JP6384485B2 - Inkjet ink composition for three-dimensional modeling and method for producing three-dimensional modeling - Google Patents

Description

  The present invention relates to an inkjet ink composition for three-dimensional modeling and a method for producing a three-dimensional modeling object.

  In recent years, as a method for producing a three-dimensional structure, a method of irradiating a liquid photocurable composition with laser light or ultraviolet rays to cure and laminate the irradiated portion (see Patent Documents 1 and 2), an inkjet method There is widely known a method (see Patent Documents 3 and 4) in which a photocurable liquid is landed on a base material and the landed liquid is irradiated with ultraviolet rays and cured.

  The method of manufacturing a three-dimensional structure using the inkjet method (hereinafter also referred to as “3D printing”) is more complicated because it can be cured by laminating a photo-curable liquid only at a necessary position as compared with the conventional method. It is easy to form a simple shape. In addition, there is a merit that the amount of use of the modeling material is small, and mechanical characteristics can be easily adjusted by simultaneously emitting a plurality of photocurable liquids having different properties from a plurality of nozzles (see Patent Document 5). Therefore, it is used for various prototype applications. Recently, there is a demand to confirm not only the shape of the prototype but also the function at the prototype stage. In particular, there is a demand for confirming the function of a prototype using a rubber-like material.

  A normal model using a general rubber material can be obtained by crosslinking a very small part of a linear polymer having a molecular weight of 300,000 or more. However, in 3D printing, the photocurable liquid is cured to obtain a cured product, and it is difficult to grow a linear polymer on the cured product. That is, it is difficult to produce a three-dimensional print including a rubber material having sufficient elongation and resilience by 3D printing. Therefore, there has been a demand for an ink-jet ink composition for three-dimensional modeling that can produce a three-dimensional modeled article having elasticity and elasticity like rubber.

JP 62-101408 A Japanese Patent Laid-Open No. 5-24119 JP 2002-067174 A JP 2003-299679 A JP 2010-155926 A

  An object of the present invention is to provide an inkjet ink composition for three-dimensional modeling having a rubber-like elongation and elasticity when cured, and a method for producing a three-dimensional model using the same.

（式（１）において、
Ｒ^１は、ＨもしくはＣＨ_３を表し、
Ｒ^２は、脂環式炭化水素を有する１価の置換基、又は炭素原子数１１〜２２のアルキル基を表す)

（式（２）において、
Ｒ^３はＨもしくはＣＨ_３を表し、
Ｒ^４は炭素原子数６〜１２のアリール基で置換されていてもよい炭素原子数２〜２２のアルキル基、又は炭素原子数６〜１２のアリール基を表し、
ｍは２〜４の整数を表し、
ｎは１または２の整数を表す） The first of the present invention relates to an inkjet ink composition for three-dimensional modeling.
[1] A monofunctional (meth) acrylate containing a compound represented by the general formula (1) or (2) and a polyfunctional monomer having a plurality of polymerizable groups containing carbon-carbon double bonds in the molecule. An inkjet ink composition for three-dimensional modeling, comprising a photocurable reactive compound,
The ratio of the sum of the weight of the compound represented by the general formula (1) and the weight of the compound represented by the general formula (2) to the total mass of the monofunctional (meth) acrylate is 65% by mass or more. Yes,
The molar fraction of the monofunctional (meth) acrylate and the polyfunctional monomer is such that the monofunctional (meth) acrylate / the polyfunctional monomer = 99.9 / 0.1-92 . An inkjet ink composition for three-dimensional modeling that satisfies a relationship of 3 / 7.7 and has a Tg of a cured product of the inkjet ink composition for three-dimensional modeling of less than 25 ° C.

(In Formula (1),
R ¹ represents H or CH ₃
R ² represents a monovalent substituent having an alicyclic hydrocarbon or an alkyl group having 11 to 22 carbon atoms)

(In Formula (2),
R ³ represents H or CH ₃ ,
R ⁴ represents an alkyl group having 2 to 22 carbon atoms which may be substituted with an aryl group having 6 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
m represents an integer of 2 to 4,
n represents an integer of 1 or 2)

[2] The inkjet ink composition for three-dimensional modeling according to [1], which contains 80% by mass or more of the compound represented by the general formula (2) with respect to the total mass of the monofunctional (meth) acrylate.
[3] The three-dimensional structure according to [1], wherein the polymerizable group containing a carbon-carbon double bond of the polyfunctional monomer is a functional group selected from an acrylic group, a methacryl group, a vinyl ether group, and an allyl ether group. Ink jet ink composition.
[4] The inkjet ink composition for three-dimensional modeling according to any one of [1] to [3], further containing a photopolymerization initiator.
[5] The inkjet ink composition for three-dimensional modeling according to [4], wherein the content of the hydrogen abstraction initiator relative to the photopolymerization initiator is 30% by weight or less.
[6] The inkjet ink for three-dimensional modeling according to [1], further including 0.01% by mass to 3.0% by mass of a peeling accelerator with respect to the total mass of the inkjet ink composition for three-dimensional modeling. Composition.
[7] The inkjet ink composition for three-dimensional modeling according to any one of [1] to [6], wherein the viscosity at 25 ° C. is 150 mPa · s or less.

The second of the present invention relates to a method for producing a three-dimensional structure.
[8] A step of discharging the inkjet ink composition for three-dimensional modeling according to any one of [1] to [7] onto a base material or a support material;
Photocuring the ink-jet ink composition for three-dimensional modeling; and
Of manufacturing a three-dimensional structure including
[9] A three-dimensional structure formed using the ink-jet ink composition for three-dimensional structure according to any one of [1] to [7] and a support material. Manufacturing method.

