JP2024095609A - Photocurable resin composition, three-dimensional object, and method for manufacturing three-dimensional object - Google Patents

Abstract

The present invention provides a photocurable resin composition having excellent curing properties and capable of providing an optically molded object having excellent heat resistance and impact resistance, and a three-dimensional object obtained using the same, the three-dimensional object having excellent heat resistance and impact resistance.
General formula (1)

(wherein R ₁ to R ₉ are each a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group which may contain a halogen atom, or an alkoxy group which may have a substituent, and may be the same or different. R ₁₀ is a divalent hydrocarbon group, and R ₁₀ may or may not be present. When R ₁₀ is present, either R ₂ or R ₃ and either R ₇ or R ₈ are not present. Z is a polyvalent organic group (excluding ester bond-containing groups) which may have a branched chain or a substituent, and n is an integer of 2 to 10.)
[Selection diagram] None

Description

The present invention relates to a photocurable resin composition, a three-dimensional object using the photocurable resin composition, and a method for manufacturing the three-dimensional object.

As a three-dimensional modeling method using a curable composition, there are known a method of melting a material from a heated nozzle and discharging it while stacking the material layer by layer (fused deposition modeling), a method of applying ultraviolet light to a liquid resin to form a hardened layer and repeating this process many times to create a three-dimensional object (stereolithography), a method of stacking resin sprayed from an inkjet head while hardening it with ultraviolet light (inkjet model), a method of irradiating a powdered material (resin, metal) with a laser beam to sinter it (powder sintering model), a method of spreading a powdered material such as gypsum and then hardening it with an adhesive discharged from a head (powder adhesion model), etc. Of these, the fused deposition modeling, stereolithography, and powder sintering models are beginning to be used when manufacturing industrial products.
However, the fused deposition modeling method has the drawback of having weak strength in the Z direction during three-dimensional (XYZ axes) molding, and the powder sintering method has the disadvantage of requiring sintering at high temperatures.

In response to this, in recent years, optical three-dimensional modeling methods (the optical modeling method described above) have begun to be adopted, in which a three-dimensional object is created by irradiating light onto selected areas of a liquid photocurable resin composition based on three-dimensional CAD data.
More specifically, this is an optical stereolithography method (three-dimensional optical stereolithography) in which a step of forming a thin film made of a resin composition for optical stereolithography and a step of irradiating the thin film with light energy to cure the thin film are repeated multiple times to laminate the cured thin films and produce a three-dimensional object of a desired shape (Patent Documents 1 and 2, etc.). According to this optical stereolithography method, even if the shape of the three-dimensional object to be produced is complex, it is possible to produce the desired three-dimensional object easily and in a relatively short time.

As photocurable compositions used in optical three-dimensional modeling, for example, a resin composition that is liquid at 23°C and contains a monomer or oligomer or a mixture of a monomer and an oligomer that can be polymerized by a ring-opening reaction, a curable composition that contains an impact resistance modifier that contains one or more types of block copolymers having at least one block composed of methyl methacrylate, and one or more types of polymerization initiators is known (Patent Document 3).

Japanese Patent Application Laid-Open No. 3-21432 Japanese Patent Application Laid-Open No. 3-41126 JP 2010-520949 A

The resin composition is required to have a fast curing property whereby it is quickly cured by irradiation with light energy, and also to have mechanical properties of the resulting object. In particular, the three-dimensional object obtained by the optical three-dimensional modeling method is used not as a model for various products or components, but as a mold or component itself, and therefore is required to have both excellent heat resistance and impact resistance.
With respect to these demands, the photocurable resin composition disclosed in Patent Document 3 is insufficient in terms of satisfying all of the requirements for curability, heat resistance, and impact resistance.
In view of the above, an object of the present invention is to provide a photocurable resin composition having excellent curing properties and resulting in an optically molded object having excellent heat resistance and impact resistance, and a three-dimensional object obtained using the photocurable resin composition, the three-dimensional object having excellent heat resistance and impact resistance.

The present inventors have conducted extensive research to solve the above problems, and as a result have completed the present invention.
[1] The following general formula (1):
(In formula (1), R ₁ to R ₉ are each a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group which may contain a halogen atom, or an alkoxy group which may have a substituent, and may be the same or different. R ₁₀ is a divalent hydrocarbon group, and R _{10 may be present or absent. When R 10 is} present, either R ₂ or R ₃ and either R ₇ or R ₈ are not present. Z is a polyvalent organic group (excluding ester bond-containing groups) which may have a branched chain or a substituent, and n is an integer of 2 to 10.) A photocurable resin composition comprising an alicyclic epoxy compound (A) represented by the following formula (1), an acrylic material (B) containing a urethane (meth)acrylate compound, and a photopolymerization initiator (C).
[2] The photocurable resin composition according to the above [1], wherein the alicyclic epoxy compound (A) has a molecular weight of 260 or more and 2000 or less and has at least two polymerizable alicyclic epoxy groups in the molecule.
[3] The photocurable resin composition according to the above [1] or [2], wherein the content of the alicyclic epoxy compound (A) is 1 to 50% by weight based on the total weight of the photocurable resin composition.
[4] The photocurable resin composition according to any one of the above [1] to [3], wherein the alicyclic epoxy compound (A) is a polymer having a glass transition temperature of 80° C. or higher.
[5] The photocurable resin composition according to any one of the above [1] to [4], wherein the urethane (meth)acrylate compound has at least two (meth)acryloyl groups in the molecule.
[6] The photocurable resin composition according to any one of [1] to [5] above, wherein the content of the acrylic material (B) containing the urethane (meth)acrylate compound is 50 to 99 wt % based on the total weight of the photocurable resin composition.
[7] The photocurable resin composition according to any one of the above [1] to [6], wherein the photopolymerization initiator (C) contains both a cationic initiator and a radical initiator.
[8] The photocurable resin composition according to any one of [1] to [7] above, wherein the photocurable resin composition has a viscosity of 2000 cP or less at room temperature (25° C.).
[9] A three-dimensional object comprising a cured resin layer having a predetermined pattern formed by irradiating the photocurable resin composition according to any one of [1] to [8] above with light, wherein at least a part of the resin layer after curing has a micro sea-island structure in which islands made of a polymer different from the cured resin constituting the sea part are dispersed in a sea part made of the cured resin.
[10] The three-dimensional object according to the above-mentioned [9], wherein all of the cured resin layers have a micro sea-island structure in which fine islands made of a polymer different from the cured resin constituting the sea part are dispersed in a sea part made of the cured resin.
[11] The three-dimensional object according to the above [9] or [10], wherein the island portion has a fine structure with a particle size of 1 to less than 20 nm.
[12] The three-dimensional object according to any one of [9] to [11] above, wherein in the cured resin layer having a micro-sea-island structure, a total amount of island portions relative to a weight of the cured resin layer is 1 to 50% by weight.
[13] The three-dimensional object according to any one of the above [9] to [12], wherein the polymer forming the island portion is formed from the alicyclic epoxy compound (A).
[14] The three-dimensional object according to any one of the above [9] to [13], wherein the polymer forming the sea portion is formed from an acrylic material (B) containing the urethane (meth)acrylate compound.
[15] The method for producing a three-dimensional object according to any one of the above [9] to [14], wherein a content of the polymer component that becomes the islands is 1 to 50% by weight based on a weight of a photocurable resin composition used to form a cured resin layer having a micro-island-sea structure.
[16] The method for producing a three-dimensional object according to the above [15], wherein the photocurable resin composition contains an oxetane compound together with an alicyclic epoxy.

