Alkali-soluble UV-curable organopolysiloxane, UV-curable composition including same, and use therefor

Abstract

[Problem] To provide a UV-curable organopolysiloxane whose cured product (cured film) has sufficient mechanical strength, has good transparency, and is designable so as to have a desired refractive index, and which has high UV curability and good alkali solubility, even without using a polyfunctional polymerizable monomer, and a UV-curable composition including the same. [Solution] Provided are: a UV-curable organopolysiloxane that has, in one molecule, one or more monovalent functional groups which bond on a silicon atom and which comprise both a hydrophilic group and a UV-curable group, and that, as the entirety of the organopolysiloxane, is soluble in an alkali aqueous solution; and a UV-curable composition including the same.

Description

Alkali-soluble ultraviolet-curable organopolysiloxane, ultraviolet-curable composition containing same, and uses thereof

[0001] The present invention relates to an alkali-soluble, UV-curable organopolysiloxane that can be cured by actinic rays, such as UV or electron beams, and a UV-curable composition containing the same. The curable polysiloxane of the present invention has high solubility in an aqueous alkaline solution and good UV-curability, and therefore exhibits excellent lithography performance and is suitable as an insulating material for electronic and electrical devices that require patterning, particularly as a material for use as a coating agent.

[0002] Due to their high heat resistance and excellent chemical stability, silicone resins have been used as coating agents, potting agents, insulating materials, etc. for electronic and electrical devices. Among silicone resins, ultraviolet-curable silicone compositions have also been reported.

[0003] Touch panels are used in a variety of display devices, including mobile devices, industrial equipment, and car navigation systems. To improve their detection sensitivity, it is necessary to suppress electrical influences from light-emitting elements, such as light-emitting diodes (LEDs) and organic light-emitting diode (OLED) devices, and an insulating layer is typically placed between the light-emitting elements and the touch screen. Meanwhile, thin display devices, such as OLEDs, have a structure in which many thin functional layers are stacked. In recent years, studies have been conducted to improve the visibility of display devices by stacking insulating layers formed from high-refractive-index acrylate polymers and polyfunctional polymerizable monomers above and below the touch screen layer (see, for example, Patent Documents 1 and 2).

[0004] Meanwhile, Patent Document 3 discloses a lithographically applicable curable composition comprising a silsesquioxane having a carboxyl group and a methacryloxy group, a polyfunctional polymerizable monomer, an inorganic filler, a polymerization initiator, and an organic solvent. This composition contains the polyfunctional polymerizable monomer at a concentration of 33% or more of the total curable components in order to improve sensitivity during curing and adhesion of the cured product.

[0005] Similarly, Patent Document 4 discloses a lithographically applicable curable composition comprising a silsesquioxane having a polymerizable double bond and a group selected from a carboxy group, a carboxylic acid anhydride group, and a phenolic hydroxyl group, a photopolymerization initiator, and an organic solvent. However, this composition leaves room for improvement in terms of the mechanical strength (particularly brittleness) and transparency of thick coatings, and the composition essentially contains a silicon-free polyfunctional polymerizable monomer at a concentration of 64% or more of the total curable components. That is, although a UV-curable composition containing an organopolysiloxane having a UV-curable group and a hydrophilic group is disclosed, there is no description or suggestion of an organopolysiloxane or a UV-curable composition containing the same that has high solubility in an alkaline aqueous solution, exhibits high UV curability without the addition of a polyfunctional polymerizable monomer, and provides a transparent cured product.

[0006] JP 2013-140229 A JP 2021-61056 A JP 2018-123234 A JP 2020-184010 A

[0007] As described above, there is still a need for UV-curable organopolysiloxanes that have high UV-curability and good alkali solubility without using a polyfunctional polymerizable monomer, and for UV-curable compositions containing the same that produce cured products (cured films) that have sufficient mechanical strength and good transparency.

[0008] The present invention was made to solve the above-mentioned problems, and was completed based on the discovery that ultraviolet-curable organopolysiloxanes, which have one or more monovalent functional groups on silicon atoms that have both a hydrophilic group and an ultraviolet-curable group per molecule, and which have solubility in alkaline aqueous solutions as a whole, and ultraviolet-curable compositions containing the same, have excellent coatability to substrates and alkali solubility, and that the cured products (cured films) thereof have sufficient mechanical strength and good transparency even without the use of polyfunctional polymerizable monomers.

[0009] The present invention relates to an ultraviolet-curable organopolysiloxane and an ultraviolet-curable composition containing the same. This composition cures through the formation of bonds via the ultraviolet-curable functional groups, but the curing method is not limited to ultraviolet irradiation; any method that can cause a curing reaction of the ultraviolet-curable functional groups can be used. For example, the composition of the present invention may be cured using electron beam irradiation.

[0010] The ultraviolet-curable organopolysiloxane of the present invention is characterized in that it contains, in each molecule, one or more monovalent functional groups bonded to silicon atoms and having both a hydrophilic group and an ultraviolet-curable group, and the organopolysiloxane as a whole is soluble in an alkaline aqueous solution.

[0011] The ultraviolet-curable organopolysiloxane may have one or more siloxane units selected from the following repeating units (1) and (2) in one molecule. (R １ RSiO ２／２ ) (1) (A ３ SiO １／２ ) (2) (wherein, R １ is a monovalent functional group having both a hydrophilic group and an ultraviolet-curable group, and R is a group selected from an unsubstituted or fluorine-substituted monovalent hydrocarbon group, an alkoxy group, and a hydroxyl group. １ or R, and A is at least one R １ (including

[0012] The ultraviolet-curable organopolysiloxane may have one or more siloxane units (1) in one molecule (i.e., may essentially have the siloxane unit (1)).

[0013] The ultraviolet-curable organopolysiloxane may further contain the following siloxane unit (3): (R ２ RSiO ２／２ ) (3) (wherein, R ２ is a monovalent group having an ultraviolet-curable group and no hydrophilic group, and R is the above-mentioned group.

[0014] The hydrophilic group in the monovalent functional group in the ultraviolet-curable organopolysiloxane is preferably a group selected from a carboxyl group, a hydroxyl group, a phenolic hydroxyl group, and a polyether group.

[0015] The ultraviolet-curable group in the monovalent functional group in the ultraviolet-curable organopolysiloxane is preferably a group selected from an epoxy group, an oxetane group, a vinyl ether group, and a (meth)acryloxy group.

[0016] The ultraviolet-curable organopolysiloxane has the average unit formula: ３ SiO １／２ ) ａ (R １ RSiO ２／２ ) ｂ１ (R ２ RSiO ２／２ ) ｂ２ (RSiO ３／２ ) ｃ (SiO ４／２ ) ｄ (4) (wherein, R １ , R ２ , R are each independently the same groups as defined above, and B is each independently R １ , R ２ and R, a is 0 or a positive number, b1 is a number in the range of 1 to 100, b2 is a number in the range of 0 to 50, and (c+d) is a positive number).

[0017] In the average unit formula (4) of the ultraviolet-curable organopolysiloxane, the value of (b1+b2) / (a+b1+b2+c+d) is preferably 0.1 or more and 0.5 or less.

[0018] The ultraviolet-curable organopolysiloxane preferably contains one or more of the following siloxane units (5) in the molecule: (RSiO ３／２ ) (5) (wherein R is the same group as defined above)

[0019] The R １ is preferably a group represented by the following formula (6): (6) {wherein, R ４ is a chain divalent hydrocarbon group having 2 to 10 carbon atoms, R ５ is a trivalent hydrocarbon group having 3 to 10 carbon atoms and being linear, cyclic, or a combination thereof; X is an oxygen atom, a sulfur atom, or —NR ７ - (wherein, R ７ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms), n is 0 or 1, Y is a monovalent group containing an ultraviolet-curable group, and Z is a hydroxyl group, a hydroxyl-containing group, or —O(C═O)—R ６ -CO ２ H (wherein, R ６ is a linear, branched, or cyclic divalent hydrocarbon group having 2 to 12 carbon atoms, which may optionally contain oxygen or sulfur atoms, and * is the bonding site to a silicon atom on the organopolysiloxane.

[0020] It is preferable that the hydrophilic group in the monovalent functional group in the ultraviolet-curable organopolysiloxane is a carboxyl group, and the ultraviolet-curable group is a (meth)acryloxy group.

[0021] The solubility of the ultraviolet-curable organopolysiloxane in an aqueous alkaline solution is preferably such that, when the organopolysiloxane is applied to a glass plate so that the thickness after application is 4 μm, and the coating film is then immersed in a 2.38 mass % aqueous solution of tetramethylammonium hydroxide (TMAH) for 1 minute and then washed with water, the coating film made of the organopolysiloxane exhibits a mass loss rate of 90 mass % or more, 95 mass % or more, or 98 mass % or more.

[0022] The present invention further provides an ultraviolet-curable composition containing at least the following components: (A) the ultraviolet-curable organopolysiloxane described above, (B) a photopolymerization initiator in an amount of 0.5 to 10 parts by mass per 100 parts by mass of component (A), and (C) an organic solvent.

[0023] The present invention further provides a cured product of the above ultraviolet-curable composition, and a method for using the cured product as an insulating coating layer.

[0024] The present invention further provides a display device, such as a liquid crystal display, an organic EL display, or an organic EL flexible display, which comprises a layer made of a cured product of the above-mentioned ultraviolet-curable composition.

