JP2016196134A - Radiation-curable binder and production method of three-dimensional molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-curable binder having a low viscosity, which can give a three-dimensional molded object excellent in tensile strength and tensile elongation, and to provide a production method of a three-dimensional molded object.SOLUTION: The radiation-curable binder is used for a production method of a three-dimensional molded object, including: a deposition step of depositing a radiation-curable binder on a base material comprising particles; and a binding step of binding the particles by the radiation-curable binder to form a three-dimensional molded object. The radiation-curable binder comprises a monofunctional monomer and a difunctional monomer, in which the total content of the monofunctional monomer and the difunctional monomer is 70 mass% or more with respect to the total amount of the radiation-curable binder, and the content of the difunctional monomer is 40 to 60 mass% with respect to the total amount of the monofunctional monomer and the difunctional monomer.SELECTED DRAWING: None

Description

  The present invention relates to a radiation curable binder and a method for producing a three-dimensional structure.

  The ink jet recording method is capable of recording high-definition images with a relatively simple device, and has been rapidly developed in various fields. Among them, various studies have been made on a method for producing a three-dimensional three-dimensional structure using an inkjet method. For example, Patent Document 1 discloses that a powder material is applied to a layer having a predetermined thickness on a support for the purpose of providing a method for producing a three-dimensional structure that has good dischargeability and excellent curability. In the method of manufacturing a three-dimensional structure, including a step of forming and a step of sequentially repeating a step of bonding the powder material layer with a radiation curable binder so as to have a cross-sectional shape obtained by cutting the object to be formed in parallel, 25 A method for producing a three-dimensional structure in which the viscosity of the radiation curable binder at 5 ° C. is 5 to 100 mPa · s is disclosed.

JP 2005-67138 A

  In such a three-dimensional structure, physical properties peculiar to the three-dimensional structure such as tensile strength and tensile elongation are required as compared with a two-dimensional recorded object. However, the three-dimensional structure obtained by the method described in Patent Document 1 is inferior in the balance between the tensile strength and the tensile elongation, and has a practical problem. Further, the radiation curable binder described in Patent Document 1 has a relatively high viscosity.

  The present invention has been made in order to solve at least a part of the above-described problems, and a radiation curable binder and a three-dimensional object capable of providing a three-dimensional structure having a low viscosity and excellent tensile strength and tensile elongation. It aims at providing the manufacturing method of a molded article.

  The present inventors diligently studied to solve the above problems. As a result, it has been found that the above-mentioned problems can be solved by containing a predetermined amount of a predetermined monomer, and the present invention has been completed.

That is, the present invention is as follows.
[1]
An adhesion step of attaching a radiation curable binder to a base material containing particles, and a binding step of binding the particles with the radiation curable binder to form a three-dimensional object. The radiation curable binder used in the method for producing a three-dimensional structure,
The radiation curable binder contains a monofunctional monomer and a bifunctional monomer,
The total content of the monofunctional monomer and the bifunctional monomer is 70% by mass or more based on the total amount of the radiation curable binder,
The content of the bifunctional monomer is 40 to 60% by mass with respect to the total amount of the monofunctional monomer and the bifunctional monomer.
Radiation curable binder.
[2]
The monofunctional monomer includes a monomer that gives a homopolymer having a glass transition point of 50 ° C. or lower,
The bifunctional monomer includes a monomer that gives a homopolymer having a glass transition point of 30 ° C. or higher.
The radiation curable binder according to [1] above.
[3]
The monofunctional monomer has a monofunctional (meth) acrylate having an aromatic group, a monofunctional (meth) acrylate having a hydroxyl group, a monofunctional (meth) acrylate having a cyclic ether group, and a (meth) cyclic aliphatic group. Including at least one selected from the group consisting of acrylates,
The radiation curable binder according to [1] or [2] above.
[4]
The bifunctional monomer includes at least one selected from the group consisting of (meth) acrylate having a vinyl ether group, polyalkylene glycol di (meth) acrylate, and alkyldiol di (meth) acrylate,
The radiation curable binder according to any one of [1] to [3] above.
[5]
The base material is a paste-type base material further containing a solvent;
The radiation curable binder according to any one of [1] to [4] above.
[6]
The particles comprise an inorganic powder;
The radiation curable binder according to any one of [1] to [5] above.
[7]
Further comprising a trifunctional or higher monomer and a polymerizable compound having a molecular weight of 500 or higher,
The total content of the tri- or higher functional monomer and the polymerizable compound is 20% by mass or less based on the total amount of the radiation curable binder.
The radiation curable binder according to any one of [1] to [6] above.
[8]
The radiation curable binder according to any one of [1] to [7] above, wherein in the attaching step, the radiation curable binder is ejected by an ink jet method to adhere to the base material.
[9]
The radiation curable binder according to any one of [1] to [8], wherein the method for producing the three-dimensional structure is performed by a lamination method.
[10]
A base material comprising particles;
The radiation curable binder according to any one of [1] to [9] above,
Modeling material set.
[11]
An attachment step of attaching the radiation curable binder according to any one of [1] to [9] above to a base material containing particles;
Binding the particles by the radiation curable binder to form a three-dimensional model, and
Manufacturing method of a three-dimensional molded item.

It is a 1st schematic diagram which shows each process of the manufacturing method of the three-dimensional molded item of this embodiment. It is a 2nd schematic diagram which shows each process of the manufacturing method of the three-dimensional molded item of this embodiment.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to this, and the gist thereof is described below. Various modifications are possible without departing from the scope. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, positional relationships such as up, down, left and right are based on the positional relationships shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. In the present specification, “(meth) acrylate” means both acrylate and the corresponding methacrylate.