It is possible to provide a photocurable resin composition that has excellent curing properties and provides an optically shaped object with excellent heat resistance and impact resistance, and a three-dimensional object obtained using this photocurable resin composition that has excellent heat resistance and impact resistance.

3 is a transmission electron microscope photograph of a layer of the three-dimensional object produced in Example 1. 4 is a transmission electron microscope photograph of a layer of a three-dimensional object produced in Example 2. 1 is a transmission electron microscope photograph of a layer of a three-dimensional object produced in Example 3. 1 is a transmission electron microscope photograph of a layer of a three-dimensional object produced in Example 4. 4 is a transmission electron microscope photograph of a layer of a three-dimensional object produced in Comparative Example 1. 1 is a transmission electron microscope photograph of a layer of a three-dimensional object produced in Comparative Example 2.

Representative aspects for carrying out the present invention are specifically described below, but the present invention is not limited to the following aspects as long as it does not deviate from the gist of the invention. In this specification, when "~" is used to express a numerical value or physical property value before and after the value, the value before and after the value is included.

[Photocurable resin composition]
The photocurable resin composition of the present invention contains an alicyclic epoxy compound (A) represented by the following general formula (1), an acrylic material (B) containing a urethane (meth)acrylate compound, and a photopolymerization initiator (C).

<Alicyclic epoxy compound (A)>
The photocurable resin composition of the present invention contains an alicyclic epoxy compound (A) represented by the following general formula (1).

In formula (1), R ₁ to R ₉ are each a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group which may contain a halogen atom, or an alkoxy group which may have a substituent, and may be the same or different from each other. R ₁₀ is a divalent hydrocarbon group, and R ₁₀ may or may not be present. When R ₁₀ is present, either R ₂ or R ₃ and either R ₇ or R ₈ are not present. Z is a polyvalent organic group (excluding ester bond-containing groups) which may have a branched chain or a substituent, and n is an integer from 2 to 10.

In the above formula (1), R ₁ to R ₉ are as described above, and examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the hydrocarbon group containing a halogen atom include those in which some or all of the hydrogen atoms of the hydrocarbon group are substituted with halogen atoms. Examples of the hydrocarbon group containing an oxygen atom include those in which some or all of the -CH ₂ - groups of the hydrocarbon group are substituted with oxygen atoms. Examples of the hydrocarbon group that may contain an oxygen atom or a halogen atom include hydrocarbon groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group.

R ₁₀ may be present or absent, and when R ₁₀ is absent, formula (1) is as follows.

Of these, R ₁ to R ₉ are preferably hydrogen atoms. R ₁₀ is preferably a divalent hydrocarbon group having 1 to 3 carbon atoms, specific examples of which include a methylene group and an ethylene group. Of these, a methylene group is particularly preferred because it has low steric hindrance during ring-opening polymerization and is highly reactive.

Z in formula (1) may be a polyvalent organic group that may have a branched chain or a substituent, and is an n-valent organic group. For example, when n is 2, a divalent group is an example. From the viewpoint of polarity, it is preferable to have an ether bond or a siloxane bond, but ester bonds have high polarity and interact strongly with acrylic materials, making them undesirable for forming an island-sea structure. Specifically, groups represented by the following formulas are preferred.

n is an integer from 2 to 10, and preferably n is 2 or 3. If n is less than 4, the flowability does not decrease and the viscosity does not increase, and the toughness of the resin does not decrease due to an increase in crosslink density.

The molecular weight of the alicyclic epoxy compound (A) is preferably 260 or more and 2000 or less. A molecular weight of 260 or more is advantageous in terms of forming a phase-separated structure during polymerization, while a molecular weight of 2000 or less is advantageous in terms of reducing the viscosity.
From the above viewpoints, the molecular weight of the alicyclic epoxy compound (A) is more preferably 280 to 1,800, and further preferably 300 to 1,600.
The alicyclic epoxy compound (A) preferably has at least two polymerizable alicyclic epoxy groups in the molecule, and the number of the alicyclic epoxy groups is preferably two or three, and most preferably two.

The alicyclic epoxy compound (A) preferably has a glass transition temperature (Tg) of 80° C. or higher when polymerized by itself. When the Tg of the polymer is 80° C. or higher, the heat resistance of the three-dimensional object is increased. From the above viewpoints, the Tg of the polymer of the alicyclic epoxy compound (A) is more preferably 90° C. or higher, and further preferably 100° C. or higher.
On the other hand, the upper limit of the Tg of the polymer is not particularly limited, but is usually 250° C. or lower.

The content of the alicyclic epoxy compound (A) is preferably 1 to 50% by weight based on the total weight of the photocurable resin composition. If the content of the alicyclic epoxy compound (A) is 1% by weight or more, the heat resistance and impact resistance are improved. On the other hand, if the content is 50% by weight or less, the solution viscosity of the resin composition does not become too high, making it easier to obtain a three-dimensional object. From the above viewpoints, the content of the alicyclic epoxy compound (A) is more preferably 5 to 40% by weight, and even more preferably 10 to 30% by weight.

