Ultraviolet curable composition and use thereof

Abstract

Provided is a silicon-atom-containing ultraviolet-curable composition which exhibits excellent workability when applied to a substrate even if the composition is of a solvent-free type, and which is obtained by curing a product that has a high ability to adjust mechanical properties. The ultraviolet-curable composition is characterized in that: when the total mass of the composition is 100 parts by mass, the content of the ultraviolet-curable composition is 100 parts by mass; the composition is characterized by containing (A) 1-99 parts by mass of a compound having one or more (meth) acryloyloxy groups in one molecule and (B) 99-1 part by mass of an organopolysiloxane having two or more alkenyl groups and at least one C6-20 aromatic hydrocarbon group in one molecule and not having an ultraviolet-curable functional group, and the composition substantially does not contain an organic solvent.

Description

Technical Field

[0001] The present invention relates to a UV curable composition that can be cured by actinic rays, such as ultraviolet rays or electron beams, and particularly to a UV curable composition comprising an organosilicon compound, preferably an organopolysiloxane, and particularly, a UV curable composition having a high viscosity adjustment capability and excellent coating properties. The curable composition of the present invention is suitable as an insulating material for electronic devices and electrical equipment, and is particularly suitable as a material for use as a coating agent. Further, it is useful as an injection molding material and an inkjet printing material from the perspective of having excellent coating properties and excellent wettability and viscosity adjustment capabilities for a substrate. Background Art

[0002] Silicone resins have been used as coating agents, potting agents, and insulating materials for electronic devices and electrical equipment due to their high heat resistance and excellent chemical stability. Among silicone resins, ultraviolet 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. In order to improve its sensing sensitivity, it is necessary to suppress the film response from the light-emitting parts such as light-emitting diodes (LEDs) and organic EL devices (OLEDs), and an insulating layer is usually configured between the light-emitting part and the touch screen.

[0004] On the other hand, thin display devices such as OLED have a structure in which multiple functional thin layers are stacked. In recent years, research has begun on improving the reliability of display devices, especially flexible display devices, by stacking a highly flexible insulating layer on a touch screen layer. In addition, inkjet printing is used as a processing method for organic layers for the purpose of improving productivity. Therefore, materials that can be processed by inkjet printing are also required for the above-mentioned insulating layer.

[0005] Japanese Patent Application Laid-Open No. 2016-56330 discloses an ultraviolet-curable organopolysiloxane composition comprising a polysiloxane having a methacryloxy functional group, a polysiloxane having two or more acryloxy functional groups in one molecule, and a polysiloxane having alkenyl groups at both ends, and a silicone gel cured product obtained from the composition.

[0006] Furthermore, International Patent Application Publication No. WO2018-3381 discloses an inkjet ink composition, which includes a UV-curable silicone composition composed of a polysiloxane having two (meth)acryloyloxy functional groups in one molecule and an acrylate compound containing no silicon atoms. The composition disclosed herein cannot be said to have a sufficiently high viscosity adjustment capability, and it is difficult to provide a low-viscosity composition that can be used as an inkjet method.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2016-56330

[0010] Patent Document 2: WO2018-3381 Summary of the invention

[0011] Problems to be solved by the invention

[0012] As described above, many UV-curable compositions containing organopolysiloxanes having acryloxy functional groups are known, but there is now a further demand for UV-curable compositions that can easily adjust the mechanical properties of the cured product and have excellent workability for coating on a substrate, particularly high viscosity adjustment capability. The present invention aims to provide a curable composition, particularly a UV-curable composition, which has both high adjustability of the mechanical properties of the product obtained by curing and excellent workability when coated on a substrate even in a solvent-free type, and contains silicon atoms.

[0013] Solutions for solving problems

[0014] The present invention is based on the discovery that the composition, when the total mass of the composition is 100 parts by mass, contains the following:

[0015] (A) 1 to 99 parts by mass of a compound having one or more (meth)acryloyloxy groups in one molecule; and

[0016] (B) 99 to 1 parts by mass of an organopolysiloxane having two or more alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms in one molecule and having no ultraviolet curable functional group,

[0017] The present invention has been completed because the composition has a viscosity that allows coating even without substantially using an organic solvent, and its cured product has excellent mechanical properties. Furthermore, the viscosity of the composition and the mechanical properties of the cured product can be easily adjusted.

[0018] The present invention relates to an ultraviolet curable composition comprising an organosilicon compound, and in particular to an ultraviolet curable organopolysiloxane composition. The composition can also be cured by forming a bond based on an ultraviolet curable functional group, but the curing method is not limited to ultraviolet irradiation, and any method that can cause a curing reaction using the ultraviolet curable functional group can also be used, for example, electron beam irradiation can be used to cure the composition of the present invention.

[0019] The ultraviolet curable composition of the present invention is characterized in that, based on 100 parts by mass of the total mass of the composition, it contains the following:

[0020] (A) 1 to 99 parts by mass of a compound having one or more (meth)acryloyloxy groups in one molecule; and

[0021] (B) 99 to 1 parts by mass of an organopolysiloxane having two or more alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms in one molecule and having no ultraviolet curable functional group,

[0022] The composition contains substantially no organic solvent.

[0023] It should be noted that, unless otherwise specified in the present specification, the viscosity of a substance is a value measured at 25° C. using an E-type viscometer.

[0024] The viscosity of the entire composition measured at 25° C. using an E-type viscometer is preferably in the range of 500 mPa·s or less.

[0025] The above-mentioned component (B) is preferably composed of the average composition formula:

[0026] R a R' b SiO (4-a-b) / 2 (1)

[0027] (wherein R is an alkenyl group,

[0028] R' is a group selected from a monovalent hydrocarbon group other than an alkenyl group, a hydroxyl group, and an alkoxy group,

[0029] a and b are numbers satisfying the following conditions: 1≤a+b≤3 and 0.05≤a / (a+b)<1.0, and the molecule has at least two R's, and at least one of the R's is an aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0030] The linear, branched or cyclic organopolysiloxane shown.

[0031] The organopolysiloxane of the component (B) is preferably selected from the following formula (2):

[0032] [Chemical formula 1]

[0033]

[0034] (In the formula, in all R 1 ~R 8 In the group, there are at least two alkenyl groups in the molecule; there is at least one aromatic hydrocarbon group with 6 to 20 carbon atoms in the molecule; other R 1 ~R 8 an organopolysiloxane represented by an unsubstituted or fluorine-substituted monovalent hydrocarbon group, a hydroxyl group, and an alkoxy group, wherein n is a numerical value of 0 to 1,000,

[0035] From the average unit formula (3):

[0036] (R3SiO 1 / 2 ) c (R2SiO 2 / 2 ) d (RSiO 3 / 2 ) e (SiO 4 / 2 ) f (3)

[0037] (wherein, R is independently a group selected from alkenyl, unsubstituted or fluorine-substituted monovalent hydrocarbon group, hydroxyl group and alkoxy group, at least two of all R are alkenyl, at least one is an aromatic hydrocarbon group having 6 to 20 carbon atoms, (e+f) is a positive number, c is 0 or a positive number, and d is a number in the range of 0 to 100) a branched organopolysiloxane,

[0038] From the following formula (4):

[0039] [Chemical formula 2]

[0040]

[0041] (wherein, R is independently a group selected from an alkenyl group and a monovalent hydrocarbon group which is unsubstituted or substituted by fluorine, x is an integer of 3 to 10, and the molecule contains at least two alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms) a cyclic organopolysiloxane represented by

[0042] And one or more organopolysiloxanes having at least two alkenyl groups and one or more aromatic hydrocarbon groups having 6 to 20 carbon atoms in the molecule, from the group consisting of a mixture of these organopolysiloxanes.

