Stereolithography curable resin composition, cured product, and three-dimensional object

Abstract

The present invention provides a curable resin composition for stereolithography having low shrinkage when cured, the cured product thereof, and a three-dimensional object. [Solution] The photopolymerizable resin composition of the present invention comprises a urethane resin (A) having two (meth)acryloyl groups, an α,β-unsaturated carbonyl compound (B), and a photopolymerization initiator. The urethane resin (A) is prepared using a polycarbonate diol (a1), a diisocyanate (a2), a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials. The polycarbonate diol (a1) has an alicyclic structure. The α,β-unsaturated carbonyl compound (B) has a glass transition temperature (Tg) of 90°C or higher when used as a monomer polymer.

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition for stereolithography, a cured product, and a three-dimensional object. [Background technology]

[0002] In recent years, optical stereolithography (stereolithography) has been used as a manufacturing method for resin molded products. This method involves selectively polymerizing and curing a curable resin composition using active energy rays such as ultraviolet lasers, based on three-dimensional shape data designed using 3D design systems such as CAD, to create three-dimensional objects. This optical stereolithography method can handle complex shapes that are difficult to create with machining, has a short manufacturing time, and is easy to handle. As a result, it is increasingly being used not only for resin molded products but also for the production of prototype models of industrial products.

[0003] A typical example of optical 3D printing is a method in which a computer-controlled spot-shaped ultraviolet laser is shone from above onto a liquid photocurable resin in a container to cure one layer of a predetermined thickness. The printed object is then lowered by one layer to supply liquid resin on top of the layer, and the next layer is similarly irradiated and cured with ultraviolet laser light to build up the layers. This process is repeated to obtain a 3D object. Recently, in addition to the pointillist method using a spot-shaped ultraviolet laser described above, there has been an increase in surface exposure methods that use light sources other than lasers, such as LEDs, and use a surface drawing mask called a DMD (Digital Micromirror Device), which has multiple digital micromirror shutters arranged in a planar shape. Ultraviolet light is shone from below through a transparent container containing photocurable resin to cure one layer of a predetermined cross-sectional shape pattern, the printed object is then pulled up by one layer, and the next layer is irradiated and cured in the same way as above, and the layers are sequentially built up to obtain a 3D object.

[0004] The above-mentioned optical stereolithography method (stereolithography) is undergoing active development due to its high printing speed and accuracy (see, for example, Patent Documents 1 and 2). As a result, with improvements in stereolithography machines and materials, the scope of application of stereolithography is expanding from prototypes to final products. However, a stereolithography-curable resin composition with low shrinkage when cured has not yet been obtained. Furthermore, optical stereolithography objects with excellent impact resistance or heat resistance have not yet been obtained for automotive parts, home appliance parts, etc.

[0005] Therefore, there was a need for a curable resin composition for stereolithography that exhibits low shrinkage when cured. Furthermore, there was a need for a curable resin composition for stereolithography that could form optically three-dimensional objects with excellent impact resistance or heat resistance. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2019-199448 [Patent Document 2] International Publication No. 2022 / 209689 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a curable resin composition for stereolithography that exhibits low shrinkage when cured, as well as the cured product thereof and a three-dimensional object. Furthermore, when the composition includes a urethane resin (C) having two or more (meth)acryloyl groups and not having an alicyclic structure, the objective is to provide a curable resin composition for stereolithography, a cured product thereof, and a stereolithographic product that can form optically three-dimensional objects with excellent impact resistance. Furthermore, when a urethane resin (A) having two (meth)acryloyl groups is included in an amount of 20% by mass or more relative to the total amount of the photocurable compound, the objective is to provide a photopolymerizable resin composition capable of forming optically three-dimensional objects with excellent heat resistance, a cured product thereof, and a three-dimensional object.