[0025] The UV-curable organopolysiloxane of the present invention has good coatability on substrates and exhibits high solubility in alkaline aqueous solutions commonly used in the development step performed to form patterns of desired shapes. Therefore, in the development step involving selective UV irradiation, unreacted / uncured organopolysiloxane and curable compositions containing the same can be easily removed by washing with an alkaline aqueous solution, enabling high-precision patterning through a simple process. Furthermore, cured products formed from UV-curable compositions containing the UV-curable organopolysiloxane of the present invention have the advantages of being optically transparent, allowing for a wide range of hardness and other properties to be designed, and having a low dielectric constant. Therefore, the curable composition of the present invention is useful as a material for forming low-dielectric-constant layers, particularly low-dielectric-constant materials for electronic devices, particularly materials for insulating layers, and particularly patterning and coating materials, in any field where a material with a low dielectric constant is required.

[0026] The constitution of the present invention will be explained in more detail below. The ultraviolet-curable organopolysiloxane of the present invention has one or more monovalent functional groups bonded to silicon atoms and having both a hydrophilic group and an ultraviolet-curable group per molecule, and the organopolysiloxane as a whole is soluble in an alkaline aqueous solution (sometimes referred to as "alkali-soluble" in the present invention). The ultraviolet-curable composition of the present invention contains, as essential components, (A) the organopolysiloxane, (B) a photopolymerization initiator, and (C) an organic solvent.

[0027] Here, alkali-soluble means that the coating film formed in the development step for forming a pattern of a desired shape is soluble in an alkaline aqueous solution that is commonly used. Well-known alkaline aqueous solutions include basic aqueous solutions of sodium hydroxide, potassium hydroxide, and quaternary ammonium salts, but an aqueous solution of tetramethylammonium hydroxide is commonly used, and in the present invention, the term "alkali-soluble" means that the coating film is soluble in this alkaline aqueous solution.

[0028] More specifically, "soluble in an alkaline aqueous solution" means that when an organopolysiloxane according to the present invention is applied to a glass plate to a thickness of 4 μm, the coating film is immersed in a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) for 1 minute, and then washed with water, the coating film comprising the organopolysiloxane exhibits a mass loss rate of 90% by mass or more. In particular, when the mass loss rate of the coating film comprising the organopolysiloxane is 95% by mass or more or 98% by mass or more as evaluated by the above method, the solubility in an alkaline aqueous solution is particularly excellent. Note that the organopolysiloxane is generally applied to a glass plate by spin coating or the like, and when the organic solvent described below is used for application, the organic solvent must be removed beforehand by drying or the like. Furthermore, the solubility in an alkaline aqueous solution of an ultraviolet-curable composition containing an organopolysiloxane according to the present invention can be evaluated by the above method, provided that the composition is primarily composed of an organopolysiloxane. In addition, the water rinsing step is generally carried out by immersing the substrate in a water bath at about room temperature (25°C) or by rinsing the substrate for about 10 to 15 seconds in running water at a flow rate similar to that of household tap water, so as not to adversely affect the formed pattern or the substrate.

[0029] Organopolysiloxanes containing one or more siloxane units selected from the repeating units (1) and (2) described above tend to have improved solubility in alkaline aqueous solutions compared to organopolysiloxanes consisting only of silsesquioxane units. When the solubility in alkaline aqueous solutions of coating films made from organopolysiloxanes containing these siloxane units is evaluated using the method described above, organopolysiloxanes tend to have coating film mass loss rates of 98% by mass or more, and thus tend to have particularly excellent alkali solubility.

[0030] [Alkali-Soluble UV-Curable Organopolysiloxane] The UV-curable organopolysiloxane of the present invention is an organopolysiloxane that has one or more monovalent functional groups bonded to silicon atoms and having both a hydrophilic group and a UV-curable group per molecule, and that has the alkali-solubility described above. As long as this purpose can be achieved, there are no limitations on the molecular structure, and it can be any, such as linear, branched, cyclic, or cage-shaped.

[0031] In particular, from the viewpoint of alkali solubility, the ultraviolet-curable organopolysiloxane of the present invention preferably contains one or more siloxane units selected from the following repeating units (1) and (2) in one molecule: (R １ RSiO ２／２ ) (1) (A ３ SiO １／２ ) (2) (wherein, R １ is a monovalent functional group having both a hydrophilic group and an ultraviolet-curable group, R is a group selected from an unsubstituted or fluorine-substituted monovalent hydrocarbon group, an alkoxy group, and a hydroxyl group, and A is R １ or R, and A is at least one R １ (including

[0032] The organopolysiloxane preferably contains the siloxane unit (1) above. The presence of this siloxane unit results in a coating with a particularly large thickness that is tougher and more transparent than a cured product composed solely of silsesquioxane units.

[0033] The organopolysiloxane may further contain the following siloxane unit (3): ２ is a monovalent functional group having an ultraviolet curable group and no hydrophilic group, and R is the above-mentioned group. (R ２ RSiO ２／２ ) (3)

[0034] The UV-curable organopolysiloxane of the present invention has a monovalent functional group bonded to a silicon atom and having both a hydrophilic group and a UV-curable group, and the hydrophilic group in the monovalent functional group is preferably a group selected from a carboxyl group, a hydroxyl group, a phenolic hydroxyl group, and a polyether group. Of these, a carboxyl group is most preferred because of its significant effect in increasing alkali solubility.

[0035] Similarly, the ultraviolet-curable group in the monovalent functional group is preferably selected from an epoxy group, an oxetane group, a vinyl ether group, and a (meth)acryloxy group. Among these, from the viewpoints of ease of production and availability of raw materials, an epoxy group and a (meth)acryloxy group are more preferred, and a (meth)acryloxy group is most preferred.

[0036] In one preferred embodiment, the organopolysiloxane has an average unit formula (4): ３ SiO １／２ ) ａ (R １ RSiO ２／２ ) ｂ１ (R ２ RSiO ２／２ ) ｂ２ (RSiO ３／２ ) ｃ (SiO ４／２ ) ｄ (4) is a branched organopolysiloxane represented by the formula: １ , R ２ , R are each independently the same groups as defined above, and B is each independently R, R １ , and R ２ a is 0 or a positive number, b1 is a number in the range of 1 to 100, b2 is a number in the range of 0 to 50, and (c+d) is a positive number.

[0037] In the branched organopolysiloxane represented by the average unit formula (4), there are no restrictions on the ratio of each constituent unit, but the lower limit of the value of (b1 + b2) / (a + b1 + b2 + c + d) is preferably 0.1 or more, more preferably 0.15 or more. On the other hand, the upper limit of this value is preferably 0.5, more preferably 0.4 or less. By setting the ratio represented by the above formula within this range, the ultraviolet curability, alkali solubility, and surface tackiness of the organopolysiloxane of the present invention after application to a substrate can be appropriately controlled.

[0038] The branched organopolysiloxane is (RSiO ３／２ ) and T units represented by (SiO ４／２ ), and in particular, may further comprise a siloxane unit selected from Q units represented by (RSiO ３／２ ) may have a siloxane T unit represented by the formula:

[0039] Specific examples of the ultraviolet-curable organopolysiloxane preferably used in the present invention include polysiloxanes composed of the following combinations of siloxy units: where M is a trimethylsiloxy unit, M Vi is a dimethylvinylsiloxy unit, M R1 is a siloxane unit having a monovalent group having both a hydrophilic group and an ultraviolet curable group and two methyl groups, D is a dimethylsiloxy unit, D R1 represents a siloxane unit having a monovalent group having both a hydrophilic group and an ultraviolet-curable group and a methyl group; D R2 represents a siloxane unit having a monovalent group having an ultraviolet curable group and a methyl group, T represents a methylsiloxy unit, T R represents an alkylsiloxy or alkenylsiloxy unit (the alkyl group is an alkyl group which may be partially substituted with fluorine, and is a vinyl, propyl, hexyl, hexenyl, cyclohexyl, or trifluoropropyl group), T Ph is a phenylsiloxy unit, T R1 represents a siloxane unit having a monovalent group having both a hydrophilic group and an ultraviolet-curable group, T R2represents a siloxane unit having a monovalent group with an ultraviolet-curable group, and Q represents a siloxy unit having no organic group. Note that in the examples of combinations below, the specific number of each siloxy unit is omitted.

[0040] Examples of preferred combinations of siloxy units constituting the UV-curable organopolysiloxane are: R1 T Ph , M.M. R1 T Ph , M Vi M R1 T Ph , M R1 DT Ph , M.M. R1 DT Ph , M Vi M R1 DT Ph , M R1 Q, M.M. R1 Q, M Vi M R1 Q, M R1 DQ, MM R1 DQ, M Vi M R1 DQ, M R1 T., M.M. R1 T.M. Vi M R1 T.M. R1 T.T. R , M.M. R1 T.T. R , M Vi M R1 T.T. R , M R1 D.T., M.M. R1 D.T., M. Vi M R1 D.T., M. R1 DTT R , M.M. R1 DTT R , M Vi M R1 DTT R , M.D. R1 T., M.D. R1 D R2 T.D. R1 T.D. R1 D R2 T.D. R1 T R , D R1 D R2 T R、MD R1 TT R 、MD R1 D R2 TT R 、MD R1 T R 、MD R1 D R2 T R 、D R1 TT R 、D R1 D R2 TT R 、MD R1 T Ph 、MD R1 D R2 T Ph 、D R1 T Ph 、D R1 D R2 T Ph 、D R1 T Ph Q、D R1 D R2 T Ph Q、MD R1 Q、MD R1 D R2 Q、M Vi D R1 Q、M Vi D R1 D R2 Q、MD R1 TQ、MD R1 D R2 TQ、MD R1 T Ph Q、MD R1 D R2 T Ph Q、MD R1 T R Q、MD R1 D R2 T R Q、MD R1 TT R Q、MD R1 D R2 TT R Q、MD R1 T R T Ph Q、MD R1 D R2 T R T Ph Q、MD Ｒ D R1 TQ、D Ｒ DR1 T.Q., D. Ｒ D R1 D R2 TQ