[Radiation curable binder]
The radiation curable binder of the present embodiment includes an adhesion process in which a radiation curable binder is attached to a base material containing particles, and the particles are bound by the radiation curable binder to form a three-dimensional model. The radiation curable binder used in the method of manufacturing a three-dimensional structure, wherein the radiation curable binder comprises a monofunctional monomer and a bifunctional monomer. And the total content of the monofunctional monomer and the bifunctional monomer is 70% by mass or more based on the total amount of the radiation curable binder, and the content of the bifunctional monomer is the monofunctional monomer. And it is 40-60 mass% with respect to the total amount of the said bifunctional monomer.

  As one of the methods for forming a three-dimensional structure, a radiation curable binder is attached to a base material containing particles, the attached radiation curable binder is cured, and an uncured portion is removed. There exists a method of manufacturing the three-dimensional molded item which has arbitrary shapes. In this method, the composition of the base material and the radiation curable binder affects the physical properties of the resulting three-dimensional model. For example, from the viewpoint of increasing the hardness of the resulting three-dimensional structure, it is conceivable to use a polyfunctional polymerizable compound in the radiation curable binder. However, since the three-dimensional model obtained in this case is inferior in tensile strength, the practicality may be limited when the three-dimensional model is to be used for some purpose. Moreover, when there are many functional groups, there also exists a problem that a crack arises in the three-dimensional molded item obtained by shrinkage | contraction at the time of hardening. Furthermore, depending on the type of polymerizable compound used, the viscosity of the binder is increased. This increase in viscosity not only makes it difficult to eject the binder by the ink jet method, but also the binder to the base material. As a result, the mechanical properties of the resulting three-dimensional structure may be reduced.

  On the other hand, the radiation curable binder of the present embodiment uses a predetermined amount of monofunctional monomer and bifunctional monomer to improve the binding force while keeping the viscosity low, thereby increasing the tensile strength and tensile elongation. An excellent 3D object can be obtained. Hereinafter, each component position of the radiation curable binder will be described.

[Use]
The radiation curable binder of the present embodiment is used in a method for producing a three-dimensional structure, and can be particularly suitably used for a laminating method. The “lamination method” is an adhesion process in which a radiation curable binder is attached to a base material containing particles, and particles are bound by a radiation curable binder to form a layer in a given direction of a three-dimensional structure. It is a manufacturing method of a three-dimensional modeled object in which a three-dimensional modeled object is formed by repeatedly performing a binding step of layer formation and laminating layers. The detail of the manufacturing method of a three-dimensional molded item is mentioned later.

[Monofunctional monomer]
The monofunctional monomer is not particularly limited as long as it is a compound having one polymerizable functional group. The polymerizable functional group is not particularly limited. For example, (meth) acryloyl group, (meth) acrylamide group, styryl group, conjugated polyene group, maleate group, fumarate group, maleimide group, itaconic acid residue, vinyl ketone group, Anionic polymerizable groups such as vinyl halide groups, vinyl cyanide groups, cyano (meth) acrylate groups, vinyl nitrate groups, and epoxy groups; cationic polymerizable groups such as styryl groups, epoxy groups, vinyl ether groups, and oxetane groups And radical polymerizable groups such as (meth) acryloyl group, (meth) acrylamide group, (meth) allyl group, styryl group and maleimide group. These polymerizable functional groups can be polymerized by a photopolymerization initiator. Among these, a (meth) acryloyl group is preferable. By using such a monofunctional monomer, the tensile elongation of the resulting three-dimensional structure tends to be further improved.

  The functional group other than the polymerizable functional group possessed by the monofunctional monomer is not particularly limited, and examples thereof include an aromatic group, a hydroxyl group, a cyclic ether group, a linear ether group, a cyclic aliphatic group, a linear aliphatic group, and a branched group. Aliphatic groups are mentioned. Among these, the monofunctional monomer has a monofunctional (meth) acrylate having an aromatic group, a monofunctional (meth) acrylate having a hydroxyl group, a monofunctional (meth) acrylate having a cyclic ether group, and a cyclic aliphatic group. It is preferable to include at least one selected from the group consisting of (meth) acrylates, and monofunctional (meth) acrylates having aromatic groups, monofunctional (meth) acrylates having hydroxyl groups, and monofunctionals having cyclic ether groups ( More preferably, it contains at least one selected from the group consisting of (meth) acrylates. By using such a monofunctional monomer, the tensile elongation of the resulting three-dimensional structure tends to be further improved.

  In addition, although it does not specifically limit as monofunctional (meth) acrylate which has an aromatic group, For example, the compound which has 6-10 carbon atoms other than a (meth) acrylate group, the compound which has a phenyl group as an aromatic group, A compound in which at least one of the hydrogen atoms of the aromatic group is substituted with a linear or branched alkyl group is preferred.

  Moreover, it does not specifically limit as monofunctional (meth) acrylate which has a hydroxyl group, For example, the compound which has a saturated hydrocarbon group which has a hydroxyl group, a C1-C7 saturated hydrocarbon group, substitution other than a hydroxyl group A compound having a linear or branched saturated hydrocarbon group which may be substituted with a group is preferred.

  Although it does not specifically limit as monofunctional (meth) acrylate which has a cyclic ether group, For example, the compound which has a C3-C9 cyclic ether and the compound which has a C1-C2 cyclic ether group are preferable.

  The (meth) acrylate having a cycloaliphatic group is not particularly limited. For example, a compound having a 5- or 6-membered cyclic aliphatic group, a compound having 5 to 13 carbon atoms other than the (meth) acrylate group Is preferred.