Means for Solving the Problem

[0008] The present invention includes the following aspects. [1] A curable resin composition for optical modeling, comprising a urethane resin (A) having two (meth)acryloyl groups, an α,β-unsaturated carbonyl compound (B), and a photopolymerization initiator, wherein the urethane resin (A) is obtained by using a polycarbonate diol (a1), a diisocyanate (a2), and a compound (a3) having a hydroxyl group and a (meth)acryloyl group as reaction raw materials, the polycarbonate diol (a1) has an alicyclic structure, and the α,β-unsaturated carbonyl compound (B) has a glass transition temperature (Tg) of 50°C or higher when it is a monomer polymer, the curable resin composition for optical modeling. [2] The curable resin composition for optical modeling according to [1], further comprising a urethane resin (C) having two or more (meth)acryloyl groups and not having an alicyclic structure. [3] The curable resin composition for optical modeling according to [1] or [2], wherein the α,β-unsaturated carbonyl compound (B) is a compound having one (meth)acryloyl group. [4] Further comprising a compound (D) having two or more (meth)acryloyl groups, and the compound (D) having two or more (meth)acryloyl groups has a glass transition temperature (Tg) of 60°C or higher when it is a monomer polymer, the curable resin composition for optical modeling according to any one of [1] to [3]. [5] The curable resin composition for optical modeling according to any one of [1] to [4], wherein the content of the (meth)acryloyl group in the urethane resin (A) is 0.6 mmol / g or more and 2.0 mmol / g or less. [6] The curable resin composition for optical molding according to any one of [1] to [5], wherein the content of the urethane resin (A) is 20% by mass or more and 50% by mass or less, the content of the α,β-unsaturated carbonyl compound (B) is 50% by mass or more and 80% by mass or less, and the total of the urethane resin (A) and the α,β-unsaturated carbonyl compound (B) is 100% by mass or less. [7] The curable resin composition for optical molding according to any one of [2] to [5], wherein the content of the urethane resin (A) is 10% by mass or more and 20% by mass or less, the content of the α,β-unsaturated carbonyl compound (B) is 20% by mass or more and 60% by mass or less, the content of the urethane resin (C) is 20% by mass or more and 60% by mass or less, and the total of the urethane resin (A), the α,β-unsaturated carbonyl compound (B), and the urethane resin (C) is 100% by mass or less. [8] The curable resin composition for optical molding according to any one of [2] to [7], wherein when the compound (D) having two or more (meth)acryloyl groups is included, its content is 1% by mass or more and 50% by mass or less. [9] The curable resin composition for optical molding according to any one of [1] to [8], wherein the urethane resin (A) is a resin represented by the following formula (1). [Chemical formula] (In the above formula (1), R1 and R7 each independently represent a hydrogen atom or a methyl group, R2 and R6 each independently represent -C2H4-, -C3H6-, -C4H8-, or -C2H4O(COC5H 10 ) s -(s = 1 to 4), R3 and R5 each independently represent -C5H 10 -, -C6H 12 -, -C 10 H 18 -, or -C9H 18 -, R4 may be one kind or two or more kinds, and represents an alicyclic structure having 3 to 10 carbon atoms. n represents an integer of 2 to 50.)

[10] A cured product which is a cured reaction product of a stereolithography curable resin composition described in any of [1] to [9].

[11] A three-dimensional object made of hardened material from

[10] . [Effects of the Invention]

[0009] The present invention provides a curable resin composition for stereolithography having low shrinkage when cured, a cured product thereof, and a three-dimensional object. Furthermore, when the composition includes a urethane resin (C) having two or more (meth)acryloyl groups and not having an alicyclic structure, it is possible to provide a curable resin composition for stereolithography, a cured product thereof, and a stereolithographic product that can form optically three-dimensional objects with excellent impact resistance. Furthermore, when a urethane resin (A) having two (meth)acryloyl groups is included in an amount of 20% by mass or more relative to the total amount of the photocurable compound, it is possible to provide a photopolymerization-curable resin composition capable of forming optically three-dimensional objects with excellent heat resistance, a cured product thereof, and a three-dimensional object. [Modes for carrying out the invention]

[0010] (Curable resin composition for stereolithography) The curable resin composition for stereolithography of the present invention will be described in detail using the following first and second embodiments. The present invention is not limited to specific examples of each embodiment.

[0011] (First Embodiment) The stereochemical curable resin composition of this embodiment comprises a urethane resin (A) having two (meth)acryloyl groups (sometimes simply referred to as "urethane resin (A)"), an α,β-unsaturated carbonyl compound (B), and a photopolymerization initiator. The urethane resin (A) is reacted using a polycarbonate diol (a1), a diisocyanate (a2), and a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials. The polycarbonate diol (a1) has an alicyclic structure. The α,β-unsaturated carbonyl compound (B) has a glass transition temperature (Tg) of 50°C or higher when used as a monomer polymer. Preferably, the α,β-unsaturated carbonyl compound (B) is a compound (Bac) having one (meth)acryloyl group.

[0012] The stereochemical curable resin composition of this embodiment preferably further comprises a compound (D) having two or more (meth)acryloyl groups. The compound (D) having two or more (meth)acryloyl groups has a glass transition temperature (Tg) of 60°C or higher when it is used as a monomer polymer. It is preferable that the (meth)acryloyl group content of the urethane resin (A) is 0.6 mmol / g or more and 2.0 mmol / g or less.

[0013] Furthermore, the stereochemical curable resin composition of this embodiment may also contain other trifunctional or higher (meth)acrylic compounds (E) other than the α,β-unsaturated carbonyl compound (B) and / or the compound (D) having two or more (meth)acryloyl groups, as long as they do not impede the effects of the present invention. Furthermore, the stereochemical curable resin composition of this embodiment may also contain other additives such as photosensitizers, ultraviolet absorbers, polymerization inhibitors, and inorganic fillers, as needed.

[0014] [Urethane resin (A)] The urethane resin (A) used in this embodiment can be obtained by reacting the polycarbonate diol (a1), the diisocyanate (a2), and the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group.

