Ultraviolet-curable silicone composition and cured product thereof

Abstract

The present application provides a kind of ultraviolet curable silicone composition capable of inkjet injection and capable of imparting cured product with excellent rubber properties. The ultraviolet curable silicone composition includes: (A) monoterminally polymerizable organopolysiloxane represented by the following general formula (1), (in general formula (1), R 1 ~R 5 Each independently is linear alkyl or branched alkyl having 1 to 20 carbon atoms or aryl-containing group having 6 to 10 carbon atoms; R 6 Is divalent organic group having 2 to 20 carbon atoms; R 7 Is alkylene having 2 to 20 carbon atoms; R 8 Is hydrogen atom or methyl group; n is a number of 1 to 500; X is alkylene having 2 to 20 carbon atoms; Y is -OCH2CH2-, -OCH(CH3)CH2- or -OCH2CH(CH3)-; p is a number of 1 or more; Z is -O- or -NH-; and (B) photopolymerization initiator.

Description

TECHNICAL FIELD

[0001] The present application relates to an ultraviolet-curable silicone composition and a cured product thereof. Specifically, it relates to an ultraviolet-curable silicone composition capable of inkjet ejection, and a cured product thereof. BACKGROUND

[0002] As for the ultraviolet-curable inkjet ink used in the field of industrial inkjet, since it has quick-drying property and low volatility, it is becoming mainstream that it can be used for printing on non-absorbing materials.

[0003] An inkjet material in which silicone is used as a main component (Patent Literature 1) is expected to have a wider industrial use than ever before because it can impart good rubber properties and the ink itself has excellent weather resistance, but for such a silicone material, it is desired that the strength after curing be further improved.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2018 / 003381 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Therefore, an object of the present application is to provide an ultraviolet-curable silicone composition capable of inkjet ejection and imparting a cured product having excellent rubber properties.

[0009] SOLUTION TO PROBLEM

[0010] As a result of intensive studies made by the present inventors in order to achieve the above object, it has been found that an ultraviolet-curable silicone composition capable of inkjet ejection and imparting a cured product having excellent rubber properties can be provided by using a specific ultraviolet-curable organopolysiloxane component, and the present application has been completed.

[0011] The present application is an application for providing an ultraviolet-curable silicone composition described below.

[0012] [1] An ultraviolet-curable silicone composition comprising:

[0013] (A) a mono-terminal polymeric organopolysiloxane represented by the following general formula (1),

[0014]

[0015] (In the general formula (1), R 1 , R 2 , R 3, R 4 and R 5 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms or an aryl-containing group having 6 to 10 carbon atoms; R 6 is a divalent organic group having 2 to 20 carbon atoms; R 7 is an alkylene group having 2 to 20 carbon atoms; R 8 is a hydrogen atom or a methyl group; n is a number of 1 to 500; X is an alkylene group having 2 to 20 carbon atoms; Y is -OCH2CH2-, -OCH(CH3)CH2- or -OCH2CH(CH3)-; p is a number of 1 or more; and Z is -O- or -NH-.

[0016] (B) a photopolymerization initiator.

[0017] [2] The ultraviolet-curable silicone composition according to [1],

[0018] In General Formula (1), R 1 is a n-butyl group, R 2 , R 3 , R 4 and R 5 are methyl groups, R 7 is a dimethylene group, and Z is -O-.

[0019] [3] The ultraviolet-curable silicone composition according to [1] or [2],

[0020] In General Formula (1), R 6 is a divalent residue derived from a diisocyanate selected from the group consisting of trimethylhexamethylene diisocyanate (TMHMDI), isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI) and 1,6-hexamethylene diisocyanate (HMDI).

[0021] [4] The ultraviolet-curable silicone composition according to any one of [1] to [3], wherein

[0022] Further, (C) an organopolysiloxane represented by the following General Formula (2) is contained.

[0023]

[0024] (In General Formula (2), R 9each independently is a group selected from the group consisting of a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, an acryloyl group, a methacryloyl group, an alkyl acrylate group, an alkyl methacrylate group, an acrylamide group, and a methacrylamide group, but the organic polysiloxane represented by General Formula (2) has at least two groups selected from the group consisting of an acryloyl group, a methacryloyl group, an alkyl acrylate group, an alkyl methacrylate group, an acrylamide group, and a methacrylamide group in one molecule, and m is a number satisfying 10 ≤ m ≤ 500.

[0025] [5] The ultraviolet-curable silicone composition according to any one of [1] to [4], wherein

[0026] Further, (D) an organic polysiloxane represented by General Formula (3) is contained.