[0041] The substituent R in the branched organopolysiloxane is a group selected from unsubstituted or fluorine-substituted monovalent hydrocarbon groups, alkoxy groups, and hydroxyl groups. The unsubstituted or fluorine-substituted monovalent hydrocarbon group is preferably a group selected from unsubstituted or fluorine-substituted alkyl, cycloalkyl, arylalkyl, and aryl groups having 1 to 20 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, pentyl, hexyl, and octyl groups, with methyl and hexyl groups being particularly preferred. Examples of the cycloalkyl group include cyclopentyl and cyclohexyl. Examples of the arylalkyl group include benzyl and phenylethyl groups. Examples of the aryl group include phenyl and naphthyl groups. Examples of fluorine-substituted monovalent hydrocarbon groups include 3,3,3-trifluoropropyl and 3,3,4,4,5,5,6,6,6-nonafluorohexyl, with 3,3,3-trifluoropropyl being preferred. Examples of alkoxy groups include methoxy, ethoxy, propoxy, and isopropoxy. Depending on the type of substituent R in the branched organopolysiloxane, the refractive index of the branched organopolysiloxane can be designed within a desired range (e.g., 1.40 to 1.60). More specifically, when at least a portion of R is a fluorine-substituted monovalent hydrocarbon group such as 3,3,3-trifluoropropyl, the refractive index of the branched organopolysiloxane can be reduced to 1.50 or less, or 1.45 or less, allowing it to be used as a raw material for curable compositions with lower refractive indices.

[0042] Substituent R described in formula (1) １ is a monovalent functional group bonded to a silicon atom and having both a hydrophilic group and an ultraviolet-curable group.

[0043] The monovalent functional group (particularly, the above-mentioned substituent R １) is preferably a group represented by the following formula (6): (6) {wherein, R ４ is a chain divalent hydrocarbon group having 2 to 10 carbon atoms, and R ５ is a trivalent hydrocarbon group having 3 to 10 carbon atoms and being linear, cyclic, or a combination thereof; X is an oxygen atom, a sulfur atom, or —NR ７ - (wherein, R ７ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms), n is 0 or 1, Y is a monovalent group containing an ultraviolet-curable group, and Z is a hydroxyl group or —O(C═O)—R ６ -CO ２ H (wherein, R ６ is a monovalent hydrophilic group represented by the formula (wherein * is a linear, branched, or cyclic divalent hydrocarbon group having 2 to 12 carbon atoms, which may optionally contain oxygen or sulfur atoms), and * is the bonding site to a silicon atom on the polysiloxane.

[0044] Linking group R ４ is a chain divalent hydrocarbon group having 2 to 10 carbon atoms, and examples thereof include ethylene, propylene, butylene, and hexylene, with ethylene and propylene being preferred.

[0045] The linking group X is an oxygen atom, a sulfur atom, or NR ７ It is a group, and an oxygen atom can be preferably used. ７ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms.

[0046] On the other hand, the linking group R ５ is a trivalent hydrocarbon group having 3 to 10 carbon atoms and which is linear, cyclic, or a combination thereof, i.e., an alkanetriyl group. Examples of the alkanetriyl group include a propanetriyl group, a butanetriyl group, a hexanetriyl group, an octanetriyl group, an ethylcyclohexanetriyl group, and a propylcyclohexanetriyl group. Of these, the propanetriyl group and the ethylcyclohexanetriyl group of the following structural formula (7) can be used as preferred linking groups. (7) (where * represents a binding site)

[0047] The Y is a group containing a monovalent ultraviolet-curable group. Usable ultraviolet-curable groups include epoxy groups, oxetane groups, vinyl ether groups, and (meth)acryloxy groups, with the (meth)acryloxy group being preferred. Therefore, preferred examples of Y include acryloxy groups and methacryloxy groups.

[0048] Z is a hydrophilic group, and is preferably a hydroxyl group, a hydroxyl-containing group, or a carboxyl-containing group. As the hydroxyl-containing group, an alcoholic hydroxyl group or a phenolic hydroxyl group bonded via a divalent linking group may be used. Also, -CO ２ Z may preferably have a carboxyl group represented by H. Such Z may be a hydroxyl group, a hydroxyl-containing group, or —O(C═O)—R ６ -CO ２ The monovalent hydrophilic groups are at least one group selected from the group consisting of monovalent hydrophilic groups represented by H.

[0049] The linking group R ６ is a divalent hydrocarbon group which may optionally contain an oxygen atom or a sulfur atom as a heteroatom, and specifically includes a straight-chain, branched, or cyclic divalent hydrocarbon group having 2 to 12 carbon atoms; a sulfur-containing straight-chain, branched, or cyclic divalent hydrocarbon group; and an oxygen-containing straight-chain, branched, or cyclic divalent hydrocarbon group. More specifically, the divalent groups exemplified by the following structural formula (8) can be mentioned. Among them, 6a, 6b, 6c, 6d, 6e, 6i, 6k, 6m, 6p, 6q, 6q, and 6s can be preferably used. (8) (wherein * represents a binding site)

[0050] On the other hand, the substituent R ２ is a monovalent group having an ultraviolet curable group but not having a hydrophilic group. As the ultraviolet curable group, a group selected from an epoxy group, an oxetane group, a vinyl ether group, and a (meth)acryloxy group can be preferably used, but as mentioned above, an epoxy group and a (meth)acryloxy group are more preferred. Therefore, R ２Specific examples of the alkyl group include a glycidoxyethyl group, a glycidoxypropyl group, a 2-(3,4-epoxycyclohexyl)ethyl group, a 3-(3,4-epoxycyclohexyl)propyl group, an acryloxypropyl group, a methacryloxypropyl group, an acryloxyoctyl group, and a methacryloxyoctyl group.

[0051] The UV-curable organopolysiloxane of the present invention is preferably a branched organopolysiloxane having a monovalent functional group containing both a (meth)acryloxy group and a carboxyl group bonded to a silicon atom. In order to impart good UV-curability and excellent alkali solubility to the organopolysiloxane, it is preferable that the molecule contains an average of 2.5 or more of each of these monovalent functional groups.

[0052] As described above, the ultraviolet-curable organopolysiloxane has an ultraviolet-curable group and a monovalent group (the substituent R ２ ) may be contained. Therefore, the number of ultraviolet-curable groups and the number of hydrophilic groups in the molecule may be different. The number of ultraviolet-curable groups in the molecule is preferably 2 or more on average, more preferably 3 or more, or 5 or more. On the other hand, the number of hydrophilic groups in the molecule is preferably 2 or more on average, more preferably 3 or more.

[0053] There are no particular restrictions on the molecular weight of the ultraviolet-curable organopolysiloxane of the present invention. However, taking into consideration the coatability and the mechanical strength properties of the coated film, the weight-average molecular weight, calculated in terms of polystyrene by gel permeation chromatography, is preferably from 1,000 to 100,000, more preferably from 1,000 to 50,000, and even more preferably from 2,000 to 30,000.

[0054] There are no particular limitations on the method for producing the UV-curable organopolysiloxane of the present invention. Typical production methods include, but are not limited to, the following three methods: 1) producing a UV-curable organopolysiloxane and adding functional groups having hydrophilic groups; 2) producing a reactive organopolysiloxane that does not have hydrophilic groups or UV-curable groups and adding functional groups having hydrophilic groups and UV-curable functional groups; and 3) producing an organopolysiloxane that has hydrophilic groups and adding UV-curable functional groups. Methods 1) and 2) are preferably applicable. A specific example is a method in which an epoxy-containing UV-curable organopolysiloxane is produced, the epoxy groups are converted into functional groups in stages, and functional groups having (meth)acryloxy groups and carboxyl groups are added.

[0055] [UV-Curable Composition] The UV-curable composition of the present invention contains the following three components. Component (A) is the main component of the present invention described in detail. (A) the UV-curable organopolysiloxane described above; (B) a photopolymerization initiator, in an amount of 0.1 to 10 parts by mass per 100 parts by mass of component (A); and (C) an organic solvent.

[0056] [Component (B)] Component (B) is a component that catalyzes the curing reaction of component (A) by ultraviolet light, and compounds known as photopolymerization initiators can typically be used. When the ultraviolet-curable functional group of component (A) is a cationic polymerizable functional group containing an epoxy group or a vinyl ether group, a photocationic polymerization initiator is used as the photopolymerization initiator. Known examples of photocationic polymerization initiators include compounds that can generate a Brønsted acid or Lewis acid upon irradiation with ultraviolet light or an electron beam, known as photoacid generators. It is known that an acid is generated upon irradiation with ultraviolet light, and this acid triggers a reaction between cationic polymerizable functional groups. On the other hand, when the ultraviolet-curable functional group of component (A) is a radically polymerizable functional group such as a (meth)acryloxy group, a photoradical polymerization initiator can be used as the photopolymerization initiator. The photoradical polymerization initiator generates free radicals upon irradiation with ultraviolet light, which trigger a radical polymerization reaction, thereby curing the composition of the present invention.