  ADVANTAGE OF THE INVENTION According to this invention, when hardened | cured, the inkjet ink composition for three-dimensional modeling which has elasticity and elasticity like rubber | gum, and the manufacturing method of a three-dimensional molded item using the same are provided.

It is a figure which shows the one aspect | mode of the manufacturing system of a three-dimensional structure. It is a flowchart of the manufacturing method of a three-dimensional structure. It is a figure which shows the 1st process of the manufacturing method of a three-dimensional structure. It is a side view (Drawing 4A) and a top view (Drawing 4B) of a modeling thing in the 2nd process of a manufacturing method of a three-dimensional modeling thing. It is a side view (Drawing 5A) and a top view (Drawing 5B) of a modeling thing in the 3rd process of a manufacturing method of a three-dimensional modeling thing. It is a side view (Drawing 6A) and a top view (Drawing 6B) of a modeling thing in the 4th process of a manufacturing method of a three-dimensional modeling thing. It is a side view (Drawing 7A) and a top view (Drawing 7B) of a modeling thing in the 5th process of a manufacturing method of a three-dimensional modeling thing. It is a perspective view of the three-dimensional structure obtained by the inkjet three-dimensional modeling method.

  Hereinafter, the present invention will be described with reference to embodiments, but the present invention is not limited to the following embodiments.

1. About the three-dimensional modeling ink-jet ink composition The three-dimensional modeling ink-jet ink composition (ink composition) according to the embodiment contains a photocurable reactive compound and, if necessary, a photopolymerization initiator.

1-1. About the photocurable reactive compound The photocurable reactive compound contained in the ink composition includes a monofunctional (meth) acrylate and a polyfunctional monomer having a plurality of polymerizable groups containing carbon-carbon double bonds in the molecule. , Containing. The photocurable reactive compound may further contain other photocurable reactive compounds as necessary. “(Meth) acrylate” refers to acrylate monomer and / or acrylate oligomer, methacrylate monomer and / or methacrylate oligomer.

1-1-1. Monofunctional (meth) acrylate Monofunctional (meth) acrylate refers to a compound having one (meth) acrylate group. At least a part of the monofunctional (meth) acrylate contained in the inkjet ink composition is preferably a compound represented by the general formula (1) or (2).

In the formula (1), R ¹ represents H or CH ₃ . In Formula (1), R ² represents a monovalent substituent having an alicyclic hydrocarbon or an alkyl group having 11 to 22 carbon atoms.

  Examples of monovalent substituents having an alicyclic hydrocarbon include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, and a t-butylcyclohexyl group; a bridged lipid such as an adamantyl group, an isobornyl group, and a dicyclopentanyl group. A cyclic hydrocarbon group and the like are included.

  The alkyl group having 11 to 22 carbon atoms may be linear or branched.

式（２）において、Ｒ^３はＨもしくはＣＨ_３を表す。式（２）において、Ｒ^４は、炭素原子数６〜１２のアリール基で置換されていてもよい炭素原子数２〜２２のアルキル基、又は炭素原子数６〜１２のアリール基を表す。ｍは２〜４の整数を表す。ｎは１または２の整数を表す。Examples of the compound represented by the general formula (1) include dodecyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, isomyristyl (meth) acrylate, and isostearyl (meth). Examples include acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

In the formula (2), R ³ represents H or CH ₃ . In the formula (2), R ⁴ represents an alkyl group having 2 to 22 carbon atoms which may be substituted with an aryl group having 6 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms. m represents an integer of 2 to 4. n represents an integer of 1 or 2.

  Examples of the alkyl group having 2 to 22 carbon atoms which may be substituted with an aryl group having 6 to 12 carbon atoms include ethyl group, propyl group, butyl group, hexyl group, dodecyl group, stearyl group and the like. It is.

  Examples of the aryl group having 6 to 12 carbon atoms include phenyl group, tolyl group, ethylphenyl group, xylyl group, naphthyl group and the like.

  Examples of the compound represented by the general formula (2) include phenoxyethyl (meth) acrylate, tolyloxyethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, ethoxyethoxy acrylate, naphthylethoxy acrylate, ethoxybutoxybutoxy acrylate , Ethoxydiethylene glycol (meth) acrylate, and the like.

  The compound represented by the general formula (1) or (2) is a monofunctional monomer that gives a linear high molecular weight polymer by photopolymerization. Compared with thermal polymerization, the photopolymerization generates a large amount of radicals in a short time, and therefore the radical concentration becomes high. When the radical concentration is high, in addition to the growth reaction of the polymer, graft polymerization by hydrogen abstraction occurs, resulting in unnecessary crosslinking, resulting in a marked decrease in strength as a rubber. Moreover, it is a well-known fact that in photopolymerization, oxygen inhibition inhibits high molecular weight production. The compound of general formula (1) or (2) solves this problem. A polymerized product having a low degree of polymerization of the compound represented by the general formula (1) or (2) is also likely to increase the viscosity of the composition, and thus has less influence on oxygen inhibition. In particular, having an ethylene oxide chain tends to increase the viscosity of the composition. In addition, in a monofunctional monomer having a bulky substituent, a graft reaction hardly occurs due to steric hindrance. Therefore, a monofunctional monomer having such a substituent easily obtains a linear polymer. As a result, the three-dimensional structure produced using the compound represented by the general formula (1) or (2) and the polyfunctional monomer is considered to have obtained a cured product excellent in elongation and strength.

  The inkjet ink composition may contain “another monofunctional (meth) acrylate” other than the monomers represented by the general formulas (1) and (2). Examples of other monofunctional (meth) acrylates include isoamyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2-butoxyethyl (meth) acrylate , 2-hydroxybutyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, methoxyethoxyethoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate , 2-hydroxypropyl (meth) acrylate and the like.