[0027]

[0028] (In General Formula (3), R 2 , R 3 , R 4 , and R 5 each independently is a linear alkyl group or a branched alkyl group having 1 to 20 carbon atoms or an aryl group-containing group having 6 to 10 carbon atoms; R 6 each independently is a divalent organic group having 2 to 20 carbon atoms; R 7 each independently is an alkylene group having 2 to 20 carbon atoms; R 8 each independently is a hydrogen atom or a methyl group; n is a number of 1 to 500; X each independently is an alkylene group having 2 to 20 carbon atoms; Y each independently is -OCH2CH2-, -OCH(CH3)CH2-, or -OCH2CH(CH3)-; p each independently is a number of 1 or more; and Z each independently is -O- or -NH-.)

[0029] [6] The ultraviolet-curable silicone composition according to any one of [1] to [5], wherein

[0030] Further, (E) a (meth)acrylate-containing compound not containing a siloxane structure is contained.

[0031] [7] A cured product which is a cured product of the ultraviolet-curable silicone composition according to any one of [1] to [6].

[0032] [8] An ink composition for inkjet, wherein

[0033] The ultraviolet-curable silicone composition according to any one of [1] to [6] is contained.

[0034] [9] A composition for a 3D printer, wherein

[0035] The ultraviolet-curable silicone composition described in any one of [1] to [6].

[0036] Effects of the Invention

[0037] The ultraviolet-curable silicone composition of the present application can form a cured product that can be jetted by inkjet and has excellent rubber properties after curing. Therefore, the ultraviolet-curable silicone composition of the present application is suitable as an ink material for inkjet, and particularly suitable as a silicone material for a 3D printer using an inkjet method. DETAILED DESCRIPTION

[0038] Hereinafter, the present application will be described in more detail.

[0039] (A) Organopolysiloxane

[0040] Component (A) is an organopolysiloxane represented by the following general formula (1).

[0041]

[0042] R in General Formula (1) 1 , R 2 , R 3 , R 4 , and R 5 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms or an aryl group-containing group having 6 to 10 carbon atoms. As the linear or branched alkyl group having 1 to 20 carbon atoms, there can be mentioned methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and the like. In addition, as the aryl group-containing group having 6 to 10 carbon atoms, there can be mentioned phenyl, tolyl, xylyl, ethylphenyl, benzyl, phenethyl, and the like. Preferably, R 1 is methyl or n-butyl, and preferably R 2 , R 3 , R 4 , and R 5 are methyl.

[0043] As the alkylene group having 2 to 20 carbon atoms represented by X in General Formula (1), there can be mentioned dimethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, dodecamethylene, tetradecamethylene, 2-methylethylene, 2-methyltrimethylene, 2-methyltetramethylene, 2-methylpentamethylene, 2-methylhexamethylene, 2-methylheptamethylene, 2-methyloctamethylene, 2-methylnonamethylene, 2-methyldcamethylene, 2-methylundecamethylene, and the like. Preferable X is trimethylene, 2-methylethylene, and the like, alkylene groups having 3 carbon atoms.

[0044] In General Formula (1), Z is -O- or -NH-, and preferably Z is -O-.

[0045] In General Formula (1), R 6 is a divalent organic group having 2 to 20 carbon atoms, and particularly preferably is a divalent residue derived from a diisocyanate. As the diisocyanate from which such a divalent residue is derived, there can be mentioned trimethylhexamethylene diisocyanate (TMHMDI), isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HMDI). Of these, isophorone diisocyanate (IPDI) is preferable as the diisocyanate.

[0046] As the alkylene group having 2 to 20 carbon atoms represented by R 7 in General Formula (1), there can be mentioned dimethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, dodecamethylene, tetradecamethylene, 2-methylethylene, 2-methyltrimethylene, 2-methyltetramethylene, 2-methylpentamethylene, 2-methylhexamethylene, 2-methylheptamethylene, 2-methyloctamethylene, 2-methylnonamethylene, 2-methyldcamethylene, 2-methylundecamethylene, and the like. Preferable R 7 is trimethylene, 2-methylethylene, and the like, alkylene groups having 3 carbon atoms.

[0047] In General Formula (1), R 8 is a hydrogen atom or a methyl group, and preferably R 8 is a methyl group.

[0048] In General Formula (1), Yp represents a polyoxyalkylene segment. p represents the degree of polymerization of the polyoxyalkylene segment, and is not particularly limited as long as it is 1 or more, but is preferably 1 to 10. Y is -OCH2CH2-, -OCH(CH3)CH2-, or -OCH2CH(CH3)-, and preferably Y is represented by -OCH2CH2-.

