive functional group of component (A) of the present invention is preferably a cationic polymerizable reactive group. The cationic polymerizable reactive group is more preferably an epoxy group.

[0021] The ratio of the component (A) in the ultraviolet curable composition of the present invention is preferably 80% or more of the mass of the whole composition.

[0022] Preferably, the above-mentioned component (A) of the present invention contains one or more organosilicon compounds selected from the group consisting of the following (A1) and (A2) in a mass ratio of 100 / 0 to 0 / 100 (A1 / A2): (A1) one or more organosilicon compounds having an average of two or more ultraviolet reactive functional groups in one molecule, preferably polyorganosiloxane; and (A2) one or more organosilicon compounds having one ultraviolet reactive functional group in one molecule, preferably organosilane and polyorganosiloxane. Therefore, the component (A) can be only the component (A1), only the component (A2), or a combination of the component (A1) and (A2).

[0023] Preferably, the above-mentioned component (A2) is an organosilicon compound selected from the group consisting of linear, branched or cyclic organosilanes and polyorganosiloxanes represented by the following average composition formula,

[0024] R c R' d SiO (4-c-d) / 2 (2)

[0025] (In the formula, R is an ultraviolet reactive functional group,

[0026] R' is a group selected from a monovalent hydrocarbon group, a hydroxyl group and an alkoxy group other than the ultraviolet reactive functional group,

[0027] c and d are numbers satisfying the following conditions: 1 < c + d ≤ 4 and 0.05 ≤ c / (c + d) ≤ 0.25, and the number of R in the molecule is 1.)

[0028] Preferably, the ratio of the component (A2) contained in the ultraviolet curable composition of the present invention is 80% by mass or more of the whole composition.

[0029] Preferably, the above-mentioned component (A1) is an organosilicon compound of linear, branched or cyclic polyorganosiloxane represented by the following average composition formula,

[0030] R a R' b SiO (4-a-b) / 2 (1)

[0031] (In the formula, R is an ultraviolet reactive functional group,

[0032] R' is a group selected from a monovalent hydrocarbon group, a hydroxyl group and an alkoxy group other than the ultraviolet reactive functional group,

[0033] a and b are numbers that satisfy the following conditions: 1 ≤ a + b ≤ 3 and 0.01 ≤ a / (a + b) ≤ 0.34, and have at least two R's in the numerator.

[0034] The viscosity of component (A1) at 25°C is 1–1000 mPa·s.

[0035] Preferably, the organosilicon compound of component (A2) is a silicon-containing compound having an ultraviolet-reactive functional group in its molecule, selected from the group consisting of polyorganosiloxanes represented by formula (3'), cyclic polyorganosiloxanes represented by formula (4'), or organosilicones represented by formula (5').

[0036] [Chemical Formula 1]

[0037]

[0038] (where R is in the formula) 1 ~R 8 Of the functional groups, only one ultraviolet-reactive functional group exists in the molecule; the other R groups... 1 To R 8 Each is an independent monovalent hydrocarbon group, either unsubstituted or fluorinated; n is a value greater than or equal to 0 and less than or equal to 3.

[0039] [Chemical Formula 2]

[0040]

[0041] (In the formula, R is a group independently selected from ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups, x is an integer from 3 to 5, and the molecule has only one ultraviolet-reactive functional group.)

[0042] RSiR'3(5')

[0043] (In the formula, R is a UV-reactive functional group, and R' is a group selected from monovalent hydrocarbon groups, hydroxyl groups, and alkoxy groups, other than the aforementioned UV-reactive functional group.)

[0044] Furthermore, preferably, the organosilicon compound of the above-mentioned component (A1) is one or more organosilicon compounds having ultraviolet-reactive functional groups selected from the group consisting of polyorganosilicon represented by the following formula (3), polyorganosilicon represented by the following average unit formula, cyclic polyorganosilicon represented by the following formula (5), and mixtures of two or more polyorganosilicon compounds selected from them.

[0045] [Chemical Formula 3]

[0046]

[0047] (where R is in the formula)1 ~R 8 In the functional groups, each molecule has an average of more than two UV-reactive functional groups; other R 1 To R 8 Each is a monovalent hydrocarbon group that is either unsubstituted or fluorinated; n is the viscosity of the polyorganosiloxane shown in formula (3) at 25°C, which is 1 to 1000 mPa·s, and n is optionally 0.

[0048] Average unit type:

[0049] (R3SiO 1 / 2 ) e (R2SiO 2 / 2 ) f (RSiO 3 / 2 ) g (SiO 4 / 2 ) h (4)

[0050] (In the formula, R is a group independently selected from ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups, at least two of all R are ultraviolet-reactive functional groups, (g+h) is a positive number, e is 0 or a positive number, and f is a number in the range of 0 to 10.)

[0051] [Chemical Formula 4]

[0052]

[0053] (In the formula, R is a group independently selected from ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups, x is an integer from 3 to 10, and the molecule has at least two ultraviolet-reactive functional groups.)

[0054] Preferably, the number of ultraviolet-reactive functional groups in the above-mentioned component (A1) is two per molecule on average.

[0055] Preferably, the above-mentioned component (A2) is a polyorganosiloxane having a UV-reactive functional group in the molecule.

[0056] Preferably, the viscosity of the UV-curable composition of the present invention, as measured by an E-type viscometer at 25°C, is below 80 mPa·s, particularly in the range of 5 to 30 mPa·s.

[0057] Preferably, the above-mentioned component (A) is (A2) 1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane, or a mixture of (A2) 1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane and at least one compound selected from (A1) below, wherein the mass ratio is in the range of 100 / 0 to 20 / 80 (A2 / A1).

[0058] (A1):

[0059] 1,3-Bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3-tetramethyldisiloxane, 1,5-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,5,5-hexamethyltrisiloxane, methyl(tris[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, tetra([2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, 1,3,5,7-tetramethyl-1,3,5,7-tetra[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane [Oxycyclohexyl]ethyl-cyclotetrasiloxane, 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane, 1,5-bis(3-epoxypropoxypropyl)-1,1,3,3,5,5-hexamethyltrisiloxane, methyl[tris(3-epoxypropoxypropyl)dimethylsiloxy]silane, tetra[(3-epoxypropoxypropyl)dimethylsiloxy]silane, 1,3,5,7-tetramethyl-1,3,5,7-tetra(3-epoxypropoxypropyl)-cyclotetrasiloxane.

[0060] However, the mass ratio of component (A2) to component (A1) described above is a particularly preferred range, and the curable composition of the present invention can also be obtained when the proportion of component (A1) relative to the total mass of components (A2) and (A1) is more than 80% to 100% by mass. That is, component (A1) alone may also be used as component (A).

[0061] In a preferred embodiment of the invention, (A2)1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane is included as component (A) in the range of 50-95% by mass of the composition as a whole.

[0062] In a preferred embodiment of the UV-curable composition of the present invention, the composition further comprises (B) a compound having one or more, preferably two or more, UV-reactive functional groups and not having silicon atoms in a molecule, wherein the mass ratio of component (B) to the total of components (A1), (A2) and (B) is less than 20%.

[0063] When using the above-mentioned component (B), component (A) can be any of the following: component (A1) only, component (A2) only, or a combination of component (A1) and component (A2). However, when using component (A2) which has a UV-reactive functional group in a molecule instead of component (A1) as component (A), component (B) is particularly preferred.

[0064] The present invention also provides an insulating coating agent comprising the above-described ultraviolet-curable composition. The ultraviolet-curable composition of the present invention is useful as an insulating coating agent.

[0065] The present invention also provides a method for using the cured product of the above-described ultraviolet-curable composition as an insulating coating.

[0066] The present invention also provides a display device, such as a liquid crystal display or an organic EL display, the display device comprising a layer composed of a cured product of the above-described ultraviolet-curable composition. Detailed Implementation

[0067] The structure of the present invention will now be described in further detail.

[0068] The UV-curable composition of the present invention comprises one or more organosilicon compounds (component (A)) having an average of more than one UV-reactive functional group per molecule as an essential component, and may, as needed, include components selected from photocationic polymerization initiators and various additives. However, the curable composition of the present invention is characterized by being free of organic solvents.

[0069] In this specification, the term "organosilicon compound" is used to refer to the concepts of organosilicones, organosiloxane oligomers, and polyorganosiloxanes.

[0070] In this specification, the term "polysiloxane" refers to a polysiloxane whose degree of polymerization of siloxane units (Si-O) is 2 or higher, meaning that each molecule has an average of more than two Si-O bonds. Polysiloxanes include siloxane oligomers such as disiloxane, trisiloxane, and tetrasiloxane, as well as siloxane polymers with higher degrees of polymerization.