  The monofunctional monomer is preferably a monomer that gives a homopolymer having a predetermined glass transition point. The glass transition point of a homopolymer composed of a monofunctional monomer is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, still more preferably 50 ° C. or lower, still more preferably 30 ° C. or lower, More preferably, it is 10 degrees C or less, Especially preferably, it is 0 degrees C or less. When the glass transition point of the homopolymer composed of a monofunctional monomer is 100 ° C. or lower, the tensile elongation of the resulting three-dimensional structure tends to be further improved. Moreover, the glass transition point of the homopolymer which consists of a monofunctional monomer becomes like this. Preferably it is -50 degreeC or more, More preferably, it is -30 degreeC or more. When the glass transition point of the homopolymer composed of the monofunctional monomer is −50 ° C. or higher, the tensile strength of the resulting three-dimensional structure tends to be further improved. Tg can be obtained by the DSC method.

  The homopolymer having a glass transition point of 50 ° C. or lower is not particularly limited. For example, 2-ethylhexyl acrylate homopolymer (Tg: −70 ° C.), 2-ethylhexyl methacrylate homopolymer (Tg: −10 ° C.), 2-hydroxy Ethyl acrylate homopolymer (Tg: −15 ° C.), 2-hydroxybutyl acrylate homopolymer (Tg: −7 ° C.), 2-hydroxybutyl methacrylate homopolymer (Tg: 26 ° C.), 2-methoxyethyl acrylate homopolymer (Tg) : -50 ° C), 4-hydroxybutyl acrylate homopolymer (Tg: -80 ° C), iso-octyl methacrylate homopolymer (Tg: -45 ° C), iso-butyl acrylate homopolymer (Tg: 43 ° C), iso- Propyl acrylate homo Limer (Tg: -3 ° C), N, N-diethylaminoethyl methacrylate homopolymer (Tg: 20 ° C), N, N-dimethylaminoethyl acrylate homopolymer (Tg: 18 ° C), N, N-dimethylaminoethyl methacrylate Homopolymer (Tg: 18 ° C), n-butyl acrylate homopolymer (Tg: -54 ° C), tert-butyl acrylate homopolymer (Tg: 43 ° C), tert-butyl methacrylate homopolymer (Tg: 20 ° C), isoamyl Acrylate homopolymer (Tg: -45 ° C), isobutyl acrylate homopolymer (Tg: -26 ° C), isobutyl methacrylate homopolymer (Tg: 48 ° C), ethyl acrylate homopolymer (Tg: -22 ° C to -24 ° C) , Ethyl carbitol acrylate Mopolymer (Tg: -67 ° C), ethoxyethyl acrylate homopolymer (Tg: -50 ° C), ethoxyethyl methacrylate homopolymer (Tg: 15 ° C), ethoxydiethylene glycol acrylate homopolymer (Tg: -70 ° C), octyl acrylate homo Polymer (Tg: -65 ° C), iso-octyl acrylate homopolymer (Tg: -70 ° C), cyclohexyl acrylate homopolymer (Tg: 15 ° C to 19 ° C), stearyl acrylate homopolymer (Tg: 35 ° C), tertiary Butyl acrylate homopolymer (Tg: 41 ° C), tetradecyl acrylate homopolymer (Tg: 24 ° C), tetradecyl methacrylate homopolymer (Tg: -72 ° C), tetrahydrofurfuryl acrylate homopolymer ( Tg: -12 ° C), phenoxyethyl acrylate homopolymer (Tg: -22 ° C), butyl acrylate homopolymer (Tg: -56 ° C), butyl methacrylate homopolymer (Tg: 20 ° C), propyl acrylate homopolymer (Tg: 3 ° C), propyl methacrylate homopolymer (Tg: 35 ° C), hexadecyl acrylate homopolymer (Tg: 35 ° C), hexadecyl methacrylate homopolymer (Tg: 15 ° C), hexyl acrylate homopolymer (Tg: -57 ° C) Hexyl methacrylate homopolymer (Tg: -5 ° C, benzyl acrylate homopolymer (Tg: 6 ° C), pentyl acrylate homopolymer (Tg: 22 ° C), pentyl methacrylate homopolymer (Tg: -5 ° C), carboxyethyl acrylate Homopolymer (Tg: 37 ° C), methyl acrylate homopolymer (Tg: 8 ° C), methoxyethyl acrylate homopolymer (Tg: -50 ° C), methoxy methacrylate homopolymer (Tg: -16 ° C), lauryl acrylate homopolymer ( Tg: 10 ° C.), lauryl methacrylate homopolymer (Tg: −65 ° C.), and vinyl acetate homopolymer (Tg: 32 ° C.). Tg is not limited to the above because it may vary depending on the homopolymer production method and stereoregularity.

  The content of the monofunctional monomer is preferably 30 to 60% by mass, more preferably 35 to 55% by mass, and further preferably 40 to 50% by mass with respect to the total amount of the radiation curable binder. is there. When the content of the monofunctional monomer is 30% by mass or more, the tensile elongation of the three-dimensional structure to be obtained tends to be further improved. Moreover, it exists in the tendency which the tensile strength of the three-dimensional molded item obtained improves more because content of a monofunctional monomer is 60 mass% or less.

[Bifunctional monomer]
The bifunctional monomer is not particularly limited as long as it is a compound having two polymerizable functional groups. Examples of the polymerizable functional group include those described above. Among these, a (meth) acryloyl group is preferable. By using such a bifunctional monomer, the tensile strength of the resulting three-dimensional structure tends to be further improved. The two polymerizable functional groups may be the same or different from each other, but are preferably the same from the viewpoint of production suitability.

  The functional group other than the polymerizable functional group possessed by the bifunctional monomer is not particularly limited. For example, an aromatic group, a hydroxyl group, a cyclic ether group, a linear ether group, a cyclic aliphatic group, a linear aliphatic group, a branched group. Aliphatic groups are mentioned. Among these, the bifunctional monomer preferably contains at least one selected from the group consisting of (meth) acrylates having a vinyl ether group, polyalkylene glycol di (meth) acrylates, and alkyldiol di (meth) acrylates. By using such a bifunctional monomer, the tensile strength of the resulting three-dimensional structure tends to be further improved.