[0049] n represents the degree of polymerization of the polyoxyalkylene segment, and is a number of 1 to 500, preferably a number of 10 to 100. The value of n can be calculated as an average value by, for example 29 Si-NMR measurement, or the like.

[0050] As such an organopolysiloxane, for example, the following compounds can be cited.

[0051]

[0052] The monoterminally polymerizable organopolysiloxane represented by General Formula (1) can be produced by, for example, the following method.

[0053] That is, as represented by Reaction Formula [b], by subjecting the monoterminally hydroxyl polyoxyalkylene-polysiloxane block copolymer (20) to a urethane reaction with an isocyanate compound (30) containing a polymerizable group, a monoterminally polymerizable organopolysiloxane represented by General Formula (1) can be produced.

[0054]

[0055] wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , n, X, Y, Z, and p are the same as represented in General Formula (1).

[0056] In Reaction Formula [b] in which the monoterminally hydroxyl polyoxyalkylene-polysiloxane block copolymer (20) is subjected to a urethane reaction with an isocyanate compound (30) containing a polymerizable group, as a reaction catalyst, a commonly known catalyst can be used, and as representative catalysts, acid catalysts such as inorganic acids, esters of phosphoric acid or boric acid, p-toluenesulfonic acid; amine catalysts such as triethylamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine, N,N'-dimethylpiperazine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylhexamethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, hexamethylenetetramine; organometallic compounds or metal chlorides such as cobalt naphthenate, lead naphthenate, zinc naphthenate, stannous chloride, stannic chloride, tri-n-butyltin acetate, iron acetylacetonate, bismuth acetylacetonate, trimethyltin hydroxide, tetraoctyl titanate, dibutyltin dilaurate, tin octoate, cobalt octoate, antimony trichloride, or the like can be cited. These can be used alone or in combination of two or more.

[0057] The amount of the catalyst used can be appropriately determined by the practitioner in accordance with conventional methods. Generally, the amount of the catalyst used is preferably 10 ppm to 5000 ppm, further preferably 50 ppm to 500 ppm, relative to the mass of the monohydroxy-terminated polyoxyalkylene-polysiloxane block copolymer (20), taking into account economic efficiency and the like.

[0058] In the reaction formula [b], since the monohydroxy-terminated polyoxyalkylene-polysiloxane block copolymer of general formula (20) has a high viscosity, the viscosity of the reaction liquid can also be reduced by adding a solvent to allow the reaction to be sufficiently completed. As the reaction solvent, there is no limitation as long as it does not hinder the reaction, and examples include hydrocarbon-based solvents such as hexane and heptane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; ether-based solvents such as diethyl ether, tetrahydrofuran, and dioxane; halogenated hydrocarbon-based solvents such as dichloromethane and carbon tetrachloride; and ester-based solvents such as ethyl acetate. These solvents can be used alone or in combination with two or more. These solvents preferably have as little as possible content of components (water, alcohols, amines, and the like) that react with isocyanate compounds.

[0059] The reaction temperature for the urethane-forming reaction is not particularly limited, and in the case where a solvent is used in the reaction, the reaction temperature is preferably below the boiling point of the solvent. In the case where no solvent is used, the reaction temperature for the urethane-forming reaction is preferably in the range of 0 to 250°C. The reaction temperature for the urethane-forming reaction is preferably in the range of 20 to 100°C, taking into account side reactions of the polymerizable group and the like.

[0060] In addition, a polymerization inhibitor can also be added as needed in the above reaction. As the polymerization inhibitor, a polymerization inhibitor conventionally used for (meth)acrylic compounds can be used. Examples include phenol-based polymerization inhibitors such as hydroquinone, methylhydroquinone (MQ), hydroquinone monomethyl ether (MEHQ), 2-tert-butylhydroquinone, 4-methoxyphenol, and 2,6-di-tert-butyl-4-methylphenol (tert-butylhydroxytoluene, BHT). These polymerization inhibitors can be used alone or in combination with two or more. The amount of the polymerization inhibitor is not particularly limited, and is preferably in the range of 5 to 500 ppm, more preferably in the range of 20 to 200 ppm, relative to the mass of the obtained compound.

[0061] In order to obtain the isocyanate containing a polymerizable group represented by general formula (30) in the reaction formula [b], a method in which a compound A represented by general formula (60) and a compound B represented by general formula (70) are reacted can be exemplified.

[0062]

[0063] wherein R 6 , R 7 , R8 and Z is the same as represented in the general formula (1).

[0064] As the compound A represented by the general formula (60), diisocyanate compounds such as trimethylhexamethylene diisocyanate (TMHMDI), isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HMDI) can be exemplified.