[0071] Component (A) is selected from one or more organosilicon compounds selected from (A1) having an average of two or more UV-reactive functional groups per molecule and (A2) having one or more UV-reactive functional groups per molecule. The ratio of component (A1) to component (A2) can be selected in the range of 100 / 0 to 0 / 100. Here, when component (A) is a component with only one UV-reactive functional group per molecule (e.g., a component consisting only of component (A2)), in order to carry out the crosslinking reaction as a whole composition, it is preferable to include (B) a compound having one or more, preferably two or more, UV-reactive functional groups per molecule and without silicon atoms as a crosslinking component. It should be noted that when component (A) includes one or more organosilicon compounds with an average of two or more UV-reactive functional groups per molecule (A1), the crosslinking reaction as a whole composition will proceed even if component (B) is not present. That is, component (B) can be any crosslinking component used depending on the type of component (A).

[0072] [Component (A): An organosilicon compound having an average of more than one ultraviolet-reactive functional group per molecule]

[0073] The organosilicon compound used as component (A) having a UV-reactive functional group is preferably a compound selected from organosilanes and polyorganosiloxanes, wherein each molecule has an average of one or more UV-reactive functional groups. Its molecular structure can be arbitrary as long as this objective is achieved. The UV-reactive functional group of component (A) is particularly preferably a cationic polymerizable functional group, and more preferably an epoxy-containing group.

[0074] More specifically, component (A) is preferably one or more organosilicon compounds selected from the group consisting of components (A1) and components (A2) described below.

[0075] Components (A1) and (A2) can be used individually or in combination as component (A), and the ratio of component (A1) to component (A2) can be a mass ratio of 100 / 0 to 0 / 100 (A1 / A2). This mass ratio is preferably 100 / 20 to 0 / 100 (A1 / A2). Using only component (A2) as component (A) is also a preferred option.

[0076] The viscosity of component (A) at 25°C is preferably 1 to 1000 mPa·s, more preferably 1 to 500 mPa·s, particularly preferably 1 to 100 mPa·s, and most preferably 1 to 50 mPa·s.

[0077] In addition, each molecule of component (A) contains 1 to 20 silicon atoms, preferably 1 to 4 silicon atoms.

[0078] <Component (A1): An organosilicon compound having an average of two or more UV-reactive functional groups per molecule>

[0079] The organosilicon compound of component (A1) is a linear, branched, or cyclic polyorganosiloxane, preferably linear or branched, and particularly preferably linear, as shown in the average composition below.

[0080] R a R' b SiO (4-a-b) / 2 (1)

[0081] In equation (1),

[0082] R is an ultraviolet-reactive functional group.

[0083] R' is a group selected from monovalent hydrocarbon groups, hydroxyl groups, and alkoxy groups, excluding ultraviolet-reactive functional groups.

[0084] a and b are numbers that satisfy the following conditions: 1≤a+b≤3 and 0.01≤a / (a+b)≤0.34, preferably 2≤a+b≤3 and 0.05≤a / (a+b)≤0.34.

[0085] In formula (1), R represents an ultraviolet-reactive functional group that can bond with each other through ultraviolet irradiation, whether in the presence or absence of a photoinitiator. Examples of ultraviolet-reactive functional groups include free radical polymerizable groups and cationic polymerizable groups. There are no particular limitations on free radical polymerizable groups as long as they are functional groups that can form new bonds through the free radical reaction mechanism, especially bonds between free radical polymerizable groups. Examples include: propenyl, methpropenyl, maleimide, and organic groups containing any of these groups. As specific examples of free radical polymerizable groups, examples include: propenyloxypropyl, methpropenyloxypropyl, acrylamidopropyl, methacrylamidopropyl, and 3-(N-maleimide)propyl. Examples of cationic polymerizable groups include: vinyl ether groups, epoxy-containing groups, and oxy-heterocyclic butyl groups, such as CH2=CH-O-(CH2)n- (n is an integer from 3 to 20) and glycidoxy-(CH2). n -(n is an integer from 3 to 20), 3,4-epoxycyclohexyl-(CH2) n - (n is an integer from 2 to 20) and other groups.

[0086] The UV-reactive functional group is preferably an epoxy group. Particularly preferred groups include glycidoxyalkyl groups, such as glycidoxypropyl; and epoxycyclohexylalkyl groups, particularly 3,4-epoxycyclohexylethyl. Each molecule of the linear, branched, or cyclic polyorganosiloxane shown in the above average composition has an average of at least two UV-reactive functional groups (R). The number of UV-curable groups per molecule is preferably 2 to 6, more preferably 2 to 4, particularly preferably 2 to 3, and most preferably 2.

[0087] R' is a monovalent hydrocarbon group, including unsubstituted monovalent hydrocarbon groups and fluorinated monovalent hydrocarbon groups. The unsubstituted or fluorinated monovalent hydrocarbon group is preferably selected from unsubstituted or fluorinated alkyl, cycloalkyl, arylalkyl, and aryl groups having 1 to 20 carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, octyl, etc., with methyl being particularly preferred. Examples of such cycloalkyl groups include cyclopentyl, cyclohexyl, etc. Examples of such arylalkyl groups include benzyl, phenethyl, etc. Examples of such aryl groups include phenyl, naphthyl, etc. Examples of such fluorinated monovalent hydrocarbon groups include 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl. 3,3,3-trifluoropropyl is preferred as a fluorinated monovalent hydrocarbon group.

[0088] The viscosity of the polyorganosiloxane shown in formula (1) at 25°C is 1–1000 mPa·s, 1–500 mPa·s, or 1–100 mPa·s, with the most preferred value being 1–50 mPa·s. The viscosity of the polyorganosiloxane can be adjusted by changing the ratio of a and b in formula (1) and the molecular weight.

[0089] Each molecule of the polyorganosiloxane shown in formula (1) preferably has an average of 2 to 20 silicon atoms, and more preferably 2 to 5 silicon atoms.

[0090] In a preferred embodiment, the polyorganosiloxane of component (A1) is a compound represented by the following formula (3).

[0091] [Chemical Formula 5]

[0092]

[0093] Similar to the compound shown in formula (1) above, each molecule of the polyorganosiloxane shown in formula (3) has an average of more than two UV-reactive functional groups. In formula (3), in all R... 1 ~R 8In this group, each molecule typically has two or more UV-reactive functional groups. UV-reactive functional groups are organic groups that can bond with each other through UV irradiation, whether in the presence or absence of a photoinitiator. Examples of UV-reactive functional groups include free radical polymerizable groups and cationic polymerizable groups. Free radical polymerizable groups are not particularly limited in that they are functional groups capable of forming new bonds through a free radical reaction mechanism, especially bonds between free radical polymerizable groups themselves; examples include: propenyl, methpropenyl, maleimide, and organic groups containing any of these groups. Specific examples of free radical polymerizable groups include: propenyloxypropyl, methpropenyloxypropyl, acrylamidopropyl, methacrylamidopropyl, and 3-(N-maleimide)propyl. Examples of cationic polymerizable groups include: vinyl ether groups, epoxy-containing groups, and oxy-heterocyclic butyl groups, such as CH2=CH-O-(CH2)n- (n is an integer from 3 to 20) and glycidoxy-(CH2). n -(n is an integer from 3 to 20), 3,4-epoxycyclohexyl-(CH2) n - (n is an integer from 2 to 20) and other groups.

[0094] As a UV-reactive functional group, one or more epoxy-containing groups are preferred. Particularly preferred groups include glycidoxyalkyl groups, especially 3-glycidoxypropyl groups; and epoxycyclohexylalkyl groups, especially 3,4-epoxycyclohexylethyl groups.

[0095] In equation (3), R other than the ultraviolet reactive functional group 1 To R 8 Each of the groups is an unsubstituted or fluorinated monovalent hydrocarbon group, preferably selected from unsubstituted or fluorinated alkyl, cycloalkyl, arylalkyl, and aryl groups having 1 to 20 carbon atoms. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, octyl, etc., with methyl being particularly preferred. Examples of cycloalkyl groups include cyclopentyl, cyclohexyl, etc. Examples of arylalkyl groups include benzyl, phenethyl, etc. Examples of aryl groups include phenyl, naphthyl, etc. Examples of fluorinated monovalent hydrocarbon groups include 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl. 3,3,3-trifluoropropyl is preferred as a fluorinated monovalent hydrocarbon group. By introducing fluorine atoms into the polyorganosiloxane of formula (3), the refractive index of the cured product obtained from the composition of the present invention can sometimes be further reduced.