[0015] <Polycarbonate diol (a1)> The polycarbonate diol (a1) has an alicyclic structure. The alicyclic structure is preferably one with 3 to 10 carbon atoms, more preferably one with 4 to 10 carbon atoms, and even more preferably one with 5 to 8 carbon atoms. Furthermore, an "alicyclic structure" is a group of divalent atoms formed by removing two hydrogen atoms bonded to opposite carbon atoms in an alicyclic compound; in other words, it is an alkylene group having the skeleton of an alicyclic compound (hereinafter sometimes referred to as an "alicyclic alkylene group"). In addition, some of the "CH2" substituents in the above alicyclic compound may be replaced with oxygen atoms. Examples of alicyclic structures having 3 to 10 carbon atoms include cycloalkanes such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, and cyclodecane, and cycloalkenes such as cyclopropene, cyclobutene, cyclopropene, cyclohexene, cycloheptene, and cyclooctene. These alicyclic structures may be linked via linking groups or directly, and may be bicyclic or polycyclic structures.

[0016] Examples of the alicyclic structures having 3 to 10 carbon atoms include the skeleton of isosorbide (ISB) and the skeleton of cyclohexanedimethanol (CHDM). In this specification, "diol skeleton" refers to the structure of a diol after the -OH group has been removed.

[0017] The polycarbonate diol (a1) is preferably a diol represented by the following formula (2).

[0018] H(O-R4-OC(=O)) n -O-R4-OH (2)

[0019] In equation (2), R4 may consist of one or more substituents, and at least one substituent is an alicyclic structure having 3 to 10 carbon atoms. R4 and R5 may consist of one or more substituents, and are aliphatic, alicyclic, or aliphatic / alicyclic alkylene groups. The number of carbon atoms in at least one alicyclic structure having 3 to 10 carbon atoms in R4 is 3 to 10, preferably 4 to 10, and more preferably 5 to 8. n is an integer between 2 and 50. R4 may be one or more types, and it is preferable that at least one of them is an alicyclic alkylene group represented by the following structural formula (G-ISB) or structural formula (G-CHDM).

[0020] [ka]

[0021] [ka]

[0022] The number-average molecular weight (Mn) of the polycarbonate diol (a1) is not particularly limited, as long as the urethane resin (A) of this embodiment falls within the range of the number-average molecular weight (Mn) of the urethane resin (A), in accordance with the structure derived from the diisocyanate (a2) described later, the structure derived from the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group, and optionally the structure derived from the compound (D) having two or more (meth)acryloyl groups. For example, the number-average molecular weight (Mn) of the polycarbonate diol (a1) may be 200 or more, 400 or more, or 600 or more. It may also be 10,000 or less, or 8,000 or less.

[0023] Specific examples of the polycarbonate diol (a1) include, but are not limited to, polycarbonate diols HS0830B and HS0840H manufactured by Mitsubishi Chemical Corporation, and polycarbonate diols UM-90(1 / 1), UM-90(1 / 3), and UM-90(3 / 1) manufactured by Ube Industries, Ltd. The content (mol%) of the polycarbonate diol (a1) skeleton in the urethane resin (A) may be 2 mol% or more, 6 mol% or more, or 10 mol% or more. It may also be 80 mol% or less, 70 mol% or less, or 60 mol% or less. In 100% by mass of the total mass of raw materials used to synthesize the urethane resin (A), the content of polycarbonate diol (a1) may be 5% by mass or more, 10% by mass or more, or 15% by mass or more. It may also be 80% by mass or less, 70% by mass or less, or 60% by mass or less. In this specification, "the skeleton of polycarbonate diol (a1)" refers to the structure of polycarbonate diol (a1) after the -OH group has been removed.

[0024] <Diisocyanate (a2)> The above diisocyanate (a2) may be any organic isocyanate having two free isocyanate groups. Examples of such organic isocyanates include aliphatic, alicyclic, aromatic, and aromaticaliphatic isocyanates. The diisocyanate (a2) is not particularly limited as long as it can form the urethane resin (A) of this embodiment, and can be appropriately selected depending on the purpose. For example, aliphatic diisocyanate compounds such as butane diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate (TMDI), and 2,4,4-trimethylhexamethylene diisocyanate (TMDI); norbornane diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane. Examples include alicyclic diisocyanate compounds such as diisocyanates; aromatic diisocyanate compounds such as tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, and o-tolidine diisocyanate; and isocyanurate-modified, biuret-modified, allophanate-modified, etc. Any combination of the above is also acceptable. Preferably, the diisocyanate (a2) is, for example, hexamethylene diisocyanate (HDI), 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or 2,2,4-trimethylhexamethylene diisocyanate (TMDI). Any combination of the above is also acceptable. It is more preferable that the diisocyanate (a2) is isophorone diisocyanate (IPDI). The content (molar ratio %) of the diisocyanate (a2) skeleton in the urethane resin (A) may be 10 mol% or more, 20 mol% or more, or 30 mol% or more. It may also be 95 mol% or less, 90 mol% or less, or 85 mol% or less. Furthermore, in 100% by mass of the total mass of the raw materials used to synthesize the urethane resin (A), the content of diisocyanate (a2) may be 10% by mass or more, 20% by mass or more, or 30% by mass or more. It may also be 95% by mass or less, 90% by mass or less, or 85% by mass or less. In this specification, "the skeleton of diisocyanate (a2)" refers to the structure of diisocyanate (a2) after the removal of two isocyanate groups.