1-1-2. About a polyfunctional monomer A polyfunctional monomer means the polyfunctional monomer which has two or more polymeric groups containing a carbon-carbon double bond in a molecule | numerator. The polymerizable group containing a carbon-carbon double bond refers to a polymerizable group selected from a (meth) acryl group, a vinyl ether group, an allyl ether group, a styrene group, and a (meth) acrylamide group. A plurality of polymerizable functional groups contained in one molecule may be the same as or different from each other.

  Among these, the polyfunctional monomer is preferably a polyfunctional monomer having a polymerizable functional group selected from an acrylic group, a methacryl group, a vinyl ether group, and an allyl ether group. This is because the photopolymerization sensitivity of the polyfunctional monomer is good.

  Moreover, the inkjet ink composition may contain a plurality of types of polyfunctional monomers having different structures.

  More specifically, preferable examples of the polyfunctional monomer contained in the inkjet ink composition include polyfunctional (meth) acrylate, polyfunctional vinyl ether, polyfunctional allyl ether, and the like.

Examples of polyfunctional (meth) acrylates include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di ( (Meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol -Tricyclodecane di (meth) acrylate, PO adduct di (meth) acrylate of bisphenol A, neopentyl glycol di (meth) acrylate of hydroxypivalate, polytetramethylene glycol di (meth) Difunctional monomers acrylate;
Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin propoxytri (meth) acrylate And trifunctional or higher polyfunctional monomers such as pentaerythritol ethoxytetra (meth) acrylate.

  Further, the polyfunctional (meth) acrylate may be urethane acrylate.

  The polyfunctional (meth) acrylate may be a modified product. Examples of modified products include ethylene oxide-modified (meth) acrylate compounds such as ethylene oxide-modified trimethylolpropane tri (meth) acrylate and ethylene oxide-modified pentaerythritol tetraacrylate; caprolactone such as caprolactone-modified trimethylolpropane tri (meth) acrylate Modified (meth) acrylate compounds; and caprolactam-modified (meth) acrylate compounds such as caprolactam-modified dipentaerythritol hexa (meth) acrylate.

  The polyfunctional vinyl ether may be difunctional, trifunctional, tetrafunctional or higher.

  Examples of bifunctional vinyl ethers include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol vinyl ether, butylene divinyl ether, dibutylene glycol divinyl ether, neopentyl glycol divinyl ether, cyclohexane Examples include diol divinyl ether, cyclohexane dimethanol divinyl ether, norbornyl dimethanol divinyl ether, isovinyl divinyl ether, divinyl resorcin, and divinyl hydroquinone.

  Examples of trifunctional vinyl ethers include glycerin trivinyl ether, glycerin ethylene oxide adduct trivinyl ether (ethylene oxide addition mole number 6), trimethylolpropane trivinyl ether, trivinyl ether ethylene oxide adduct trivinyl ether (ethylene oxide addition mole number 3), and the like. included. Examples of tetra- or higher functional vinyl ether compounds include pentaerythritol trivinyl ether, ditrimethylolpropane hexavinyl ether, and oxyethylene adducts thereof.

  The polyfunctional allyl ether may be difunctional, trifunctional or higher.

  Examples of the bifunctional allyl ether include 1,4-cyclohexanedimethanol diallyl ether, alkylene (2 to 5 carbon atoms) glycol diallyl ether, and polyethylene glycol (weight average molecular weight: 100 to 4000) diallyl ether. Further, glyceryl diallyl ether, trimethylolpropane diallyl ether, pentaerythritol diallyl ether, polyglycerol (degree of polymerization 2 to 5) diallyl ether and the like are included.

  Examples of trifunctional or higher functional allyl ethers include trimethylolpropane triallyl ether, glyceryl triallyl ether, pentaerythritol tetraallyl ether, and tetraallyloxyethane. Also included are pentaerythritol triallyl ether, diglycerol triallyl ether, sorbitol triallyl ether, polyglycerol (degree of polymerization 3 to 13) polyallyl ether, and the like.

1-1-3. About other photocurable reactive compounds The photocurable reactive compounds contained in the inkjet ink composition include monofunctional (meth) acrylates and polyfunctional monomers having a plurality of carbon-carbon double bonds in the molecule, “Other photocurable reactive compounds” may be included. Examples of other photocurable reactive compounds include monofunctional monomers other than monofunctional (meth) acrylates.

  The monofunctional monomer may be a compound having a monovalent radical polymerizable group. Examples of radically polymerizable groups include ethylene groups (vinyl ether groups, allyl ether groups, styrene groups, (meth) acrylamide groups, acetyl vinyl groups, vinyl amide groups), acetylene groups, and the like.

  Examples of monofunctional monomers having a vinyl ether group include butyl vinyl ether, butyl propenyl ether, butyl butenyl ether, hexyl vinyl ether, ethyl hexyl vinyl ether, phenyl vinyl ether, benzyl vinyl ether, ethyl ethoxy vinyl ether, acetyl ethoxy ethoxy vinyl ether, cyclohexyl vinyl ether, adamantyl vinyl ether Etc. are included.

  Examples of monofunctional monomers having an allyl ether group include phenyl allyl ether, o-, m-, p-cresol monoallyl ether, biphenyl-2-ol monoallyl ether, biphenyl-4-ol monoallyl ether, butyl allyl Ether, cyclohexyl allyl ether, cyclohexane methanol monoallyl ether and the like are included.

  Examples of the monofunctional monomer having an acetyl vinyl group include vinyl acetate.

  Examples of the monofunctional monomer having a (meth) acrylamide group include acrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, and methacrylamide.

  Examples of the monofunctional monomer having a vinylamide group include N-vinyl-ε-caprolactam, N-vinylformamide, N-vinylpyrrolidone and the like.