[0043] The component (B) is preferably a linear organopolysiloxane represented by the formula (2) having two alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms in one molecule.

[0044] The component (A) may be a compound having one (meth)acryloyloxy group, or a mixture of a compound having one (meth)acryloyloxy group and a compound having two or more (meth)acryloyloxy groups.

[0045] The compound having one (meth)acryloyloxy group in the component (A) is preferably the following (A1) or (A2).

[0046] (A1) One or more compounds having one (meth)acryloyloxy group and no silicon atom

[0047] (A2) A mixture of (A1) and one or more compounds having one (meth)acryloyloxy group and having a silicon atom

[0048] The component (A) preferably contains a compound having at least one acryloyloxy group.

[0049] The content of the aromatic hydrocarbon group having 6 to 20 carbon atoms in the component (B) is preferably 10 mol% or more relative to all substituents on the silicon atom.

[0050] The viscosity of the entire composition measured at 25° C. using an E-type viscometer is preferably in the range of 5 to 60 mPa·s.

[0051] The present invention further provides an insulating coating agent or insulating adhesive comprising the above-mentioned ultraviolet curable composition. The ultraviolet curable composition of the present invention is useful as an insulating coating agent or insulating adhesive.

[0052] The present invention further provides a cured product of the ultraviolet curable composition and a method of using the cured product as an insulating coating or insulating adhesive layer.

[0053] The present invention further provides a display device including a layer composed of a cured product of the ultraviolet curable composition, such as a liquid crystal display, an organic EL display, and an organic EL flexible display. DETAILED DESCRIPTION

[0054] Hereinafter, the configuration of the present invention will be described in further detail.

[0055] The ultraviolet curable composition of the present invention is characterized in that, based on 100 parts by mass of the total mass of the composition, it contains, as a curing essential component:

[0056] (A) 1 to 99 parts by mass of a compound having one or more (meth)acryloyloxy groups in one molecule; and

[0057] (B) 99 to 1 parts by mass of an organopolysiloxane having two or more alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms in one molecule and having no ultraviolet curable functional group,

[0058] If necessary, the composition may contain a component selected from a photoradical polymerization initiator and various additives. The curable composition of the present invention is characterized in that it does not substantially contain an organic solvent.

[0059] In this specification, the term "polysiloxane" refers to a polysiloxane having a degree of polymerization of siloxane units (Si-O) of 2 or more, that is, a polysiloxane having an average of more than two Si-O bonds per molecule, and polysiloxane includes siloxane oligomers such as disiloxane, trisiloxane, and tetrasiloxane to siloxane polymers with higher degrees of polymerization.

[0060] [Ingredients (A)]

[0061] Component (A) is a compound having one or more (meth)acryloyloxy groups in one molecule. As long as the purpose can be achieved, the molecular structure is not limited, and can be any molecular structure such as linear, branched, cyclic, cage-like, etc. In this specification, "(meth)acryloyloxy" refers to a group selected from methacryloxy and acryloxy, and can include both. In addition, the compound having a (meth)acryloyloxy group includes both methacrylate compounds and acrylate compounds.

[0062] The viscosity of the component (A) at 25° C. is preferably 1 to 1,000 mPa·s, more preferably 1 to 500 mPa·s, and particularly preferably 1 to 20 mPa·s.

[0063] In addition, the component (A) contains an average of 1 to 4, preferably 1 to 3, and more preferably 1 to 2 (meth)acryloyloxy groups per molecule. In a compound having multiple (meth)acryloyloxy groups, the positions of the (meth)acryloyloxy groups in the molecule are not limited and they may exist close to each other or separately.

[0064] The component (A) may be a compound having one (meth)acryloyloxy group, or a mixture of a compound having one (meth)acryloyloxy group and a compound having two or more (meth)acryloyloxy groups.

[0065] Furthermore, the compound having one (meth)acryloyloxy group in the above-mentioned component (A) may be (A1) one or more compounds having one (meth)acryloyloxy group and no silicon atom or a mixture thereof, and is preferably. Specifically, the component (A) may be the following (A1) or (A2).

[0066] (A1) One or more compounds having one (meth)acryloyloxy group and no silicon atom

[0067] (A2) A mixture of (A1) and one or more compounds having one (meth)acryloyloxy group and having a silicon atom

[0068] The mixture as (A2) is a mixture of a compound having one (meth)acryloyloxy group and having a silicon atom (e.g., (meth)acryloyloxy-functional polydimethylsiloxane, (meth)acryloyloxy-functional branched organopolysiloxane, etc.) and (A1) having no silicon atom.

[0069] Furthermore, the component (A) may include at least one compound having an acryloyloxy group, or may be a mixture of compounds having two or more acryloyloxy groups.

[0070] Specific examples of the compound having one (meth)acryloyloxy group include isopentyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, (meth)diethylene glycol monoethyl ether acrylate, (meth)diethylene glycol monomethyl ether acrylate, 2-ethylhexyl (meth)acrylate, phenoxyethyl (meth)acrylate, (meth)diethylene glycol monophenyl ether acrylate, (meth)acrylic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-1-methylethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. , 4-hydroxybutyl (meth)acrylate, 1-hydroxymethylpropyl (meth)acrylate, 4-(meth)acryloyloxyphenol, 6-hydroxyhexyl (meth)acrylate, methyl-2-(2-hydroxy-1-methylethyl (meth)acrylate), tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, single-end (meth)acryloyloxy-functional polydimethylsiloxane, single-end (meth)acryloyloxy-functional polydimethyldiphenylsiloxane copolymer, (meth)acryloyloxy-functional branched organic polysiloxane, etc., which can be used alone or in combination of two or more.

[0071] Examples of the (meth)acryloxy-functional branched organopolysiloxane include acryloxypropyl tris(trimethylsiloxy)silane, methacryloxypropyl tris(trimethylsiloxy)silane, acryloxypropyl tris(trimethylsilylethyldimethylsiloxy)silane, methacryloxypropyl tris(trimethylsilylethyldimethylsiloxy)silane, acryloxypropyl tris((tritrimethylsiloxysilyl)ethyldimethylsiloxy)silane, and methacryloxypropyl tris((tritrimethylsiloxysilyl)ethyldimethylsiloxy)silane. These may be used alone or in combination of two or more.