[0096] Regarding the number of ultraviolet-reactive functional groups in the polyorganosiloxane of formula (3) which is component (A1), the average number per molecule is 2 to 6, preferably 2 to 5, further preferably 2 to 4, particularly preferably 2 to 3, and most preferably 2.

[0097] In particular, one of R1 to R3 and one of R6 to R8 in formula (3) is a UV-reactive functional group. Moreover, it is particularly preferred that only one of R1 to R3 and one of R6 to R8 in formula (3) is a UV-reactive functional group.

[0098] In formula (3), n represents the viscosity of the polyorganosiloxane shown in formula (3) at 25°C, preferably 1–1000 mPa·s, more preferably 1–500 mPa·s, particularly preferably 1–100 mPa·s, and most preferably 1–50 mPa·s. Those skilled in the art can easily determine the value of n by using the viscosity of the polyorganosiloxane in formula (3) within the aforementioned viscosity range, without excessive trial and error. However, generally, in order to achieve the desired viscosity of the compound in formula (3), the number of silicon atoms per molecule is preferably 2–20, particularly preferably 2–5.

[0099] The polyorganosiloxane of formula (3) can be used as one or in a mixture of two or more. When two or more polyorganosiloxanes are used as a mixture, the viscosity of the mixture at 25°C is preferably the viscosity described above.

[0100] In addition, the compound of formula (1) above can also be a polyorganosiloxane as shown in the average unit formula (4) below.

[0101] (R3SiO 1 / 2 ) e (R2SiO 2 / 2 ) f (RSiO 3 / 2 ) g (SiO 4 / 2 ) h (4)

[0102] In formula (4), R is independently selected from ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups, at least two of all R are ultraviolet-reactive functional groups, (g+h) is a positive number, e is 0 or a positive number, and f is a number in the range of 0 to 10.

[0103] The UV-reactive functional groups and monovalent hydrocarbon groups are as defined above for formula (1). Furthermore, the preferred viscosity of the polyorganosiloxane shown in formula (4) is also as specified above for the polyorganosiloxane shown in formula (1).

[0104] The number of ultraviolet-reactive functional groups in the polyorganosiloxane shown in formula (4) is preferably 2 to 5 per molecule, more preferably 2 to 4, particularly preferably 2 to 3, and most preferably 2.

[0105] The polyorganosiloxane shown in formula (4) preferably has 2 to 20 silicon atoms per molecule, particularly 2 to 5 silicon atoms.

[0106] Specific examples of the polyorganosiloxanes shown in (1) above, especially formula (3) or formula (4), include: 1,3-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3-tetramethyldisiloxane, 1,5-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,5,5-hexamethyltrisiloxane, methyl(tris[2-(3,4-epoxycyclohexyl)ethyl) [2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy]silane, 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane, 1,5-bis(3-epoxypropoxypropyl)-1,1,3,3,5,5-hexamethyltrisiloxane, methyl[tris(3-epoxypropoxypropyl)dimethylsiloxy]silane, tetra[ [(3-epoxypropoxypropyl)dimethylsiloxane]silane, two-terminated (3,4-epoxycyclohexylethyldimethylsilyl)-polydimethylsiloxane, two-terminated (3-epoxypropoxypropyldimethylsilyl)-polydimethylsiloxane, two-terminated trimethylsilyl-dimethylsiloxane / (methyl-3,4-epoxycyclohexylethylsiloxane) copolymer, two-terminated trimethylsilyl-dimethylsiloxane / (methyl-3-epoxypropoxypropylsiloxane) copolymer, two-terminated (3,4-epoxycyclohexylethyldimethylsilyl)-dimethylsiloxane / (methyl-3,4-epoxycyclohexylethylsiloxane) copolymer, two-terminated (3-epoxypropoxypropyldimethylsilyl)-dimethylsiloxane / (methyl-3-epoxypropoxypropylsiloxane) copolymer.

[0107] In addition, the compound of formula (1) above can also be a cyclic polyorganosiloxane as shown in formula (5) below.

[0108] [Chemical Formula 6]

[0109]

[0110] (In the formula, R is a group independently selected from ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups, x is an integer from 3 to 10, and the molecule has at least two ultraviolet-reactive functional groups.)

[0111] R in equation (5) can represent ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups as defined above for equation (1).

[0112] Furthermore, the preferred viscosity of the polyorganosiloxane shown in formula (5) is also as specified above for the polyorganosiloxane shown in formula (1).

[0113] Specific examples of the cyclic polyorganosiloxanes shown in formula (5) include: 1,3,5-trimethyl-1,3,5-tris[2-(3,4-epoxycyclohexyl)ethyl]cyclotrisiloxane, 1,3,5-trimethyl-1,3,5-tris(3-epoxypropoxypropyl)cyclotrisiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetra[2-(3,4-epoxycyclohexyl) [Ethyl]cyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetra(3-epoxypropoxypropyl)cyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-penta[2-(3,4-epoxycyclohexyl)ethyl]cyclopentasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-penta(3-epoxypropoxypropyl)cyclopentasiloxane.

[0114] The polyorganosiloxanes shown in formulas (1), (3) to (5) above can be used alone or in combination of two or more as components (A1).

[0115] As a component (A1), it is particularly preferred to use one or more organosilicon compounds selected from the group consisting of polyorganosiloxanes represented by formula (3), cyclic polyorganosiloxanes represented by formula (5), and combinations thereof.

[0116] Regarding component (A1), the overall viscosity of component (A1) at 25°C is preferably 1–1000 mPa·s, 1–500 mPa·s, 1–100 mPa·s, and more preferably 1–50 mPa·s.

[0117] When component (A1) is used in combination with component (A2) and / or component (B), even if the viscosity of component (A1) is high to some extent, the viscosity can be achieved as desired as the composition as a whole by using low-viscosity compounds as component (A2) and / or component (B).

[0118] As component (A1), particularly preferred compounds are one or a combination of two or more compounds selected from the group consisting of: 1,3-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3-tetramethyldisiloxane, 1,5-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,5,5-hexamethyltrisiloxane, methyl(tris[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, tetra([2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, 1,3,5, 7-Tetramethyl-1,3,5,7-tetra[2-(3,4-epoxycyclohexyl)ethyl]-cyclotetrasiloxane, 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane, 1,5-bis(3-epoxypropoxypropyl)-1,1,3,3,5,5-hexamethyltrisiloxane, methyl[tris(3-epoxypropoxypropyl)dimethylsilyloxy]silane, tetra[(3-epoxypropoxypropyl)dimethylsilyloxy]silane, and 1,3,5,7-tetramethyl-1,3,5,7-tetra(3-epoxypropoxypropyl)-cyclotetrasiloxane.

[0119] [Component (A2): An organosilicon compound having one ultraviolet-reactive functional group per molecule]

[0120] Component (A2) is an organosilicon compound having one ultraviolet-reactive functional group per molecule in an organosilane or polyorganosiloxane backbone, primarily having the following effects: controlling the crosslinking density of the cured product obtained from the composition of the present invention, adjusting the physical properties of the cured product, and simultaneously reducing the viscosity of the composition. Its molecular structure can be arbitrary as long as this objective is achieved. As an example, the organosilicon compound of component (A2) is an organosilane as shown in the following average composition formula, or a linear, branched, or cyclic polyorganosiloxane.

[0121] R c R' d SiO (4-c-d) / 2 (2)

[0122] (In the formula, R is the UV-curable functional group)

[0123] R' is a group selected from monovalent hydrocarbon groups, hydroxyl groups, and alkoxy groups, excluding UV-curable functional groups.

[0124] c and d are numbers that satisfy the following conditions: 1 ≤ c + d ≤ 4 and 0.05 ≤ c / (c + d) ≤ 0.25. Furthermore, the number of R in the numerator is 1.

[0125] You may use one of the groups consisting of these organosilanes and polyorganosiloxanes, or you may use any combination of two or more.

[0126] In formula (2), R represents an ultraviolet-reactive functional group that can bond with each other through ultraviolet irradiation, whether in the presence or absence of a photoinitiator. Examples of ultraviolet-reactive functional groups include free radical polymerizable groups and cationic polymerizable groups. There are no particular limitations on free radical polymerizable groups as long as they are functional groups that can form new bonds through the free radical reaction mechanism, especially bonds between free radical polymerizable groups. Examples include: propenyl, methpropenyl, maleimide, and organic groups containing any of these groups. As specific examples of free radical polymerizable groups, examples include: propenyloxypropyl, methpropenyloxypropyl, acrylamidopropyl, methacrylamidopropyl, and 3-(N-maleimide)propyl. Examples of cationic polymerizable groups include: vinyl ether groups, epoxy-containing groups, and oxy-heterocyclic butyl groups, such as CH2=CH-O-(CH2)n- (n is an integer from 3 to 20) and glycidoxy-(CH2). n -(n is an integer from 3 to 20), 3,4-epoxycyclohexyl-(CH2) n - (n is an integer from 2 to 20) and other groups.