  Examples of the monofunctional monomer having an acetylene group include acetylene. The monofunctional monomer is not limited to those described above.

1-1-4. About composition of photocurable reactive compound The molar fraction of monofunctional (meth) acrylate and polyfunctional monomer contained in the ink-jet ink composition is monofunctional (meth) acrylate / polyfunctional monomer = 99.9 / 0.1. Satisfies the relationship of ~ 92/8. By setting the molar fraction of the monofunctional monomer and the polyfunctional monomer to 99.9 / 0.1 to 92/8, when the ink jet ink is irradiated with light to cause a polymerization reaction, the monofunctional monomer becomes a linear polymer. And the polyfunctional monomer acts as a crosslinking agent between the linear polymers, and the linear polymers can be appropriately crosslinked. Therefore, the crosslinked body (cured product) produced by the polymerization reaction has high elongation and becomes a rubber-like substance.

  While adjusting the cross-link density by adjusting the quantitative ratio of monofunctional (meth) acrylate and polyfunctional monomer, the elongation increases by lowering the cross-linking rate; on the other hand, the cured product is easily plastically deformed, It became clear that it became a hardened | cured material with low resilience. Therefore, the ratio of the compound represented by the general formula (1) or (2) in the monofunctional (meth) acrylate contained in the ink composition is 65% by mass or more (preferably 80% by mass or more). Thus, it was found that a cured product having excellent elongation and strength can be obtained.

  Moreover, it is preferable that content of the monomer represented by General formula (2) with respect to the total mass of the monofunctional (meth) acrylate contained in an inkjet ink composition is 80 mass% or more. This is because the higher the content of the monomer represented by the general formula (2), the higher the breaking strength and the higher the breaking elongation.

1-2. About Photopolymerization Initiator etc. The inkjet ink composition may further contain a photopolymerization initiator. Specifically, when the actinic ray is an electron beam, a photopolymerization initiator may ordinarily not be included. However, when the actinic ray is an ultraviolet ray, a photopolymerization initiator is preferably contained.

  Photopolymerization initiators include a cleavage type and a hydrogen abstraction type. The inkjet ink composition of the present invention preferably contains at least a cleavage type photopolymerization initiator. That is, the inkjet ink composition of the present invention may contain (a) both a cleavage type and a hydrogen abstraction type photopolymerization initiator, and (b) contains only a cleavage type photopolymerization initiator. May be. What is necessary is just to use properly the aspect of the photoinitiator used for an inkjet ink composition according to a desired effect.

  When the ink-jet ink composition contains both (a) a cleavage type and a hydrogen abstraction type, it is preferable to have a large amount of a cleavage type initiator as a mass ratio. The ratio of the hydrogen abstraction type initiator in the photopolymerization initiator is preferably 30% by mass or less.

  When both the cleavage type and the hydrogen abstraction type photopolymerization initiators are contained in the inkjet ink composition, the curing rate of the inkjet ink composition is increased. Although the reason for this is not clear, it is considered that when a photopolymerization initiator of a cleavage type and a hydrogen abstraction type coexist, the hydrogen abstraction type initiator plays a role as a sensitizer and the curing rate is improved. This is important in 3D modeling printing, which takes much longer time than normal printing.

  When the ink-jet ink composition contains only (b) a cleavage type photopolymerization initiator (no hydrogen abstraction type initiator), (a) both the cleavage type and the hydrogen abstraction type Compared to the case of having a photopolymerization initiator, the stretchability or elasticity of the cured product of the ink composition may be improved. The reason for this is not clear, but can be considered as follows. When a graft reaction occurs between linear polymers obtained by polymerization of monofunctional monomers with a hydrogen abstraction type initiator, irregular crosslinking may occur. If the cross-linking is regular, a uniform force is applied when the cured product is stretched, so that high stretchability can be maintained. However, if there are irregular crosslinks in the cured product, stress is concentrated at specific sites in the composition when the cured product is stretched. For this reason, it is considered that the elongation or elasticity is lowered because the cross-linked sites or the linear polymer chains are broken.

  Therefore, when it is required to increase the production speed of the three-dimensional structure, it is preferable that the ink-jet ink composition contains (a) both a cleavage type and a hydrogen abstraction type photopolymerization initiator. On the other hand, when emphasizing the durability of the cured product, the inkjet ink composition contains (b) a cleavage-type photopolymerization initiator only (substantially does not contain a hydrogen abstraction type photopolymerization initiator). It is preferable.

  Examples of the cleavage type photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy- 2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino (4-thiomethyl) Acetophenones such as phenyl) propan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone; benzoins such as benzoin, benzoin methyl ether and benzoin isopropyl ether; Such as 6-trimethylbenzoindiphenylphosphine oxide Sill phosphine oxide system; such as benzyl and methyl phenylglyoxylate esters include.

  Examples of hydrogen abstraction type photopolymerization initiators include benzophenone, methyl-4-phenylbenzophenone o-benzoylbenzoate, 4,4′-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, Benzophenone series such as acrylated benzophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 3,3′-dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2,4-dimethyl Thioxanthone series such as thioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone; Aminobenzophenone series such as Mihira-ketone, 4,4′-diethylaminobenzophenone; 10-butyl-2-chloroacridone, 2-ethylacetate Surakinon, 9,10-phenanthrenequinone, include camphorquinone, and the like.

  The content of the photopolymerization initiator in the ink-jet ink composition is preferably 0.01% by mass to 10% by mass, although it depends on the type of actinic ray or actinic ray curable compound.