  In addition, although it does not specifically limit as (meth) acrylate which has a vinyl ether group, For example, the compound which has 2-10 carbon atoms other than a (meth) acrylate group, and the compound which has an alkylene glycol residue are preferable.

  Although it does not specifically limit as polyalkylene glycol di (meth) acrylate, For example, the compound which has 2-5 repeating number of alkylene glycol residues, and the compound which has C2-C6 alkylene glycol residue are preferable.

  Although it does not specifically limit as alkyldiol di (meth) acrylate, For example, the compound which has a C2-C9 alkyldiol residue is preferable.

  Further, the bifunctional monomer is preferably a monomer that gives a homopolymer having a predetermined glass transition point. The glass transition point of a homopolymer composed of a bifunctional monomer is preferably 10 ° C. or higher, more preferably 30 ° C. or higher, still more preferably 40 ° C. or higher, still more preferably 50 ° C. or higher, More preferably, it is 80 ° C. or higher. When the glass transition point of the homopolymer composed of the bifunctional monomer is 10 ° C. or higher, the tensile strength of the resulting three-dimensional structure tends to be further improved. Moreover, the glass transition point of the homopolymer consisting of a bifunctional monomer is preferably 150 ° C. or lower, more preferably 120 ° C. or lower, and further preferably 110 ° C. or lower. When the glass transition point of the homopolymer composed of the bifunctional monomer is 150 ° C. or lower, the tensile elongation of the resulting three-dimensional structure tends to be further improved. Tg can be obtained by the DSC method.

  The homopolymer having a glass transition point of 30 ° C. or higher is not particularly limited. For example, dipropylene glycol diacrylate homopolymer (Tg: 104 ° C.), 2- (2-vinyloxyethoxy) ethyl acrylate homopolymer (Tg: 39 ° C.) and 1,6-hexanediol diacrylate homopolymer (Tg: 43 ° C.). Tg is not limited to the above because it may vary depending on the homopolymer production method and stereoregularity.

  In particular, the tensile strength and tensile strength of the three-dimensional structure obtained by using a monofunctional monomer that gives a homopolymer having a glass transition point of 50 ° C. or lower and a bifunctional monomer that gives a homopolymer having a glass transition point of 30 ° C. or higher in combination. The elongation tends to be improved more together.

  The content of the bifunctional monomer is preferably 20 to 65% by mass, more preferably 25 to 60% by mass, and further preferably 30 to 55% by mass with respect to the total amount of the radiation curable binder. is there. When the content of the bifunctional monomer is 20% by mass or more, the tensile strength of the obtained three-dimensional model tends to be further improved. Moreover, it exists in the tendency which the tensile elongation of the three-dimensional molded item obtained improves more because content of a bifunctional monomer is 60 mass% or less.

  The total content of the monofunctional monomer and the bifunctional monomer is 70% by mass or more, preferably 75-97.5% by mass, more preferably 80%, based on the total amount of the radiation curable binder. It is -95 mass%. When the total content of the monofunctional monomer and the bifunctional monomer is 70% by mass or more, the viscosity tends to be further reduced.

  Furthermore, the content of the bifunctional monomer is 40 to 60% by mass, preferably 42.5 to 57.6% by mass, and more preferably 45 to 5% by mass with respect to the total amount of the monofunctional monomer and the bifunctional monomer. It is 57.6 mass%. When the content of the bifunctional monomer is within the above range, the tensile strength and the tensile elongation of the resulting three-dimensional structure are both improved.

[Trifunctional or higher monomer]
The radiation curable binder of this embodiment may further contain a trifunctional or higher functional monomer. The trifunctional or higher monomer is not particularly limited as long as it is a compound having three or more polymerizable functional groups. Examples of the polymerizable functional group include those described above. The polymerizable functional groups may be the same or different from each other, but are preferably the same from the viewpoint of production suitability. In addition, the functional group other than the polymerizable functional group of the trifunctional monomer is not particularly limited. For example, an aromatic group, a hydroxyl group, a cyclic ether group, a linear ether group, a cyclic aliphatic group, and a linear aliphatic group. And branched aliphatic groups.

  The content of the trifunctional or higher monomer is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, and still more preferably 0 to 5% by mass with respect to the total amount of the radiation curable binder. 0% by mass. When the content of the trifunctional or higher monomer is 20% by mass or less, the tensile elongation of the resulting three-dimensional model tends to be further improved. Moreover, it can also suppress that a crack and hardening shrinkage generate | occur | produce at the time of hardening.

[Polymerizable compound having a molecular weight of 500 or more]
The radiation curable binder of the present embodiment may further contain a polymerizable compound having a molecular weight of 500 or more. The polymerizable compound having a molecular weight of 500 or more is not particularly limited, and examples thereof include oligomers having a polymerizable functional group and polymers having a polymerizable functional group. In this embodiment, “monomer” means a monomer having a weight average molecular weight of less than 500. The term “oligomer” means a multimer having a weight average molecular weight of 500 or more and less than 5000. Further, “polymer” means a multimer having a weight average molecular weight of 5000 or more.

  Although the molecular weight of the polymeric compound of molecular weight 500 or more is not specifically limited, Preferably it is 500-5000, More preferably, it is 500-2000.

  The content of the polymerizable compound having a molecular weight of 500 or more is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, further preferably 0 to 0% by mass with respect to the total amount of the radiation curable binder. 5.0% by mass. When the content of the polymerizable compound having a molecular weight of 500 or more is 20% by mass or less, the viscosity tends to be further reduced.