<Acrylic material (B) containing a urethane (meth)acrylate compound>
The photocurable resin composition of the present invention contains an acrylic material (B) (hereinafter, sometimes referred to as "acrylic material (B)") containing a urethane (meth)acrylate compound. The acrylic material (B) may contain a urethane (meth)acrylate compound, and there are no particular limitations on the other acrylic materials. Here, the acrylic material refers to one having an acrylic acid ester structure or a methacrylic acid ester structure. In the present invention, the urethane (meth)acrylate compound contained in the acrylic material (B) preferably has at least two (meth)acryloyl groups in the molecule. By having a (meth)acryloyl group, the urethane (meth)acrylate compound has radical polymerizability.
The urethane (meth)acrylate can be obtained by addition reaction of an amide hydroxy compound (b1) having one or more amide groups and two or more hydroxy groups in the molecule, a diol (b2) selected from the group consisting of polyether diols, polyester diols, and polycarbonate diols, an organic diisocyanate compound (b3), and a hydroxy group-containing (meth)acrylate (b4).
The hydroxyl groups in the components b1 and b4 have reactivity with the NCO group in the component b3. In addition, in this specification, "(meth)acrylate" means "acrylate" or "methacrylate".

The amide hydroxy compound (b1) is a component that improves the strength (toughness) of the three-dimensional object of the present invention while maintaining its elongation. There are no particular limitations on the component, but a reaction product of a cyclic hydroxycarboxylic acid ester with ammonia or a compound containing primary or secondary amino nitrogen is preferred.

Examples of cyclic hydroxycarboxylic acid esters include γ-butyrolactone, γ-valerolactone, δ-valerolactone, and ε-caprolactone. These may be used alone or in combination of two or more. Among these, γ-butyrolactone and γ-valerolactone are particularly preferred.
Examples of compounds containing primary or secondary amino nitrogen include ethanolamine, diethanolamine, N-methylethanolamine, N-ethylethanolamine, N-phenylethanolamine, 2-amino-1-butanol, 2-amino-2-ethyl-1,3-propanediol, 6-amino-1-hexanol, 1,4-diaminobutane, 1,2-diaminocyclohexane, and 1,10-diaminodecane. These can be used alone or in combination. Among these, ethanolamine, diethanolamine, and N-methylethanolamine are particularly preferred.

The reaction of a cyclic hydroxycarboxylic acid ester with ammonia or a compound containing a primary or secondary amino nitrogen can be carried out by mixing equimolar amounts of the two and heating at about 80 to 100°C for 8 to 24 hours. Among the components (b1) thus obtained, 4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide is particularly preferred.

Diol (b2) is a component that improves the flexibility and elongation of the cured product of the urethane (meth)acrylate compound. Note that trifunctional or higher polyols are prone to crosslinking and gelling during the production of the urethane (meth)acrylate compound, so it is preferable to use a diol that does not have this risk.

As the (b2) component, one or more diols selected from polyether diols, polyester diols, and polycarbonate diols can be used. Commercially available products can be used, and specific examples include polyethylene glycol (number of repeating units: 6 to 20), polypropylene glycol (number of repeating units: 6 to 20), polybutylene glycol (number of repeating units: 6 to 20), 1-methylbutylene glycol (number of repeating units: 6 to 20), polycaprolactone diol, caprolactone addition (number of repeating units: 2 to 10) diol of alkylene (2 to 10 carbon atoms), polycarbonate diol (aliphatic skeleton with 4 to 6 carbon atoms), polyester diol derived from phthalic acid and alkylene diol, polyester diol derived from maleic acid and alkylene diol, polyester diol derived from fumaric acid and alkylene diol, etc. Among these, polybutylene glycol (number of repeating units: 6 to 20), polycaprolactone diol, and caprolactone-added diols (number of repeating units: 2 to 10) of alkylene diols (having 2 to 10 carbon atoms) are particularly preferred. Also, those with a weight average molecular weight of about 300 to 2000 are preferred.

The organic diisocyanate compound (b3) is a component that reacts with the hydroxyl group of another component to produce a urethane group. The component (b3) is not particularly limited, but examples thereof include isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, bis(4-isocyanatophenyl)methane, bis(3-chloro-4-isocyanatophenyl)methane, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, tris(4-isocyanatophenyl)methane, 1,2-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,2-hydrogenated xylylene diisocyanate, 1,4-hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, and hexamethylene diisocyanate.
These may be used alone or in combination. Among these, isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,2-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,2-hydrogenated xylylene diisocyanate, and 1,4-hydrogenated xylylene diisocyanate are preferred. In particular, those having an aliphatic or alicyclic skeleton, such as isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 1,2-hydrogenated xylylene diisocyanate, and 1,4-hydrogenated xylylene diisocyanate, are preferred because they provide excellent weather resistance to the cured product.

Hydroxy group-containing (meth)acrylate (b4) is a component that is added to the end of the polyurethane precursor obtained by the reaction to impart radical reactivity to the urethane (meth)acrylate compound. As the (b4) component, those having one or more (meth)acryloyl groups and one NCO-reactive hydroxy group in the molecule are preferred, and specific examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, cyclohexane dimethanol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-hydroxybutyl (meth)acrylate, and adducts of these with caprolactone. These can be used alone or in combination. Of these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are particularly preferred.

The urethane (meth)acrylate compound can be obtained, for example, by charging the (b1) component and 0.9 molar equivalents of the (b2) component in a synthesis vessel, adding 2.0 molar equivalents of the (b3) component dropwise under heating and stirring to obtain a precursor isocyanate-terminated polyurethane, and then dropping 1.1 to 1.3 molar equivalents of the (b4) component thereto and adding under heating. The molar equivalent ratios of (b1) to (b4) in the above reaction are preferably (b3):[(b1)+(b2)]:(b4)=2.0:0.5-4.0:0.5-4.0, (b1):(b2)=0.2-1.0:1.0-0.2.

In this specification, "molar equivalent" means the number obtained by multiplying the number of moles of the compound used by the number of functional groups. That is, for the amide hydroxy compound (b1), diol (b2), and hydroxy group-containing (meth)acrylate (b4), the "molar equivalent" is the number obtained by multiplying the number of hydroxy groups in the molecule by the number of moles used, and for the organic diisocyanate compound (b3), the "molar equivalent" is the number obtained by multiplying the number of NCO groups in the molecule by the number of moles used.