[0057] [Cationic Photopolymerization Initiator] The cationic photopolymerization initiator used in the ultraviolet-curable composition of the present invention can be arbitrarily selected from those known in the art, and is not particularly limited to a specific one. Known cationic photopolymerization initiators include strong acid-generating compounds such as diazonium salts, sulfonium salts, iodonium salts, and phosphonium salts, and these can be used. Examples of photocationic polymerization initiators include bis(4-tert-butylphenyl)iodonium hexafluorophosphate, cyclopropyldiphenylsulfonium tetrafluoroborate, dimethylphenacylsulfonium tetrafluoroborate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, diphenyliodonium tetrafluoromethanesulfonate, 2-(3,4-dimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-[2-(furan-2-yl)vinyl]-4,6-bis(trichloromethyl)-1,3,5-triazine, and 4-isopropyl-4'-methyldiphenyliodonium. Tetrakis(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-nitrobenzenediazonium tetrafluoroborate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium bromide, tri-p-tolylsulfonium hexafluorophosphate, tri-p-tolylsulfonium trifluoromethanesulfonate, diphenyliodonium triflate, triphenylsulfonium triflate, diphenyliodonium nitrate, bis(4-tert-butylphenyl)iodonium perfluoro-1-butanesulfonate, bis(4-tert-butylphenyl)iodonium triflate, triphenylsulfonium perfluoro-1-butanesulfonate, N-hydroxynaphthalimide triflate, p-toluenesulfonate, diphenyliodonium p-toluenesulfonate, (4-tert-butylphenyl)diphenylsulfonium triflate, tris(4-tert-butylphenyl)sulfonium triflate, N-hydroxy-5-norbornene-2,3-dicarboximide Examples of photocationic polymerization initiators include, but are not limited to, perfluoro-1-butanesulfonate, (4-phenylthiophenyl)diphenylsulfonium triflate, and 4-(phenylthio)phenyldiphenylsulfonium triethyltrifluorophosphate. In addition to the above compounds, commercially available photoinitiators include Omnicat 250 and Omnicat 270 (both from IGM Resins BV), CPI-310B and IK-1 (both from San-Apro Co., Ltd.), DTS-200 (Midori Chemical Co., Ltd.), and Irgacure 290 (BASF).

[0058] The amount of cationic photopolymerization initiator added to the UV-curable composition of the present invention is not particularly limited as long as the desired photocuring reaction occurs, but it is generally preferred to use the cationic photopolymerization initiator in an amount of 0.1 to 10 parts by mass, preferably 0.2 to 5 parts by mass, and particularly 0.5 to 5 parts by mass, per 100 parts by mass of the UV-curable alkali-soluble organopolysiloxane, component (A), of the present invention.

[0059] A photosensitizer can also be used in combination with the cationic photopolymerization initiator. The use of a sensitizer can increase the photon quantum efficiency of the polymerization reaction, allowing longer wavelength light to be utilized in the polymerization reaction compared to when a photopolymerization initiator alone is used. This is known to be particularly effective when the coating thickness of the composition is relatively thick or when a relatively long wavelength LED light source is used. Known sensitizers include anthracene-based compounds, phenothiazine-based compounds, perylene-based compounds, cyanine-based compounds, merocyanine-based compounds, coumarin-based compounds, benzylidene ketone-based compounds, (thio)xanthene or (thio)xanthone-based compounds, such as isopropylthioxanthone, 2,4-diethylthioxanthone, alkyl-substituted anthracenes, squarylium-based compounds, (thia)pyrylium-based compounds, and porphyrin-based compounds. However, any photosensitizer can be used in the curable composition of the present invention, without limitation.

[0060] [Photoradical polymerization initiator] Known photoradical polymerization initiators are broadly divided into photocleavage type and hydrogen abstraction type. The photoradical polymerization initiator used in the composition of the present invention can be arbitrarily selected from those known in the art and is not particularly limited to a specific one. Examples of photoradical polymerization initiators include acetophenone, p-anisil, benzil, 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-benzodioxol-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-benzyl-2-(dimethylamino)- 4'-Morpholinobutyrophenone, (±)-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, Ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate, 1,4-Dibenzoylbenzene, 2-Ethylanthraquinone, 1-Hydroxycyclohexylphenylketone, 2-Hydroxy-2-methylpropiophenone, 2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-Isopropylthioxanthone, Lithium These include, but are not limited to, phenyl(2,4,6-trimethylbenzoyl)phosphinate, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-isonitrosopropiophenone, 2-phenyl-2-(p-toluenesulfonyloxy)acetophenone, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.In addition to the above compounds, other examples of photoradical polymerization initiators include Omnirad (registered trademark) 651, 184, 1173, 2959, 127, 907, 369, 369E, and 379EG (alkylphenone-based photopolymerization initiators, IGM Resins BV), Omnirad (registered trademark) TPO H, TPO-L, and 819 (acylphosphine oxide-based photopolymerization initiators, IGM Resins BV), Omnirad (registered trademark) MBF and 754 (intramolecular hydrogen abstraction photopolymerization initiators, IGM Resins BV), and Irgacure (registered trademark) OXE01 and OXE02 (oxime ester-based non-polymerization initiators, BASF).

[0061] The amount of photoradical polymerization initiator added to the curable composition of the present invention is not particularly limited as long as the desired photopolymerization reaction or photocuring reaction occurs, but it is generally used in an amount of 0.1 to 10 parts by mass, and preferably 0.5 to 5 parts by mass, per 100 parts by mass of the UV-curable alkali-soluble organopolysiloxane, component (A), of the present invention.

[0062] A photosensitizer can also be used in combination with the above-mentioned photoradical polymerization initiator. The use of a sensitizer can be expected to have the effect of increasing the photoquantum efficiency of the polymerization reaction, as in the case of using the above-mentioned photocationic polymerization initiator. Examples of the photosensitizer include the photosensitizers described above as being usable in combination with the photocationic polymerization initiator, and these can be preferably used.

[0063] [Organic Solvent] The ultraviolet-curable composition of the present invention preferably contains an organic solvent (C) for the purposes of improving the coatability of the ultraviolet-curable organopolysiloxane, adjusting the thickness of the coating film, improving the dispersibility of the photopolymerization initiator, etc. As such an organic solvent, any organic solvent that has conventionally been blended in various ultraviolet-curable compositions can be used without particular limitation.

[0064] Suitable examples of the organic solvent include (poly)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, and dipropylene glycol mono-n-butyl ether; (Poly)alkylene glycol monoalkyl ether acetates such as methyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), and propylene glycol monoethyl ether acetate; other ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol diethyl ether; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, 5-methyl-3-heptanone, 2,4-dimethyl-3-pentanone, and 2,6-dimethyl-4-heptanone; alkyl lactate esters such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate;Ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl formate, i-pentyl acetate, n-butyl propionate, butyric acid Examples of suitable organic solvents include ethyl butyrate, n-propyl butyrate, i-propyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, and ethyl 2-oxobutanoate; aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, propylbenzene, diethylbenzene, and 1,3-diisopropylbenzene; and aromatic ethers such as anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 3,4-dimethoxytoluene, and 1,4-bis(methoxymethyl)benzene. The organic solvent may be used alone, or multiple organic solvents may be used in combination, taking into consideration the miscibility with components (A) and (B).

[0065] The content of the organic solvent is not particularly limited and is set appropriately depending on factors such as miscibility with the UV-curable organopolysiloxane (A) and the thickness of the coating film formed from the UV-curable composition. Typically, an amount of 50 to 10,000 parts by mass per 100 parts by mass of component (A) is used. That is, the solute concentration of the UV-curable organopolysiloxane is preferably 1 to 50% by mass, more preferably 2 to 40% by mass.

[0066] The cured product obtained from the UV-curable composition of the present invention can be designed to have the desired physical properties and curing speed depending on the molecular structure of component (A) and the number of hydrophilic groups and UV-curable groups per molecule, as well as the molecular structure and amount of component (B). Furthermore, the viscosity of the curable composition can be designed to a desired value depending on the amount of component (C). Cured products obtained by curing the UV-curable composition of the present invention are also encompassed within the scope of the present invention. The shape of the cured product obtained from the curable composition of the present invention is not particularly limited, and it may be a thin-film coating layer or a molded product such as a sheet. It may be used as a sealant or intermediate layer in laminates or display devices. The cured product obtained from the composition of the present invention is preferably in the form of a thin-film coating layer, and more preferably a thin-film insulating coating layer.

[0067] The ultraviolet-curable composition of the present invention is suitable for use as a coating, particularly as an insulating coating for electronic and electrical devices.

[0068] [Other Additives] In addition to the above components, further additives may be added to the composition of the present invention as desired. Examples of additives include, but are not limited to, those listed below.

[0069] [Adhesion promoter] An adhesion promoter can be added to the ultraviolet-curable composition of the present invention in order to improve adhesion or adhesion to a substrate in contact with the composition. When the curable composition of the present invention is used for applications requiring adhesion or adhesion to a substrate, such as a coating agent or a sealant, it is preferable to add an adhesion promoter to the curable composition of the present invention. Any known adhesion promoter can be used as this adhesion promoter, as long as it does not inhibit the curing reaction of the composition of the present invention.