  The ink-jet ink composition may further contain a photopolymerization initiator auxiliary agent, a polymerization inhibitor, and the like as necessary. The photopolymerization initiator assistant may be a tertiary amine compound, preferably an aromatic tertiary amine compound. Examples of aromatic tertiary amine compounds include N, N-dimethylaniline, N, N-diethylaniline, N, N-dimethyl-p-toluidine, N, N-dimethylamino-p-benzoic acid ethyl ester, N, N-dimethylamino-p-benzoic acid isoamyl ethyl ester, N, N-dihydroxyethylaniline, triethylamine, N, N-dimethylhexylamine and the like are included. Of these, N, N-dimethylamino-p-benzoic acid ethyl ester and N, N-dimethylamino-p-benzoic acid isoamyl ethyl ester are preferred. Only one kind of these compounds may be contained in the actinic ray curable inkjet ink composition, or two or more kinds thereof may be contained.

  Examples of polymerization inhibitors include (alkyl) phenol, hydroquinone, catechol, resorcin, p-methoxyphenol, t-butylcatechol, t-butylhydroquinone, pyrogallol, 1,1-picrylhydrazyl, phenothiazine, p-benzoquinone , Nitrosobenzene, 2,5-di-t-butyl-p-benzoquinone, dithiobenzoyl disulfide, picric acid, cupron, aluminum N-nitrosophenylhydroxylamine, tri-p-nitrophenylmethyl, N- (3-oxyanilino- 1,3-dimethylbutylidene) aniline oxide, dibutylcresol, cyclohexanone oxime cresol, guaiacol, o-isopropylphenol, butyraloxime, methyl ethyl ketoxime, cyclohexanone oxime, etc. It is included.

1-3. Peeling accelerator The inkjet ink composition may further contain a peeling accelerator. The peeling accelerator is preferably contained in an amount of 0.01% by mass to 3.0% by mass with respect to the total mass of the ink. If it is less than 0.01% by mass, the releasability from the substrate is lowered, and if it exceeds 3.0% by mass, the ink composition droplets before curing are likely to coalesce, which may cause ink bleeding. is there.

  Examples of the release accelerator include silicon surfactants, fluorine surfactants, and higher fatty acid esters such as stearyl sebacate, with silicon surfactants being preferred.

  The peeling accelerator may be contained in the inkjet ink composition; however, it may be contained in the composition for a support material described later, and more preferably in both of them. This is to make it easier to separate the cured product from the support agent.

1-4. Characteristics of Inkjet Ink Composition for Three-Dimensional Modeling The inkjet ink composition of the present invention is applied by an inkjet method. Therefore, from the viewpoint of ejection performance from the inkjet head, the viscosity of the inkjet ink composition at 25 ° C. is preferably 150 mPa · s or less. The viscosity of the ink composition can be measured with a rotational viscometer.

  The cured product of the inkjet ink composition of the present invention preferably has a glass transition temperature of less than 25 ° C, preferably less than 0 ° C. This is because a cured product having a glass transition temperature of less than 25 ° C. becomes a rubber-like substance and the elongation at break increases. The glass transition temperature of the cured product can be determined by DSC measurement.

1-5. Use of inkjet ink composition for three-dimensional modeling The inkjet ink composition of the present invention is used for the production of a three-dimensional modeling object. The inkjet ink composition is applied to a substrate using an inkjet method, and the inkjet ink composition landed on the substrate is irradiated with actinic rays and cured. By repeating application and curing, a three-dimensional structure is manufactured. Thus, the ink-jet ink composition is used as a “model material” for producing a three-dimensional structure.

  The inkjet ink composition of the present invention is cured by being irradiated with actinic rays. The actinic ray is, for example, ultraviolet rays or electron beams.

When the actinic ray is an ultraviolet ray, examples of the actinic ray irradiation unit (ultraviolet irradiation means) include a fluorescent tube (low pressure mercury lamp, germicidal lamp), a cold cathode tube, an ultraviolet laser, and an operating pressure of several hundreds Pa to 1 MPa. Low pressure, medium pressure, high pressure mercury lamp, metal halide lamp, LED and the like are included. From the viewpoint of curability, ultraviolet irradiation means for irradiating ultraviolet rays having an illuminance of 100 mW / cm ² or more; specifically, high-pressure mercury lamps, metal halide lamps, and LEDs are preferable, and LEDs are more preferable from the viewpoint of low power consumption. Specifically, a 395 nm, water-cooled LED manufactured by Phoseon Technology can be used.

  When the active light beam is an electron beam, examples of the active light beam irradiation unit (electron beam irradiation unit) include electron beam irradiation units such as a scanning method, a curtain beam method, and a broad beam method. From the viewpoint of processing capability, a curtain beam type electron beam irradiation means is preferable. Examples of the electron beam irradiation means include “Curetron EBC-200-20-30” manufactured by Nissin High Voltage Co., Ltd., “Min-EB” manufactured by AIT Co., Ltd., and the like.

  When the actinic ray is an electron beam, the acceleration voltage for electron beam irradiation is preferably 30 to 250 kV and more preferably 30 to 100 kV in order to perform sufficient curing. When the acceleration voltage is 100 to 250 kV, the electron beam irradiation amount is preferably 30 to 100 kGy, and more preferably 30 to 60 kGy.

2. Manufacture of a three-dimensional structure by the inkjet method A method of manufacturing a three-dimensional structure by the ink-jet method includes a step of discharging the above-described ink-jet ink composition for three-dimensional structure onto a substrate or a support material, and an ink-jet for three-dimensional structure And a step of photocuring the ink composition. Particularly preferred is a method of producing a three-dimensional structure while printing the above-described ink-jet ink composition for three-dimensional modeling and the ink-jet ink composition for a support material by inkjet.