[0072] In consideration of the viscosity, curability, hardness after curing and glass transition temperature of the compound, the compound having a (meth)acryloyloxy group may be used alone or in combination of two or more. Among them, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, and (meth)acryloyloxypropyl tris(trimethylsiloxy)silane may be preferably used, and 2-ethylhexyl acrylate, isobornyl acrylate, dicyclopentyl acrylate, and (meth)acryloyloxypropyl tris(trimethylsiloxy)silane may be particularly preferably used.

[0073] Specific examples of the compound having two or more (meth)acryloyloxy groups include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4-bis(acryloyloxy)butane, 1,6-bis((meth)acryloyloxy)hexane, 1,9-bis(acryloyloxy)nonane, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tri(2-acryloyloxy)ethyl isocyanate, pentaerythritol tetraacrylate, 3-acryloyloxy-2-hydroxypropyl methacrylate, Ester, 3-methacryloyloxy-2-hydroxypropyl methacrylate, 3-(meth)acryloyloxy-2-hydroxypropyl (meth)acrylate, glycerol di(meth)acrylate, glycerol-1,3-diglyceryl di(meth)acrylate, (meth)acryloyloxy-functional polydimethylsiloxane at both ends, (meth)acryloyloxy-functional polydimethyldiphenylsiloxane copolymer at both ends, trimethylsilyl-functional polydimethyl((meth)acryloyloxyalkylmethyl)siloxane copolymer at both ends, and acryloxy-functional polydimethyl((meth)acryloyloxyalkylmethyl)siloxane copolymer at both ends.

[0074] Regarding the compound having two or more (meth)acryloyloxy groups, it is possible to use them alone or in combination of two or more, taking into account the viscosity, curability, compatibility with the above-mentioned compound having one acryloyloxy group, hardness after curing, and glass transition temperature of the compound. Preferably, diethylene glycol di(meth)acrylate, 1,6-bis((meth)acryloyloxy)hexane, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and polydimethylsiloxane having (meth)acryloyloxy functional groups at both ends can be used, but it is more preferable to use a compound having no silicon atom, i.e., diethylene glycol di(meth)acrylate, 1,6-bis((meth)acryloyloxy)hexane, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

[0075] Furthermore, considering the above-mentioned physical properties, the compounds having two or more (meth)acryloyloxy groups may be used in combination with compounds having one (meth)acryloyloxy group. In this case, the two may be combined in any ratio, but usually, [compound having two or more (meth)acryloyloxy groups] / [compound having one (meth)acryloyloxy group] is in the range of 1 / 99 to 75 / 25 (mass ratio), may be in the range of 1 / 99 to 50 / 50, and preferably in the range of 1 / 99 to 30 / 70. This is because if the ratio of the compound having two or more (meth)acryloyloxy groups is too high, there is a tendency for the hardness of the cured product to become higher and brittle.

[0076] [Ingredient (B)]

[0077] Component (B) is an organopolysiloxane having two or more alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms in one molecule and having no UV-curable functional group. Such component (B) improves the viscosity and mechanical strength (particularly toughness and tensile elongation) of the cured product in the UV composition of the present invention as a whole, which is substantially solvent-free, and has the advantage of not impairing the UV curability of the composition as a whole because it has an aromatic hydrocarbon group such as an aryl group in the molecule.

[0078] The alkenyl group in the component (B) is preferably a terminal alkenyl group in its molecular structure. In particular, the component (B) having alkenyl groups at both ends of the molecular chain acts as a crosslinking agent and / or a chain extender in the crosslinked structure, and contributes to improving the rubber properties of the cured product, especially the elongation and tensile strength.

[0079] The above-mentioned component (B) may be of the following average composition formula:

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

[0081] (wherein R is an alkenyl group,

[0082] R' is a group selected from a monovalent hydrocarbon group other than an alkenyl group, a hydroxyl group, and an alkoxy group,

[0083] a and b are numbers satisfying the following conditions: 1≤a+b≤3 and 0.05≤a / (a+b)<1.0, and the molecule has at least two R's, and at least one of the R's is an aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0084] The linear, branched or cyclic organopolysiloxane shown.

[0085] Examples of the alkenyl group represented by R in formula (1) include alkenyl groups having 2 to 8 carbon atoms, and specific examples thereof include vinyl, allyl, butenyl, pentenyl, hexenyl, and octenyl. Among them, vinyl and hexenyl are particularly preferred.

[0086] At least one of R' is an aromatic hydrocarbon group having 6 to 20 carbon atoms, and the rest are groups selected from monovalent hydrocarbon groups, hydroxyl groups and alkoxy groups. In particular, the aromatic hydrocarbon group having 6 to 20 carbon atoms as R' can be listed as: phenyl, tolyl, xylyl, naphthyl and the like, but phenyl is preferred. In the case where R' does not contain an aromatic hydrocarbon group having 6 to 20 carbon atoms, even if an organopolysiloxane containing an alkenyl group is used instead of component (B), the UV curability of the composition as a whole is significantly reduced, and sometimes the improvement in mechanical strength and good UV curability of the cured product involved in the present invention cannot be achieved.

[0087] Other monovalent hydrocarbon groups as R' include unsubstituted monovalent hydrocarbon groups and monovalent hydrocarbon groups substituted by fluorine. The unsubstituted or fluorine-substituted monovalent hydrocarbon group is preferably a group selected from an unsubstituted or fluorine-substituted alkyl group and a cycloalkyl group having 1 to 20 carbon atoms. As the above-mentioned alkyl group, groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, hexyl, and octyl can be listed, but methyl and hexyl are particularly preferred. As the above-mentioned cycloalkyl group, cyclopentyl, cyclohexyl, etc. can be listed. As examples of monovalent hydrocarbon groups substituted by fluorine, 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl can be listed. As a monovalent hydrocarbon group substituted by fluorine, 3,3,3-trifluoropropyl is preferred.

[0088] The viscosity of the organopolysiloxane represented by the above formula (1) at 25° C. is 1 to 25,000 mPa·s, more preferably 1 to 5,000 mPa·s. The viscosity of the organopolysiloxane can be adjusted by changing the ratio of a and b and the molecular weight in the formula (1).

[0089] The organopolysiloxane represented by the formula (1) preferably has an average of 2 to 1,000, more preferably 2 to 500, silicon atoms per molecule.

[0090] In a preferred embodiment, the organopolysiloxane of component (B) is

[0091] The following formula (2):

[0092] [Chemical formula 3]

[0093]

[0094]

[0095] The compounds shown.

[0096] Similar to the compound represented by the above formula (1), the organopolysiloxane represented by the formula (2) has at least two alkenyl groups in one molecule and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms. The structure of the alkenyl group is not limited to an alkenyl group of a specific chemical structure as long as it has a carbon-carbon double bond. The alkenyl group is particularly preferably a terminal alkenyl group, and examples thereof include: vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl and 4-vinylphenyl and other alkenyl groups having 2 to 20 carbon atoms, but are not limited thereto, and are particularly preferably vinyl and hexenyl. The aromatic hydrocarbon groups having 6 to 20 carbon atoms include phenyl, tolyl, xylyl, naphthyl and the like, but phenyl is preferred.