[0070] Examples of adhesion promoters that can be used in the present invention include organosilanes having a trialkoxysiloxy group (e.g., trimethoxysiloxy group, triethoxysiloxy group) or a trialkoxysilylalkyl group (e.g., trimethoxysilylethyl group, triethoxysilylethyl group) and a hydrosilyl group or an alkenyl group (e.g., vinyl group, allyl group), or organosiloxane oligomers having a linear, branched, or cyclic structure and about 4 to 20 silicon atoms; organosilanes having a trialkoxysiloxy group or a trialkoxysilylalkyl group and a methacryloxyalkyl group (e.g., 3-methacryloxypropyl group); or organosiloxane oligomers having a linear, branched, or cyclic structure and having about 4 to 20 silicon atoms; organosilanes having a trialkoxysiloxy group or trialkoxysilylalkyl group and an epoxy group-bonded alkyl group (e.g., 3-glycidoxypropyl group, 4-glycidoxybutyl group, 2-(3,4-epoxycyclohexyl)ethyl group, 3-(3,4-epoxycyclohexyl)propyl group) or organosiloxane oligomers having a linear, branched, or cyclic structure and having about 4 to 20 silicon atoms; organic compounds having two or more trialkoxysilyl groups (e.g., trimethoxysilyl group, triethoxysilyl group);Examples thereof include reaction products of aminoalkyltrialkoxysilanes and epoxy group-bonded alkyltrialkoxysilanes, and epoxy group-containing ethyl polysilicates. Specific examples thereof include vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hydrogentriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 1,6-bis(trimethoxysilane), silyl)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 group-blocked methylvinylsiloxane oligomer and 3-glycidoxypropyltrimethoxysilane, a condensation reaction product of a silanol group-blocked methylvinylsiloxane oligomer and 3-methacryloxypropyltriethoxysilane, and tris(3-trimethoxysilylpropyl)isocyanurate;

[0071] The amount of adhesion promoter added to the ultraviolet-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 0.01 to 2 parts by mass, per 100 parts by mass of component (A), in order not to promote the curing characteristics of the curable composition or discoloration of the cured product.

[0072] [Additional Optional Additives] Other additives may be added to the UV-curable composition of the present invention, if desired, in addition to or instead of the adhesion promoter described above. Examples of additives that can be used include leveling agents, silane coupling agents not included in the adhesion promoters listed above, UV absorbers, antioxidants, polymerization inhibitors, and fillers (functional fillers such as reinforcing fillers, insulating fillers, and thermally conductive fillers). If necessary, appropriate additives can be added to the composition of the present invention. Furthermore, if necessary, a thixotropic agent may be added to the composition of the present invention, particularly when used as a sealing material.

[0073] [Method for Producing Cured Film] The method for producing a cured film is not particularly limited as long as it is a method that can cure a film made of the above-mentioned ultraviolet-curable composition. Known lithography processes can be applied, and it is preferable to produce a patterned cured film. A typical production method includes: 1) forming a coating film of the above-mentioned ultraviolet-curable composition on a substrate; 2) heating the resulting coating film for a short time at a temperature of about 100°C or less to remove the solvent; 3) exposing the coating film regioselectively to light; 4) developing the exposed coating film; and 5) heating the patterned cured film at a temperature exceeding 100°C to completely cure the film. A method including the following steps is recommended.

[0074] The manufacturing method will now be described in detail. The substrate is not particularly limited, and various substrates such as glass substrates, silicon substrates, and glass substrates coated with a transparent conductive film can be used. To apply the above-mentioned ultraviolet-curable composition to a substrate, known methods using coating devices such as spin coaters, roll coaters, bar coaters, and slit coaters can be applied. The applied curable composition is heated and dried, as needed, to remove the solvent. Typical methods include drying on a hot plate at 80 to 120°C, preferably 90 to 100°C, for 1 to 2 minutes, leaving the composition at room temperature for several hours, or heating in a hot air heater or infrared heater for several tens of minutes to several hours. The position-selective exposure of the coating film is typically performed through a photomask or the like using a known active energy ray source, including ultraviolet light sources such as high-pressure mercury lamps, metal halide lamps, and LED lamps, and laser light sources such as excimer laser light. Negative or positive photomasks can be used depending on the properties of the curable composition. The amount of energy radiation to be irradiated depends on the structure of the curable composition, but is typically about 100 to 1,000 mJ / cm 2 .

[0075] Development is carried out with a developer to form a pattern of the desired shape. Known developers include aqueous alkaline solutions and organic solvents, but development with an aqueous alkaline solution is the mainstream. Both aqueous alkaline solutions of inorganic bases and aqueous organic bases can be used. Suitable developers include aqueous solutions of basic substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, and quaternary ammonium salts, with an aqueous solution of tetramethylammonium hydroxide being particularly preferred. The development method is not particularly limited, and examples of applicable methods include dipping and spraying.

[0076] As described above, the ultraviolet-curable organopolysiloxane of the present invention and the ultraviolet-curable composition containing it as a main component have excellent ultraviolet curability, and also have remarkably excellent alkali solubility. Therefore, particularly when subjected to a development step using an aqueous alkaline solution, they have the advantages of being able to easily form patterns with high precision and of producing cured films with excellent mechanical strength and transparency.

[0077] It is usually preferable to subject the patterned cured film after development to post-exposure baking (PEB). The PEB temperature is not particularly limited as long as it does not cause thermal decomposition or deformation of the patterned cured film, but is preferably 150 to 250°C, and more preferably 150 to 200°C. By the above-mentioned procedure, a cured film of the ultraviolet-curable composition patterned into a desired shape can be formed.

[0078] [Uses] The UV-curable composition of the present invention is particularly useful as a material for forming insulating layers constituting various articles, particularly electronic and electrical devices. The composition can be designed to have a low dielectric constant of less than 3.0 after curing. Furthermore, the curable composition of the present invention has good transparency in the cured product obtained therefrom, making it particularly suitable as a material for forming insulating layers in display devices such as touch panels and displays. In this case, the insulating layer may be formed into any desired pattern as described above, if necessary. Therefore, display devices such as touch panels and displays that include an insulating layer obtained by curing the UV-curable composition of the present invention also constitute one aspect of the present invention.

[0079] Furthermore, an insulating coating layer (insulating film) can be formed by coating an article with the curable composition of the present invention and then curing the coating. Therefore, the composition of the present invention can be used as an insulating coating agent. Furthermore, a cured product formed by curing the curable composition of the present invention can also be used as an insulating coating layer.

[0080] The insulating film formed from the curable composition of the present invention can be used in various applications other than the display device. In particular, it can be used as a component of an electronic device or as a material used in the process of manufacturing an electronic device. Electronic devices include electronic devices such as semiconductor devices and magnetic recording heads. For example, the curable composition of the present invention can be used as an insulating film for semiconductor devices, such as LSIs, system LSIs, DRAMs, SDRAMs, RDRAMs, D-RDRAMs, and multi-chip module multilayer wiring boards, an interlayer insulating film for semiconductors, an etching stopper film, a surface protective film, a buffer coat film, a passivation film in LSIs, a cover coat for flexible copper-clad boards, a solder resist film, and a surface protective film for optical devices.

[0081] The present invention will be further described below based on examples, but the present invention is not limited to the following examples.

[0082] The synthesis of the ultraviolet-curable organopolysiloxane of the present invention, the preparation and evaluation of the ultraviolet-curable composition, and the preparation and evaluation of the cured product thereof will be described in detail with reference to examples.

[0083] [Refractive Index of UV-Curable Organopolysiloxane] The refractive index (n Ｄ Solutions with various polymer concentrations were prepared, measurements were carried out, and the n of the synthesized organopolysiloxane was determined by extrapolation. Ｄ was calculated.

[0084] [Appearance of Curable Composition and Cured Product] The curable composition and the cured product were visually observed and the appearance was judged.

[0085] [Alkali Solubility of Curable Branched Organopolysiloxanes] A 20% by mass PGMEA solution of each curable branched organopolysiloxane was spin-coated onto an optical glass substrate to a film thickness of 1.0 μm, and the substrate was heated (pre-baked) at 90° C. for 2 minutes using a hot plate to form a coating film. The coating was then developed at 25° C. for 1 minute using a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH), and then immersed in a water bath at room temperature (25° C.) for 15 seconds before being rinsed. After rinsing and drying to remove moisture, the glass substrate was visually observed, and its solubility in alkaline solution (developability) was evaluated according to the following criteria: A: Completely dissolved: The coating film was completely removed; B: Almost completely dissolved: A small amount of remaining coating film (scum) was observed; C: Partially dissolved: A large amount of scum (20% or more of the coating area) was observed; D: Insoluble

[0086] [High-energy ray curability of curable compositions] A PGMEA solution of each curable composition (concentration of curable branched organopolysiloxane: 20% by mass) was used to form a coating film of the curable composition in the same manner as above. This coating film was irradiated with high-energy rays (LED light of 365 nm, light intensity: 500 mJ / cm). ２ ) and then heated at 150°C for 2 minutes to obtain a cured coating film. The high-energy ray curability was evaluated according to the following criteria: A: The cured coating film was insoluble in the TMAH dissolution test. B: Only the edge portions of the cured coating film (less than 5% of the total area of ​​the cured coating film) were dissolved in the TMAH dissolution test. C: Approximately half of the cured coating film (approximately 5-50% of the total area of ​​the cured coating film) was dissolved in the TMAH dissolution test. D: The cured coating film was completely or almost dissolved in the TMAH dissolution test.

[0087] Synthesis Example 1 Synthesis of Epoxy-Functional Branched Polysiloxane (A-1) 25.0 g of 3-glycidyloxypropyl(dimethoxy)methylsilane, 67.5 g of phenyltrimethoxysilane, 100.0 g of toluene, 50.0 g of water, and 1.4 g of a 50% aqueous solution of cesium hydroxide were added to a 200 mL three-neck flask equipped with a thermometer and a nitrogen inlet tube, and the mixture was stirred at 80°C for 2 hours. The mixture was subjected to azeotropic dehydration and methanol removal with toluene, and concentrated to a solids content of 78%. The mixture was then stirred at 115°C for an additional 6 hours. The mixture was then allowed to cool to room temperature, and 11.6 g of an alkali adsorbent (Kyoward® KW-700PL) was added. After stirring at room temperature for 30 minutes, the solids were filtered to obtain a solution of epoxy-functional branched polysiloxane (A-1) with a solids concentration of 78%. 29 The Si-NMR measurement results indicated that the ratio of epoxy-functional D structural units to phenyl-functional T structural units in the obtained polysiloxane was 24:76. The gel permeation chromatogram analysis results indicated that the number-average molecular weight (Mn), weight-average molecular weight (Mw), and polydispersity index (PDI) of (A-1) were 2,400, 5,600, and 2.33, respectively. These analysis results suggested that the epoxy-functional branched polysiloxane contained an average of four epoxy groups per molecule.