[0127] As a UV-reactive functional group, one or more epoxy-containing groups are preferred. Particularly preferred groups include glycidoxyalkyl groups, particularly glycidoxypropyl groups; and epoxycyclohexylalkyl groups, particularly 3,4-epoxycyclohexylethyl groups. The organosilicon compounds shown in the above average formula have one UV-reactive functional group (R) in one molecule.

[0128] In formula (2), the monovalent hydrocarbon group represented by R' is independently selected from the group consisting of unsubstituted monovalent hydrocarbon groups and fluorinated monovalent hydrocarbon groups. The unsubstituted or fluorinated monovalent hydrocarbon group is preferably selected from unsubstituted or fluorinated alkyl, cycloalkyl, arylalkyl, and aryl groups having 1 to 20 carbon atoms. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, octyl, etc., with methyl being particularly preferred. Examples of cycloalkyl groups include cyclopentyl, cyclohexyl, etc. Examples of arylalkyl groups include benzyl, phenethyl, etc. Examples of aryl groups include phenyl, naphthyl, etc. Examples of fluorinated monovalent hydrocarbon groups include 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl. 3,3,3-trifluoropropyl is preferred as a fluorinated monovalent hydrocarbon group. By introducing fluorine atoms into the polyorganosiloxane of formula (2), the refractive index of the cured product obtained from the composition of the present invention can sometimes be further reduced.

[0129] The viscosity of the organosilicon compound shown in formula (2) at 25°C is preferably 1–500 mPa·s, more preferably 1–100 mPa·s, and particularly preferably 1–50 mPa·s. The viscosity of the organosilicon compound can be adjusted by changing the ratio of c and d in formula (2) and the molecular weight.

[0130] Preferably, the organosilicon compound represented by formula (2) above is a compound having 1 to 20 silicon atoms per molecule, preferably having 1 to 4 silicon atoms.

[0131] In a preferred embodiment, the organosilicon compound of component (A2) is a polyorganosiloxane compound represented by the following formula (3').

[0132] [Chemical Formula 7]

[0133]

[0134] Similarly to the compound shown in formula (2) above, all R of the polyorganosiloxane shown in formula (3') 1 ~R 8 One of the functional groups is a UV-reactive functional group.

[0135] Similar to the compound shown in formula (2) above, the UV-reactive functional group is an organic group that can bond with each other through UV irradiation, whether in the presence or absence of a photoinitiator. Examples of UV-curable functional groups include free radical polymerizable groups and cationic polymerizable groups. There are no particular limitations on the free radical polymerizable group as long as it is a functional group that can form new bonds through a free radical reaction mechanism, especially bonds between free radical polymerizable groups. Examples include: propenyl, methpropenyl, maleimide, and organic groups containing any of these groups. As specific examples, free radical polymerizable groups include: propenyloxypropyl, methpropenyloxypropyl, acrylamidopropyl, methacrylamidopropyl, and 3-(N-maleimide)propyl. Examples of cationic polymerizable groups include: vinyl ether groups, epoxy-containing groups, and oxy-heterocyclic butyl groups, such as CH2=CH-O-(CH2)n- (n is an integer from 3 to 20) and glycidoxy-(CH2). n -(n is an integer from 3 to 20), 3,4-epoxycyclohexyl-(CH2) n - (n is an integer from 2 to 20) and other groups.

[0136] As a UV-reactive functional group, one or more epoxy-containing groups are preferred. Particularly preferred groups include glycidoxyalkyl groups, such as glycidoxypropyl; and epoxycyclohexylalkyl groups, especially 3,4-epoxycyclohexylethyl.

[0137] In equation (3'), R other than the ultraviolet-reactive functional group 1 To R 8 Each alkyl group is independently unsubstituted or fluorinated monovalent hydrocarbon group, preferably selected from unsubstituted or fluorinated alkyl, cycloalkyl, arylalkyl, and aryl groups having 1 to 20 carbon atoms. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, octyl, etc., with methyl being particularly preferred. Examples of cycloalkyl groups include cyclopentyl, cyclohexyl, etc. Examples of arylalkyl groups include benzyl, phenethyl, etc. Examples of aryl groups include phenyl, naphthyl, etc. Examples of fluorinated monovalent hydrocarbon groups include 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl. 3,3,3-trifluoropropyl is preferred as a fluorinated monovalent hydrocarbon group. By introducing fluorine atoms into the polyorganosiloxane of formula (3'), the refractive index of the cured product obtained from the composition of the present invention can sometimes be further reduced.

[0138] The polyorganosiloxane shown in formula (3') has a UV-reactive functional group in one molecule.

[0139] There are no restrictions on the position of the UV-curable functional group in the polyorganosiloxane shown in formula (3'). It can be a molecular end group, that is, only one of R1 to R3 or only one of R6 to R8 is a UV-reactive functional group. In addition, only one of the non-end group R4 to R5 in formula (3') can be set as a UV-reactive functional group.

[0140] In formula (3'), n is preferably a value where the viscosity of the polyorganosiloxane shown in formula (3') at 25°C is 1 to 500 mPa·s, more preferably 1 to 100 mPa·s, and particularly preferably 1 to 50 mPa·s. Those skilled in the art can easily determine the value of n by ensuring that the viscosity of the polyorganosiloxane of formula (3') falls within the specified viscosity range, without excessive trial and error. Generally, to achieve the desired viscosity of the compound of formula (3'), the number of silicon atoms per molecule is preferably 2 to 20, more preferably 2 to 5.

[0141] The polyorganosiloxane of formula (3') can be used as one or in a mixture of two or more. When two or more polyorganosiloxanes are used as a mixture, the viscosity of the mixture at 25°C is 1 to 500 mPa·s, preferably 1 to 100 mPa·s, more preferably 1 to 50 mPa·s, and particularly preferably 5 to 20 mPa·s.

[0142] As specific examples of polyorganosiloxanes with an ultraviolet-reactive functional group in the molecule as shown in formula (3'), the following can be listed: 1-[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,3-pentamethyldisiloxane, 1-[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,5,5,5-heptamethyltrisiloxane, 3-[2-(3,4-epoxycyclohexyl)ethyl]-1,1,1,3,5,5,5-heptamethyltrisiloxane, and 1-[2-(3,4-epoxycyclohexyl)ethyl]-1,1,1,3,5,5,5-heptamethyltrisiloxane, [Oxycyclohexyl)ethyl]-1,1,3,3,5,5,7,7,7-nonamethyltetrasiloxane, 1-(3-epoxypropoxypropyl)-1,1,3,3,3-pentamethyldisiloxane, 1-(3-epoxypropoxypropyl)-1,1,3,3,5,5,5-heptamethyltrisiloxane, 3-(3-epoxypropoxypropyl)-1,1,1,3,5,5,5-heptamethyltrisiloxane, and 1-(3-epoxypropoxypropyl)-1,1,3,3,5,5,7,7,7-nonamethyltetrasiloxane.

[0143] In addition, the organosilicon compound of formula (2) above can also be a cyclic polyorganosiloxane as shown in formula (4').

[0144] Mode:

[0145] [Chemical Formula 8]

[0146]

[0147] In formula (4'), R is independently selected from ultraviolet-reactive functional groups and unsubstituted or fluorinated monovalent hydrocarbon groups, x is an integer from 3 to 5, and the molecule has only one ultraviolet-reactive functional group.

[0148] The UV-reactive functional groups and monovalent hydrocarbon groups are as defined above for equation (2).

[0149] The preferred viscosity of the cyclic polyorganosiloxane shown in formula (4') is also as specified above for the polyorganosiloxane shown in formula (2). Therefore, the viscosity at 25°C is preferably 1 to 500 mPa·s, more preferably 1 to 100 mPa·s, and particularly preferably 1 to 50 mPa·s.

[0150] Specific examples of the cyclic polyorganosiloxanes shown in formula (4') include: [2-(3,4-epoxycyclohexyl)ethyl]-pentamethylcyclotrisiloxane, [2-(3,4-epoxycyclohexyl)ethyl]-heptamethylcyclotetrasiloxane, [2-(3,4-epoxycyclohexyl)ethyl]-nonamethylcyclopentasiloxane, 3-epoxypropoxypropyl-pentamethylcyclotrisiloxane, 3-epoxypropoxypropyl-heptamethylcyclotetrasiloxane, and 3-epoxypropoxypropyl-nonamethylcyclopentasiloxane.

[0151] Furthermore, component (A2) can also be an organosilane as shown in formula (5').