[0097] In formula (2), R other than the alkenyl group and the 6-20 aromatic hydrocarbon groups 1 ~R 8 Each is independently an unsubstituted or fluorine-substituted monovalent hydrocarbon group, preferably a group selected from an unsubstituted or fluorine-substituted alkyl group and a cycloalkyl group having 1 to 20 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, octyl and the like, but methyl is particularly preferred. Examples of the cycloalkyl group include cyclopentyl, cyclohexyl and the like. Examples of the monovalent hydrocarbon group substituted with fluorine include 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl. As a monovalent hydrocarbon group substituted with fluorine, 3,3,3-trifluoropropyl is preferred.

[0098] n in formula (2) is the viscosity of the organopolysiloxane represented by formula (2) at 25° C., and is preferably 1 to 25,000 mPa·s, and more preferably 1 to 5,000 mPa·s. A person skilled in the art can easily determine the value of n without excessive trial and error so that the viscosity of the organopolysiloxane represented by formula (2) falls within the above viscosity range.

[0099] The number of alkenyl groups in the organopolysiloxane of formula (2) as the component (B) is 2 or more, preferably 2 or more and 10 or less, and more preferably 2 or more and 8 or less per molecule.

[0100] The organopolysiloxane of formula (2) can be used alone or as a mixture of two or more. When two or more organopolysiloxanes are used as a mixture, the viscosity of the mixture at 25° C. is preferably the above-mentioned viscosity.

[0101] The compound of the formula (1) may be a branched organopolysiloxane represented by the following average unit formula (3).

[0102] Average unit formula (3):

[0103] (R3SiO 1 / 2 ) c (R2SiO 2 / 2 ) d (RSiO 3 / 2 ) e (SiO 4 / 2 ) f (3)

[0104] In formula (3), R is independently a group selected from an alkenyl group, an unsubstituted or fluorine-substituted monovalent hydrocarbon group, a hydroxyl group, and an alkoxy group, at least two of all R are alkenyl groups, at least one is an aromatic hydrocarbon group having 6 to 20 carbon atoms, (e+f) is a positive number, c is 0 or a positive number, and d is a number in the range of 0 to 100.

[0105] The alkenyl group, the aromatic hydrocarbon group with 6 to 20 atoms and the monovalent hydrocarbon group are as defined above for formula (2). In addition, the preferred viscosity of the organopolysiloxane represented by formula (3) is also defined as for the organopolysiloxane represented by formula (2). Furthermore, if the amount is small, the alkoxy group and the silanol group may remain in the molecule.

[0106] The organopolysiloxane represented by the formula (3) preferably has 4 to 30, particularly 6 to 20 silicon atoms per molecule.

[0107] The number of alkenyl groups in the organopolysiloxane represented by the formula (3) is 2 or more, and preferably 2 or more and 10 or less, per molecule on average.

[0108] In a preferred embodiment, component (B), in particular the organopolysiloxane of formula (3), is an organopolysiloxane having (RSiO 3 / 2 ) units.

[0109] In the above (1), in particular, specific examples of the linear organopolysiloxane represented by formula (2) include: polymethylphenylsiloxane having dimethylvinylsilyl groups at both ends, polydimethyl / methylphenylsiloxane copolymers having dimethylvinylsilyl groups at both ends, polydimethyl / diphenylsiloxane copolymers having dimethylvinylsilyl groups at both ends, polymethylphenylsiloxane having dimethylhexenylsilyl groups at both ends, polydimethyl / methylphenylsiloxane copolymers having dimethylhexenylsilyl groups at both ends, and polydimethylphenylsiloxane having dimethylhexenylsilyl groups at both ends. Silyl polydimethyl / diphenylsiloxane copolymer, both-terminal trimethylsilyl polymethylphenyl / methylvinylsiloxane copolymer, both-terminal trimethylsilyl polymethylphenyl / methylhexenylsiloxane copolymer, both-terminal diphenylvinylsilyl polymethylphenylsiloxane, both-terminal diphenylhexenylsilyl polymethylphenylsiloxane, both-terminal methylphenylvinylsilyl polydimethylsiloxane, 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, etc., but are not limited thereto.

[0110] Specific examples of the branched organopolysiloxane represented by the above formula (1), especially by the formula (3), include: Vi (dimethylvinylsiloxane) units and T Ph (phenyl siloxane) units, polysiloxane composed of M Vi Unit and M (trimethylsiloxane) unit and T Ph (phenyl siloxane) units, polysiloxane composed of M Vi Units and D (dimethylsiloxane) units and T Ph Polysiloxane composed of M Hex (dimethylhexenylsiloxane) units and T Ph Polysiloxane composed of M Hex Unit and M unit and T Ph Polysiloxane composed of M Hex Unit and D unit and T Ph Polysiloxane composed of M units and D Vi (methylvinylsiloxane) units and T Ph Polysiloxane composed of D Vi Unit and D unit and T Ph Polysiloxane composed of D Vi Unit and T Ph Polysiloxane composed of M units and D Hex (methylhexenylsiloxane) units and T Ph Polysiloxane composed of D Hex Unit and D unit and T Ph Polysiloxane composed of DHex Unit and T Ph Polysiloxane composed of T Hex Unit and T Ph Polysiloxane composed of M units and T Hex Unit and T Ph The present invention may be polysiloxane composed of a unit, but is not limited thereto.

[0111] In addition, the compound of the above formula (1) may also be represented by the following formula (4):

[0112] [Chemical formula 4]

[0113]

[0114] (wherein, R is independently a group selected from an alkenyl group and a monovalent hydrocarbon group that is unsubstituted or substituted by fluorine, x is an integer from 3 to 10, and the molecule has at least two alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms).

[0115] The alkenyl group, the aromatic hydrocarbon group having 6 to 20 carbon atoms, and the unsubstituted or fluorine-substituted monovalent hydrocarbon group which may be represented by R in the formula (4) are as defined in the above formula (1).

[0116] The preferred viscosity of the organopolysiloxane represented by the formula (4) is also defined as that of the organopolysiloxane represented by the formula (1).

[0117] Specific examples of the cyclic organopolysiloxane represented by formula (4) include cyclic trisiloxane composed of methylvinylsiloxy groups and methylphenylsiloxy groups, and cyclic tetrasiloxane composed of methylvinylsiloxy groups and methylphenylsiloxy groups.

[0118] The organopolysiloxane represented by the above formula (1), more specifically, any one of (2) to (4), can be used alone or in any combination of two or more as the component (B).

[0119] As component (B), it is particularly preferred to use one or more organopolysiloxanes selected from the group consisting of the organopolysiloxane represented by the above formula (2), the branched organopolysiloxane represented by the formula (3), and a combination thereof. It is particularly preferred that the organopolysiloxane represented by the above formula (2) has R 2 and R 7 is alkenyl, other substituents (R 1 , R 3 , R 4 , R 5 , R 6 and R 8) is an aromatic hydrocarbon group having 6 to 20 carbon atoms, and n in formula (2) is a value of the viscosity of the organopolysiloxane represented by formula (2) at 25°C, which is preferably 1 to 25,000 mPa·s, and more preferably 1 to 5,000 mPa·s.