[0065] The compound A represented by the general formula (60) and the compound B represented by the general formula (70) are preferably reacted at a molar fraction A / B = 1 / 1.1 to 1 / 1.6. If the molar fraction of the compound B with respect to 1 mole of the compound A is less than 1.1, it is likely that a large amount of the diisocyanate compound A remains after the reaction, and a dimer of the general formula (20) (a compound in which the compound of the general formula (20) is bonded to both terminals of the compound A) is generated in the reaction represented by the reaction formula [b] and remains as an impurity in the target product. In addition, if the molar fraction of the compound B with respect to 1 mole of the compound A exceeds 1.6, the generation ratio of the compound represented by the general formula (30) decreases, and further, the yield of the target product decreases, which is not economical.

[0066] The other reaction conditions are the same as those in the urethane reaction represented by the reaction formula [b].

[0067] The mono-terminal hydroxyl group-containing polyoxyalkylene-polysiloxane block copolymer represented by the formula (20) can be produced, for example, by the addition reaction (hydrosilylation reaction) of a polyorganosiloxane (40) having a SiH group at a mono-terminal with an alcohol (50) having a mono-terminal hydroxyl group and an alkenyl group, which is represented by the following reaction formula [a].

[0068]

[0069] wherein R 1 , R 2 , R 3 , R 4 , R 5 , n, X, Y, and p are the same as represented in the general formula (1). X' represents an alkenyl group having 2 to 20 carbon atoms.

[0070] As the alkenyl group having 2 to 20 carbon atoms represented by X' in the general formula (50), a vinyl group, a hexenyl group, an octenyl group, and the like can be exemplified. Preferably, X' is an allyl group, a methallyl group, or the like.

[0071] In the above hydrosilylation reaction formula [a], although a reaction solvent is not necessarily required, a suitable solvent can be used as needed without inhibiting the reaction. Specifically, aliphatic hydrocarbon solvents such as hexane and heptane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; ether solvents such as diethyl ether, tetrahydrofuran (THF), and dioxane; halogenated hydrocarbon solvents such as dichloromethane and carbon tetrachloride; alcohol solvents such as methanol, ethanol, and propanol; and water can be exemplified. These solvents can be used alone or in combination of several kinds.

[0072] Although the reaction temperature of the hydrosilylation reaction is not particularly limited, it is generally below the boiling point of the reaction solvent. In the case where no reaction solvent is used, the reaction can be performed at 0 to 250°C, but in view of economy and the like, it is preferable to perform at 20 to 120°C. A reaction catalyst can be used in the hydrosilylation reaction, and as a generally used catalyst, compounds containing platinum, rhodium, iridium, ruthenium, palladium, molybdenum, and manganese can be exemplified. In addition, these catalysts can be used in any one of a so-called homogeneous catalyst system in which the catalyst is dissolved in a solvent, a supported catalyst system in which the catalyst is supported on carbon, silica, or the like, and a catalyst system in which phosphine or amine, potassium acetate, or the like is used as a cocatalyst.

[0073] The alcohol having a terminal hydroxyl group and an alkenyl group (50) can use commercially available allyl glycol, diethylene glycol monoallyl ether, triethylene glycol monoallyl ether, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, and the like.

[0074] For example, in the case of polyethylene glycol monoallyl ether, the following products manufactured by NOF Corporation are shown.

[0075] "UNIOX PKA-5001" (in formula (50), X' is an allyl group, and Y is a polyethylene glycol monoallyl ether having an average molecular weight of 200 of -OCH2CH2-)

[0076] "UNIOX PKA-5002" (in formula (50), X' is an allyl group, and Y is a polyethylene glycol monoallyl ether having an average molecular weight of 400 of -OCH2CH2-)

[0077] In the ultraviolet-curable silicone composition of the present application, the (A) component is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass.

[0078] (B) Photopolymerization initiator

[0079] As the (B) photopolymerization initiator, 2,2-diethoxyacetophenone, 2,2-dimethoxy- 1,2-diphenylethan-l-one (Omnirad 651), l-hydroxy-cyclohexyl-phenyl-ketone (Omnirad 184), 2-hydroxy-2-methyl-l-phenyl-l-propanone (Omnirad 1173), 2-hydroxy-l-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-l-one (Omnirad 127), methyl benzoylformate (Omnirad MBF), 2-methyl-l-[4-(methylthio)phenyl]-2-morpholinopropan-l-one (Omnirad 907), 2-benzyl-2-dimethylamino-l-(4-morpholinophenyl)-l-butanone (Omnirad 369), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad 819), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO H, all manufactured by IGM Resins B.V.), and a mixture of these photopolymerization initiators, and the like can be exemplified.