By adding the urethane (meth)acrylate compounds exemplified above, it is possible to improve the strength and elongation, elastic modulus, heat resistance, etc. of the three-dimensional object.
The content of the urethane (meth)acrylate in the acrylic material is preferably in the range of 10 to 80% by weight, more preferably in the range of 20 to 70% by weight, and even more preferably in the range of 30 to 60% by weight.

(Macromonomer)
The photocurable resin composition of the present invention may contain a macromonomer as an acrylic material other than the urethane (meth)acrylate compound.
A macromonomer is a polymer having a polymerizable functional group. In the present invention, by using a macromonomer having a radical polymerizable group, a shaped object having unprecedented bending strength and tensile strength and excellent elongation can be obtained.
In particular, when the radical polymerizable group has (meth)acrylate, the polarity of the carbonyl group results in high radical reactivity and rapid curing. Furthermore, the reactivity of methacrylate is milder than that of acrylate due to the steric hindrance of the methyl group, and it is possible to use methacrylate and acrylate depending on the properties of the photocurable resin composition.

The structure of the macromonomer is preferably that represented by the following formula (3), that is, that has a radical polymerizable group at one end of a poly(meth)acrylate segment.
In this specification, one end of the poly(meth)acrylate segment refers to an end group of a carbon-carbon bond chain in which the unsaturated double bond moieties of the (meth)acrylate are open and connected, and means a group located on the opposite side to Y.

In the formula (3), each R is independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. The alkyl group, the cycloalkyl group, the aryl group, or the heterocyclic group may have a substituent.

Examples of the alkyl group for R include branched or linear alkyl groups having 1 to 20 carbon atoms. Specific examples of branched or linear alkyl groups having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl. Among these, in view of ease of availability, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group and octyl group are preferred, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group and t-butyl group are more preferred, and methyl group is particularly preferred.

Examples of the cycloalkyl group for R include cycloalkyl groups having 3 to 20 carbon atoms. Specific examples of cycloalkyl groups having 3 to 20 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and adamantyl groups. In view of ease of availability, cyclopropyl, cyclobutyl, and adamantyl groups are preferred.

Examples of the aryl group for R include aryl groups having 6 to 18 carbon atoms. Specific examples of aryl groups having 6 to 18 carbon atoms include phenyl and naphthyl groups.

The heterocyclic group represented by R may, for example, be a heterocyclic group having 5 to 18 carbon atoms. Specific examples of heterocyclic groups represented by multiple R include a γ-lactone group and an ε-caprolactone group. Examples of heteroatoms contained in the heterocycle include an oxygen atom, a nitrogen atom, and a sulfur atom.

The substituents of the R group each independently include a group or atom selected from the group consisting of an alkyl group, an aryl group, a carboxyl group, an alkoxycarbonyl group (-COOR'), a carbamoyl group (-CONR'R"), a cyano group, a hydroxyl group, an amino group (-NR'R"), a halogen, an allyl group, an epoxy group, an alkoxy group (-OR'), or a group exhibiting hydrophilicity or ionicity. Note that R' and R" each independently include the same groups as R, except for heterocyclic groups.
The alkoxycarbonyl group as the substituent of the R group includes, for example, a methoxycarbonyl group.
Examples of the carbamoyl group as a substituent of the R group include an N-methylcarbamoyl group and an N,N-dimethylcarbamoyl group.
Halogen substituents on the R group include, for example, fluorine, chlorine, bromine and iodine.
The alkoxy group as the substituent of the R group includes, for example, an alkoxy group having 1 to 12 carbon atoms, and a specific example is a methoxy group.

Examples of the hydrophilic or ionic substituent of the R group include an alkali salt of a carboxyl group or an alkali salt of a sulfoxyl group, a poly(alkylene oxide) group such as a polyethylene oxide group or a polypropylene oxide group, and a cationic substituent such as a quaternary ammonium base.

R is preferably at least one selected from an alkyl group and a cycloalkyl group, and more preferably an alkyl group.
As the alkyl group, from the viewpoint of easy availability, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a t-butyl group are more preferable, and a methyl group is particularly preferable.

X is at least one selected from a hydrogen atom and a methyl group, and is preferably a methyl group.
From the viewpoint of ease of synthesis of the macromonomer, it is preferable that at least half of the multiple Xs are methyl groups, and more preferably, all of them are methyl groups. In order to make at least half of the multiple Xs methyl groups, the proportion of methacrylate in the raw material composition for producing the macromonomer may be 80% by weight or more.

Y is an end group of the macromonomer. Examples of the end group of the macromonomer include a hydrogen atom and a group derived from a radical polymerization initiator, similar to the end groups of polymers obtained by known radical polymerization.

n represents the number of moles of monomer units contained in one molecule of the macromonomer (excluding monomer units having double bonds). n is an integer from 2 to 10,000. n is preferably from 10 to 400, and more preferably from 20 to 100. If n is too small, the tensile strength and tensile elongation cannot be improved, and if n is too large, the viscosity of the resin composition becomes too high for practical use.

The content of the macromonomer in the photocurable resin composition of the present invention is preferably 1 to 10% by weight based on the total amount of the photocurable resin composition. A macromonomer content of 1% by weight or more is advantageous in that the cured resin has high bending strength, tensile strength, and a highly elongated molded object. On the other hand, a macromonomer content of 10% by weight or less is advantageous in that the viscosity of the composition is low. From the above viewpoints, the macromonomer content is more preferably in the range of 2 to 8% by weight, and even more preferably in the range of 3 to 5% by weight.

The weight average molecular weight of the macromonomer is preferably from 2,000 to 40,000, and more preferably from 5,000 to 20,000, from the viewpoint of handleability.
The weight average molecular weight is a weight average molecular weight calculated as polymethyl methacrylate, measured by gel permeation chromatography (GPC).