[0152] Formula: RSiR'3(5')

[0153] In formula (5'), R is an ultraviolet-reactive functional group, and R' is a group selected from monovalent hydrocarbon groups, hydroxyl groups, and alkoxy groups other than ultraviolet-reactive functional groups.

[0154] The UV-reactive functional group and the monovalent hydrocarbon group are as defined in formula (2), wherein the alkoxy group has 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, or a cycloalkyl group with 5 to 20 carbon atoms. Specifically, methoxy, ethoxy, isopropoxy, cyclopentyl, or cyclohexyl are preferred.

[0155] Furthermore, the preferred viscosity of the organosilane shown in formula (5') is the same as the viscosity specified for the polyorganosiloxane shown in formula (2) above. Therefore, the viscosity at 25°C is preferably 1 to 500 mPa·s, more preferably 1 to 100 mPa·s, and particularly preferably 1 to 50 mPa·s.

[0156] Specific examples of organosilanes represented by formula (5') include: [2-(3,4-epoxycyclohexyl)ethyl]triethylsilane, [2-(3,4-epoxycyclohexyl)ethyl]dimethylphenylsilane, [2-(3,4-epoxycyclohexyl)ethyl]dimethyloctylsilane, [2-(3,4-epoxycyclohexyl)ethyl]dimethylcyclohexylsilane, [2-(3,4-epoxycyclohexyl)ethyl]trihexylsilane, [2-(3,4-epoxycyclohexyl)ethyl]tributylsilane, 3-epoxypropoxypropyltriethylsilane, 3-epoxypropoxypropyldimethylphenylsilane, 3-epoxypropoxypropyldimethyloctylsilane, 3-epoxypropoxypropyldimethylcyclohexylsilane, 3-epoxypropoxypropyltrihexylsilane, and 3-epoxypropoxypropyltributylsilane.

[0157] The organosilicon compounds represented by formulas (2), (3'), (4'), or (5') above can be used alone or in combination of two or more. That is, the organosilicon compounds represented by formulas (2), (3'), (4'), or (5') and mixtures of two or more selected from them can be used as components of the compositions of the present invention (A2).

[0158] As component (A2), one or more organosilicon compounds selected from the group consisting of polyorganosiloxanes of formula (3'), cyclic polyorganosiloxanes of formula (4'), and combinations thereof are preferred.

[0159] As a component (A2), 1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane is particularly preferred.

[0160] As component (A), only component (A1) or only component (A2) may be used, or components (A1) and (A2) may be used together. The mass ratio of components (A1) and (A2) may be any mass ratio in the range of 100 / 0 to 0 / 100 (A1 / A2). The proportion of component (A2) relative to the total amount of components (A1) and (A2) is 50% by mass or more, preferably 65% ​​by mass or more, more preferably 70% by mass or more, and most preferably 75% by mass or more.

[0161] Furthermore, regarding the curable composition of the present invention, the mass ratio of component (A) to the total composition is preferably 80% by mass or more, preferably 85% by mass or more, and particularly preferably 90% by mass or more. The curable composition of the present invention may consist solely of component (A), therefore, the upper limit of this ratio is 100% by mass.

[0162] When both component (A1) and component (A2) are used as component (A), it is preferable to use one or more compounds selected from the group consisting of the following compounds as component (A1) and 1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane as component (A2), wherein the compounds are:

[0163] 1,3-Bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3-tetramethyldisiloxane, 1,5-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,5,5-hexamethyltrisiloxane, methyl(tris[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, tetra([2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, 1,3,5,7-tetramethyl-1,3,5,7-tetra[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, [Cyclohexyl)ethyl]-cyclotetrasiloxane, 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane, 1,5-bis(3-epoxypropoxypropyl)-1,1,3,3,5,5-hexamethyltrisiloxane, methyl[tris(3-epoxypropoxypropyl)dimethylsilyloxy]silane, tetra[(3-epoxypropoxypropyl)dimethylsilyloxy]silane, and 1,3,5,7-tetramethyl-1,3,5,7-tetra(3-epoxypropoxypropyl)-cyclotetrasiloxane.

[0164] The mass ratio of component (A2) to component (A1) is preferably 100 / 0 to 20 / 80 (A2 / A1), more preferably 100 / 0 to 50 / 50, and particularly preferably in the range of 100 / 0 to 75 / 25. However, since this mass ratio of component (A1) to component (A2) is specified as a particularly preferred range, the curable composition of the present invention can also be prepared using only component (A1) described above.

[0165] When the curable composition of the present invention contains (A2)1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane as component (A), the amount thereof is in the range of 50 to 95% of the total mass of the curable composition, preferably 65 to 95%, and more preferably 75 to 95%.

[0166] When both components (A1) and (A2) are used as component (A), the UV-reactive functional groups of component (A1) and component (A2) are preferably the same type of reactive functional group. Therefore, if the UV-reactive functional group of component (A1) is a free radical polymerizable group, the UV-reactive functional group of component (A2) is also preferably a free radical polymerizable group. Furthermore, if the UV-reactive functional group of component (A1) is a cationic polymerizable group, the UV-reactive functional group of component (A2) is also preferably a cationic polymerizable group. Preferably, both components (A1) and (A2) have cationic polymerizable reactive groups as UV-reactive functional groups.

[0167] [Component (B): A compound having one or more ultraviolet-reactive functional groups in one molecule and not having silicon atoms]

[0168] In the curable composition of the present invention, in addition to the above-described components (A), or components (A1) and / or components (A2), a compound having one or more ultraviolet-reactive functional groups in a molecule and not having silicon atoms (component (B)) may be added. In particular, when only component (A2) is used as component (A), component (B) is preferably used in addition to component (A2). By using component (B) in combination with component (A2), the curability of the composition is sometimes improved.

[0169] The ultraviolet-reactive functional group of component (B) may be the same as the groups listed in components (A), (A1), and (A2). Component (B) differs from components (A), (A1), and (A2) in that the latter have silicon atoms within their molecules, while component (B) does not. There are no particular limitations on the chemical structure of any compound that does not contain silicon atoms within its molecule and has one or more of the aforementioned ultraviolet-reactive functional groups; any compound can be used as component (B).

[0170] As component (B), organic compounds having an intramolecular epoxy group can be used, particularly compounds having an epoxy group but not a cyclic structure. Preferred specific examples of component (B) include: 2-ethylhexyl glycidyl ether, glycidyl lauryl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,2-epoxydecane, 1,2-epoxydodecane, and 1,7-octadiene diepoxide, but are not limited thereto. 1,2-epoxydodecane, 1,7-octadiene diepoxide, and 1,4-butanediol diglycidyl ether are particularly preferred as component (B).

[0171] As component (B), organic compounds having intramolecularly polymerizable reactive groups can also be listed as ultraviolet-reactive functional groups. Specific examples include known (meth)acrylate compounds having one intramolecularly polymerizable reactive group, and (meth)acrylate compounds having two or more intramolecularly polymerizable reactive groups.

[0172] Preferably, the UV-reactive functional group of component (B) is the same type of functional group as that of component (A) or component (A1) and / or component (A2) used in combination with component (B). Therefore, for example, if the UV-reactive functional group of component (A1) and / or component (A2) is a free radical polymerizable group, the UV-reactive functional group of component (B) is also preferably a free radical polymerizable group. Furthermore, if the UV-reactive functional group of component (A1) and / or component (A2) is a cationic polymerizable group, the UV-reactive functional group of component (B) is also preferably a cationic polymerizable group. Both component (A1) and / or component (A2) and component (B) preferably have cationic polymerizable reactive groups, and particularly preferably have epoxy groups as UV-reactive functional groups.

[0173] The viscosity of component (B) at 25°C is preferably 1 to 1000 mPa·s, more preferably 1 to 500 mPa·s, particularly preferably 1 to 100 mPa·s, and most preferably 1 to 50 mPa·s.

[0174] In addition to the above-mentioned components (A1) and / or (A2), when component (B) is used, the mass ratio of component (B) in the curable composition of the present invention to the total amount of components (A1), (A2) and component (B) is less than 20%, preferably less than 10%, and particularly preferably less than 5%.

[0175] [Compositions without organic solvents]

[0176] In this specification, "free of organic solvents" means that the content of organic solvents is less than 0.05% by mass of the total composition, preferably below the analytical limit when analyzed by methods such as gas chromatography. In this invention, by adjusting the molecular structure and molecular weight of components (A) and (B), the desired viscosity can be achieved even without the use of organic solvents.