[0080] Among the above-mentioned component (B), from the viewpoint of compatibility with component (A), 2,2-diethoxyacetophenone, 2-hydroxy-2-methyl-l-phenyl-l-propanone (Omnirad 1173), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad 819), and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO H) are preferred.

[0081] Among the above-mentioned component (B), from the viewpoint of compatibility with component (A), 2-hydroxy-2-methyl-l-phenyl-l-propanone (Omnirad 1173) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO H) are more preferred.

[0082] The blending amount of the photopolymerization initiator is preferably in the range of 0.1 to 50 parts by mass, relative to 100 parts by mass of component (A), from the viewpoint of curability.

[0083] (C) Organopolysiloxane

[0084] In the ultraviolet-curable silicone composition of the present application, an organopolysiloxane represented by the following general formula (2) as component (C) can be further contained as needed. By adding component (C), the hardness of the obtained cured product can be improved.

[0085]

[0086] R in the above general formula (2) 9 are each independently a group selected from monovalent aliphatic hydrocarbon groups having 1 to 10 carbon atoms, acryloyl groups, methacryloyl groups, alkyl acrylate groups, alkyl methacrylate groups, acrylamide groups and methacrylamide groups. As the monovalent aliphatic hydrocarbon groups, monovalent aliphatic hydrocarbon groups having 1 to 8 carbon atoms are preferred, and examples thereof include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl and octyl. Further, monovalent aliphatic hydrocarbon groups having 1 to 6 carbon atoms are further preferred, and among them, R 9 of all of the above are methyl groups.

[0087] Further, at least 2 of R 9 in one molecule of the organopolysiloxane represented by the above general formula (2) are groups selected from acryloyl groups, methacryloyl groups, alkyl acrylate groups, alkyl methacrylate groups, acrylamide groups and methacrylamide groups. As the alkyl acrylate groups, examples include butyl acrylate groups, propyl acrylate groups and the like; and as the alkyl methacrylate groups, examples include butyl methacrylate groups, propyl methacrylate groups and the like. Among the R 9 present in at least 2 of the compounds represented by the above general formula (2), methacryloyl groups, acryloyl groups, propyl acrylate groups and propyl methacrylate groups are preferred, and propyl methacrylate groups, propyl acrylate groups, acrylamide groups and methacrylamide groups are more preferred. They can be the same as or different from each other.

[0088] m in the general formula (2) is a number satisfying 10 < m < 500, preferably a number satisfying 20 < m < 400, and more preferably a number satisfying 30 < m < 300. If m is less than 10, the composition tends to volatilize, and if m is greater than 500, the viscosity of the composition increases, thereby making inkjet ejection difficult. The value of m can be calculated as an average value by, for example, 29 Si-NMR measurement or the like.

[0089] As the organopolysiloxane represented by the above general formula (2), from the viewpoint of ease of synthesis and cost, it is preferred that 1 group selected from the group consisting of propyl methacrylate groups, propyl acrylate groups, acrylamide groups and methacrylamide groups be present at each of the two terminals of one molecule.

[0090] As such an organopolysiloxane, for example, the following compounds can be mentioned.

[0091]

[0092] The amount of the organic polysiloxane of component (C) to be added is preferably in the range of 1 to 300 parts by mass and more preferably in the range of 10 to 200 parts by mass, relative to 100 parts by mass of component (A), in order to keep the viscosity of the composition within a range in which inkjet ejection is possible and to make the hardness of the cured product appropriate.

[0093] (D) Organic Polysiloxane

[0094] In the ultraviolet-curable silicone composition of the present application, an organic polysiloxane represented by General Formula (3) below can also be contained as component (D) as needed. By adding component (D), the hardness of the obtained cured product can be improved.

[0095]

[0096] (In General Formula (3), R 2 , R 3 , R 4 , and R 5 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms or an aryl group-containing group having 6 to 10 carbon atoms; R 6 are each independently a divalent organic group having 2 to 20 carbon atoms; R 7 are each independently an alkylene group having 2 to 20 carbon atoms; R 8 are each independently a hydrogen atom or a methyl group; n is 1 to 500; X is each independently an alkylene group having 2 to 20 carbon atoms; Y is each independently -OCH2CH2-, -OCH(CH3)CH2-, or -OCH2CH(CH3)-; p is each independently a number of 1 or more; and Z is each independently -O- or -NH-.)

[0097] In General Formula (3), R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , n, X, Y, p, and Z can be the same groups exemplified in the above-mentioned component (A).

[0098] As such an organic polysiloxane, for example, the following compounds can be exemplified.