[0088] Synthesis Example 2 Synthesis of epoxy-functional branched polysiloxane (A-2) A solution of epoxy-functional branched polysiloxane (A-2) with a solids concentration of 92% was obtained by carrying out the reaction in the same manner as in Synthesis Example 1, except that 70.2 g of hexyltrimethoxysilane was used instead of 67.5 g of phenyltrimethoxysilane. 29 The Si-NMR measurement results indicated that the ratio of epoxy-functional D structural units to phenyl-functional T structural units in the obtained polysiloxane was 25:75. The gel permeation chromatogram analysis results indicated that the Mn, Mw, and PDI of (A-2) were 1400, 3600, and 2.57, respectively. These analysis results suggested that the epoxy-functional branched polysiloxane had an average of 2.5 epoxy groups per molecule.

[0089] Synthesis Example 3 Synthesis of epoxy-functional branched polysiloxane (A-3) A reaction was carried out in the same manner as in Synthesis Example 1, except that 30.0 g of 3-glycidyloxypropyltrimethoxysilane was used instead of 25.0 g of 3-glycidyloxypropyl(dimethoxy)methylsilane, the amount of phenyltrimethoxysilane was 75.0 g, the amount of water was 37.0 g, and the amount of 50% aqueous cesium hydroxide solution was 1.6 g, to obtain a solution of epoxy-functional branched polysiloxane (A-3) with a solids concentration of 78%. 29 The Si-NMR measurement results indicated that the ratio of epoxy-functional T structural units to phenyl-functional T structural units in the obtained polysiloxane was 25:75. The gel permeation chromatogram analysis results indicated that the Mn, Mw, and PDI of (A-3) were 5,000, 12,000, and 2.40, respectively. These analysis results suggested that each molecule of the epoxy-functional branched polysiloxane contained an average of nine epoxy groups.

[0090] Synthesis Example 4 Synthesis of epoxy-functional branched polysiloxane (A-4) A solution of epoxy-functional branched polysiloxane (A-4) with a solids concentration of 39% was obtained by carrying out a reaction in the same manner as in Synthesis Example 1, except that the amount of 3-glycidyloxypropyl(dimethoxy)methylsilane was 24.0 g, and 13.0 g of trimethoxy(methyl)silane, 46.8 g of cyclohexyltrimethoxysilane, 17.1 g of toluene, 15.0 g of water, 17 mg of dibutylhydroxytoluene, and 0.6 g of a 43% aqueous solution of potassium hydroxide were used. 29 From the results of Si-NMR measurement, the ratio of epoxy-functional D structural units, methyl-functional T structural units, and cyclohexyl-functional T structural units in the obtained polysiloxane was 24:21:55.

[0091] Synthesis Example 5 Synthesis of Epoxy-Functional Branched Polysiloxane (A-5) 20.0 g of hexamethyldisiloxane, 38.0 g of trimethoxy(methyl)silane, 59.0 g of polymethoxysiloxane (MKC silicate "MS51" manufactured by Mitsubishi Chemical Corporation), 38.2 g of toluene, 28.5 g of water, 39 mg of dibutylhydroxytoluene, and 0.164 g of trifluoroacetic acid were added and stirred for 1 hour at 80° C. Thereafter, 0.610 g of a 43% aqueous solution of potassium hydroxide, 76.0 g of 3-glycidyloxypropyl(dimethoxy)methylsilane, 25.1 g of toluene, and 12.5 g of water were added, and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain a solution of epoxy-functional branched polysiloxane (A-5) with a solids concentration of 39%. 29 The Si-NMR measurement results showed that the ratio of M structural units, epoxy-functional D structural units, methyl-functional T structural units, and Q structural units in the obtained polysiloxane was 16:26:20:38.

[0092] Synthesis Example 6 Synthesis of Epoxy-Functional Branched Polysiloxane (A-6) 11.0 g of hexamethyldisiloxane, 33.0 g of trimethoxy(3,3,3-trifluoropropyl)silane, 32.5 g of polymethoxysiloxane (MKC silicate "MS51" manufactured by Mitsubishi Chemical Corporation), 20.5 g of toluene, 15.5 g of water, 26 mg of dibutylhydroxytoluene, and 0.107 g of trifluoroacetic acid were added and stirred for 1 hour at 80° C. Subsequently, 0.340 g of a 43% aqueous solution of potassium hydroxide, 41.8 g of 3-glycidyloxypropyl(dimethoxy)methylsilane, 6.77 g of toluene, and 5.11 g of water were added, and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain a solution of epoxy-functional branched polysiloxane (A-5) with a solids concentration of 36%. 29 The Si-NMR measurement results showed that the ratio of M structural units, epoxy-functional D structural units, trifluoropropyl-functional T structural units, and Q structural units in the resulting polysiloxane was 16:29:19:36.

[0093] Synthesis Example 7 Synthesis of Epoxy-Functional Branched Polysiloxane (A-7) 10.0 g of hexamethyldisiloxane, 11.0 g of trimethoxy(methyl)silane, 35.0 g of trimethoxy(3,3,3-trifluoropropyl)silane, 28.0 g of polymethoxysiloxane (MKC silicate "MS51" manufactured by Mitsubishi Chemical Corporation), 72.0 g of toluene, 30.0 g of water, 30 mg of dibutylhydroxytoluene, and 0.118 g of trifluoroacetic acid were added and stirred for 1 hour at 80° C. Subsequently, 0.370 g of a 43% aqueous solution of potassium hydroxide, 44.0 g of 3-glycidyloxypropyl(dimethoxy)methylsilane, 7.21 g of toluene, and 5.40 g of water were added, and the reaction was carried out in the same manner as in Synthesis Example 1 to obtain a solution of epoxy-functional branched polysiloxane (A-5) with a solids concentration of 44%. 29 From the results of Si-NMR measurement, the ratio of M structural units, epoxy-functional D structural units, methyl-functional T structural units, trifluoropropyl-functional T structural units, and Q structural units in the obtained polysiloxane was 13:26:10:20:31.

[0094] Synthesis Example 8 Synthesis of Acryloxy-Functional Branched Polysiloxane (B-1) 31.8 g of the (A-1) solution, 3.6 g of acrylic acid, 11.7 mg of dibutylhydroxytoluene, and 86.0 mg of 1,1,3,3-tetramethylguanidine were added to a 200 mL three-neck flask equipped with a thermometer and a nitrogen inlet tube, and the mixture was stirred at 90°C for 24 hours. The reaction solution was then allowed to cool to room temperature, neutralized with an aqueous sodium bicarbonate solution, and washed three times with water. Next, propylene glycol methyl ether acetate (PGMEA) was added to perform solvent substitution, yielding a PGMEA solution of acryloxy-functional branched polysiloxane (B-1) with a solids concentration of 50%. The product 13 From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and hydroxyl-functional D structural units to phenyl-functional T structural units in the obtained polysiloxane was 24:76.

[0095] Synthesis Example 9 Synthesis of acryloxy-functional branched polysiloxane (B-2) A PGMEA solution of acryloxy-functional branched polysiloxane (B-2) with a solids concentration of 50% was obtained by carrying out the reaction in the same manner as in Synthesis Example 4, except that 32.0 g of (A-2) solution was used instead of 31.8 g of (A-1) solution, the amount of acrylic acid was 2.0 g, the amount of dibutylhydroxytoluene was 4.7 mg, and the amount of 1,1,3,3-tetramethylguanidine was 48.0 mg. 13 From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and hydroxyl-functional D structural units, epoxy-functional D structural units, and hexyl-functional T structural units in the obtained polysiloxane was 23:2:75.

[0096] Synthesis Example 10 Synthesis of acryloxy-functional branched polysiloxane (B-3) A PGMEA solution of acryloxy-functional branched polysiloxane (B-3) with a solids concentration of 50% was obtained by carrying out the reaction in the same manner as in Synthesis Example 4, except that 44.2 g of (A-3) solution was used instead of 31.8 g of (A-1) solution, the amount of acrylic acid was 5.4 g, the amount of dibutylhydroxytoluene was 12.0 mg, and the amount of 1,1,3,3-tetramethylguanidine was 146 mg. 13 From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and hydroxyl-functional T structural units, epoxy-functional T structural units, and phenyl-functional T structural units in the obtained polysiloxane was 24:1:75.

[0097] Synthesis Example 11 Synthesis of acryloxy-functional branched polysiloxane (B-4) The reaction was carried out in the same manner as in Synthesis Example 8, except that 121 g of (A-4) solution was used instead of 31.8 g of (A-1) solution, the amount of acrylic acid was 7.1 g, the amount of dibutylhydroxytoluene was 10.0 mg, and the amount of 1,1,3,3-tetramethylguanidine was 1.72 g. However, without carrying out neutralization treatment or solvent substitution after the reaction, a toluene solution of acryloxy-functional branched polysiloxane (B-4) with a solids concentration of 39% was obtained. 13From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and hydroxyl-functional D structural units, epoxy-functional D structural units, methyl-functional T structural units, and cyclohexyl-functional T structural units in the obtained polysiloxane was 22:2:21:55.