[0177] [Photopolymerization initiator]

[0178] In the UV-curable composition of the present invention, a photopolymerization initiator may be added as desired, in addition to component (A) described above. In this case, if the UV-reactive functional group of component (A) is a cationic polymerizable functional group including epoxy or vinyl ether, a photocationic polymerization initiator is used as the photopolymerization initiator. As a photocationic polymerization initiator, compounds that can generate Brønsted acids or Lewis acids by irradiation with ultraviolet light or an electron beam, i.e., so-called photoacid generators, are known to generate acids by irradiation with ultraviolet light, etc., which cause reactions between cationic polymerizable functional groups. Furthermore, if the UV-reactive functional group is a free radical polymerizable functional group, a photoradical polymerization initiator can be used as the photopolymerization initiator. A photoradical polymerization initiator can generate free radicals by irradiation with ultraviolet light or an electron beam, and these free radicals can cause free radical polymerization reactions, thereby curing the composition of the present invention. In the case of curing the composition of the present invention by electron beam irradiation, a polymerization initiator is generally not required.

[0179] (1) Photocationic polymerization initiator

[0180] The photocationic polymerization initiator used in the curable composition of the present invention can be selected from any photocationic polymerization initiator known in the art, and is not particularly limited to a specific photocationic polymerization initiator. For photocationic polymerization initiators, strong acid-producing compounds such as diazonium salts, sulfonium salts, iodonium salts, and phosphonium salts are known, and these compounds can be used. Examples of photocationic polymerization initiators include: bis(4-tert-butylphenyl)iodonium hexafluorophosphate, cyclopropyl diphenylsulfonium tetrafluoroborate, dimethylbenzoylmethylsulfonium tetrafluoroborate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, diphenyliodonium tetrafluoromethane sulfonate, 2-(3,4-dimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and 2-[2-(furan-2-yl)vinyl] ]-4,6-bis(trichloromethyl)-1,3,5-triazine, 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate, 2-[2-(5-methylfuran-2-yl)vinyl]-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1, 3,5-Triazine, 4-Nitrophenyldiazonium tetrafluoroborate, Triphenylsulfonium tetrafluoroborate, Triphenylsulfonium bromide, Tri-tolylsulfonium hexafluorophosphate, Tri-tolylsulfonium trifluoromethanesulfonate, Diphenyliodonium trifluoromethanesulfonate, Triphenylsulfonium trifluoromethanesulfonate, Diphenyliodonium nitrate, Bis(4-tert-butylphenyl)iodonium perfluoro-1-butanolate, Bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, Perfluoro-1-butylsulfonic acid triphenylsulfonate, N- Hydroxynaphthalimide trifluoromethanesulfonate, p-toluenesulfonate, diphenyliodonium p-toluenesulfonate, (4-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(4-tert-butylphenyl)sulfonium trifluoromethanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide perfluoro-1-butylsulfonate, (4-phenylthiophenyl)diphenylsulfonium trifluoromethanesulfonate, and 4-(phenylthio)phenyldiphenylsulfonium triethyltrifluorophosphate, etc., but not limited to these. In addition to the compounds mentioned above, other commercially available photoinitiators that can be used as photocationic polymerization initiators include: Omnicat 250, Omnicat 270 (both from IGM Resins BV), CPI-310B, IK-1 (both from San-Apro Corporation), DTS-200 (Midori Chemical Co., Ltd.), and Irgacure 290 (BASF).

[0181] The amount of photocationic polymerization initiator added to the curable composition of the present invention is not particularly limited as long as the target photocuring reaction occurs. Generally, it is preferred to use the photocationic polymerization initiator in an amount of 0.1 to 10% by mass, preferably 0.2 to 5% by mass, and particularly 0.5 to 4% by mass, relative to the total amount of components (A) and (B) of the present invention.

[0182] In the case where component (A) is a photocationic polymerization initiator with an ultraviolet-reactive functional group such as an epoxy group, in addition to the aforementioned photocationic polymerization initiator, a photoradical polymerization initiator described below can also be used as the polymerization initiator. By using both initiators together, the curability of the ultraviolet-curable polyorganosiloxane composition is sometimes improved.

[0183] (2) Photoradical polymerization initiator

[0184] It is known that photoradical polymerization initiators are broadly classified into photolytic polymerization type and hydrogen abstraction type. However, the photoradical polymerization initiator used in the compositions of the present invention can be arbitrarily selected from photoradical polymerization initiators known in the art, and is not particularly limited to a specific photoradical polymerization initiator. Examples of photoradical polymerization initiators include: acetophenone, p-Anisil, benzoyl, benzoin, benzophenone, 2-benzoylbenzoic acid, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin ethyl ether, 4-benzoylbenzoic acid, 2, 2'-Bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, methyl 2-benzoylbenzoate, 2-(1,3-benzodioxolane-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-benzyl-2-(dimethylamino)-4'-morpholinylphenylbutanone, (±)-camphorquinone, 2-chlorothioxanone, 4,4'-dichlorodiphenylmethyl Ketones, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4-diethylthioxanthion-9-one, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphine sulfate, 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylacetone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, 2-isopropylthioxanthionone, phenyl(2,4,6-trimethylbenzoyl)lithium phosphate, 2-methyl-4'-(methylthio)-2-morpholinylphenylacetone, 2-isonitrosophenylacetone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, etc., but not limited to these. In addition to the compounds mentioned above, other photoradical polymerization initiators include: Omnirad 651, 184, 1173, 2959, 127, 907, 369, 369E and 379EG (alkyl phenyl ketone photopolymerization initiator, IGM Resins BV), Omnirad TPO H, TPO-L and 819 (acyl phosphorus oxide photopolymerization initiator, IGM Resins BV), Omnirad MBF and 754 (intramolecular hydrogen abstraction photopolymerization initiator, IGM Resins BV), Irgacure OXE01 and OXE02 (oxime ester non-associative polymerization initiator, BASF), etc.

[0185] The amount of photoradical polymerization initiator added to the composition of the present invention is not particularly limited as long as it causes the target photopolymerization or photocuring reaction. Generally, the photoradical polymerization initiator is used in an amount of 0.01 to 5% by mass, preferably 0.05 to 1% by mass, relative to the total mass of the composition of the present invention.

[0186] Furthermore, photosensitizers can also be used in combination with the aforementioned photocationic polymerization initiators or photoradical polymerization initiators. It is known that the use of sensitizers can improve the quantum efficiency of the polymerization reaction, allowing the use of longer wavelengths of light in the polymerization reaction compared to using only a photoinitiator. Therefore, it is particularly effective when the coating thickness of the composition is thick or when using a longer wavelength LED light source. Known sensitizers include: anthracene compounds, phenothiazine compounds, perylene compounds, anthocyanin compounds, sans-cyanin compounds, coumarin compounds, benzylene ketone compounds, (thio)xanthone or (thio)xanthone compounds, such as isopropylthioxanthone, 2,4-diethylthioxanthone, squarylium compounds, (thia)pyranium compounds, porphyrin compounds, etc., but are not limited to these; any photosensitizer can be used in the curable composition of the present invention.

[0187] The cured product obtained from the curable composition of the present invention can be customized based on the molecular chain length of component (A) or component (A1) and / or component (A2), the number of ultraviolet-reactive functional groups in each molecule, the position of ultraviolet-reactive functional groups within the molecule, and the molecular structure. The desired physical properties and curing speed of the cured product can be obtained, and the viscosity of the cured product can be designed to be the desired value. Furthermore, cured products obtained by curing the curable composition of the present invention are also included within the scope of the present invention. Moreover, the shape of the cured product obtained from the composition of the present invention is not particularly limited; it can be a thin film coating, a sheet, or other molded material. The composition can also be injected into specific locations in its uncured state to form a filler, or used as a sealing material or intermediate layer in laminates or display devices. The cured product obtained from the composition of the present invention is particularly preferably a thin film coating, and particularly preferably an insulating coating.

[0188] Furthermore, the curable compositions of the present invention are suitable for use as coating agents or potting agents, particularly as insulating coating agents or potting agents for electronic and electrical equipment.

[0189] The curable composition of the present invention has an overall viscosity of 80 mPa·s or less, preferably 30 mPa·s or less, and more preferably 20 mPa·s or less, as measured using an E-type viscometer at 25°C.

[0190] The cured product obtained by curing the curable composition of the present invention has the following characteristics: the refractive index is less than 1.45 when measured at 25°C and a wavelength of 589 nm.

[0191] As desired, the cured product obtained by curing the curable composition of the present invention can be designed to have a relative permittivity of less than 3.0, less than 2.8, etc., and the curable composition of the present invention can also be used to form a coating with a low relative permittivity.