(Compound having a radically polymerizable group)
The photocurable resin composition of the present invention may contain a compound having a radical polymerizable group as an acrylic material other than the urethane (meth)acrylate compound.
More specifically, it is preferable to add a compound having one radical polymerizable group, which is a compound having a radical polymerizable group.
Examples of compounds having one radical polymerizable group include ester-type (meth)acrylates derived from various alkyl mono- or polyalcohols, mono(meth)acrylamides, urethane poly(meth)acrylates, epoxy (meth)acrylates, polyester (meth)acrylates and other monofunctional (meth)acrylates, vinyl ether compounds, vinyl ester compounds, allyl compounds, etc. These can be used alone or in combination of two or more.

Specific examples of compounds having one radical polymerizable group include aromatic vinyl monomers such as styrene, α-methylstyrene, α-chlorostyrene, vinyltoluene, and divinylbenzene; vinyl ester monomers such as vinyl acetate, vinyl butyrate, N-vinylformamide, N-vinylacetamide, N-vinyl-2-pyrrolidone, N-vinylcaprolactam, and divinyl adipate; vinyl ethers such as ethyl vinyl ether and phenyl vinyl ether; allyl compounds such as diallyl phthalate, trimethylolpropane diallyl ether, and allyl glycidyl ether; acrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, N-t-butylacrylamide, acrylmorpholine, and methylenebisacrylamide; (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Examples of mono(meth)acrylates include propyl acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, morpholyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, phenoxyethyl (meth)acrylate, tricyclodecane (meth)acrylate, dicyclopentenyl (meth)acrylate, allyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, isobornyl (meth)acrylate, and phenyl (meth)acrylate.

Among the above examples, N,N-dimethyl(meth)acrylamide, (meth)acryloylmorpholine, 2-ethylhexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, phenoxyethyl (meth)acrylate, tricyclodecane (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, etc. are preferred because they have low viscosity and dilution properties, and further increase elongation. Furthermore, the use of monofunctional (meth)acrylates (meth)acryloylmorpholine and isobornyl (meth)acrylate is preferred because they have a ring skeleton, which increases the elastic modulus of the three-dimensional object and improves toughness. In particular, the use of (meth)acryloylmorpholine is more preferred because it has strong hydrogen bonds, further increasing the elastic modulus and improving toughness.

The content of the compound having one radical polymerizable group is not particularly limited, but is preferably in the range of 10 to 60% by weight based on the total amount of the photopolymerizable resin composition. By including it in this range, the elastic modulus of the three-dimensional object is improved. From the above viewpoints, the content of the compound having one radical polymerizable group is more preferably in the range of 20 to 50% by weight, and even more preferably in the range of 30 to 45% by weight.

The content of the acrylic material (B) containing a urethane (meth)acrylate compound is preferably 50 to 99% by weight based on the total weight of the photocurable resin composition. If the content of the acrylic material (B) is 99% by weight or less, the content of the (A) component is sufficient, improving heat resistance and impact resistance. On the other hand, if it is 50% by weight or more, the solution viscosity of the resin composition does not become too high, making it easier to obtain a molded object. From the above perspectives, the content of the acrylic material (B) is more preferably 60 to 90% by weight, and even more preferably in the range of 70 to 85% by weight.

<Photopolymerization initiator (C)>
The photopolymerization initiator (C) is a component that polymerizes and cures the photocurable resin composition of the present invention when irradiated with active energy rays such as ultraviolet rays.
In the present invention, it is preferable to use both a cationic initiator and a radical initiator in combination as the photopolymerization initiator (C). The cationic initiator promotes the polymerization of epoxy groups, and the radical initiator promotes the polymerization of meth(acrylic) groups, so that polymerization can be performed efficiently.

Specific examples of the photopolymerization initiator (C) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone (commercial product; Omnirad 184), 2-methyl acetophenones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer; benzoins such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone, o-benzoyl methyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetrabenzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetrabenzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetrabenzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetrabenzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetrabenzoyl benzoate, 4-phenylbenzophenone, 4-phenyl ... benzophenones such as 1-(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzenemethanaminium bromide, and (4-benzoylbenzyl)trimethylammonium chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one methoxide; thioxanthones such as chloride; acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)phenyl-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime).
The component (C) may be used alone or in combination of two or more kinds.
The content of component (C) is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, and even more preferably 1 to 10 parts by weight, relative to 100 parts by weight of the total content of components (A) and (B). When the content of component (C) is equal to or more than the lower limit, the curability of the three-dimensional object can be improved, and the heat resistance and impact resistance of the three-dimensional object can be improved.

The content of the cationic initiator in component (C) is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, and even more preferably 0.3 to 5 parts by weight, per 100 parts by weight of the total content of components (A) and (B). If the content of the cationic initiator is equal to or greater than the lower limit above, the curing properties of the three-dimensional object can be improved.

The content of the radical initiator in component (C) is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, and even more preferably 0.3 to 5 parts by weight, per 100 parts by weight of the total content of components (A) and (B). If the content of the radical initiator is equal to or greater than the above lower limit, the curing properties of the three-dimensional object can be improved.

<Other ingredients>
In addition to the above components (A) to (C), the photocurable resin composition of the present invention may contain, if necessary, a known photosensitizer such as ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, amyl 4-dimethylaminobenzoate, or 4-dimethylaminoacetophenone.

In addition, various additives such as elastomer particles, release agents, lubricants, plasticizers, antioxidants, antistatic agents, light stabilizers, UV absorbers, flame retardants, flame retardant assistants, polymerization inhibitors, fillers, pigments, dyes, silane coupling agents, leveling agents, defoamers, fluorescent agents, and chain transfer agents can be added to the photocurable resin composition of the present invention as appropriate according to the intended use, etc., within the scope of the present invention. An oxetane compound, which will be described later, can also be added.

Furthermore, as another component, the ultraviolet absorber is an effective component for controlling the curing depth of the resin composition. The amount of the ultraviolet absorber to be added is not particularly limited, but is preferably 0.005 to 1 part by weight, more preferably 0.01 to 0.8 parts by weight, based on 100 parts by weight of the resin composition.
Furthermore, an organic solvent or water may be added to the resin composition of the present invention, if necessary, within the limits not impairing the performance of the resulting three-dimensional object.