2-1. Inkjet three-dimensional modeling system and apparatus As described above, the inkjet ink composition of the present invention is used as a model material for producing a three-dimensional modeled object using an inkjet method. An example of a system and apparatus for manufacturing a three-dimensional structure will be described below.

  The three-dimensional structure can be manufactured by a method using a model material and a support material. Specifically, a space portion of a three-dimensional structure to be manufactured is formed by discharging a support material by an ink jet method. Next, the model material is ejected by inkjet onto the support material to form a three-dimensional structure. Then, a three-dimensional structure can be obtained by removing the cured product of the support material that constitutes the space portion.

  The support material is not particularly limited, but is preferably a heat-meltable material, or a photocurable material whose water-soluble product is water-soluble or water-swellable. Moreover, it is preferable that the hardened | cured material of a support material and the hardened | cured material of a model material are easy to peel.

  Examples of heat-meltable materials include paraffin wax, microcrystalline wax, carnauba wax, ester wax, amide wax, PEG 20000 and other waxes. What is photocurable and the cured product is water-soluble or water-swellable is, for example, a water-soluble compound (water-soluble monomer) having a photopolymerizable functional group (carbon-carbon unsaturated group, etc.) And a photo-curable resin composition mainly composed of a photocleavable initiator and water, but is not particularly limited. The support material may further contain a water-soluble polymer.

  Examples of water-soluble monomers contained in the support material include water-soluble (meth) acrylate, polyoxyethylene diacrylate, polyoxypropylene diacrylate, achloroyl morpholine, hydroxyalkyl acrylate; water-soluble acrylamides such as acrylamide, N, N-dimethylacrylamide, N-hydroxyethylacrylamide and the like are included. Examples of the water-soluble polymer contained in the support material include polyethylene glycol, polypropylene glycol, polyvinyl alcohol and the like. Examples of the photocleavable initiator included in the support material include 1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propan-1-one, but are not particularly limited.

  FIG. 1 shows an outline of an example of an inkjet three-dimensional modeling system. The inkjet three-dimensional modeling system shown in FIG. 1 includes a driving means (not shown) for driving up and down (drawing Z direction), and a stage 11 on which a three-dimensional modeling object is arranged, and is movable left and right (drawing XY direction). And an inkjet 12 that ejects an inkjet ink composition for a model material and a support material, which is disposed on a rail (not shown).

  The ink jet 12 includes a model material ink jet head 13, a support material ink jet head 14, a film thickness adjusting roller 15, and a light source 16. The model material inkjet head 13 communicates with a pump 13b and an inkjet ink composition tank 13c via a pipe 13a. The support material inkjet head 14 communicates with a pump 14b and an inkjet ink composition tank 14c via a pipe 14a.

  As shown in FIG. 1, the inkjet three-dimensional modeling system is further converted from the calculation control unit 2, an input device 4 for inputting three-dimensional modeling data such as CAD (Computer Aided Design) data, and CAD data. To produce an output device 5 that outputs STL (Stereo Lithography) data and slice data obtained from the STL data, a display device 6 that displays STL data, a virtual three-dimensional structure, and the like, and a three-dimensional structure For example, a lot number, a CAD data number, an STL data number, an inkjet ink composition set number, and the like are stored in association with each other.

  The calculation control unit 2 includes an STL calculation unit 21 that calculates STL data based on CAD data, and an inkjet ink composition set control unit that sends information to select an inkjet ink composition set that matches a desired three-dimensional structure. 22, stage control means 23 for sending information for driving the stage, ink-jet control means 24 for sending information for ejecting the ink jet ink composition for model material or support material, and polishing the layer to a desired thickness It comprises roller control means 25 for sending information, and UV light source control means 26 for sending information to irradiate light to cure the ejected ink-jet ink composition.

  The arithmetic control unit 2 may be configured by an arithmetic device used in a normal computer system such as a CPU. Examples of the input device 4 include pointing devices such as a keyboard and a mouse. Examples of the output device 5 include a printer. Examples of the display device 6 include an image display device such as a liquid crystal display and a monitor. As the storage device 3, a storage device such as a ROM, a RAM, or a magnetic disk can be used.

2-2. Manufacturing Flow of Three-Dimensional Modeling by Inkjet Method An inkjet three-dimensional modeling method using the inkjet three-dimensional modeling system shown in FIG. 1 will be described in detail with reference to the flowchart of FIG.

  (A) In step S101, for example, CAD data is input. In step S102, the CAD data is converted into STL data as three-dimensional modeling data. Note that a virtual three-dimensional structure (virtual model material) formed from the STL data is displayed on the monitor to check whether a desired shape is formed. If the desired shape is not formed, the STL data Modifications may be made to.

  (B) In step S103, as shown in FIG. 3, the virtual three-dimensional structure is subdivided into a plurality of lamellar layers in the Z direction in FIG. 3, and “first plane data D1, second plane data D2” is obtained. ,... X-th plane data DX ”. In each plane data, support material arrangement data for supporting or fixing the model material is also created. This is because the support material is disposed around the model material in the X and Y directions, so that a so-called overhang portion, for example, the second image portion of the letter “K” is supported from below by the support material.

  (C) In step S105, based on the data of the virtual three-dimensional structure and the plurality of plane data, the optimum ink-jet ink composition for model material and the ink-jet ink composition for support material are prepared.

  (D) In step S108, based on the first plane data D1, the driving means is operated to perform relative alignment between the stage and the inkjet.

  (E) In step S110, as shown in FIG. 4, the position of the ink jet is controlled based on the first plane data D1, and the ink jet ink composition for the model material and the ink jet for the support material are placed at appropriate positions on the stage. Either one of the ink compositions is ejected to form the first film. The amount of droplets ejected from each nozzle is preferably 1 pl to 70 pl, more preferably 2 to 50 pl, although it depends on the resolution of the image. Thereafter, in step S112, the first film is obtained by light irradiation to obtain a first layer. Note that it is preferable to check whether or not the thickness of the first layer is uniform, and if it is not uniform, the thick portion is polished to make the thickness of the first layer uniform. In addition, it is preferable that the thickness of each layer after hardening is about 1-25 micrometers.