[0120] The compound recommended as component (B) is selected from the group consisting of: polymethylphenylsiloxane with dimethylvinylsilyl at both ends, polydimethyl / methylphenylsiloxane copolymer with dimethylvinylsilyl at both ends, polydimethyl / diphenylsiloxane copolymer with dimethylvinylsilyl at both ends, polymethylphenylsiloxane with dimethylhexenylsilyl at both ends, polydimethyl / methylphenylsiloxane copolymer with dimethylhexenylsilyl at both ends, polymethylphenyl / methylvinylsiloxane copolymer with trimethylsilyl at both ends, polymethylphenyl / methylhexenylsiloxane copolymer with trimethylsilyl at both ends, polydimethylphenyl at both ends, 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, and polydimethylphenylsiloxane with M units and D units. Vi Unit and T Ph Polysiloxane composed of M Vi Unit and T Ph Polysiloxane composed of M Vi Unit and D unit and T Ph Polysiloxane composed of M units and D Hex Unit and T Ph Polysiloxane composed of M Hex Unit and T Ph Polysiloxane composed of M Hex Unit and D unit and T Ph Polysiloxane composed of T Hex Unit and T Ph Among them, polymethylphenylsiloxanes having dimethylvinylsilyl groups at both ends, polydimethyl / diphenylsiloxane copolymers having dimethylvinylsilyl groups at both ends, polysiloxanes having M units and D units, and polysiloxanes having dimethylvinylsilyl groups at both ends are particularly preferably used. Hex Unit and T Ph Polysiloxane composed of D Hex Unit and T Ph Polysiloxane composed of T Hex Unit and T Ph Polysiloxane composed of units.

[0121] [Mixing ratio of component (A) / (B)]

[0122] With respect to the mixing ratio of component (A) and component (B), relative to the total amount of component (A) and component (B) 100% by mass, the ratio of component (A) is 1 to 99% by mass, and the ratio of component (B) is 99 to 1% by mass. When the ratio of component (A) to (B) is within this range, the viscosity of the curable composition can be appropriately adjusted, good ultraviolet curability can be maintained, and the mechanical properties of the obtained cured product, particularly the material with large tensile elongation, can be designed. By increasing the ratio of component (A), it is easy to design the hardness of the cured product to be high. The preferred ratio of component (A) is 15% by mass or more and 85% by mass or less of the total amount of components (A) and (B), more preferably 25% by mass or more and 75% by mass or less.

[0123] The contents of component (A) and component (B) in the ultraviolet curable composition of the present invention are within the above-mentioned content ranges, but when the total mass of the composition is 100 parts by mass, the sum of the contents of component (A) and component (B) is preferably 90 parts by mass or more, particularly preferably in the range of 90 to 99.9 parts by mass, or 90 to 99 parts by mass. That is, in the preferred ultraviolet curable composition, most of it is a composition consisting of component (A) and component (B). However, the present composition may also contain other components described later.

[0124] [No use of organic solvents]

[0125] The ultraviolet curable composition of the present invention is a ultraviolet curable composition that can achieve a viscosity suitable for a coating agent by using the above-mentioned components without substantially using an organic solvent, and does not substantially contain an organic solvent. In this specification, substantially not containing an organic solvent means that the content of the organic solvent is less than 0.1% by mass of the entire composition, preferably below the analytical limit using an analytical method such as gas chromatography. In the present invention, by adjusting the molecular structure and molecular weight of component (A) and component (B), the desired viscosity can be achieved even without using an organic solvent.

[0126] In the ultraviolet curable composition of the present invention, in addition to the above-mentioned components (A) and (B), a photopolymerization initiator can be added as desired. As the photopolymerization initiator, a photoradical polymerization initiator can be used. The photoradical polymerization initiator can generate free radicals by irradiation of ultraviolet rays or electron beams, and the free radicals can cause a free radical polymerization reaction to cure 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 usually not required.

[0127] It is known that photoradical polymerization initiators are roughly divided into photolysis type and hydrogen abstraction type, but the photoradical polymerization initiator used in the composition of the present invention can be arbitrarily selected from photoradical polymerization initiators known in the technical field and is not particularly limited to a specific photoradical polymerization initiator. Examples of photoradical polymerization initiators include: acetophenone, p-anisil, dibenzoyl, 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, 2-benzoylbenzoic acid methyl ester, 2-(1,3-benzodioxolan-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-benzyl-2-(dimethylamino)-4'-morpholinophenyl butanone, (±)-camphorquinone, 2-chlorothioxanthone, 4,4'-dichlorobenzophenone , 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,4-diethylthioxanthen-9-one, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, (2,4,6-trimethylbenzoyl) phenyl phosphinate ethyl ester, 1,4-dibenzoylbenzene, 2-ethylanthraquinone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isopropylthioxanthone, phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-isonitrosopropiophenone, 2-phenyl-2-(p-toluenesulfonyloxy) acetophenone and phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, but are not limited to these. In addition, as the photoradical polymerization initiator, in addition to the above-mentioned compounds, Omnirad (registered trademark) 651, 184, 1173, 2959, 127, 907, 369, 369E and 379EG (alkyl phenone-based photopolymerization initiators, IGM Resins BV), Omnirad (registered trademark) TPO H, TPO-L and 819 (acylphosphine oxide-based photopolymerization initiators, IGM RESINS B.V.), Omnirad (registered trademark) MBF and 754 (intramolecular hydrogen abstraction type photopolymerization initiators, IGM Resins B.V.), Irgacure (registered trademark) OXE01 and OXE02 (oxime ester-based non-associative polymerization initiators, BASF) and the like can be listed.

[0128] The amount of the photoradical polymerization initiator added to the composition of the present invention is not particularly limited as long as it causes the target photopolymerization reaction 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.

[0129] In addition, a photosensitizer can also be used in combination with the above-mentioned photoradical polymerization initiator. It is known that the use of a sensitizer can improve the photon efficiency of the polymerization reaction, and compared with the case of using only a photoinitiator, it becomes possible to use longer wavelength light in the polymerization reaction, so it is particularly effective when the coating thickness of the composition is thicker or when a longer wavelength LED light source is used. As a sensitizer, it is known that there are: anthracene compounds, phenothiazine compounds, perylene compounds, anthocyanin compounds, merocyanine compounds, coumarin compounds, benzylidene ketone compounds, (thio) xanthene or (thio) xanthone compounds, such as isopropyl thioxanthone, 2,4-diethyl thioxanthone, alkyl substituted anthracene, squarylium compounds, (thio) pyrylium compounds, porphyrin compounds, etc., but are not limited to these, and any photosensitizer can be used for the curable composition of the present invention.