(viscosity)
The viscosity of the photocurable resin composition of the present invention is preferably 2000 cP or less at room temperature (25° C.). If the viscosity is 2000 cP or less, a thin film can be formed well when subjected to optical modeling. In addition, the composition has the property of being rapidly cured by irradiation with light energy and having a small volumetric shrinkage rate during curing. Therefore, a three-dimensional object having a desired shape and dimensions can be produced accurately, stably, and efficiently.
From the above viewpoints, the viscosity of the photocurable resin composition at room temperature is more preferably 1800 cP or less, and even more preferably 1500 cP or less.
There is no particular restriction on the lower limit of the viscosity at room temperature, but from the viewpoint of the mechanical strength of the three-dimensional object, it is preferably 500 cP or more, and more preferably 800 cP or more.

<Three-dimensional objects>
The three-dimensional object of the present invention is a three-dimensional object composed of a cured resin layer having a predetermined shape pattern formed by irradiating the above-mentioned photocurable resin composition with light, and at least a part of the resin layer after curing has a micro sea-island structure in which island parts made of a polymer different from the cured resin constituting the sea part are dispersed in a sea part made of the cured resin.
For example, in the case of Example 1 described later, it is seen from the TEM observation results that a micro-island-sea structure is exhibited, as shown in Fig. 1. That is, island structures of about 10 nm in size are observed in the sea portion. It is sufficient that at least a part of the resin layer after curing has such a micro-island-sea structure, but it is preferable that the entire cured resin layer has a micro-structure in which islands made of a polymer different from the cured resin constituting the sea portion are dispersed in a sea portion made of a cured resin.

The islands in the micro-island-sea structure of the three-dimensional object of the present invention are preferably formed from the alicyclic epoxy compound (A) constituting the photocurable resin composition described above, and the sea portion is preferably formed from the acrylic material (B) containing the urethane (meth)acrylate compound described above.
The photocurable resin composition of the present invention is a resin composition in which an alicyclic epoxy compound (A) and an acrylic material (B) containing a urethane (meth)acrylate compound are uniformly mixed, and it is believed that this changes to a sea-island structure during the polymerization process, and that this has a so-called polymerization-induced phase separation structure. It is presumed that by adopting such a structure, when cracks or the like occur in the sea portion, the cracks or the like are suppressed in the island portion, and impact resistance is improved.

The three-dimensional object of the present invention may have the above-mentioned micro-island-sea structure, and although there is no particular restriction on the size of the micro-islands, it is preferable that the particle size of the micro-islands is 1 to less than 20 nm. If the particle size of the islands is 1 nm or more, the heat resistance and impact resistance of the three-dimensional object can be improved, and if it is less than 20 nm, the micro-island-sea structure can be easily maintained. From the above viewpoints, the particle size of the islands is more preferably in the range of 2 to 18 nm, and even more preferably in the range of 5 to 15 nm.
Furthermore, the content of the polymer component constituting the island portions is preferably 1 to 50% by weight, based on the total weight of the photocurable resin composition used to form a cured resin layer having a micro-island-sea structure. When the content of the polymer component constituting the island portions is 1% by weight or more, the three-dimensionally shaped portion can have both heat resistance and impact resistance. On the other hand, when the content is 50% by weight or less, the sea-island structure can be stably present. From the above viewpoints, the content of the polymer component constituting the island portions is more preferably 5 to 40% by weight, and even more preferably 10 to 30% by weight.

<Method of manufacturing a three-dimensional object>
In the method for producing a three-dimensional object, the composition of the photocurable resin composition for forming the three-dimensional object is important. That is, as described above, the content of the polymer component that forms the island portions is preferably in the range of 1 to 50% by weight, more preferably 5 to 40% by weight, and further preferably 10 to 30% by weight, based on the total amount of the photocurable resin composition used to form the cured resin layer having a micro-sea-island structure.
In addition, it is preferable that the photocurable resin composition contains an oxetane compound together with the alicyclic epoxy compound, which is component (A). By containing an oxetane compound, high reactivity can be maintained. The content of the oxetane compound is not particularly limited, but is preferably in the range of 1 to 20% by weight with respect to the total amount of the photocurable resin composition. When the content of the oxetane compound is 1% by weight or more, the effect of adding the oxetane compound is fully exhibited, and when it is 20% by weight or less, the amount of other components can be secured. From the above viewpoints, the content of the oxetane compound is more preferably in the range of 2 to 10% by weight, and even more preferably in the range of 2.5 to 5.5% by weight.

<Applications>
The photocurable resin composition of the present invention is useful as a material for 3D printers. By using the photocurable resin composition of the present invention, it is easy to handle and easy to shape, and productivity can be improved.
In addition, the three-dimensional object of the present invention has excellent heat resistance and impact resistance, and can therefore be used as an industrial product. For example, it is expected to be widely used in mobility applications.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples as long as the gist of the invention is not exceeded. The methods for measuring various physical properties are as follows.

[Viscosity of composition]
The viscosity of the photocurable resin compositions prepared in the following examples was measured at a constant temperature using a Brookfield Digital E-type viscometer "LV DV3T" (with thermostatic bath) by adjusting the temperature of the photocurable resin composition in the thermostatic bath to 25°C. A CPA-52Z was used as the cone spindle, and the viscosity was calculated from the value when the data stabilized under the condition of a rotation speed of 0.5 to 100 rpm.

[Glass-transition temperature]
For the photocurable resin compositions produced in the following examples, compositions containing only the epoxy component and the acrylic component were prepared, and test pieces of photo-stereoscopic objects which were cured and molded by the method described below were clamped and fixed in a chuck, and the temperature dependence of the dynamic viscoelasticity was measured using a Hitachi High-Tech Science dynamic viscoelasticity measuring device "DMA 7100" under the following conditions: measurement mode: tension, measurement frequency: 1, 2, 4, 10, 20 Hz, heating rate (measurement temperature): 5°C/min (-10°C to 240°C).
The storage and loss moduli during heating were measured, and the loss tangent (tan δ), which is the ratio between them, was calculated. The temperature at which tan δ (10 Hz) peaked was defined as the glass transition temperature. Note that there were cases where the test piece broke near the chuck before reaching the glass transition temperature, and in such cases, the glass transition temperature was considered to be equal to or higher than the temperature immediately before the breakage.

[Heat-resistant]
For the photo-stereoscopic objects (bar-shaped test pieces conforming to ASTM D648) produced in the following examples, a load of 0.45 MPa was applied to the test pieces using an "HDT Tester 6M-2" manufactured by Toyo Seiki Co., Ltd., and the heat distortion temperatures of the test pieces were measured in accordance with ASTM D648 (Method B).