[0099]

[0100] By subjecting, for example, a dihydroxyl-terminated polyoxyalkylene-polysiloxane block copolymer to a urethane reaction with an isocyanate (30) containing a polymerizable group, an organic polysiloxane represented by General Formula (3) can be produced.

[0101] In order to keep the viscosity of the composition within a range capable of inkjet ejection and to form the hardness of the cured product to an appropriate degree, the amount of addition when component (D) is used is preferably in the range of 1 to 300 parts by mass, more preferably in the range of 10 to 200 parts by mass, relative to 100 parts by mass of component (A).

[0102] (E) (Meth)acrylate-containing compound not containing a siloxane structure

[0103] In the ultraviolet-curable silicone composition of the present application, a (meth)acrylate-containing compound not containing a siloxane structure can also be further contained as component (E) as needed. By adding component (E), the viscosity of the composition is reduced, and the viscosity of the composition can be adjusted to a range suitable for inkjet ejection.

[0104] As the monofunctional (meth)acrylate compound not containing a siloxane structure, mention can be made of isopentyl acrylate, lauryl acrylate, stearyl acrylate, ethoxy-diethylene glycol acrylate, methoxy-triethylene glycol acrylate, 2-ethylhexyl-diethylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, and mixtures thereof, with isobornyl acrylate being particularly preferred.

[0105] As the multifunctional (meth)acrylate compound not containing a siloxane structure, mention can be made of triethylene glycol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, bis(hydroxymethyl)-tricyclodecane diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and mixtures thereof, with bis(hydroxymethyl)-tricyclodecane diacrylate being particularly preferred.

[0106] The amount of addition when component (E) is used is preferably in the range of 1 to 500 parts by mass, more preferably in the range of 10 to 400 parts by mass, relative to 100 parts by mass of component (A). If within such a range, the hardness of the obtained cured product can be inhibited from being excessively high.

[0107] Other components

[0108] Within a range that does not impair the effects of the present application, a color material (pigment or dye), a silane coupling agent, an adhesion aid, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, and other additives can also be compounded in the ultraviolet-curable silicone composition of the present application. In addition, the composition of the present application can also be used by being appropriately mixed with other resin compositions.

[0109] Method for producing ultraviolet-curable silicone composition

[0110] The ultraviolet-curable silicone composition of the present application can be obtained by stirring, mixing, or the like of the above-mentioned (A) component, (B) component, and, as necessary, (C) component, (D) component, and (E) component and other components in given amounts. The device used for the stirring or the like is not particularly limited, and a mortar, a three-roll mill, a ball mill, a planetary mixer, or the like can be used. In addition, these devices can be used in combination as appropriate.

[0111] In the ultraviolet-curable silicone composition of the present application, as a standard for inkjet ejection, the kinematic viscosity of the composition at 25°C is preferably 5 to 300 mm 2 / s, more preferably 10 to 200 mm 2 / s. In addition, the surface tension of the composition is preferably 21 mN / m or more and 36 mN / m or less. If within these ranges, stable inkjet ejection can be performed. In order to make the kinematic viscosity and the surface tension of the composition within the above-mentioned ranges, it is necessary to use the (A) component in which n in the above-mentioned formula (1) is 1 to 500. In addition, by adding the (E) component, the kinematic viscosity of the composition can be adjusted.

[0112] The ultraviolet-curable silicone composition of the present application is rapidly cured by irradiation of ultraviolet rays. As a light source for irradiating the ultraviolet rays to the ultraviolet-curable silicone composition of the present application, for example, a UV LED lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a carbon arc lamp, a xenon lamp, or the like can be exemplified. For example, with respect to the composition of the present application shaped into a sheet having a thickness of about 2.0 mm, the amount of irradiation of ultraviolet rays (integrated light amount) is preferably 1 to 5000 mJ / cm 2 , more preferably 10 to 4000 mJ / cm 2 . That is, in the case where ultraviolet rays having an illuminance of 100 mW / cm 2 are used, it is sufficient to irradiate the ultraviolet rays for about 0.01 to 50 seconds.

[0113] In addition, in order to make the cured product formed from the ultraviolet-curable silicone composition of the present application exhibit excellent rubber properties, the hardness after curing (Type A) is preferably 30 or more, more preferably 35 or more. The tensile strength of the cured product is preferably 2.0 MPa or more, more preferably 2.5 MPa or more. The elongation at break of the cured product is preferably 100% or more, more preferably 140% or more. Note that these values are values measured in accordance with the JIS-K6249:2003 standard.

[0114] Example

[0115] Hereinafter, the present application will be specifically described by showing examples and comparative examples, but the present application is not limited to the following examples.