  The total content of the trifunctional or higher monomer and the polymerizable compound having a molecular weight of 500 or higher is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, based on the total amount of the radiation curable binder. Yes, more preferably 0 to 10% by mass, and even more preferably 0 to 3.0% by mass. When the total content of the trifunctional or higher functional monomer and the polymerizable compound having a molecular weight of 500 or higher is within the above range, the tensile elongation of the resulting three-dimensional structure tends to be further improved, or the viscosity can be reduced. it can.

(Polymerization inhibitor)
The radiation curable binder of this embodiment may further contain a polymerization inhibitor. Although it does not specifically limit as a polymerization inhibitor, For example, hydroquinones represented by hydroquinone, hydroquinone monomethyl ether (MEHQ), 1-o-2,3,5-trimethylhydroquinone, 2-tert-butylhydroquinone; Catechols typified by 4-methylcatechol and 4-tert-butylcatechol; phenol, butylhydroxytoluene, butylhydroxyanisole, p-methoxyphenol, cresol, pyrogallol, 3,5-di-t-butyl-4-hydroxy Toluene, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-butylphenol), and 4,4′-thiobis (3-methyl-6- Phenol represented by t-butylphenol) A compound having a 2,2,6,6-tetramethylpiperidine-N-oxyl skeleton represented by 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl, 2,2 , 6,6-Tetramethylpiperidine skeleton compound, 2,2,6,6-tetramethylpiperidine-N-alkyl skeleton compound, and 2,2,6,6-tetramethylpiperidine-N-acyl skeleton Hindered amines represented by the compound having In addition, a polymerization inhibitor may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the polymerization inhibitor is preferably 0.050 to 0.50% by mass, more preferably 0.10 to 0.30% by mass, based on the total amount of the radiation curable binder. Preferably it is 0.15-0.25 mass%. When the content of the polymerization inhibitor is within the above range, the storage stability of the radiation curable binder and the curability of the particles tend to be further improved while maintaining the curability.

[Surfactant]
The radiation curable binder of this embodiment may further contain a surfactant. The surfactant is not particularly limited, and examples thereof include acetylene glycol surfactants, fluorine surfactants, and silicone surfactants. Of these, silicone surfactants are preferred from the viewpoint of wettability to particles.

  Although it does not specifically limit as a silicone type surfactant, For example, it does not specifically limit as a commercial item of surfactant, For example, BYK UV3500, UV3570, BYK350 (BIC Chemie Japan company brand name) is mentioned.

  The content of the surfactant is preferably 0.10 to 1.25% by mass, more preferably 0.20 to 1.0% by mass, with respect to the total amount of the radiation curable binder. Preferably it is 0.25-0.75 mass%. When the content of the surfactant is within the above range, the wettability of the radiation curable binder to the particles is further improved, and as a result, the binding properties of the particles tend to be further improved.

(Polymerization initiator)
The radiation curable binder of this embodiment may further contain a polymerization initiator. The polymerization initiator is not particularly limited. For example, aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, Examples thereof include azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds. Of these, acylphosphine compounds are preferred. By using such a polymerization initiator, since the internal curability is excellent, the binding property of the particles tends to be further improved, and curing with an inexpensive LED light source becomes possible.

  Although it does not specifically limit as a commercial item of a polymerization initiator, For example, IRGACURE 651 (2,2-dimethoxy-1,2-diphenylethane-1-one), IRGACURE 184 (1-hydroxy-cyclohexyl-phenyl-ketone) DAROCUR 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 2959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1 -Propan-1-one), IRGACURE 127 (2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl] -2-methyl-propan-1-one} IRGACURE 907 (2-methyl-1- (4-methylthiophenyl)- -Morpholinopropan-1-one), IRGACURE 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2- [ (4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), DAROCUR TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 784 (bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole) -1-yl) -phenyl) titanium), IRGACURE OXE 01 (1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), IRGACURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methyl) Benzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime)), IRGACURE 754 (oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester mixture (above, manufactured by Ciba Japan KK), KAYACURE DETX-S (2,4-diethylthioxanthone) (Nippon Chemical Co., Ltd. (Nippon) Kayaku Co. , Ltd., Ltd. ), Lucirin TPO, LR 8893, LR 8970 (above, manufactured by BASF), Speedcure TPO (above, made by Lambson) and Ubekrill P36 (made by UCB). A polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the polymerization initiator is preferably 2.5 to 12.5% by mass, more preferably 5.0 to 10% by mass, and still more preferably based on the total amount of the radiation curable binder. It is 7.5-9.0 mass%. When the content of the polymerization initiator is within the above range, the binding property of the particles tends to be further improved.

[Modeling material set]
The modeling material set of the present embodiment includes a base material containing particles and the radiation curable binder. The components that can be included in the base material will be described in detail later. By using such a modeling material set, it is possible to obtain a three-dimensional modeled object that has an excellent balance between tensile elongation and tensile strength.

[Method for producing three-dimensional model]
The manufacturing method of the three-dimensional structure according to the present embodiment includes an attachment step in which the radiation curable binder is attached to a base material containing particles, and the particles are bound by the radiation curable binder, thereby forming a three-dimensional structure. A binding step for forming an object.

  Hereinafter, each step will be described. FIG.1 and FIG.2 is a schematic diagram which shows each process of the manufacturing method of the three-dimensional molded item of this embodiment.

[Layer formation process]
The manufacturing method of the three-dimensional molded item of this embodiment may have a layer formation process which forms the layer 1 containing a base material before an adhesion process (1a, 1d). The layer forming method is not particularly limited, and examples thereof include a squeegee method, a screen printing method, a doctor blade method, and a spin coating method. Moreover, formation of the layer 1 may be performed on the support body 9, or may be performed on the three-dimensional molded item already formed partially.