  (F) In step S114, the process returns to step S108 prior to the formation of the second layer, and the position of the stage 11 is moved downward (Z direction) by the thickness of the first layer as shown in FIG. Let Thereafter, similarly to the first layer, the second layer is formed on the first layer by steps S110 and S112. Then, as shown in FIGS. 6 and 7, the steps S108, S110, and S112 are repeated to stack a plurality of layers until the final layer (Xth layer) is stacked.

  (G) In step S116, the support material is removed. For example, the support material is removed by swelling with water. In combination with this removal step, the support material may be removed from the model material by performing another removal step, for example, spraying high-pressure water on the support material.

  By the above, the three-dimensional structure M as shown in FIG. 8 can be produced.

[Modification of Embodiment]
In the embodiment, one example of the inkjet nozzle for the model material is shown, but the number of inkjet nozzles for the model material is not limited to one. For example, two inkjet nozzles may be provided for a model material, and model materials having different physical properties may be simultaneously discharged from each nozzle, and the model materials may be mixed to form a composite material.

  An ink-jet ink composition for three-dimensional modeling, which is a model material, was prepared using the following materials.

Monofunctional (meth) acrylate represented by formula (1) Isobornyl acrylate: molecular weight 208.3, viscosity 10.7 mPa · s, glass transition temperature 94 ° C. when polymer is used
Dicyclopentanyl acrylate: molecular weight 204.26, viscosity 7-17 mPa · s, glass transition temperature 120 ° C. when polymerized
n-lauryl acrylate: molecular weight 240.38, viscosity 6 mPa · s, glass transition temperature -30 ° C. when polymerized
Isodecyl acrylate: molecular weight 212.33, viscosity 5 mPa · s, glass transition temperature -60 ° C. when polymerized
Isostearyl acrylate: molecular weight 324.54, viscosity 18 mPa · s, glass transition temperature -18 ° C. when polymerized

Monofunctional (meth) acrylate represented by formula (2): Phenoxyethyl acrylate: molecular weight 192.21, viscosity 12 mPa · s, glass transition temperature -22 ° C. when polymerized
Phenoxyethoxyethyl acrylate: molecular weight 236.26, viscosity 13 mPa · s, glass transition temperature -25 ° C. when polymerized
Ethoxyethoxyethyl acrylate: molecular weight 188.22, viscosity 2.9 mPa · s, glass transition temperature −54 ° C. when polymerized

Other monofunctional (meth) acrylate tetrafurfuryl acrylate: molecular weight 156.18, viscosity 2.8 mPa · s, glass transition temperature −12 ° C. when polymerized
Benzyl acrylate: molecular weight 162.19, viscosity 8 mPa · s, glass transition temperature 6 ° C. when polymerized
Methoxyethoxyethyl acrylate: molecular weight 218.25, viscosity 5 mPa · s, glass transition temperature -50 ° C. when polymerized

Multifunctional monomer 1,6-hexanediol diacrylate: molecular weight 226.27
1,9-nonanediol diacrylate: molecular weight 268.35
Diethylene glycol divinyl ether: molecular weight 158.19
Diethylene glycol diallyl ether: molecular weight 186.25
Urethane acrylate (CN962 Sartamar Co.): Molecular weight 12000

Open photoinitiator
Darocure 1173: 2-Hydroxy-2-methyl-1-phenyl-propan-1-one
TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

Hydrogen abstraction type photoinitiator benzophenone
DETX: 2,4-diethylthioxanthen-9-one

Exfoliation accelerator Silicone surfactant (TSF-4442 manufactured by Shin-Etsu Chemical Co., Ltd.)

[Example 1] Preparation of model material (inkjet ink composition for three-dimensional modeling) As monofunctional (meth) acrylate, 30 g (156.1 mmol) of phenoxyethyl acrylate, 50 g (211.6 mmol) of phenoxyethoxyethyl acrylate, 20.0 g (91.6 mmol) of methoxyethoxyethoxyethyl acrylate, 5.0 g (22.1 mmol) of 1,6-hexanediol diacrylate as a polyfunctional (bifunctional) monomer, and 1.0 g of TPO as a photoinitiator Then, 0.2 g of a silicon surfactant as a peeling accelerator was mixed and dissolved to obtain a model material of Sample 1.

  The total molar amount of monofunctional (meth) acrylate contained in the model material of Sample 1 is 459.3 mmol, and the total molar amount of the polyfunctional monomer is 22.1 mmol. The molar ratio between them (monofunctional (meth) acrylate / polyfunctional monomer) is 95.4 / 4.6.

  The viscosity of the obtained model material was measured using a rotational viscometer according to JIS Z8803.

  The model materials of Sample 2 to Sample 24 were prepared in the same manner as Sample 1 by changing to the component compositions shown in Tables 1 to 4.

Preparation of photocurable composition for support material 40 g of polyoxyethylene (n≈9) diacrylate, 60 g of water, 5 g of photoinitiator irgacure 2959 ′ (manufactured by BASF), and silicon surfactant (TSF-4442) 0 0.1 g was mixed and dissolved to obtain a support material.

Manufacture of three-dimensional structure The support layer was formed on the polyethylene terephthalate film by discharging the photocurable composition for the support material using an inkjet head KM512MH manufactured by Konica Minolta IJ. Specifically, the amount of droplets per dot was 14 pl, and the droplets were emitted at 720 dpi × 720 dpi. The landing droplet was irradiated with light having a light amount of 400 ml / cm ² with a high-pressure mercury lamp and cured, and a support layer having a thickness of 10 cm × 2 cm and a thickness of 1 mm was formed.