[0025] <Compounds having a hydroxyl group and a (meth)acryloyl group (a3)> The compound (a3) ​​having the hydroxyl group and (meth)acryloyl group described above is not particularly limited as long as it can form the urethane resin (A) of this embodiment, and can be appropriately selected depending on the purpose. Examples include hydroxyethyl (meth)acrylate (HEA / HEMA), hydroxypropyl (meth)acrylate (HPA / HPMA), 4-hydroxybutylene (meth)acrylate (4-HBA), trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol (meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane (meth)acrylate, ditrimethylolpropane di(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate. Furthermore, (poly)oxyalkylene modified compounds, in which (poly)oxyalkylene chains such as (poly)oxyethylene chains, (poly)oxypropylene chains, and (poly)oxytetramethylene chains are introduced into the molecular structure of the above-mentioned compounds having various hydroxyl groups and (meth)acryloyl groups, and lactone modified compounds, in which a (poly)lactone structure is introduced into the molecular structure of the above-mentioned compounds having various hydroxyl groups and (meth)acryloyl groups, can also be used. The compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group is preferably hydroxyethyl (meth)acrylate (HEA / HEMA), hydroxypropyl (meth)acrylate (HPA / HPMA), 4-hydroxybutylene (meth)acrylate (4-HBA), or lactone-modified hydroxyethyl (meth)acrylate (lactone-modified HEA / HEMA). Lactone-modified hydroxyethyl (meth)acrylate is a lactone-modified product in which a (poly)lactone structure is introduced into the molecular structure of hydroxyethyl (meth)acrylate.

[0026] The compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as described above can be used alone or in combination of two or more.

[0027] The content (molar ratio) of the backbone of compound (a3) ​​having hydroxyl groups and (meth)acryloyl groups in urethane resin (A) may be 10 mol% or more, 20 mol% or more, or 30 mol% or more. It may also be 95 mol% or less, 90 mol% or less, or 85 mol% or less. Furthermore, in 100% by mass of the total mass of raw materials used to synthesize urethane resin (A), the content of compound (a3) ​​having hydroxyl groups and (meth)acryloyl groups may be 10% by mass or more, 20% by mass or more, or 30% by mass or more. It may also be 90% by mass or less, 85% by mass or less, or 80% by mass or less. In this specification, "the skeleton of compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group" refers to the structure of compound (a3) ​​having a hydroxyl group and a (meth)acryloyloxy group.

[0028] It is preferable that the above-mentioned urethane resin (A) is a resin represented by the following formula (1).

[0029] [ka]

[0030] In the above equation (1), R1 and R7 each independently represent a hydrogen atom or a methyl group. R2 and R6 are the skeletons of the compound (a3) having the hydroxyl group and (meth)acryloyl group, preferably a divalent substituent derived from HEA or HEMA, HPA or HPMA, or 4-HBA lactone-modified HEA / HEMA. The skeleton of the compound (a3) having the hydroxyl group and (meth)acryloyl group is a divalent substituent obtained by removing the hydroxyl group and (meth)acryloyloxy group from the compound (a3). R3 and R5 are the skeletons of the diisocyanate (a2), preferably a divalent substituent derived from PDI, HDI, IPDI, or TMDI. The skeleton of the diisocyanate (a2) is a divalent substituent obtained by removing two diisocyanate groups from the diisocyanate (a2).

[0031] R4 is the skeleton of the polycarbonate diol (a1) represented by the above formula (2). It has the same meaning as R4 of the polycarbonate diol (a1) represented by the formula (2). n is an integer from 2 to 50.

[0032] The urethane resin (A) is preferably a resin represented by the above formula (1), and each substituent in the formula (1) is as follows. R1 and R7 each independently represent a hydrogen atom or a methyl group. R2 and R6 each independently represent -C2H4-, -C3H6-, -C4H8-, or -C2H4O(COC5H 10 )s- (s = 1 to 4). R3 and R5 each independently represent -C5H 10 -, -C6H 12 -, -C 10 H 18 -, or -C9H 18 -. R4 may be one or more types, and it is more preferable that at least one substituent has an alicyclic structure with 3 to 10 carbon atoms, and even more preferable that it has an alicyclic structure with 4 to 10 carbon atoms. R4 may be one or more types, and it is more preferable that it has an alicyclic structure with 2 to 12 carbon atoms, even more preferable that it has an alicyclic structure with 3 to 10 carbon atoms, and even more preferable that it has an alicyclic structure with 5 to 8 carbon atoms. R4 may consist of one or more substituents, and it is preferable that at least one substituent represents the isosorbide skeleton represented by the following structural formula (G-ISB) or the cyclohexanedimethanol skeleton represented by the following structural formula (G-CHDM).