  The thickness of the layer 1 to be formed is preferably 10 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less. Thereby, while making the productivity of the three-dimensional structure 100 sufficiently excellent, the occurrence of unintentional unevenness in the three-dimensional structure 100 to be manufactured is more effectively prevented, and the dimensional accuracy of the three-dimensional structure 100 is improved. It can be made particularly excellent.

[Drying process]
The manufacturing method of the three-dimensional molded item of this embodiment may have a drying process which heat-drys the layer 1 obtained by the layer formation process (1a, 1d). In the case where the base material contains a binder resin, the particles can be bonded (temporarily fixed) by the drying step to effectively prevent unintentional scattering of the particles. When the base material contains a solvent, at least a part of the solvent contained in the base material can be removed by a drying process. By removing the solvent, the strength of the coating film after curing tends to be improved because there are few uncured substances compared to the case of performing the adhesion step and the binding step without removing the solvent, There is a tendency that the penetration of the ink into the voids is further improved.

  The heating temperature in the drying step is preferably not less than the glass transition temperature of the binder resin, more preferably not less than 30 ° C and not more than 140 ° C, and further preferably not less than 40 ° C and not more than 120 ° C.

[Adhesion process]
The attaching step is a step of attaching the radiation curable binder 2 to the base material (layer 1) containing particles (1b, 1e). The attachment method is not particularly limited. For example, a method in which a radiation curable binder is ejected by an inkjet method and adhered to a base material containing particles; a particle is obtained by spraying a radiation curable binder with a spray or the like. The method of making it adhere to the base material containing is mentioned. Among these, it is preferable to use an inkjet system from the viewpoint of the accuracy of the three-dimensional structure to be obtained. As the inkjet method, a piezo method, a method in which a radiation curable binder is ejected by bubbles generated by heating the radiation curable binder, or the like can be used. By using an inkjet system, a three-dimensional model with higher accuracy can be obtained. The base material to which the radiation curable binder is attached later becomes a three-dimensional model.

[Base material]
The base material contains particles, and may contain other components such as a binder resin and a solvent as necessary. In the present embodiment, the base material may be in the form of a powder or a paste containing a solvent. In particular, the paste-type base material tends to prevent the particles from scattering, and the device reliability tends to be further improved.

(particle)
Particles can be broadly classified into inorganic particles and organic particles. Hereinafter, each is illustrated.

  Although it does not specifically limit as inorganic particle, For example, metal oxides, such as a silica, an alumina, a titanium oxide, a zinc oxide, a zircon oxide, a tin oxide, magnesium oxide, potassium titanate; Magnesium hydroxide, aluminum hydroxide, hydroxylation Metal hydroxides such as calcium; metal nitrides such as silicon nitride, titanium nitride, and aluminum nitride; metal carbides such as silicon carbide and titanium carbide; metal sulfides such as zinc sulfide; carbonates of metals such as calcium carbonate and magnesium carbonate Salt: Metal sulfate such as calcium sulfate and magnesium sulfate; Metal silicate such as calcium silicate and magnesium silicate; Metal phosphate such as calcium phosphate; Metal borate such as aluminum borate and magnesium borate Examples thereof include acid salts and composites thereof.

  Further, the organic particles are not particularly limited, but examples thereof include polyethylene resin; polypropylene; polyethylene oxide; polypropylene oxide, polyethyleneimine; polystyrene; polyurethane; polyurea; polyester; silicone resin; acryl silicone resin; Polymers having meth) acrylic acid ester as a constituent monomer; Cross-polymers having (meth) acrylic acid ester as a constituent monomer such as methyl methacrylate crosspolymer (ethylene acrylate copolymer resin, etc.); Nylon 12, nylon 6, co-polymer Polyamide resin such as polymerized nylon; polyimide; carboxymethylcellulose; gelatin; starch; chitin;

  Among these, inorganic particles are preferable, metal oxide particles are more preferable, silica, alumina, titania and zirconia are further preferable, and silica is particularly preferable. By using such relatively hard particles in combination with the radiation curable binder of this embodiment, the strength of the model can be raised with particles, so that three-dimensional modeling is possible only with the binder. In comparison, the tensile strength and tensile elongation of the three-dimensional structure tend to be improved together. In addition, a particle | grain may be used individually by 1 type, or may use 2 or more types together.

  The content of the particles is preferably 40 to 65% by mass, more preferably 45 to 60% by mass, and further preferably 50 to 55% by mass with respect to the total amount of the base material.

(Binder resin)
By including the binder resin, the particles can be bonded (temporarily fixed), and unwanted scattering of the particles can be effectively prevented. Thereby, the safety | security of an operator and the improvement of the dimensional accuracy of the three-dimensional molded item 100 manufactured can be aimed at. The binder resin is not particularly limited, and examples thereof include poly (meth) acrylic acid, polyvinyl alcohol, naphthalenesulfonate polymorpholine condensate, styrene / maleic anhydride copolymer, olefin / maleic anhydride copolymer, carboxy Examples include methylcellulose, polystyrene sulfonate, acrylamide / acrylic acid copolymer, alginic acid, polyalkylene polyamine, polyacrylamide, polyethyleneimine, aminoalkyl (meth) acrylate copolymer, polymer starch, and satkinsan. Among these, poly (meth) acrylic acid is preferable from the viewpoint of compatibility. Binder resin may be used individually by 1 type, or may use 2 or more types together.

  The content of the binder resin is preferably 1.0 to 10% by mass, more preferably 1.5 to 7.5% by mass, and further preferably 2.5 to 5%, based on the total amount of the base material. 0.0% by mass.