[0116] The composition produced with the composition represented in Table 1 was evaluated.

[0117] Note that, in the following examples, the kinematic viscosity of the composition is a value measured at 25°C using an Ostwald viscometer. The refractive index is a value measured at 25°C using a digital refractometer RX-5000 (manufactured by ATAGO CO., LTD.). The hydroxyl value is a value measured in accordance with the JIS K0070:1992 standard. The surface tension is a value measured using an automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd. In addition, the inkjet ejection property was evaluated using a droplet observation device IJK-200S (1-nozzle inkjet head IJHE-1000 made of glass) of MICROJET Co., Ltd., with the ejection conditions set to a drive voltage of 80 V and a head temperature of 80°C. The condition in which inkjet ejection was possible was evaluated as O, and the condition in which inkjet ejection was not possible was evaluated as X.

[0118] The hardness, elongation at break, and tensile strength of the cured product were measured in accordance with the JIS-K6249:2003 standard. The curing conditions at this time were such that ultraviolet irradiation was performed using a lamp H(M)06-L-61 manufactured by EYE GRAPHICS Co., Ltd., under a nitrogen atmosphere, at an irradiation amount of 4000 mJ / cm 2 The thickness of the sheet was 2.0 mm.

[0119] Each component used in the examples and comparative examples was as described below.

[0120] • (A) Component

[0121] A-1: An organopolysiloxane obtained in Synthetic Example 1 described below

[0122] [Synthetic Example 1]

[0123] 126.8 g of isophorone diisocyanate (IPDI; molecular weight 222) and 0.021 g of ferric acetylacetonate (III) were mixed in a 2 L glass reactor equipped with a stirrer, thermometer, reflux cooler, and dropping funnel. After heating to 30 °C, 104 g of hydroxyethyl methacrylate (HEMA; molecular weight 130) was added dropwise. Once heating was confirmed to be complete, 0.92 g of methylhydroquinone (MQ) and 0.92 g of 2,6-di-tert-butyl-p-cresol (BHT) as polymerization inhibitors were added, and the system was heated to 50 °C and reacted for 1.5 hours. Next, 800 g of single-terminated methanol-modified organosilicon (Shin-Etsu Chemical Industry Co., Ltd. X-22-170DX; hydroxyl value 10) and 0.16 g of bismuth carboxylate were added to the same reactor, and the mixture was heated to 80 °C and reacted for 2 hours. Finally, to deactivate any remaining isocyanate groups, 56 g of HEMA was added, and the reaction was carried out for 1 hour. The resulting reaction solution was cooled to 25°C, and after washing three times with 1080g of methanol to remove low-molecular-weight impurities generated in the side reaction, volatile components were removed by vacuum concentration, resulting in 774g of pale yellow transparent organopolysiloxane A-1 (kinematic viscosity: 419 mm). 2 / s, refractive index: 1.4116). (Will be passed through...) 29 The structure of A-1, as confirmed by Si-NMR measurements, is represented by the following general formula (5).

[0124]

[0125] A-2: Organopolysiloxane represented by the following general formula (10)

[0126]

[0127] • (B) Component

[0128] B-1: 2-Hydroxy-2-methyl-1-phenyl-1-propanone (manufactured by IGM Resins BV, Omnirad 1173).

[0129] B-2: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (manufactured by IGM Resins BV, Omnirad TPO H)

[0130] (C) Components

[0131] C-1: Organopolysiloxane represented by the following general formula (11)

[0132]

[0133] C-2: Organopolysiloxane represented by the following general formula (12)

[0134]

[0135] • (D) component

[0136] D: organic polysiloxane obtained in the following Synthesis Example 2

[0137] [Synthesis Example 2]

[0138] A mixture of 380.4 g of isophorone diisocyanate (IPDI; molecular weight 222) and 0.063 g of acetylacetone iron (III) was placed in a 2 L glass reactor having a stirrer, a thermometer, a reflux cooler, and a dropping funnel, and after heating to 30°C, 312 g of hydroxyethyl methacrylate (HEMA; molecular weight 130) was added dropwise. After confirming that the heat generation had ended, 2.76 g of methylhydroquinone (MQ) and 2.76 g of 2,6-di-tert-butyl-p-cresol (BHT) as a polymerization inhibitor were added, the system was heated to 50°C, and allowed to react for 1.5 hours. Next, 1200 g of a two-terminal methanol-modified silicone (KF-6003 manufactured by Shin-Etsu Chemical Co., Ltd.; hydroxyl value 21) and 0.48 g of bismuth carboxylate were added to the same reactor, and heated to 80°C, and allowed to react for 2 hours. In addition, in order to deactivate the remaining isocyanate groups, 168 g of HEMA was further added, and allowed to react for an additional 1 hour. The resulting reaction liquid was cooled to 25°C, and after washing the low-molecular-weight impurities generated in the side reaction with 2061 g of methanol three times, the volatile components were removed by performing a reduced-pressure concentration, thereby obtaining 758 g of an organic polysiloxane D (kinematic viscosity: 5686 mm 2 / s, refractive index: 1.41447) in a pale yellow transparent state. The structure of D confirmed by Si-NMR measurement is represented by the following general formula (8). 29