[0033] [ka]

[0034] [ka]

[0035] <Structure of urethane resin (A)> The above-mentioned urethane resin (A) is reacted using the polycarbonate diol (a1), the diisocyanate (a2), and a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials. The molar ratio [(a1-1) / (a2-1) / (a3-1)] of the structure (a1-1) derived from the polycarbonate diol (a1) that constitutes the urethane resin (A), the structure (a2-1) derived from the diisocyanate (a2) that constitutes the urethane resin (A), and the structure (a3-1) derived from the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group that constitutes the urethane resin (A) may be 5-0 / 10-85 / 10-85, 10-45 / 15-75 / 15-75, or 10-40 / 20-70 / 20-70.

[0036] <Method for manufacturing urethane resin (A)> There are no particular limitations on the method for producing the urethane resin (A), and it may be produced by any method. For example, it may be produced by reacting the reaction materials containing the polycarbonate diol (a1), the diisocyanate (a2), and the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group all at once, or by reacting the reaction materials separately in sequence. For example, the reaction materials containing the polycarbonate diol (a1) and the diisocyanate (a2) may be reacted, and then the reactant product may be reacted with the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group. Alternatively, the reaction materials containing the compound (a3) ​​having a meth)acryloyl group and the diisocyanate (a2) may be reacted, and then the reactant product may be reacted with the polycarbonate diol (a1). Furthermore, since a curable resin composition with low shrinkage when cured is obtained, the equivalent ratio [(OH-1+OH-2) / NCO] between the sum of the first hydroxyl group (OH-1) of the polycarbonate diol (a1) and the second hydroxyl group (OH-2) of the compound (a3) ​​having the hydroxyl group and (meth)acryloyl group, and the isocyanate group (NCO) of the diisocyanate (a2), is preferably in the range of 0.95 / 1.00 to 1.05 / 1.00, and more preferably 1 / 1. The equivalent ratio [OH-1 / OH-2] of the first hydroxyl group (OH-1) of the polycarbonate diol (a1) and the second hydroxyl group (OH-2) of the compound (a3) ​​having the hydroxyl group and the (meth)acryloyl group is preferably in the range of 1.8 / 1.00 to 2.2 / 1.00, and more preferably 2 / 1.

[0037] In the production of urethane resin (A), for example, dibutyltin laurate or dibutyltin acetate can be used as a catalyst, and it can be produced under the conditions of a normal urethane reaction. Furthermore, if necessary, solvents such as ethyl acetate, butyl acetate, methyl isobutyl ketone, toluene, xylene, or radical polymerizable monomers that do not contain a site for reacting with isocyanates and do not contain hydroxyl or amino groups can also be used as solvents.

[0038] <Properties of urethane resin (A)> In this embodiment, the urethane resin (A) used preferably has a (meth)acryloyl group content of 0.6 mmol / g or more and 2.0 mmol / g or less, more preferably 0.7 mmol / g or more and 1.7 mmol / g or less, and even more preferably 0.7 mmol / g or more and 1.6 mmol / g or less. By incorporating a urethane resin (A) having a specific content of (meth)acryloyl groups into a curable resin composition, a curable resin composition for stereolithography is obtained that exhibits low shrinkage when cured, as shown in the following examples. The content of (meth)acryloyl groups in urethane resin (A) is, for example, 1 The acryloyl group content can be determined by assigning each peak of the measurement sample and the internal standard using an HNMR analyzer and determining the integral ratio, or by creating a calibration curve from the ratio of the peak attributable to the acryloyl group to a specific peak of the standard substance using an IR analyzer and quantifying the result. In this application, the (meth)acryloyl group content of urethane resin (A) was calculated based on the (theoretical value) of the (meth)acryloyl group content of the raw material.

[0039] The number-average molecular weight (Mn) of the urethane resin (A) used in this embodiment is 200 or more, preferably 400 or more, and more preferably 600 or more. Furthermore, the number-average molecular weight (Mn) of the urethane resin (A) may be 10,000 or less, or 8,000 or less. By setting the number-average molecular weight (Mn) of the urethane resin (A) used in the stereolithography curable resin composition of this embodiment to the above range, a stereolithography curable resin composition with low shrinkage when cured is obtained, as shown in the following examples. The number-average molecular weight (Mn) of the (meth)acryloyl groups in the urethane resin (A) can be obtained, for example, by the measurement method described in the Examples.