(solvent)
Although it does not specifically limit as a solvent, For example, water and an organic solvent are mentioned. Although it does not specifically limit as an organic solvent, For example, Alcohol solvents, such as methanol, ethanol, isopropanol; Ketone type solvents, such as methyl ethyl ketone and acetone; Glycol ether type solvents, such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether; Propylene Glycol ether acetate solvents such as glycol 1-monomethyl ether 2-acetate and propylene glycol 1-monoethyl ether 2-acetate; polyethylene glycol and polypropylene glycol. Among these, water is preferable. A solvent may be used individually by 1 type, or may use 2 or more types together.

  The content of the solvent in the base material is preferably 5% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 80% by mass or less. Thereby, while the effect by including a solvent as mentioned above is exhibited more notably, since the solvent can be easily removed in a short time in the manufacturing process of the three-dimensional structure 100, the three-dimensional structure 100 is produced. This is advantageous from the viewpoint of improving the performance.

  The content of the solvent is preferably 30 to 55% by mass, more preferably 35 to 50% by mass, and further preferably 40 to 45% by mass with respect to the total amount of the base material.

(Other ingredients)
Further, the base material may contain components other than those described above. Examples of such components include a polymerization initiator; a polymerization accelerator; a penetration accelerator; a wetting agent (humectant); a fixing agent; an antifungal agent; an antiseptic; an antioxidant; an ultraviolet absorber; Examples include regulators.

[Binding process]
The binding step is a step of forming the three-dimensional structure 3 by binding particles with a radiation curable binder (1c, 1f). The radiation curable binder exists so as to fill the gaps between the particles, and the particles can be bound by polymerizing the polymerizable compound in the radiation curable binder. The radiation curable binder also contributes to bonding between adjacent layers. Specifically, by polymerizing a polymerizable compound in a radiation curable binder that exists so as to fill a gap between a part of a layer (three-dimensional modeled object) that has already been formed and particles before binding. , Particles can be bound.

  Although it does not specifically limit as a binding method, For example, the method of irradiating light with respect to the particle | grains which the radiation-curing type binder adhered, or the method of heating is mentioned. For example, by irradiating light to the particles to which the radiation curable binder is attached, or by heating the particles to which the radiation curable binder is attached, the water solubility contained in the radiation curable binder. The polymerization reaction of the polymerizable compound starts and the particles are settled. Examples of the light source (radiation source) include a mercury lamp, a gas / solid laser, an ultraviolet light emitting diode (UV-LED), and an ultraviolet laser diode (UV-LD).

(Laminated)
After the binding process, a layer is formed again on the obtained three-dimensional modeled object, and the three-dimensional modeled object 3 having an arbitrary shape is formed by repeating the layer forming process, the drying process, the attaching process, and the binding process. (1 g). Thereby, the particle | grains of the site | part to which the radiation-curing type binder 2 was provided will be in the state couple | bonded among each said layers 1, and the three-dimensional molded item 100 as a laminated body by which the layer 1 of such a state was laminated | stacked severally. Is obtained (1 h).

[Removal process]
The manufacturing method of the three-dimensional molded item of this embodiment may have the removal process which removes the particle | grains which are not bound by the radiation curable binder (1h). The method for removing particles is not particularly limited. For example, a method for removing unbound particles with a brush, a method for removing unbound particles by suction, a method for blowing a gas such as air, or a liquid such as water is applied. Examples thereof include a method (for example, a method of immersing the laminate obtained as described above in a liquid, a method of spraying a liquid, etc.), a method of applying vibration such as ultrasonic vibration, and the like.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited in any way by the following examples.

[Material of radiation curable binder]
The main materials of the radiation curable binder used in the following examples and comparative examples are as follows.
[Monofunctional monomer]
PEA (phenoxyethyl acrylate, homopolymer Tg: 5 ° C.)
4HBA (4-hydroxybutyl acrylate, homopolymer Tg: −32 ° C.)
THFA (tetrahydrofurfuryl acrylate, homopolymer Tg: −15 ° C.)
IBXA (isobonyl acrylate, homopolymer Tg: 88 ° C.)
[Bifunctional monomer]
DPGDA (dipropylene glycol diacrylate, homopolymer Tg: 104 ° C.)
VEEA (2- (2-vinyloxyethoxy) ethyl acrylate, homopolymer Tg: 39 ° C.)
16 HDDA (1,6-hexanediol diacrylate, homopolymer Tg: 43 ° C.)
TEGDA (tetraethylene glycol diacrylate, homopolymer Tg: 23 ° C.)
[Trifunctional or higher monomer]
TMPTA (trimethylolpropane triacrylate, homopolymer Tg: 62 ° C.)
[Bifunctional oligomer]
CN9873 (urethane oligomer, homopolymer Tg: 13 ° C.)
(Polymerization inhibitor)
MEHQ
[Surfactant]
BYK UV3500 (silicone surfactant, manufactured by Big Chemie Japan)
(Polymerization initiator)
Irgacure 819 (manufactured by Ciba Japan)
Speedcure TPO (Lambson)

[Preparation of radiation curable binder]
Each material was mixed with the composition shown in Table 1 below, and stirred sufficiently to obtain each radiation curable binder. In Table 1 below, the numerical unit is mass%, and the total is 100.0 mass%.

[Material of base material]
The main materials of the base material used in the examples and comparative examples are as follows.
〔particle〕
Silica particles (product name FB5D, manufactured by Denki Kagaku Kogyo Co., Ltd.)
Polymethyl methacrylate particles (manufactured by Sekisui Plastics Co., Ltd., product name MB20X-5)
[Binder resin]
Polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd., product name GH23)

[Base material adjustment]
Each material was mixed with the composition shown in Table 1 below, and stirred sufficiently to obtain each base material. In Table 1 below, the numerical unit is mass%, and the total is 100.0 mass%.