[0192] When using the curable composition of the present invention as a coating agent, in order to achieve suitable flowability and workability for application to a substrate, the overall viscosity of the composition is measured using an E-type viscometer, preferably below 80 mPa·s at 25°C, more preferably 1 to 60 mPa·s, further preferably 5 to 30 mPa·s, and particularly preferably 5 to 20 mPa·s. To adjust the overall viscosity of the curable composition to a desired viscosity, compounds having preferred viscosities can be used as components to achieve the desired overall viscosity of the composition.

[0193] To adjust the viscosity, improve the coatability, and adjust the properties of the cured composition, a compound having one or more ultraviolet-reactive functional groups and containing no silicon atoms in one molecule of the aforementioned component (B) can be added to the composition, or the amount added can be adjusted. To suppress an increase in refractive index, the content of component (B) in the cured composition of the present invention is preferably less than 50% by mass ratio of component (B) to the total mass of components (A) and (B). The mass ratio of component (B) to the total mass of components (A) and (B) is preferably less than 20%, more preferably less than 10%, and even more preferably less than 5%.

[0194] [Ingredient (C)]

[0195] When the UV-curable polyorganosiloxane composition of the present invention is applied to a substrate surface using any method as a coating agent, in order to improve the wettability of the composition to the substrate and form a defect-free coating film, a component (C) selected from the following components may be further added to the composition of the present invention containing the above-mentioned components. As a method for applying the composition of the present invention to a substrate, inkjet printing is particularly preferred. Therefore, component (C) is a component that improves the wettability of the UV-curable polyorganosiloxane composition of the present invention to the substrate, and particularly significantly improves the inkjet printing characteristics. Component (C) is at least one compound selected from the group consisting of (C1), (C2), and (C3).

[0196] (i) Component (C1)

[0197] Component (C1) is a nonionic surfactant that does not contain silicon atoms and is not acrylic-based, i.e., a non-acrylic nonionic surfactant. Non-acrylic means that the surfactant does not have (meth)acrylate groups in its molecule. Examples of surfactants that can be used as component (C1) include: organic nonionic surfactants such as glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, alkyl glycosides, and acetylenol polyethers, as well as fluorinated nonionic surfactants. One or more of these can be used. Specific examples of component (C1) include: organic nonionic surfactants such as Kao Corporation's EMULGEN series, Rheodol series, Evonik Industries' Surfynol 400 series, and Nissin Chemical Industries' Olfine E series; and fluorinated nonionic surfactants such as 3M's FC-4400 series and DIC Corporation's Megafac 550 and 560 series.

[0198] Among them, the Surfynol 400 series and Olfine E series are particularly preferred as alkyl alcohol polyethers.

[0199] (ii) Component (C2) is a nonionic surfactant containing silicon atoms and having an HLB value of 4 or less. Here, the HLB value is a value indicating the degree of affinity of a surfactant for water and organic compounds; the HLB value is defined using the Griffin method (20 × the sum of the formula weights of the hydrophilic portions / molecular weight). As the hydrophilic portion, known examples include silicone polyethers having polyethers, glycerol-based polysiloxanes having (di)glycerol derivatives as hydrophilic portions, and methanol silicones having hydroxyethoxy groups as hydrophilic portions, etc., as silicon-containing nonionic surfactants. Among these surfactants, surfactants with an HLB value of 4 or less, i.e., surfactants with a hydrophilic portion mass fraction of 20% or less, are preferably used in the composition of the present invention. Methanol silicones are particularly preferred.

[0200] (iii) Component (C3) is a silicone oil with a viscosity of 90 mPa·s or less at 25°C. Examples of silicone oils include: dimethylsilyl-polydimethylsiloxane, dimethylvinylsilyl-polydimethylsiloxane, dimethylsilyl-dimethylsiloxy / methylvinylsiloxy copolymer, dimethylvinylsilyl-dimethylsiloxy / methylvinylsiloxy copolymer, dimethylsilyl-dimethylsiloxy / methylvinylsiloxy copolymer, dimethylsilyl-dimethylsiloxy / methylphenylsiloxy copolymer, dimethylsilyl-dimethylsiloxy / diphenylsiloxy copolymer, dimethylvinylsilyl-dimethylsiloxy / diphenylsiloxy copolymer, dimethylvinylsilyl-dimethylsiloxy / diphenylsiloxy copolymer, etc., with dimethylsilyl-polydimethylsiloxane and dimethylvinylsilyl-polydimethylsiloxane being preferred. The preferred viscosity range of the silicone oil is 2–50 mPa·s, a more preferred range is 2–30 mPa·s, and a further preferred range is 5–20 mPa·s. It should be noted that the viscosity values ​​described here are measured at 25°C using the rotational viscometer described in the examples.

[0201] The above-mentioned components (C1) to (C3) can be used in combination of one or more of them. The amount of component (C) in the curable composition is not particularly limited, but it is preferable that the total amount of component (A) and component (B) (if present) is set to 100% by mass, and the total amount of components (C1) to (C3) (collectively referred to as component (C)) relative to its total amount is 0.05% by mass or more and 1% by mass or less. This is because if the amount of component (C) is less than 0.05% by mass relative to the total amount of components (A) and (B) (100% by mass), the effect of improving the wettability of the curable composition on the substrate may not be sufficiently obtained. Furthermore, if the amount of component (C) exceeds 1% by mass relative to the total amount of components (A) and (B) (100% by mass), component (C) may ooze out of the cured material after curing.

[0202] As component (C), it is preferred to use silicone oil as component (C3) alone, or to use component (C3) in combination with one or more components selected from the group consisting of components (C1) and components (C2), and it is particularly preferred to use component (C3) as component (C) alone.

[0203] <Other Additives>

[0204] In addition to the components described above, further additives may be added to the compositions of the present invention as desired. Examples of additives listed below are provided, but the invention is not limited thereto.

[0205] [Adhesive-enhancing agent]

[0206] In the compositions of the present invention, an adhesion promoter may be added to improve adhesion and bonding with respect to a substrate in contact with the composition. When the curable compositions of the present invention are used in applications requiring adhesion or bonding with respect to a substrate, such as coating agents or sealing materials, it is preferable to add an adhesion promoter to the curable compositions of the present invention. As this adhesion promoter, any known adhesion promoter may be used, as long as it does not hinder the curing reaction of the compositions of the present invention.

[0207] Examples of adhesion promoters that can be used in this invention include: trialkoxysilyloxy (e.g., trimethoxysilyloxy, triethoxysilyloxy) or trialkoxysilylalkyl (e.g., trimethoxysilylethyl, triethoxysilylethyl) and organosilanes having hydrogenated silyl or alkenyl (e.g., vinyl, allyl), or organosiloxane oligomers with a straight-chain, branched, or cyclic structure having about 4 to 20 silicon atoms; and trialkoxysilyloxy or trialkoxysilylalkyl and methacryloyloxyalkyl (e.g., 3-methylsilyloxy ... Organosilanes containing acryloyloxypropyl, or organosiloxane oligomers with a linear, branched, or cyclic structure having approximately 4 to 20 silicon atoms; organosilanes containing trialkoxysilyl groups or alkyl groups bonded to epoxy groups (e.g., 3-epoxypropoxypropyl, 4-epoxypropoxybutyl, 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl), or organosiloxane oligomers with a linear, branched, or cyclic structure having approximately 4 to 20 silicon atoms; organosilanes containing two or more trialkoxysilyl groups (e.g., trimethoxy... Organic compounds of silyl groups (such as silyl groups and triethoxysilyl groups); reactants of aminoalkyltrialkoxysilanes bonded to epoxy groups of alkyltrialkoxysilanes; epoxy-containing ethyl polysilicates, specifically including: vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hydrogentriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 1,6- Bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,3-bis[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane, reactants of 3-epoxypropoxypropyltriethoxysilane and 3-aminopropyltriethoxysilane, condensation products of silanol-terminated methylvinylsiloxane oligomers and 3-epoxypropoxypropyltrimethoxysilane, condensation products of silanol-terminated methylvinylsiloxane oligomers and 3-methacryloyloxypropyltriethoxysilane, and tris(3-trimethoxysilylpropyl)isocyanurate.

[0208] The amount of adhesion promoter added to the curable composition of the present invention is not particularly limited, but considering the curing characteristics of the curable composition and the fact that it does not promote discoloration of the cured product, it is preferably in the range of 0.01 to 5 parts by mass relative to a total of 100 parts by mass of components (A) and (B), or in the range of 0.01 to 2 parts by mass.

[0209] [Other additives]

[0210] In the compositions of the present invention, other additives may be added as needed, in addition to or in place of the adhesive-improving agents described above. Examples of usable additives include: leveling agents, silane coupling agents not included in the substances listed as adhesive-improving agents, ultraviolet absorbers, antioxidants, polymerization inhibitors, and fillers (functional fillers such as reinforcing fillers, insulating fillers, and thermally conductive fillers). Appropriate additives may be added to the compositions of the present invention as needed. Furthermore, thixotropic agents may be added to the compositions of the present invention as needed, particularly when used as potting compounds or sealing materials.