[0098] Synthesis Example 12 Synthesis of acryloxy-functional branched polysiloxane (B-5) A toluene solution of acryloxy-functional branched polysiloxane (B-5) with a solids concentration of 39% was obtained by carrying out the reaction in the same manner as in Synthesis Example 11, except that 120 g of (A-5) solution was used instead of 31.8 g of (A-1) solution, the amount of acrylic acid was 10.0 g, the amount of dibutylhydroxytoluene was 10.0 mg, and 2.04 g of tetrabutylammonium bromide was used instead of 1.72 g of 1,1,3,3-tetramethylguanidine. 13 From the results of C-NMR measurement, it was confirmed that the ratio of M structural units, acryloxy- and hydroxyl-functional D structural units, epoxy-functional D structural units, methyl-functional T structural units, and Q structural units in the obtained polysiloxane was 16:25:1:20:38.

[0099] Synthesis Example 13 Synthesis of acryloxy-functional branched polysiloxane (B-6) A reaction was carried out in the same manner as in Synthesis Example 11, except that 209 g of (A-6) solution was used instead of 31.8 g of (A-1) solution, the amount of acrylic acid was 13.6 g, the amount of dibutylhydroxytoluene was 15.0 mg, and the amount of tetrabutylammonium bromide was 3.05 g, to obtain a toluene solution of acryloxy-functional branched polysiloxane (B-6) with a solids concentration of 36%. 13 From the results of C-NMR measurement, it was confirmed that the ratio of M structural units, acryloxy- and hydroxyl-functional D structural units, trifluoropropyl-functional T structural units, and Q structural units in the obtained polysiloxane was 16:29:19:36.

[0100] Synthesis Example 14 Synthesis of acryloxy-functional branched polysiloxane (B-7) A reaction was carried out in the same manner as in Synthesis Example 11, except that 192 g of (A-7) solution was used instead of 31.8 g of (A-1) solution, the amount of acrylic acid was 14.6 g, the amount of dibutylhydroxytoluene was 17.0 mg, and the amount of tetrabutylammonium bromide was 3.16 g, to obtain a toluene solution of acryloxy-functional branched polysiloxane (B-7) with a solids concentration of 44%. 13 From the results of C-NMR measurement, it was confirmed that the ratio of M structural units, acryloxy- and hydroxyl-functional D structural units, methyl-functional T structural units, trifluoropropyl-functional T structural units, and Q structural units in the obtained polysiloxane was 13:26:10:20:31.

[0101] Synthesis Example 15 Synthesis of Acryloxy- and Carboxyl-Functional Branched Polysiloxane (C-1) 37.55 g of a PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (B-1), 1.9 g of succinic anhydride, and 31.8 mg of 1,1,3,3-tetramethylguanidine were added to a 200 mL separable flask equipped with a stirrer, thermometer, nitrogen inlet tube, and reflux condenser, and the mixture was stirred at 70°C for 3 hours. The reaction solution was then allowed to cool to room temperature, and 1.0 g of an alkali adsorbent (Kyoward (registered trademark) KW-700PL) was added and stirred for 30 minutes. The resulting solution was filtered and adjusted to a solids concentration of 46%, yielding a solution of acryloxy- and carboxyl-functional branched polysiloxane (C-1). The product 13 From the results of C-NMR analysis, it was confirmed that the ratio of acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, and phenyl-functional T structural units in the obtained polysiloxane was 22:2:76. The refractive index of (C-1) was 1.536.

[0102] Synthesis Example 16 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-2) A PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-2) with a solids concentration of 46% was obtained by carrying out the reaction in the same manner as in Synthesis Example 7, except that the amount of PGMEA solution of (B-1) was 34.79 g, 1.9 g of phthalic anhydride was used instead of 1.9 g of succinic anhydride, and the stirring time was 7 hours. 13 From the results of C-NMR analysis, it was confirmed that the ratio of acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, and phenyl-functional T structural units in the obtained polysiloxane was 23:1:76. The refractive index of (C-2) was 1.542.

[0103] Synthesis Example 17 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-3) A PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-3) with a solids concentration of 46% was obtained by carrying out the reaction in the same manner as in Synthesis Example 7, except that the amount of PGMEA solution of (B-1) was 38.78 g, 4.06 g of 4-nitrophthalic anhydride was used instead of 1.9 g of succinic anhydride, and the stirring time was 7 hours. 13 From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, and phenyl-functional T structural units in the obtained polysiloxane was 20:4:76. The refractive index of (C-3) was 1.560.

[0104] Synthesis Example 18 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-4) A PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-4) with a solids concentration of 46% was obtained by carrying out the reaction in the same manner as in Synthesis Example 7, except that the amount of PGMEA solution of (B-1) was 46.60 g, 4.36 g of thiodiglycolic anhydride was used instead of 1.9 g of succinic anhydride, and the amount of 1,1,3,3-tetramethylguanidine was 57.0 mg. 13From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and carboxyl-functional D structural units to phenyl-functional T structural units in the obtained polysiloxane was 24:76. The refractive index of (C-4) was 1.554.

[0105] Synthesis Example 19 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-5) A PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-5) with a solids concentration of 46% was obtained by carrying out the reaction in the same manner as in Synthesis Example 7, except that 41.61 g of PGMEA solution of (B-2) was used instead of 37.55 g of PGMEA solution of (B-1), the amount of succinic anhydride was changed to 2.3 g, and the amount of 1,1,3,3-tetramethylguanidine was changed to 40.1 mg. 13 From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and carboxyl-functional D structural units, epoxy-functional D structural units, and hexyl-functional T structural units in the obtained polysiloxane was 23:2:75. The refractive index of (C-5) was 1.463.

[0106] Synthesis Example 20 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-6) A PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-6) with a solids concentration of 46% was obtained by carrying out the reaction in the same manner as in Synthesis Example 7, except that 40.8 g of PGMEA solution of (B-3) was used instead of 37.55 g of PGMEA solution of (B-1), the amount of succinic anhydride was changed to 2.7 g, the amount of 1,1,3,3-tetramethylguanidine was changed to 46 mg, and the stirring time was changed to 21 hours. 13 From the results of C-NMR measurement, it was confirmed that the ratio of acryloxy- and carboxyl-functional T structural units, epoxy-functional T structural units, and phenyl-functional T structural units in the obtained polysiloxane was 24:1:75. The refractive index of (C-6) was 1.531.

[0107] Synthesis Example 21 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-7) The reaction was carried out in the same manner as in Synthesis Example 15, except that 121 g of a toluene solution of (B-4) was used instead of 37.55 g of a PGMEA solution of (B-1), the amount of succinic anhydride was 4.3 g, and the stirring time was 7 hours. After completion of the reaction, PGMEA was added to perform solvent substitution, yielding a PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-7) with a solids concentration of 30%. The product 13 C-NMR analysis confirmed that the ratio of acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, epoxy-functional D structural units, methyl-functional T structural units, and cyclohexyl-functional T structural units in the resulting polysiloxane was 18:4:2:21:55. The refractive index of (C-7) was 1.478. Gel permeation chromatogram analysis revealed that the Mn, Mw, and PDI of (C-7) were 1060, 1540, and 1.46, respectively. These analytical results suggested that the acryloxy- and carboxyl-functional branched polysiloxane contained an average of two acryloxy groups and one carboxyl group per molecule.

[0108] Synthesis Example 22 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-8) The reaction was carried out in the same manner as in Synthesis Example 15, except that 120 g of a toluene solution of (B-5) was used instead of 37.55 g of a PGMEA solution of (B-1), the amount of succinic anhydride was changed to 4.6 g, and the stirring time was changed to 7 hours. However, no neutralization treatment was carried out after the reaction was completed, and only solvent substitution was carried out by adding PGMEA, thereby obtaining a PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-8) with a solids concentration of 30%. 13C-NMR analysis confirmed that the ratio of M units, acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, epoxy-functional D structural units, methyl-functional T structural units, and Q structural units in the resulting polysiloxane was 16:16:9:1:20:38. The refractive index of (C-8) was 1.461. Gel permeation chromatogram analysis revealed that the Mn, Mw, and PDI of (C-8) were 7610, 34700, and 4.55, respectively. These analytical results suggested that the acryloxy- and carboxyl-functional branched polysiloxane contained an average of 14 acryloxy groups and an average of 9 carboxyl groups per molecule.

[0109] Synthesis Example 23 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-9) The reaction was carried out in the same manner as in Synthesis Example 22, except that 209 g of a toluene solution of (B-6) was used instead of 37.55 g of a PGMEA solution of (B-1), the amount of succinic anhydride was changed to 5.98 g, and the stirring time was changed to 5 hours. However, no neutralization treatment was carried out after the reaction was completed, and only solvent substitution was carried out by adding PGMEA, thereby obtaining a PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-9) with a solids concentration of 30%. 13 C-NMR analysis confirmed that the ratio of M structural units, acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, trifluoropropyl-functional T structural units, and Q structural units in the resulting polysiloxane was 16:19:10:19:36. The refractive index of (C-9) was 1.450. Analysis of the gel permeation chromatogram revealed that the Mn, Mw, and PDI of (C-9) were 4670, 6410, and 1.37, respectively. These analytical results suggested that the acryloxy- and carboxyl-functional branched polysiloxane contained an average of nine acryloxy groups and an average of six carboxyl groups per molecule.