[0040] [Compound (B)] The α,β-unsaturated carbonyl compound (B) (sometimes simply referred to as "compound (B)") has a glass transition temperature (hereinafter abbreviated as "Tg") of 50°C or higher when used as a monomer polymer, preferably 60°C or higher, and more preferably 70°C or higher. It may also be 250°C or lower. In this specification, the "glass transition temperature (Tg) of a monomer when it is used as a monomer polymer" refers to the glass transition temperature (Tg) of the monomer polymer (homopolymer). The α,β-unsaturated carbonyl compound (B) does not necessarily have to contain a (meth)acryloyl group. Specific examples of compound (B) that does not contain a (meth)acryloyl group include, for example, methyl 2-(allyloxymethyl)acrylate (methyl 2-allyloxymethyl acrylate). It is preferable that the α,β-unsaturated carbonyl compound (B) is a compound having one (meth)acryloyl group. The compound (B) may also include nitrogen-containing (meth)acrylic compounds. For example, compound (B) can be a (meth)acrylic compound such as (meth)acrylate compounds or (meth)acrylamides. Examples of the compound (B) include monofunctional (meth)acrylate compounds such as isobornyl acrylate (Tg: 94°C), isobornyl methacrylate (Tg: 180°C), dicyclopentenyl acrylate (Tg: 120°C), dicyclopentanyl acrylate (Tg: 120°C), dicyclopentanyl methacrylate (Tg: 175°C), acryloylmorpholine (Tg: 145°C), phenyl methacrylate (Tg: 110°C), dicyclopentenyl acrylate (Tg: 120°C), adamantyl methacrylate (Tg: 250°C), and (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate (Tg: 212°C). The aforementioned compound (B) can be used alone or in combination of two or more compounds. Among these, (meth)acrylic compounds having cyclic structures such as condensed polycyclic structures and heterocyclic structures are preferred, and further preferred are isobornyl acrylate (Tg: 94°C), isobornyl methacrylate (Tg: 180°C), dicyclopentenyl acrylate (Tg: 120°C), dicyclopentanyl acrylate (Tg: 120°C), and dicyclopentanyl methacrylate (Tg: 175°C).

[0041] Furthermore, when using two or more of the above-mentioned compound (B), it is preferable that the Tg of the copolymer of the two or more α,β-unsaturated carbonyl compounds be 50°C or higher.

[0042] Furthermore, the α,β-unsaturated carbonyl compound (B) may also include nitrogen-containing (meth)acrylic compounds, but (meth)acrylamide represented by the following formula (3) is particularly preferred from the viewpoint of adhesion of the cured product to the molding stage.

[0043] [ka]

[0044] In equation (3) above, R 8 R represents a hydrogen atom or a methyl group. 9 and R 10Each of these is independently a monovalent hydrocarbon group having 1 to 40 carbon atoms which may have a ring structure, a group in which some of the carbon atoms of the hydrocarbon group are replaced with oxygen atoms or nitrogen atoms, or a hydrogen atom, and R 9 and R 10 They may bond to each other to form a ring, R 9 and R 10 The monovalent hydrocarbon group having 1 to 40 carbon atoms, represented by , may or may not contain an unsaturated double bond.

[0045] Examples of the compound (B) represented by formula (3) include acryloylmorpholine, isopropylacrylamide, dimethylacrylamide, hydroxyethylacrylamide, and diethylacrylamide. Among these, (meth)acrylamide compounds having cyclic structures such as condensed polycyclic structures and heterocyclic structures are preferred, and acryloylmorpholine (Tg: 145°C) is particularly preferred.

[0046] [Compound (D)] The stereochemical curable resin composition of this embodiment preferably further contains two or more compounds (D) having (meth)acryloyl groups (sometimes simply referred to as "compound (D)"). The compound (D) having two or more (meth)acryloyl groups has a glass transition temperature (Tg) of 90°C or higher when it is a monomer polymer. Preferably, the glass transition temperature (Tg) of the monomer polymer of compound (D) is 60°C or higher, and more preferably 70°C or higher. It may also be 250°C or lower. Examples of the compound (D) having two or more (meth)acryloyl groups include dipropylene glycol diacrylate (Tg: 102°C), tricyclodecanedimethanol diacrylate (Tg: 110°C), neopentyl glycol diacrylate hydroxypivalate (Tg: 111°C), isosorbide diacrylate (Tg: 175°C), and bisphenol A diglycidyl diacrylate (Tg: 79°C). These compounds (D) can be used individually or in combination of two or more. Furthermore, among the compounds (D) mentioned above, compounds in which the Tg of the bifunctional (meth)acrylic polymer is 40°C or higher are preferred, as they yield a curable resin composition that is low viscosity and capable of forming a cured product with excellent mechanical properties. Among these, dipropylene glycol diacrylate (Tg: 102°C), tricyclodecanedimethanol diacrylate (Tg: 110°C), and neopentyl glycol diacrylate hydroxypivalate (Tg: 111°C) are more preferred.

[0047] Furthermore, when using two or more of the above-mentioned compound (D) in combination, it is preferable that the Tg of the copolymer of the two or more bifunctional (meth)acrylic compounds is 60°C or higher.

[0048] Furthermore, the α,β-unsaturated carbonyl compound (B) and the compound (D) having two or more (meth)acryloyl groups can be used in combination. In this case, it is preferable that the Tg of the copolymer of the (meth)acrylic compounds used in combination is 60°C or higher.

[0049] [Other (meth)acrylic compounds (E)] Within the limits that do not impede the effects of the present invention, the photopolymerizable resin composition of this embodiment may further contain, if necessary, other (meth)acrylic compounds (E) such as trifunctional or higher (meth)acrylic compounds (sometimes simply referred to as "compound (E)") in addition to the α,β-unsaturated carbonyl compound (B) and the compound (D) having two or more (meth)acryloyl groups. In this case as well, it is preferable that the Tg of the copolymer of the other (meth)acrylic compound (E) used in combination is 40°C or higher.