[0130] The cured product obtained by the curable composition of the present invention can be designed in a manner such that the physical properties of the desired cured product and the curing speed of the curable composition and the viscosity of the curable composition become the desired value according to the molecular chain length, molecular structure, (meth) acryloyloxy number of each molecule of component (A) and component (B) and the alkenyl number of each molecule of component (B). In addition, the cured product obtained by curing the curable composition of the present invention is also included in the scope of the present invention. Further, the shape of the cured product obtained by the composition of the present invention is not particularly limited, and can be a film-like coating or adhesive layer, or a sheet-like molding, or can be injected into a specific position in an uncured state to cure it and form a filler, and can also be used as a sealing material, an intermediate layer of a laminate or a display device, etc. The cured product obtained by the composition of the present invention is preferably in the form of an injection-molded protection / adhesive layer and a film-like coating, and is particularly preferably a film-like insulating coating or adhesive layer.

[0131] The curable composition of the present invention is suitable for use as a coating agent, a potting agent, or an adhesive, and particularly as an insulating coating agent, an insulating adhesive, or a potting agent for electronic devices and electric equipment.

[0132] The cured product obtained by curing the curable composition of the present invention has excellent mechanical properties, especially tensile properties. By optimizing the curable composition, if a test body with a thickness of 0.5 mm is used and evaluated at a tensile speed of 50 mm / min at 25° C., the tensile elongation of the cured product can be made to be 100% or more, which is useful as a layer forming material for a flexible display.

[0133] The cured product obtained by curing the curable composition of the present invention can be designed to have a relative dielectric constant of less than 3.0, less than 2.8, etc. as desired. The curable composition of the present invention can also be used to form a coating having a low relative dielectric constant.

[0134] When the curable composition of the present invention is used as an injection molding material and a coating agent, in order to have fluidity and workability suitable for applying the composition to a substrate, it is recommended that the viscosity of the entire composition be measured using an E-type viscometer and be 500 mPa·s or less at 25°C. When used as an injection molding material, although it also depends on the injection gap, its viscosity is preferably 200 mPa·s or less, and particularly preferably 80 mPa·s or less. On the other hand, when used as a coating agent, considering the application of inkjet printing, which is rapidly becoming practical, the preferred viscosity range is 5 to 60 mPa·s, more preferably 5 to 30 mPa·s, and particularly preferably 5 to 20 mPa·s. In order to adjust the viscosity of the entire curable composition to the desired viscosity, compounds with preferred viscosities can be used as each component so that the viscosity of the entire composition has the desired viscosity.

[0135] <Other additives>

[0136] In addition to the above-mentioned components, further additives may be added to the composition of the present invention as desired. Examples of the additives include the following, but are not limited thereto.

[0137] [Thickener]

[0138] In the composition of the present invention, in order to improve the adhesion and closeness relative to the base material in contact with the composition, an adhesion promoter can be added. In the case where the curable composition of the present invention is used for the purposes of coating agents, sealing materials, etc. that require adhesion or closeness relative to the base material, it is preferred to add a tackifier in the curable composition of the present invention. As the adhesion promoter, any known adhesion promoter can be used as long as the curing reaction of the composition of the present invention is not hindered.

[0139] Examples of adhesion promoters that can be used in the present invention include: organic silanes having trialkoxysilyloxy groups (e.g., trimethoxysilyloxy groups, triethoxysilyloxy groups) or trialkoxysilylalkyl groups (e.g., trimethoxysilylethyl groups, triethoxysilylethyl groups) and hydrosilyl groups or alkenyl groups (e.g., vinyl groups, allyl groups), or organic siloxane oligomers having a linear structure, a branched structure, or a cyclic structure having about 4 to 20 silicon atoms; organic silanes having trialkoxysilyloxy groups or trialkoxysilylalkyl groups and a methacryloxyalkyl group (e.g., 3-methacryloyloxy groups, oxypropyl) or an organosiloxane oligomer having a linear structure, branched structure or cyclic structure with about 4 to 20 silicon atoms; an organosilane having a trialkoxysilyloxy group or a trialkoxysilylalkyl group and an epoxy-bonded alkyl group (for example, 3-glycidoxypropyl, 4-glycidoxybutyl, 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl) or an organosiloxane oligomer having a linear structure, branched structure or cyclic structure with about 4 to 20 silicon atoms; an organosilane having two or more trialkoxysilyl groups (for example, trimethoxy Silane group, triethoxysilane group) organic compound; aminoalkyltrialkoxysilane and epoxy-bonded alkyltrialkoxysilane reaction products, epoxy-containing ethyl polysilicate, specifically, vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hydrogentriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 1,6 -Bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,3-bis[2-(trimethoxysilyl)ethyl]-1,1,3,3-tetramethyldisiloxane, a reaction product of 3-glycidoxypropyltriethoxysilane and 3-aminopropyltriethoxysilane, a condensation reaction product of a silanol-terminated methylvinylsiloxane oligomer and 3-glycidoxypropyltrimethoxysilane, a condensation reaction product of a silanol-terminated methylvinylsiloxane oligomer and 3-methacryloxypropyltriethoxysilane, and tris(3-trimethoxysilylpropyl)isocyanurate.

[0140] The amount of the adhesion promoter added to the curable composition of the present invention is not particularly limited, but is preferably in the range of 0.01 to 5 parts by mass, or in the range of 0.01 to 2 parts by mass, relative to 100 parts by mass of the total of components (A) and (B), from the perspective of the curing characteristics of the curable composition and not promoting discoloration of the cured product.

[0141] [Further optional additives]

[0142] In the composition of the present invention, other additives may be added as required in addition to or in place of the above-mentioned adhesion imparting agent. As additives that can be used, leveling agents, silane coupling agents, ultraviolet light absorbers, antioxidants, polymerization inhibitors, fillers (functional fillers such as reinforcing fillers, insulating fillers and thermally conductive fillers) etc. that are not included in the materials listed as the above-mentioned adhesion imparting agent, etc. may be listed. As required, suitable additives may be added to the composition of the present invention. In addition, in the composition of the present invention, as required, particularly when used as a potting agent or a sealing material, a thixotropic imparting agent may also be added.

[0143] [use]

[0144] By irradiating the ultraviolet-curable organopolysiloxane composition of the present invention with high-energy rays such as ultraviolet rays, a radical polymerization reaction proceeds to form a cured product.

[0145] As the high-energy rays that can be used, there are ultraviolet rays, gamma rays, X-rays, alpha rays, electron beams, etc. In particular, ultraviolet rays, X-rays, and electron beams irradiated by commercially available electron beam irradiation devices can be listed. Among them, ultraviolet rays are preferred from the perspective of catalyst activation efficiency, and ultraviolet rays with a wavelength range of 280 to 405 nm are preferred from the perspective of industrial use. In addition, the irradiation amount of ultraviolet rays is preferably a cumulative irradiation amount of 100 mJ / cm at a wavelength of 365 nm or 405 nm. 2 ~10J / cm 2 within the range.

[0146] The curable composition of the present invention has a high viscosity adjustment ability, so it is particularly useful as a material for forming an insulating layer constituting various articles, especially electronic devices and electrical equipment. The composition of the present invention can be applied to a substrate, or at least one side is clamped by two substrates composed of a material for ultraviolet rays or electron beams to pass through, and the composition is irradiated with ultraviolet rays or electron beams, thereby curing the composition to form an insulating layer. In this case, it is also possible to carry out pattern formation when the composition of the present invention is applied to a substrate, and then the composition is cured. In addition, the composition can also be applied to a substrate, and when it is cured, a part and an uncured part are left due to the irradiation of ultraviolet rays or electron beams, and then the uncured part is removed using a solvent, thereby forming an insulating layer of a desired pattern. In particular, when the cured layer involved in the present invention is an insulating layer, it can be designed to have a low relative dielectric constant less than 3.0.