[0139]

[0140] • (E) component

[0141] E: isobornyl acrylate (photocurable acrylate IB-XA manufactured by Nippon Shokubai Co., Ltd.)

[0142] [Table 1]

[0143]

[0144] ​As shown in Table 1, the ultraviolet-curable silicone composition of the present application has good inkjet jetting properties, and after curing, shows excellent hardness, tensile strength, and elongation at break, and thus is useful as an ink material for inkjet, particularly as a silicone material for 3D printers using inkjet methods. On the other hand, in Comparative Examples 1 to 4 in which an organic polysiloxane component that does not satisfy the range represented by General Formula (1) is used instead of Component (A), both the hardness and the tensile strength become insufficient.

Claims

1. An ultraviolet-curable silicone composition comprising: (A) a mono-terminal polymeric organopolysiloxane represented by the following general formula (1), In General Formula (1), R 1 , R 2 , R 3 , R 4 , and R 5 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms or an aryl-containing group having 6 to 10 carbon atoms; R 6 is a divalent organic group having 2 to 20 carbon atoms; R 7 is an alkylene group having 2 to 20 carbon atoms; R 8 is a hydrogen atom or a methyl group; n is a number of 1 to 500; X is an alkylene group having 2 to 20 carbon atoms; Y is -OCH2CH2-, -OCH(CH3)CH2-, or -OCH2CH(CH3)-; p is a number of 1 or more; and Z is -O- or -NH-. (B) a photopolymerization initiator, and (C) an organopolysiloxane represented by the following general formula (2), In General Formula (2), R 9 are each independently a group selected from a monovalent aliphatic hydrocarbon group having from 1 to 10 carbon atoms, an acryloyl group, a methacryloyl group, an alkyl acrylate group, an alkyl methacrylate group, an acrylamide group, and a methacrylamide group, but the organopolysiloxane represented by General Formula (2) has at least two groups selected from an acryloyl group, a methacryloyl group, an alkyl acrylate group, an alkyl methacrylate group, an acrylamide group, and a methacrylamide group in one molecule, and m is a number satisfying 10 < m < 500.

2. The ultraviolet-curable silicone composition according to claim 1, In general formula (1), R 1 is n-butyl, R 2 , R 3 , R 4 and R 5 are methyl, R 7 is dimethylene, and Z is -O-.

3. The ultraviolet-curable silicone composition according to claim 1, In general formula (1), R 6 is a divalent residue derived from a diisocyanate selected from the group comprising trimethylhexamethylene diisocyanate (TMHMDI), isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI) and 1,6-hexamethylene diisocyanate (HMDI).

4. The ultraviolet-curable silicone composition according to claim 1, wherein Further, (D) an organopolysiloxane represented by the following general formula (3) is contained, In General Formula (3), R 2 , R 3 , R 4 , and R 5 are each independently a linear alkyl group or a branched alkyl group having 1 to 20 carbon atoms or an aryl group-containing group having 6 to 10 carbon atoms; R 6 are each independently a divalent organic group having 2 to 20 carbon atoms; R 7 are each independently an alkylene group having 2 to 20 carbon atoms; R 8 are each independently a hydrogen atom or a methyl group; n is a number of 1 to 500; X is each independently an alkylene group having 2 to 20 carbon atoms; Y is each independently -OCH2CH2-, -OCH(CH3)CH2-, or -OCH2CH(CH3)-; p is each independently a number of 1 or more; and Z is each independently -O- or -NH-.

5. The ultraviolet-curable silicone composition according to claim 1, wherein Further, (E) a (meth)acrylate-containing compound not containing a siloxane structure is contained.

6. A cured product which is a cured product of the ultraviolet-curable silicone composition according to any one of claims 1 to 5.

7. An ink composition for inkjet, wherein The ultraviolet-curable silicone composition according to any one of claims 1 to 5 is contained.

8. A composition for a 3D printer, wherein The ultraviolet-curable silicone composition according to any one of claims 1 to 5 is contained.

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