[0050] Examples of the three- or more functional (meth)acrylic compounds include trifunctional (meth)acrylates such as EO-modified glycerol acrylate, PO-modified glycerol triacrylate, pentaerythritol triacrylate, EO-modified phosphate triacrylate, trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane triacrylate, (EO) or (PO)-modified trimethylolpropane triacrylate, alkyl-modified dipentaerythritol triacrylate, and tris(acryloxyethyl) isocyanurate;

[0051] Tetrafunctional (meth)acrylates such as ditrimethylolpropanetetraacrylate, pentaerythritol ethoxytetraacrylate, and pentaerythritol tetraacrylate;

[0052] Pentafunctional (meth)acrylates such as dipentaerythritol hydroxypentaacrylate and alkyl-modified dipentaerythritol pentaacrylate;

[0053] Examples include hexafunctional (meth)acrylates such as dipentaerythritol hexaacrylate. These trifunctional or more functional (meth)acrylic compounds (more specifically, (meth)acrylates) can be used alone or in combination of two or more types.

[0054] [Photopolymerization initiator] The stereochemical curable resin composition of this embodiment further contains a photopolymerization initiator. Examples of photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, thioxanthones and thioxanthone derivatives, 2,2'-dimethoxy-1,2-diphenylethane-1-one, diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, polymeric TPO-L, and the like.

[0055] Other commercially available photopolymerization initiators include, for example, "Omnirad-1173", "Omnirad-184", "Omnirad-127", "Omnirad-2959", "Omnirad-369", "Omnirad-379", "Omnirad-907", "Omnirad-4265", "Omnirad-1000", "Omnirad-651", "Omnirad-TPO", "Omnirad-819", "Omnirad-2022", "Omnirad-2100", "Omnirad-2959", "Omnirad-754", "Omnirad-784", "Omnirad-500", "Omnirad-81", "Omnirad TPO-L", and "Omnipol Examples include "TP" (manufactured by IGM), "KayaCure-DETX", "KayaCure-MBP", "KayaCure-DMBI", "KayaCure-EPA", "KayaCure-OA" (manufactured by Nippon Kayaku Co., Ltd.), "ByCure-10", "ByCure-55" (manufactured by Stauffa Chemicals), "Trigonal P1" (manufactured by Akzo), "Sandoz 1000" (manufactured by Sandoz), "Deep" (manufactured by Apjohn), "Quantacure-PDO", "Quantacure-ITX", "Quantacure-EPD" (manufactured by Ward Blenkinsop), "Runtecure-1104" (manufactured by Runtec), etc.

[0056] The amount of photopolymerization initiator added is preferably in the range of 1 to 20% by mass in the photopolymerization curable resin composition.

[0057] [Other additives] Furthermore, the stereochemical curable resin composition of this embodiment may optionally contain various additives such as photosensitizers, ultraviolet absorbers, antioxidants, polymerization inhibitors, silicone-based additives, fluorine-based additives, silane coupling agents, phosphate ester compounds, organic beads, inorganic fine particles, organic fillers, inorganic fillers, rheology control agents, defoaming agents, and colorants.

[0058] The stereochemical curable resin composition of this embodiment can be further improved by adding a photosensitizer as needed to enhance its curability. Examples of photosensitizers include amine compounds such as aliphatic amines and aromatic amines, urea compounds such as o-tolylthiourea, condensed polycyclic compounds such as anthraquinone derivatives, and sulfur compounds such as sodium diethyldithiophosphate and s-benzylisothironium-p-toluenesulfonate.

[0059] Examples of UV absorbers include triazine derivatives such as 2-[4-{(2-hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-{(2-hydroxy-3-tridecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2'-xanthenecarboxy-5'-methylphenyl)benzotriazole, 2-(2'-o-nitrobenzyloxy 5'-methylphenyl)benzotriazole, 2-xanthenecarboxy-4-dodecyloxybenzophenone, and 2-o-nitrobenzyloxy-4-dodecyloxybenzophenone. These UV absorbers can be used individually or in combination of two or more.

[0060] Examples of antioxidants include hindered phenol antioxidants, hindered amine antioxidants, organosulfur antioxidants, and phosphate ester antioxidants. These antioxidants can be used individually or in combination of two or more.

[0061] Examples of polymerization inhibitors include hydroquinone, methoquinone, di-t-butylhydroquinone, p-methoxyphenol, butylhydroxytoluene, and nitrosamine salts.

[0062] Examples of silicon-based additives include polyorganosiloxanes having alkyl or phenyl groups, such as dimethylpolysiloxane, methylphenylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, polyether-modified dimethylpolysiloxane copolymer, polyester-modified dimethylpolysiloxane copolymer, fluorine-modified dimethylpolysiloxane copolymer, and amino-modified dimethylpolysiloxane copolymer; polydimethylsiloxane having polyether-modified acrylic groups; and polydimethylsiloxane having polyester-modified acrylic groups. These silicon-based additives can be used individually or in combination of two or more types.