  On the formed support layer, a model layer having a thickness of 10 cm × 2 cm and a thickness of 1 mm was formed using the photocuring composition for a model material in the same manner as the support layer. Next, the three-dimensional structure (cured film) was obtained by separating the model layer from the polyethylene terephthalate film and the support layer by immersing the laminate of the support layer and the model layer in water.

  The glass transition temperature of the obtained three-dimensional structure (cured film) was measured by DSC (differential scanning calorimetry).

Evaluation of the breaking elongation and breaking strength of the cured product The breaking elongation and breaking strength of the three-dimensional structure (cured film) are stretched by applying a certain load to the three-dimensional structure (tensile speed of 500 mm / min) and breaking. It calculated | required as a rate (breaking elongation) and a load (breaking strength) at the time of fracture.

Measurement of photocuring sensitivity On the polyethylene terephthalate film, the photocurable composition for model material was discharged using the same inkjet head as when the three-dimensional structure was obtained. The impacted droplets were irradiated with light of 100 to 800 mJ / cm ² only once with a high-pressure mercury lamp, and then the presence or absence of curing was confirmed by palpation.
◎ was cured at 200mJ / cm ² less than the amount of light.
○ It was cured with a light intensity of ^{200 to} less than 400 mJ / cm2.
Δ Cured with a light amount of 400 to 800 mJ / cm ² .

Inkjet ejection property evaluation It was visually confirmed whether or not streaks were formed on the three-dimensional structure (cured film). The formation of the streaks suggests that the model material composition was not properly ejected from the inkjet head, resulting in lack of ejection.
○: No muscle is observed at all.
Δ: Slight streaks are observed.
X: Muscle is recognized.

  Regarding the ratio of the monofunctional (meth) acrylate and the polyfunctional monomer, the sample 9 in which the ratio of the polyfunctional monomer is too large has a low elongation at break and does not have sufficient rubber properties. Sample 2 and sample 18 in which the ratio of the compounds represented by the general formulas (1) and (2) to the monofunctional (meth) acrylate is low have a low breaking strength.

  Samples 20 to 22 containing an open-row photoinitiator (TPO) and a hydrogen abstraction type photoinitiator (DETX) are more sensitive to photocuring than sample 19 without a hydrogen abstraction type photoinitiator. On the other hand, it can be seen that the rubber properties are slightly lowered.

  This application claims priority based on Japanese Patent Application No. 2013-214530, which is a Japanese application filed on October 15, 2013. The contents described in the application specification and the drawings are all incorporated herein.

The inkjet ink composition of the present invention can be used as a model material for producing a three-dimensional structure.

Claims (9)

A photocurable type comprising a monofunctional (meth) acrylate containing a compound represented by the general formula (1) or (2) and a polyfunctional monomer having a plurality of polymerizable groups containing carbon-carbon double bonds in the molecule. An inkjet ink composition for three-dimensional modeling containing a reactive compound,
The ratio of the sum of the weight of the compound represented by the general formula (1) and the weight of the compound represented by the general formula (2) to the total mass of the monofunctional (meth) acrylate is 65% by mass or more. Yes,
The molar fraction of the monofunctional (meth) acrylate and the polyfunctional monomer is such that the monofunctional (meth) acrylate / the polyfunctional monomer = 99.9 / 0.1-92 . 3 / 7.7 The inkjet ink composition for three-dimensional modeling which satisfy | fills the relationship used as 3 / 7.7 , and the glass transition temperature of the hardened | cured material of the inkjet ink composition for three-dimensional modeling is less than 25 degreeC.

(In Formula (1),
R ¹ represents H or CH ₃
R ² represents a monovalent substituent having an alicyclic hydrocarbon, or an alkyl group having 11 to 22 carbon atoms)

(In Formula (2),
R ³ represents H or CH ₃
R ⁴ represents an alkyl group having 2 to 22 carbon atoms which may be substituted with an aryl group having 6 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
m represents an integer of 2 to 4,
n represents an integer of 1 or 2)   The inkjet ink composition for three-dimensional modeling of Claim 1 which contains 80 mass% or more of compounds represented by the said General formula (2) with respect to the total mass of the said monofunctional (meth) acrylate.   The inkjet ink for three-dimensional modeling according to claim 1, wherein the polymerizable group containing a carbon-carbon double bond of the polyfunctional monomer is a functional group selected from an acryl group, a methacryl group, a vinyl ether group, and an allyl ether group. Composition.   The inkjet ink composition for three-dimensional modeling according to any one of claims 1 to 3, further comprising a photopolymerization initiator.   The inkjet ink composition for three-dimensional modeling according to claim 4, wherein the content of the hydrogen abstraction type initiator with respect to the photopolymerization initiator is 30% by weight or less.   The inkjet ink composition for three-dimensional modeling according to claim 1, further comprising 0.01% by mass to 3.0% by mass of a release accelerator based on the total mass of the inkjet ink composition for three-dimensional modeling.   The inkjet ink composition for three-dimensional modeling according to any one of claims 1 to 6, wherein the viscosity at 25 ° C is 150 mPa · s or less. Discharging the inkjet ink composition for three-dimensional modeling according to any one of claims 1 to 7 onto a base material or a support material;
Photocuring the ink-jet ink composition for three-dimensional modeling; and
Of manufacturing a three-dimensional structure including   A method for producing a three-dimensional structure, wherein the three-dimensional structure is formed using the ink-jet ink composition for three-dimensional structure according to any one of claims 1 to 7 and a support material.

Images