[IZOD impact resistance]
The Izod impact strength of the photo-etched objects (test pieces in the shape of a bar with a notch conforming to ASTM D256) produced in the following examples was measured using a Digital Impact Tester DG-18 manufactured by Toyo Seiki Co., Ltd., with a notch conforming to ASTM D256.

[Observation by Transmission Electron Microscope (TEM)]
Test pieces of the stereolithography objects produced in the following examples were double stained with 0.5% ruthenium tetroxide (RuO ₄ ) and 0.5% osmium tetroxide (OsO ₄ ) aqueous solutions. The test pieces were trimmed and embedded in resin, and then sliced thinly with a microtome to produce sections. Observations and photographs were taken using a transmission electron microscope in STEM mode at an accelerating voltage of 200 kV. Note that the length of one side in Figures 1 to 5 is 280 nm. The acrylic matrix was observed as black with strong staining, and the epoxy domains were observed as bright spots with weak staining.

<Component (A): Alicyclic epoxy compound represented by formula (1)>
BCHH: _C20H34O4 ; 7-Oxabicyclo[ _4.1.0 ]heptane, _3,3 '-[1,6-hexanediylbis(oxymethylene)]bis- molecular weight 338.4
BHOO: _C22H38O4 ; 7-Oxabicyclo[ _4.1.0 ]heptane,3,3'- _[ 1,8-octanediylbis(oxymethylene)]bis- molecular weight 366.5
BHBO: _C18H30O4 ; 7-Oxabicyclo[ _4.1.0 ]heptane, _3,3 '-[1,4-butanediylbis(oxymethylene)]bis- molecular weight 310.4
BCHS: _C20H38O3Si2 ; 1,1,3,3-Tetramethyl-1,3 _- bis[2-(7-oxabicyclo[4.1.0]hept- ₃ -yl)ethyl]disiloxane, _molecular weight 382.7
BHS3: _C22H44O4Si3 ; 1,1,3,3,5,5-Hexamethyl-1,5-bis[2-(7-oxabicyclo[4.1.0]hept- ₃ -yl)ethyl]trisiloxane _{, molecular} weight 456.8
BNS2: C ₂₂ H ₃₈ O ₃ Si ₂ ; Disiloxane, 1,1,3,3-tetramethyl-1,3-bis[2-(3-oxacyclo[3.2.1.0 ^2,4 ]oct-6-yl)ethyl] - molecular weight 406.7
THS4: C ₃₁ H ₆₀ O ₆ Si ₄ ; 3-[[Dimethyl[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silyl]oxy]-1,1,3,5,5-pentamethyl-1,5-bis[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]trisiloxane Molecular weight 641.1

The components used in the comparative examples are as follows.
C2021P: _C14H20O4 ; 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate _, product name "Celloxide", manufactured by Daicel Corporation _, molecular weight 252.3

<Component (B)>
(Urethane acrylate (B-1))
The urethane acrylate used was synthesized by the following method: The end point of the reaction was determined to be the time when the residual isocyanate equivalent was less than 1% by weight.
(1) Into a 5 L three-neck flask equipped with a stirrer, a temperature controller, a thermometer, and a condenser, 1,850 g (7.0 molar equivalents) of dicyclohexylmethane-4,4-diisocyanate and 0.7 g of dibutyltin dilaurate were placed and heated in a water bath until the internal temperature reached 70° C.
(2) Separately, 193 g (1.1 molar equivalents) of 4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide and 1,200 g (1.4 molar equivalents) of polybutylene glycol (number of repeating units: 12, average molecular weight: 865) were mixed and dissolved uniformly, and a dropping funnel with a side tube was charged with this, and this was dropped into the contents of the flask in (1) above. At this time, while stirring the contents of the flask in (1) above, the temperature inside the flask was kept at 65 to 75°C, and the dropping was performed at a constant rate over 4 hours. After the dropping was completed, the mixture was stirred at the same temperature for 2 hours to react.
(3) Separately, a liquid in which 1,335 g (11.5 molar equivalents) of 2-hydroxyethyl acrylate and 2.5 g of hydroquinone monomethyl ether were uniformly mixed and dissolved was charged into another dropping funnel. After the temperature of the flask contents of (2) was lowered to 75°C, this content was dropped at a constant rate over 2 hours while maintaining the internal temperature of the flask at 55 to 65°C, and the temperature of the flask contents was further maintained at 75 to 85°C and reacted for 4 hours to obtain a colorless and transparent urethane acrylate.

(Macromonomer (B-2))
Macromonomer that is an acrylic component other than urethane acrylate, polymethyl methacrylate ELVACITE 1010 (weight average molecular weight (Mw) = 5000)

(ACMO (B-3))
ACMO: acryloylmorpholine (KJ Chemicals)

<Component (C): Photopolymerization initiator>
Ominirad 184: 1-hydroxycyclohexyl-phenyl ketone (manufactured by BASF); photoresponsive radical polymerization initiator CPI-200K: Sulfonium, diphenyl [4- (phenylthio) phenyl] -, trifluorotris (1,1,2,2,2-pentafluoroethyl) phosphate (1-) (1:1) 50% propylene carbonate solution (manufactured by San-Apro Co., Ltd.) photoresponsive cationic polymerization initiator

<Optional ingredients>
OXT-221: 3,3'-(oxybismethylene)bis(3-ethyloxetane), (manufactured by Toagosei Co., Ltd.)
It was added to maintain high reactivity.

Examples 1 to 7, Comparative Examples 1 and 2
(1) Preparation of Photocurable Resin Compositions Photocurable resin compositions were prepared by mixing the components in the amounts shown in Table 1.
To the epoxy component (A), a predetermined amount of initiator (C) CPI-200K and optional component OXT-221 were added, and the mixture was stirred and mixed with a mix rotor at a temperature of 20 to 50 ° C for 30 minutes or more to obtain an epoxy composition. Similarly, for the acrylic component (B), after mixing each component, a predetermined amount of initiator (C) Omnirad 184 was added, and the mixture was stirred and mixed with a mix rotor at a temperature of 20 to 50 ° C for 2 hours or more to obtain an acrylic composition. Next, the prepared epoxy composition and acrylic composition were mixed in a predetermined ratio, and the mixture was stirred and mixed with a mix rotor at a temperature of 20 to 50 ° C for 30 minutes or more to obtain a photocurable resin composition. When measuring the glass transition temperature of the epoxy alone and the acrylic alone, the photocurable resin composition was made only of the epoxy composition and the acrylic composition, respectively. All the liquid preparations were carried out in an environment where ultraviolet light was removed.