[Evaluation]
[Viscosity of radiation curable binder]
Using MCR-100 (manufactured by Physa), the viscosity at 20 ° C. of each of the radiation curable binders prepared above was measured. Based on the obtained viscosity, the following evaluation criteria were used.
(Evaluation criteria)
A: Less than 15 mPa · s.
B: 15 mPa · s or more and less than 25 mPa · s.
C: 25 mPa · s or more.

[Tensile strength and tensile elongation]
A paste material was applied on the modeling stage by a squeegee method and dried with a dryer to form a base material with a film thickness of 50 μm (step 1). The film thickness can be controlled by the height of the stage base and the squeegee. Next, the radiation curable binder obtained as described above is filled into a laminating apparatus (in-house manufactured by Seiko Epson), and discharged by an ink jet method to a portion to be bound, and a base material of each composition (Step 2). The base material to which the radiation curable binder was attached was irradiated with LED light of 395 nm, and the particles and the water-soluble resin were bound by the radiation curable binder (Step 3). Next, the stage was lowered by 50 μm, and the operations of Steps 1 to 3 were repeated, thereby stacking a three-dimensional object every 50 μm. This operation was repeated 200 times to form a three-dimensional structure having a 4 mm-thick dumbbell structure in accordance with JIS K 7161. Thereafter, the obtained three-dimensional model was annealed at 80 ° C. for 1 hour.

The tensile strength and tensile elongation of the three-dimensional structure obtained in this way were measured under the conditions of tensile yield stress: 50 mm / min in accordance with JIS K 7161: 1994 (ISO 527: 1993). The evaluation criteria are shown below.
(Evaluation criteria for tensile strength)
A: Tensile strength is 12 MPa or more.
B: The tensile strength is 8 MPa or more and less than 12 MPa.
C: Tensile strength is less than 8 MPa.
(Evaluation criteria for tensile elongation)
A: The tensile elongation is 2.0% or more.
B: Tensile elongation is 0.5% or more and less than 2.0%.
C: Tensile elongation is less than 0.5%.

[Laminate]
The base material was laminated by a squeegee method, and the following evaluation criteria were evaluated based on the lamination property. Note that “non-stackable” means that when the paste is stacked, the lower layer peels off or a line (scratch) enters.
(Evaluation criteria)
A: Can be stacked at a squeegee speed of 50 mm / sec. B: Cannot be stacked at a squeegee speed of 50 mm / sec. Can be stacked at 10 mm / sec. C: Cannot be stacked at a squeegee speed of 10 mm / sec.

  From the above results, it was found that in Comparative Examples 1, 4, and 5, the total content of the monofunctional monomer and the bifunctional monomer is low, so that the clay of the radiation curable binder is improved. Moreover, it turned out that the tensile strength of the three-dimensional molded item obtained by the comparative example 2 whose content of a bifunctional monomer is less than 40 mass% with respect to the total amount of a monofunctional monomer and a bifunctional monomer. Furthermore, in Comparative Example 2 in which the content of the bifunctional monomer is more than 60% by mass with respect to the total amount of the monofunctional monomer and the bifunctional monomer, it was found that the tensile elongation of the three-dimensional molded article obtained was lowered.

  DESCRIPTION OF SYMBOLS 1 ... Base material, 1 ... Layer, 2 ... Radiation hardening type binder, 3 ... Three-dimensional molded item, 100 ... Three-dimensional molded item, 9 ... Support body (stage)

Claims (11)

An adhesion step of attaching a radiation curable binder to a base material containing particles, and a binding step of binding the particles with the radiation curable binder to form a three-dimensional object. The radiation curable binder used in the method for producing a three-dimensional structure,
The radiation curable binder contains a monofunctional monomer and a bifunctional monomer,
The total content of the monofunctional monomer and the bifunctional monomer is 70% by mass or more based on the total amount of the radiation curable binder,
The content of the bifunctional monomer is 40 to 60% by mass with respect to the total amount of the monofunctional monomer and the bifunctional monomer.
Radiation curable binder. The monofunctional monomer includes a monomer that gives a homopolymer having a glass transition point of 50 ° C. or lower,
The bifunctional monomer includes a monomer that gives a homopolymer having a glass transition point of 30 ° C. or higher.
The radiation curable binder according to claim 1. The monofunctional monomer has a monofunctional (meth) acrylate having an aromatic group, a monofunctional (meth) acrylate having a hydroxyl group, a monofunctional (meth) acrylate having a cyclic ether group, and a (meth) cyclic aliphatic group. Including at least one selected from the group consisting of acrylates,
The radiation curable binder according to claim 1 or 2. The bifunctional monomer includes at least one selected from the group consisting of (meth) acrylate having a vinyl ether group, polyalkylene glycol di (meth) acrylate, and alkyldiol di (meth) acrylate,
The radiation curable binder according to any one of claims 1 to 3. The base material is a paste-type base material further containing a solvent;
The radiation curable binder according to any one of claims 1 to 4. The particles comprise an inorganic powder;
The radiation curable binder according to any one of claims 1 to 5. Further comprising a trifunctional or higher monomer and a polymerizable compound having a molecular weight of 500 or higher,
The total content of the tri- or higher functional monomer and the polymerizable compound is 20% by mass or less based on the total amount of the radiation curable binder.
The radiation curable binder according to any one of claims 1 to 6.   The radiation curable binder according to any one of claims 1 to 7, wherein, in the attaching step, the radiation curable binder is ejected by an ink jet method to adhere to the base material.   The radiation curable binder according to claim 1, wherein the manufacturing method of the three-dimensional structure is performed by a lamination method. A base material comprising particles;
A radiation curable binder according to any one of claims 1 to 9,
Modeling material set. An attachment step of attaching the radiation curable binder according to any one of claims 1 to 9 to a base material containing particles;
Binding the particles by the radiation curable binder to form a three-dimensional model, and
Manufacturing method of a three-dimensional molded item.

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