[0211] [Refractive index of the cured composition of the present invention]

[0212] The cured product obtained from the UV-curable polyorganosiloxane composition of the present invention has a low refractive index, which is measured to be less than 1.45 at 25°C and a wavelength of 589 nm.

[0213] 〔use〕

[0214] The UV-curable polyorganosiloxane composition of the present invention can be cured not only by ultraviolet light, but also by electron beam, which is also a solution of the present invention.

[0215] The curable compositions of the present invention are low in viscosity and are particularly useful as materials for forming insulating layers constituting various articles, especially electronic and electrical equipment. The compositions of the present invention can be applied to a substrate, or formed by irradiating the composition with ultraviolet light or an electron beam while at least one substrate is sandwiched between two substrates made of a material through which ultraviolet light or an electron beam passes, thereby curing the composition to form an insulating layer. In this case, patterning can also be performed while applying the composition of the present invention to the substrate, followed by curing. Alternatively, the composition can be applied to the substrate, and during curing, portions cured by ultraviolet light or an electron beam and uncured portions remain. The uncured portions are then removed using a solvent, thereby forming an insulating layer with a desired pattern. In particular, when the cured layer of the present invention is an insulating layer, it can be designed to have a low relative permittivity of less than 3.0.

[0216] Regarding the curable composition of the present invention, the cured product obtained therefrom has good transparency, and is therefore particularly suitable as a material for forming an insulating layer for display devices such as touch panels and displays. In this case, the insulating layer can also be formed into any desired pattern as described above. Therefore, a display device such as a touch panel and display comprising an insulating layer obtained by curing the UV-curable polyorganosiloxane composition of the present invention is also a solution of the present invention.

[0217] Furthermore, when an article is coated with the curable composition of the present invention and then cured, an insulating coating (insulating film) can be formed. Therefore, the composition of the present invention can be used as an insulating coating agent. In addition, the cured product formed by curing the curable composition of the present invention can also be used as an insulating coating.

[0218] The insulating film formed from the curable composition of the present invention can be used for a variety of applications. In particular, it can be used as a component of electronic devices or as a material used in the manufacturing process of electronic devices. Electronic devices include semiconductor devices, magnetic recording heads, and other electronic components. For example, the curable composition of the present invention can be used as an insulating coating for semiconductor devices such as LSI (Large Scale Integration), system LSI, DRAM (Dynamic Random Access Memory), SDRAM (Synchronous Dynamic Random Access Memory), RDRAM (Rambus Dynamic Random Access Memory), D-RDRAM (Direct Rambus Dynamic Random Access Memory), and multilayer wiring boards of multichip modules; as an interlayer insulating film for semiconductors; an etch stopper film; a surface protective film; a buffer coating; a passivation film in LSI; a cover coat for flexible copper clad laminates; a solder resist film; and a surface protective film for optical devices.

[0219] In addition to being used as a coating agent, the UV-curable composition of the present invention is also suitable as a potting compound, particularly as an insulating potting compound for electronic and electrical equipment.

[0220] The compositions of the present invention can be used in particular as materials for forming coatings on the surface of a substrate using inkjet printing, in which case the compositions of the present invention particularly preferably contain the above-mentioned component (C).

[0221] The present invention will be further described below based on embodiments, but the present invention is not limited to the following embodiments.

[0222] Example

[0223] The UV-curable compositions and cured products of the present invention will be described in detail through examples. Furthermore, the measurements and evaluations in the examples and comparative examples were performed as described below.

[0224] [Viscosity of the curing composition]

[0225] The viscosity (mPa·s) of the composition at 25°C was measured using a rotational viscometer (manufactured by TOKIMEC Corporation, E-type VISCONIC EMD).

[0226] [Refractive index of curable compositions and their cured products]

[0227] The refractive index (nD) of the cured material at 25°C was measured using a digital refractometer (ATAGO Corporation, RX-7000α).

[0228] [Appearance of the curing composition and the cured product obtained from the curing composition]

[0229] The curing composition and the appearance of the cured product obtained therefrom were evaluated by visual observation.

[0230] [Preparation of Curable Compositions]

[0231] The materials listed in Table 1 below are placed into a brown plastic container and thoroughly mixed using a planetary mixer to prepare a curable composition.

[0232] [Curing of the curable composition]

[0233] Approximately 0.2 g of the curable composition was injected between two glass substrates sandwiched with a 0.18 mm thick spacer. The curable composition was then injected through one of the glass substrates from the outside at a rate of 2 J / cm². 2 The composition is cured by irradiating it with LED light with a wavelength of 405nm, producing a plate-shaped cured material with a side diameter of 30mm and a thickness of 0.18mm.

[0234] [Examples and Comparative Examples]

[0235] Using the following ingredients, a UV-curable composition with the composition (parts by weight) shown in Table 1 was prepared.

[0236] (A1a)1,3-Bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3-tetramethyldisiloxane.

[0237] (A1b)1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane.

[0238] (A2)1,1,1,3,5,5,5-Heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane.

[0239] (B1)1,2-Epoxydodecane.

[0240] (B2)1,7-Octadiene Diepoxide

[0241] (C) Catalyst masterbatch composed of the following components.

[0242] C: (C1) / (X) / (A2) = 30 / 2.4 / 67.6 (mass ratio).

[0243] (C1): 4-Isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate.

[0244] (X): 2-Isopropylthioxanthone.

[0245] [Table 1]

[0246]

[0247]

[0248] As shown in Table 1, the UV-curable compositions of the present invention (Examples 1-3) have a viscosity at 25°C suitable for application to a substrate as a coating agent, and high transparency. Furthermore, the refractive index of the cured product is 1.45 or less. On the other hand, in the compositions without component (A2) (Comparative Examples 1 and 2), the refractive index of the cured product is 1.46 or more, or the curing is insufficient.

[0249] Industrial availability

[0250] The UV-curable composition of the present invention is particularly suitable for the above-mentioned uses, especially as a material for forming an insulating layer for display devices such as touch panels and displays.

Claims

1. A UV-curable composition, characterized in that, The composition (A) contains one or more organosilicon compounds having an average of one or more ultraviolet-reactive functional groups per molecule, and the overall viscosity of the composition, measured using an E-type viscometer at 25°C, is 80 mPa. The composition contains no organic solvents and has a refractive index of less than 1.45 as measured at 25°C and 589 nm. Component (A) is a mixture of (A2) 1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane, or (A2) 1,1,1,3,5,5,5-heptamethyl-3-[2-(3,4-epoxycyclohexyl)ethyl]trisiloxane and at least one compound selected from (A1) below, wherein the mass ratio (A2) / (A1) is in the range of 100 / 0 to 20 / 80, and the proportion of component (A2) in the composition is 80% by mass or more. （A1）： 1,3-Bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3-tetramethyldisiloxane, 1,5-bis[2-(3,4-epoxycyclohexyl)ethyl]-1,1,3,3,5,5-hexamethyltrisiloxane, methyl(tris[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, tetra([2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane, 1,3,5,7-tetramethyl-1,3,5,7-tetra[2-(3,4-epoxycyclohexyl)ethyl]dimethylsiloxy)silane [Oxycyclohexyl]ethyl]-cyclotetrasiloxane, 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane, 1,5-bis(3-epoxypropoxypropyl)-1,1,3,3,5,5-hexamethyltrisiloxane, methyl[tris(3-epoxypropoxypropyl)dimethylsilyloxy]silane, tetra[(3-epoxypropoxypropyl)dimethylsilyloxy]silane, 1,3,5,7-tetramethyl-1,3,5,7-tetra(3-epoxypropoxypropyl)-cyclotetrasiloxane.

2. The UV-curable composition according to claim 1, wherein, The overall viscosity of the composition, measured using an E-type viscometer at 25°C, was 5–30 mPa. The range of s.

3. The UV-curable composition according to claim 1, wherein, The UV-curable composition further contains (B) a compound having one or more UV-reactive functional groups in one molecule and not having silicon atoms, wherein the mass ratio of component (B) to the total mass of components (A1), (A2) and (B) is less than 20%.

4. An insulating coating agent comprising the ultraviolet-curable composition as described in any one of claims 1 to 3.

5. A method of using a cured product of the UV-curable composition as described in any one of claims 1 to 3 as an insulating coating.

6. A display device comprising a layer formed of a cured product of the ultraviolet-curable composition as described in any one of claims 1 to 3.

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