[0147] As for 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 of a display device such as a touch panel and a display. In this case, the insulating layer can also be formed into a desired optional pattern as described above as needed. Therefore, a display device such as a touch panel and a display including an insulating layer obtained by curing the ultraviolet curable organopolysiloxane composition of the present invention is also an embodiment of the present invention.

[0148] In addition, after applying the curable composition of the present invention to an article and curing it, an insulating coating (insulating film) or adhesive layer can be formed. Therefore, the composition of the present invention can be used as an insulating coating agent or an insulating adhesive. In addition, the cured product formed by curing the curable composition of the present invention can also be used as an insulating coating or an insulating adhesive layer.

[0149] The insulating film formed by the curable composition of the present invention can be used for various purposes. In particular, it can be used as a component of an electronic device, or can be used as a material used in the process of manufacturing an electronic device. The electronic device includes electronic devices such as semiconductor devices and magnetic recording heads. For example, the curable composition of the present invention can be used as a semiconductor device, 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 multi-chip module (Multichip Module) multilayer wiring board insulation coating, semiconductor interlayer insulation film, etching stopper (Etching Stopper) film, surface protection film, buffer coating, passivation film in LSI, cover coat of flexible copper clad board, solder resist film, surface protection film for optical device.

[0150] Furthermore, the ultraviolet curable composition of the present invention can be suitably used as a potting agent, in addition to being used as a coating agent or an adhesive, and is particularly suitably used as an insulating potting agent for electronic devices and electric equipment.

[0151] The composition of the present invention can provide a low-viscosity composition by adjusting the mixing ratio of the component (A) and the component (B), and therefore can be particularly used as a material for forming a coating layer on a substrate surface using an inkjet printing method.

[0152] Hereinafter, the present invention will be further described based on examples, but the present invention is not limited to the following examples.

[0153] Example

[0154] The ultraviolet curable composition of the present invention and its cured product will be described in detail by way of examples. The measurements and evaluations in the examples and comparative examples were performed as follows.

[0155] [Curable Composition and Viscosity of Each Component]

[0156] The viscosity (mPa·s) of the composition at 25° C. was measured using a rotational viscometer (manufactured by TOKIMEC CORPORATION, E-type viscometer VISCONIC EMD).

[0157] [Appearance of the curable composition and the cured product obtained therefrom]

[0158] The curable composition and the cured product obtained therefrom were visually observed to evaluate the appearance including transparency.

[0159] [Preparation of curable composition]

[0160] The respective materials in the amounts described in the following Table 1 were placed in a brown plastic container and thoroughly mixed using a planetary mixer to prepare a curable composition.

[0161] [Curing of curable composition and preparation of tensile test specimen]

[0162] About 0.2 g of the curable composition was injected between two glass substrates sandwiched by a 0.5 mm thick spacer. The curable composition was injected through one of the glass substrates from the outside at a rate of 2 J / cm 2 The composition was cured by irradiating LED light with a wavelength of 405 nm to produce a plate-shaped cured product with a long side of 50 mm and a thickness of 0.5 mm. The short piece was divided into three equal parts to prepare a 10×50×0.5 (thickness) mm 3 Long strip tensile test piece.

[0163] [Tensile properties of organopolysiloxane cured products]

[0164] Using a tensile test piece prepared from the organopolysiloxane cured product, evaluation was performed using Autograph AGS-X manufactured by Shimadzu Corporation at 25° C. and a test speed of 50 mm / min. The elongation at break (unit: %) was recorded as the measured value.

[0165] [Elastic modulus of cured organopolysiloxane]

[0166] From the stress-strain curve obtained in the tensile test of the cured organopolysiloxane, the elastic modulus (Young's modulus) (unit: MPa) was calculated from the slope between two points of deformation of 0% to 5%.

[0167] [Curing of Curable Composition and Preparation of Sample for Measurement of Relative Dielectric Constant]

[0168] A mold with a thickness of 1 mm and a circular hole with an inner diameter of 40 mm was placed on a PET film coated with a fluoropolymer release agent, and about 1.3 g of a curable composition was poured into the hole. The same PET film as above was covered on the composition, and a glass plate with a thickness of 10 mm was further placed on it. 2 The composition was cured by irradiating LED light having a wavelength of 405 nm with energy of 100 nm to prepare a disk-shaped organopolysiloxane cured product having a diameter of 40 mm and a thickness of 1 mm.

[0169] [Relative Dielectric Constant of Cured Organopolysiloxane (Example 1)]

[0170] On the organopolysiloxane cured product produced, a tin foil of 33mm in diameter and 0.007mm in thickness is crimped on both sides. In order to improve the adhesion of the cured product and the foil, as required, a trace of silicone oil can be crimped. The E4990A precision impedance analyzer (PrecisionImpedance Analyzer) manufactured by Keysight Technologies, which is connected to a parallel plate electrode of 30mm in diameter, is used to measure the electrostatic capacity at room temperature and 100KHz. The value of the electrostatic capacity measured, the thickness of the cured product measured in addition, and the value of the electrode area are used to calculate the relative dielectric constant. The relative dielectric constant of the organopolysiloxane cured product in the embodiment 1 shown in the following table is 2.8, and a cured product with a low relative dielectric constant can be obtained.

[0171] [Examples and Comparative Examples]

[0172] Using the following components, ultraviolet curable compositions having the compositions (parts by mass) shown in Tables 1 and 2 were prepared.

[0173] (A1) Isobornyl acrylate (monofunctional)

[0174] (A2) Isobornyl methacrylate (monofunctional)

[0175] (A3) 2-Ethylhexyl acrylate (monofunctional)

[0176] (A4) Tricyclodecane dimethanol dimethacrylate (difunctional)

[0177] (A5) Trimethylolpropane triacrylate (trifunctional)

[0178] (A6) Photoacrylate PDMS-DA30 (manufactured by Nagase Industrial Co., Ltd.: bifunctional)

[0179] (A7) Methacryloxypropyl tris(trimethylsiloxy)silane (monofunctional)

[0180] (B1) Polyphenylmethylsiloxane terminated with dimethylvinylsiloxy groups at both ends (vinyl content: 1.5 mass %, phenyl content: 41 mol %; viscosity: 3,000 mPa·s)

[0181] (B2) Polydimethyl / diphenylsiloxane copolymer terminated with dimethylvinylsiloxy groups at both ends (vinyl content: 0.2 mass %, phenyl content: 20 mol %; viscosity: 13,000 mPa·s)

[0182] (B3) dimethyldivinyldiphenyldisiloxane (vinyl content: 17.4 mass %, phenyl content: 33 mol %; viscosity: 20 mPa·s)

[0183] (b) Polydimethylsiloxane with dimethylvinyl groups at both ends (vinyl content: 0.4%; viscosity: 500 mPa·s)

[0184] (C1) 2,4,6-trimethylbenzoyldiphenylphosphine oxide (product name: Omnirad TPO, manufactured by IGM Resins Co., Ltd.)