[0110] Synthesis Example 24 Synthesis of acryloxy- and carboxyl-functional branched polysiloxane (C-10) The reaction was carried out in the same manner as in Synthesis Example 22, except that 192 g of a toluene solution of (B-7) was used instead of 37.55 g of a PGMEA solution of (B-1), the amount of succinic anhydride was changed to 8.0 g, and the stirring time was changed to 5 hours. However, no neutralization treatment was carried out after the reaction was completed, and only solvent substitution was carried out by adding PGMEA, thereby obtaining a PGMEA solution of acryloxy- and carboxyl-functional branched polysiloxane (C-10) with a solids concentration of 27%. 13 C-NMR analysis confirmed that the ratio of M structural units, acryloxy- and carboxyl-functional D structural units, acryloxy- and hydroxyl-functional D structural units, methyl-functional T structural units, trifluoropropyl-functional T structural units, and Q structural units in the resulting polysiloxane was 13:21:5:10:20:31. The refractive index of (C-10) was 1.450. Analysis of the gel permeation chromatogram revealed that the Mn, Mw, and PDI of (C-10) were 5040, 7890, and 1.57, respectively. These analytical results suggested that the acryloxy- and carboxyl-functional branched polysiloxane contained an average of nine acryloxy groups and an average of seven carboxyl groups per molecule.

[0111] [Examples and Comparative Examples] The following functional polysiloxane solutions and curing catalysts were used and mixed in the compositions shown in Table 1 (parts by mass; polysiloxane is calculated as solid content), and then diluted with PGMEA to a total solid content of 20 mass %, followed by filtration through a membrane filter with a pore size of 0.2 μm to prepare each ultraviolet-curable composition. UV-curable polysiloxanes (A-1) PGMEA solution of functional polysiloxane solution obtained by solvent substitution of the functional polysiloxane solution obtained in the above Synthesis Example (C-1) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-2) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-3) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-4) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-5) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-6) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-7) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-8) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-9) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example (C-10) PGMEA solution of functional polysiloxane obtained in the above Synthesis Example Curing catalyst (D-1) Omnirad (registered trademark) 819 manufactured by IGM Resin (D-2) Irgacure (registered trademark) OXE-02 manufactured by BASF (D-3) Omnirad (registered trademark) TPO-L manufactured by IGM Resin

[0112] [Dielectric Constant of Organopolysiloxane Cured Product (Cured Film)] The curable composition of Example 1 was poured into a 50 mm diameter Teflon® cup and dried at room temperature for 16 hours, then at 50°C for 5 hours, and then at 90°C for 12 hours to form a 100 μm thick transparent organopolysiloxane film. This film specimen was irradiated with ultraviolet light (365 nm LED light, 2000 mJ / cm2) and then heated in an oven at 150°C for 30 minutes to obtain a fully cured coating film. A small amount of silicone oil was applied to both sides of the cured product, and tin foil 33 mm in diameter and 0.007 mm thick was crimped onto the surface. The capacitance was measured at room temperature and 100 kHz using a Keysight Technologies E4990A Precision Impedance Analyzer connected to 30 mm diameter parallel plate electrodes. The dielectric constant was calculated to be 2.9 using the measured capacitance, the measured thickness of the cured product, and the electrode area.

[0113] On the other hand, a similar procedure was carried out using the curable composition of Example 6, which contained as the main component an ultraviolet-curable organopolysiloxane composed solely of silsesquioxane units, in an attempt to form an organopolysiloxane film with a thickness of 100 μm. However, many cracks occurred on the surface, and it was not possible to form a transparent film.

[0114] As shown in Tables 1 and 2, coating films formed from the UV-curable organopolysiloxanes of the present invention exhibit high alkali solubility. In particular, organopolysiloxanes having not only silsesquioxane units but also D structural units and curable compositions containing them (Examples 1 to 5 and 7 to 10) exhibited particularly excellent alkali solubility. Furthermore, the present organopolysiloxanes also exhibit good UV curability. Furthermore, cured coating films formed by UV irradiation are transparent, and in particular, cured coating films obtained from polysiloxanes having both UV-curable groups and hydrophilic groups in the D structural units exhibit high transparency and sufficient coating toughness. Furthermore, by adjusting the types of structural units and functional groups constituting the branched organopolysiloxanes of the present invention, the refractive index of the organopolysiloxanes can be adjusted over a wide range, and cured products having the desired refractive index can be designed from the curable compositions of the present invention. In particular, because the refractive index of branched organopolysiloxanes having trifluorofunctional structural units is 1.45 or less, the use of such branched organopolysiloxanes has the advantage of enabling the design of curable compositions capable of forming cured products with low refractive indices (Examples 9 and 10). On the other hand, the organopolysiloxane having UV-curable groups but no hydrophilic groups (Comparative Example 1) was poor in alkali solubility and was not suitable as a patterning material.

[0115] The UV-curable organopolysiloxanes and UV-curable compositions containing them as their main component have excellent UV curability and also have remarkably excellent alkali solubility, which allows for simple and high-precision pattern formation, particularly when subjected to a development step using an aqueous alkaline solution, and the resulting cured films have excellent mechanical strength and transparency and can be molecularly designed to have a wide range of refractive indexes. Therefore, the organopolysiloxanes and the like are particularly suitable as materials for forming insulating layers in display devices such as touch panels and displays, particularly flexible displays, and are particularly suitable as patterning materials and coating materials.

Claims

1. An ultraviolet-curable organopolysiloxane that has, in each molecule, at least one monovalent functional group bonded to a silicon atom and having both a hydrophilic group and an ultraviolet-curable group, and that has solubility in an alkaline aqueous solution as a whole.

2. 2. The ultraviolet-curable organopolysiloxane according to claim 1, which has one or more siloxane units selected from the following repeating units (1) and (2) in one molecule: (R １ RSiO ２／２ ) (1) (A ３ SiO １／２ ) (2) (In the formula, R １ is a monovalent functional group having both a hydrophilic group and an ultraviolet-curable group, R is a group selected from an unsubstituted or fluorine-substituted monovalent hydrocarbon group, an alkoxy group, and a hydroxyl group, and A is R １ or R, and A is at least one R １ (including

3. 3. The ultraviolet-curable organopolysiloxane according to claim 2, which has at least one siloxane unit (1) in one molecule.

4. 4. The ultraviolet-curable organopolysiloxane according to claim 3, further comprising the following siloxane unit (3): (R ２ RSiO ２／２ ) (3) (In the formula, R ２ is a monovalent functional group having a UV-curable group and no hydrophilic group, and R is the above-mentioned group.

5. 2. The ultraviolet-curable organopolysiloxane according to claim 1, wherein the hydrophilic group is selected from the group consisting of a carboxyl group, a hydroxyl group, a phenolic hydroxyl group, and a polyether group.

6. 2. The ultraviolet-curable organopolysiloxane according to claim 1, wherein the ultraviolet-curable group is selected from the group consisting of an epoxy group, an oxetane group, a vinyl ether group, and a (meth)acryloxy group.

7. Average unit formula: (B ３ SiO １／２ ) ａ (R １ RSiO ２／２ ) ｂ１ (R ２ RSiO ２／２ ) ｂ２ (RSiO ３／２ ) ｃ (SiO ４／２ ) ｄ (4) (In the formula, R １ , R ２ , R are each independently the same groups as defined above, B is independently R １ , R ２ and R, a is 0 or a positive number, b1 is a number in the range of 1 to 100, b2 is a number in the range of 0 to 50, and (c+d) is a positive number.

3. The ultraviolet-curable organopolysiloxane according to claim 2, which is a branched organopolysiloxane represented by the formula:

8. 8. The ultraviolet-curable organopolysiloxane according to claim 7, wherein the value of (b1+b2) / (a+b1+b2+c+d) in the average unit formula (4) is 0.1 or more and 0.5 or less.

9. 3. The ultraviolet-curable organopolysiloxane according to claim 2, which contains one or more of the following siloxane units (5) in the molecule: (RSiO ３／２ ) (5) (wherein R is the same group as defined above)

10. The R １ 3. The ultraviolet-curable organopolysiloxane according to claim 2, wherein is a group represented by the following formula (6): 【Chemical 1】 （６） {In the formula, R ４ is a chain divalent hydrocarbon group having 2 to 10 carbon atoms, R ５ is a trivalent hydrocarbon group having 3 to 10 carbon atoms and being linear, cyclic, or a combination thereof, X is an oxygen atom, a sulfur atom, or —NR ７ - (wherein, R ７ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms; n is 0 or 1; Y is a group containing a monovalent ultraviolet-curable group, Z is a hydroxyl group, a hydroxyl group-containing group, or —O(C═O)—R ６ -CO ２ H (wherein, R ６ is a linear, branched, or cyclic divalent hydrocarbon group having 2 to 12 carbon atoms, which may optionally contain an oxygen atom or a sulfur atom; * is the bonding site to the silicon atom on the organopolysiloxane.

11. 2. The ultraviolet-curable organopolysiloxane according to claim 1, wherein the hydrophilic group is a carboxyl group and the ultraviolet-curable group is a (meth)acryloxy group.

12. 2. The ultraviolet-curable organopolysiloxane according to claim 1, which is soluble in an aqueous alkaline solution, such that when the organopolysiloxane is applied to a glass plate so that the thickness after application is 4 μm, and the coating film is then immersed in a 2.38 mass % aqueous solution of tetramethylammonium hydroxide (TMAH) for 1 minute and then washed with water, the coating film comprising the organopolysiloxane exhibits a mass loss rate of 90 mass % or more.

13. (A) the ultraviolet-curable organopolysiloxane according to any one of claims 1 to 12; (B) a photopolymerization initiator in an amount of 0.1 to 10 parts by mass per 100 parts by mass of component (A), and (C) Organic Solvent An ultraviolet-curable composition comprising:

14. An insulating coating agent comprising the ultraviolet-curable composition according to claim 13.

15. A cured product of the ultraviolet-curable composition according to claim 13.

16. A method for using a cured product of the ultraviolet-curable composition according to claim 13 as an insulating coating layer.

17. A display device comprising a layer made of a cured product of the ultraviolet-curable composition according to claim 13.

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