(2) Manufacturing of a three-dimensional object The surface of a 1 mm thick glass plate that transmits ultraviolet light was thoroughly wiped with acetone, and then a 0.1% Optool solution, which acts as a surfactant for easy peeling, was applied and dried for about 1 hour. A bar-shaped mold of 127 mm x 12.5 mm x 3 mm conforming to the ASTM standard was made of a silicone sheet and placed on the glass plate. In a yellow room where ultraviolet light was removed, the photocurable resin composition was carefully and slowly poured into the mold so as not to trap air bubbles. After covering the upper side with the easily peeled glass, an ultraviolet irradiation curing system "FUSION LightHammer 6" manufactured by Heraeus was used to irradiate ultraviolet light twice under the condition of 1000 mJ/ ^cm2 (using an H bulb, 365 nm) to obtain an optical three-dimensional object of a predetermined size.
Furthermore, when preparing test pieces for measuring the glass transition temperature, the size of the silicone sheet mold was changed to 15 mm × 6 mm × 1 mm, and the photocurable resin composition was poured in the same manner and cured to obtain a three-dimensional object to be used as the test piece.

From the results shown in Table 1, in Examples 1 to 7 to which the present invention was applied, three-dimensional objects excellent in both heat resistance and impact resistance were produced. As shown in Figure 1, a micro-island-sea structure with island portions of 20 nm or less was observed in the test piece of Example 1, and a polymerization-induced phase separation structure was formed. Similarly, as shown in Figures 2, 3 and 4, a micro-island-sea structure with island portions of 20 nm or less was observed in the test pieces of Examples 2, 3 and 4, respectively.
On the other hand, Comparative Example 1, in which the molecular weight of component (A) was small, had poor heat resistance. No phase separation structure was observed in the test piece, and the structure was compatible with acrylic (FIG. 5).
Comparative Example 2, which does not contain component (A), was poor in impact resistance. No phase separation structure was observed, and it was believed that tough fracture, which is often observed in acrylic resins, occurred (FIG. 6).

According to the present invention, there are provided a photocurable resin composition having excellent curing properties and resulting in an optically molded object having excellent heat resistance and impact resistance, and a three-dimensional object obtained using the photocurable resin composition, the three-dimensional object having excellent heat resistance and impact resistance.
The technology targeted by the present invention is liquid-phase photopolymerization, which is a useful technology with high productivity. By combining this with the present invention, it is possible to manufacture three-dimensional objects with excellent heat resistance and impact resistance with high productivity, and the utility value of this technology is high.

Claims (16)

The following general formula (1)
(In formula (1), R ₁ to R ₉ are each a hydrogen atom, a halogen atom, an oxygen atom, a hydrocarbon group which may contain a halogen atom, or an alkoxy group which may have a substituent, and may be the same or different. R ₁₀ is a divalent hydrocarbon group, and R _{10 may be present or absent. When R 10 is} present, either R ₂ or R ₃ and either R ₇ or R ₈ are not present. Z is a polyvalent organic group (excluding ester bond-containing groups) which may have a branched chain or a substituent, and n is an integer of 2 to 10.) A photocurable resin composition comprising an alicyclic epoxy compound (A) represented by the following formula (1), an acrylic material (B) containing a urethane (meth)acrylate compound, and a photopolymerization initiator (C). The photocurable resin composition according to claim 1, wherein the alicyclic epoxy compound (A) has a molecular weight of 260 or more and 2000 or less and has at least two polymerizable alicyclic epoxy groups in the molecule. The photocurable resin composition according to claim 1, wherein the content of the alicyclic epoxy compound (A) is 1 to 50% by weight based on the total weight of the photocurable resin composition. The photocurable resin composition according to claim 1, wherein the alicyclic epoxy compound (A) is a polymer having a glass transition temperature of 80°C or higher. The photocurable resin composition according to claim 1, wherein the urethane (meth)acrylate compound has at least two (meth)acryloyl groups in the molecule. The photocurable resin composition according to claim 1, wherein the content of the acrylic material (B) containing the urethane (meth)acrylate compound is 50 to 99% by weight based on the total weight of the photocurable resin composition. The photocurable resin composition according to claim 1, wherein the photopolymerization initiator (C) contains both a cationic initiator and a radical initiator. The photocurable resin composition according to claim 1, wherein the viscosity of the photocurable resin composition is 2000 cP or less at room temperature (25°C). A three-dimensional object consisting of a cured resin layer having a predetermined shape pattern formed by irradiating the photocurable resin composition according to any one of claims 1 to 8 with light, characterized in that at least a part of the resin layer after curing has a micro sea-island structure in which islands made of a polymer different from the cured resin constituting the sea portion are dispersed in a sea portion made of the cured resin. The three-dimensional object according to claim 9, wherein all of the cured resin layers have a micro-island sea structure in which minute islands made of a polymer different from the cured resin constituting the sea portion are dispersed in a sea portion made of the cured resin. The three-dimensional object according to claim 9, wherein the island portion has a fine structure with a particle size of 1 to 20 nm or less. The three-dimensional object according to claim 9, wherein in the cured resin layer having a micro-island-sea structure, the total amount of islands relative to the weight of the cured resin layer is 1 to 50% by weight. The three-dimensional object according to claim 9, wherein the polymer forming the island portion is formed from the alicyclic epoxy compound (A). The three-dimensional object according to claim 9, wherein the polymer forming the sea portion is formed from an acrylic material (B) containing the urethane (meth)acrylate compound. The method for producing a three-dimensional object according to claim 9, wherein the content of the polymer component that will become the island portion is 1 to 50% by weight relative to the weight of the photocurable resin composition used to form the cured resin layer having a micro-island-sea structure. The method for producing a three-dimensional object according to claim 15, wherein the photocurable resin composition contains an oxetane compound together with an alicyclic epoxy.