[0185] (C2)OMNIRAD TPO-L (manufactured by IGM Resins)

[0186] (C3)Butylated Hydroxytoluene

[0187] [Table 1]

[0188] Element Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 (A1) 65.0 34.2 83.8 54.9 58.2 (A2) 65.0 10.0 (A3) 15.2 (A4) 54.2 (B1) 34.2 34.2 65.0 45.0 34.3 25.8 (B2) 15.4 (C1) 0.5 0.5 0.5 0.5 (C2) 0.5 0.5 0.5 (C3) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Silicon content in the composition (mass %) 34 34 65 15 45 34 26 Appearance of curable composition transparent transparent transparent transparent transparent transparent transparent Viscosity of the composition mPa·s 32 31 158 49 362 31 14 Appearance of cured product transparent transparent transparent translucent transparent transparent transparent Tensile elongation at break of cured product % 330 <10 >500 <10 <10 170 >500 Elastic modulus of cured product MPa 100 6.4 15 16 280 190 22

[0189] [Table 2]

[0190]

[0191]

[0192] As shown in Table 1 and Table 2, the ultraviolet curable composition of the present invention (Examples 1 to 12) is a solvent-free composition. By adjusting the type or functional group number of component (A) or the mixing ratio of component (A) and component (B), the viscosity or tensile elongation of the cured product can be easily adjusted. In particular, when the composition contains a low-viscosity component (A), the viscosity at 25°C is suitable for application as an injection molding material and as a coating agent to a substrate, and is particularly suitable for application using inkjet printing, and the transparency of the cured product obtained is high. In addition, as shown in Example 1, the cured product obtained by the composition of the present invention shows low dielectric properties.

[0193] On the other hand, in the case of a composition not containing component (A) (Comparative Example 1) or a composition in which component (B) does not have an aromatic hydrocarbon group having 6 to 20 carbon atoms (Comparative Example 2), the ultraviolet curability is insufficient, and therefore it is difficult to obtain a cured product under industrial standard curing conditions.

[0194] Industrial Applicability

[0195] The ultraviolet curable composition of the present invention is suitable for the above-mentioned uses, and is particularly suitable as a material for forming an insulating layer of a display device such as a touch panel and a display, especially a flexible display.

Claims

1. A UV curable composition, characterized in that When the total mass of the composition is 100 parts by mass, the composition contains the following: (A) 1 to 99 parts by mass of a compound having one or more (meth)acryloyloxy groups in one molecule; and (B) 99 to 1 parts by mass of an organopolysiloxane having two or more alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms in one molecule and having no ultraviolet curable functional group, The composition contains substantially no organic solvent.

2. The ultraviolet curable composition according to claim 1, wherein The viscosity of the entire composition measured at 25° C. using an E-type viscometer is 500 mPa·s or less.

3. The ultraviolet curable composition according to claim 1, wherein Component (B) has an average composition formula: R a R' b SiO (4-a-b) / 2 (1) (wherein R is an alkenyl group, R' is a group selected from a monovalent hydrocarbon group other than an alkenyl group, a hydroxyl group, and an alkoxy group, a and b are numbers satisfying the following conditions: 1≤a+b≤3 and 0.05≤a / (a+b)<1.0, and the molecule has at least two R's, at least one of which is an aromatic hydrocarbon group having 6 to 20 carbon atoms) The linear, branched or cyclic organopolysiloxane shown.

4. The ultraviolet curable composition according to claim 1, wherein The organopolysiloxane of component (B) is selected from the following formula (2): [Chemical formula 1] (In the formula, in all R 1 ~R 8 In the group, there are at least two alkenyl groups in the molecule; there is at least one aromatic hydrocarbon group with 6 to 20 carbon atoms in the molecule; other R 1 ~R 8 an organopolysiloxane represented by an unsubstituted or fluorine-substituted monovalent hydrocarbon group, a hydroxyl group, and an alkoxy group, wherein n is a numerical value of 0 to 1,000, From the average unit formula (3): (R3SiO 1 / 2 ) c (R2SiO 2 / 2 ) d (RSiO 3 / 2 ) e (SiO 4 / 2 ) f (3) (wherein, R is independently a group selected from alkenyl, unsubstituted or fluorine-substituted monovalent hydrocarbon group, hydroxyl group and alkoxy group, at least two of all R are alkenyl, at least one is an aromatic hydrocarbon group having 6 to 20 carbon atoms, (e+f) is a positive number, c is 0 or a positive number, and d is a number in the range of 0 to 100) a branched organopolysiloxane, From the following formula (4): [Chemical formula 2] (wherein, R is independently a group selected from an alkenyl group and a monovalent hydrocarbon group which is unsubstituted or substituted by fluorine, x is an integer of 3 to 10, and the molecule contains at least two alkenyl groups and at least one aromatic hydrocarbon group having 6 to 20 carbon atoms) a cyclic organopolysiloxane represented by And one or more organopolysiloxanes having at least two alkenyl groups and one or more aromatic hydrocarbon groups having 6 to 20 carbon atoms in the molecule, from the group consisting of a mixture of these organopolysiloxanes.

5. The ultraviolet curable composition according to claim 1, wherein Component (B) contains a linear organopolysiloxane represented by the above formula (2).

6. The ultraviolet curable composition according to claim 1, wherein Component (A) is a compound having one (meth)acryloyloxy group, or a mixture of a compound having one (meth)acryloyloxy group and a compound having two or more (meth)acryloyloxy groups.

7. The ultraviolet curable composition according to claim 1, wherein The compound having one (meth)acryloyloxy group in the component (A) is the following (A1) or (A2). (A1) One or more compounds having one (meth)acryloyloxy group and no silicon atom (A2) A mixture of (A1) and one or more compounds having one (meth)acryloyloxy group and having a silicon atom.

8. The ultraviolet curable composition according to claim 1, wherein Component (A) contains a compound having at least one acryloyloxy group.

9. The ultraviolet curable composition according to claim 1, wherein The content of the aromatic hydrocarbon group having 6 to 20 carbon atoms in the component (B) is 10 mol% or more based on all substituents on the silicon atom.

10. The ultraviolet curable composition according to claim 1, wherein The viscosity of the entire composition measured at 25° C. using an E-type viscometer is in the range of 5 to 60 mPa·s. 11 . An insulating coating agent or an insulating adhesive, comprising the ultraviolet curable composition according to claim 1 . 12 . A cured product of an ultraviolet curable composition, wherein the cured product of the ultraviolet curable composition is the cured product of the ultraviolet curable composition according to claim 1 . 13 . A method comprising using a cured product of the ultraviolet curable composition according to claim 1 as an insulating coating layer or an insulating adhesive layer. 14 . A display device comprising a layer composed of a cured product of the ultraviolet curable composition according to claim 1 .

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