[0063] Examples of fluorine-based additives include the "Megaface" series manufactured by DIC Corporation. These fluorine-based additives can be used individually or in combination of two or more types.

[0064] Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltri Vinyl-based silane coupling agents such as ethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, hydrochloride salt of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, special aminosilanes, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatetopropyltriethoxysilane, allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane;

[0065] Epoxy-based silane coupling agents such as diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane;

[0066] Styrene-based silane coupling agents such as p-styryltrimethoxysilane;

[0067] (Meth)acryloxy-based silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane;

[0068] Amino-based silane coupling agents such as N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane;

[0069] Ureidopropyltriethoxysilane and other ureidopropyl silane coupling agents;

[0070] Chloropropyl silane coupling agents such as 3-chloropropyltrimethoxysilane;

[0071] Mercaptopropyl silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoquinsilane;

[0072] Sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide;

[0073] Examples include isocyanate-based silane coupling agents such as 3-isocyanate-propyltriethoxysilane. These silane coupling agents can be used individually or in combination of two or more.

[0074] Examples of phosphate ester compounds include those having a (meth)acryloyl group in their molecular structure. Commercially available examples include "Kayama PM-2" and "Kayama PM-21" from Nippon Kayaku Co., Ltd., "Light Ester P-1M," "Light Ester P-2M," and "Light Acrylate P-1A(N)" from Kyoeisha Chemical Co., Ltd., "Sipomer PAM 100," "Sipomer PAM 200," "Sipomer PAM 300," and "Sipomer PAM 4000" from SOLVAY, "Viscote #3PA" and "Viscote #3PMA" from Osaka Organic Chemical Industry Co., Ltd., and "New Frontier S 23A" from Daiichi Kogyo Seiyaku Co., Ltd.; and "Sipomer PAM 5000" from SOLVAY, which is a phosphate ester compound having an allyl ether group in its molecular structure.

[0075] Examples of organic beads include polymethyl methacrylate beads, polycarbonate beads, polystyrene beads, polyacrylic styrene beads, silicone beads, glass beads, acrylic beads, benzoguanamine resin beads, melamine resin beads, polyolefin resin beads, polyester resin beads, polyamide resin beads, polyimide resin beads, polyfluoroethylene resin beads, and polyethylene resin beads. These organic beads can be used individually or in combination of two or more types. The average particle size of these organic beads is preferably in the range of 1 to 10 μm.

[0076] Examples of inorganic nanoparticles include silica, alumina, zirconia, titania, barium titanate, and antimony trioxide. These inorganic nanoparticles can be used individually or in combination of two or more types. The average particle size of these inorganic nanoparticles is preferably in the range of 95 to 250 nm, and more preferably in the range of 100 to 180 nm.

[0077] If inorganic fine particles are present, a dispersion aid can be used. Examples of dispersion aids include isopropyl acid phosphate, triisodecyl phosphate, and phosphate ester compounds such as ethylene oxide-modified dimethacrylate phosphate. These dispersion aids can be used individually or in combination of two or more. Examples of commercially available dispersion aids include "Kayama PM-21" and "Kayama PM-2" manufactured by Nippon Kayaku Co., Ltd., and "Light Ester P-2M" manufactured by Kyoeisha Chemical Co., Ltd.

[0078] Examples of organic fillers include solvent-insoluble substances derived from plants, such as cellulose, lignin, and cellulose nanofibers.

[0079] Examples of inorganic fillers include glass (particles), silica (particles), alumina silicate, talc, mica, aluminum hydroxide, alumina, calcium carbonate, and carbon nanotubes.

[0080] Examples of rheology control agents include amide waxes such as "Disparon 6900" manufactured by Kusumoto Kasei Co., Ltd.; urea-based rheology control agents such as "BYK410" manufactured by Big Chemie; polyethylene waxes such as "Disparon 4200" manufactured by Kusumoto Kasei Co., Ltd.; and cellulose acetate butyrates such as "CAB-381-2" and "CAB 32101" manufactured by Eastman Chemical Products.

[0081] Examples of defoaming agents include oligomers containing fluorine or silicon atoms, or oligomers such as higher fatty acids or acrylic polymers.

[0082] Examples of coloring agents include pigments and dyes.

[0083] As pigments, commonly known and conventional inorganic pigments and organic pigments can be used.

[0084] Examples of inorganic pigments include titanium dioxide, antimony red, red iron oxide, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine blue, carbon black, and graphite.

[0085] Examples of organic pigments include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ancenthron pigments, indanthron pigments, flavanthron pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, and azo pigments. These pigments can be used individually or in combination of two or more.

[0086] Examples of dyes include azo dyes such as monoazo and disazo, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinoimine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, perinone dyes, phthalocyanine dyes, and triallylmethane-based dyes. These dyes can be used individually or in combination of two or more.

[0087] [Characteristics of curable resin compositions for stereolithography] In this embodiment, the content of the urethane resin (A) in the stereolithography curable resin composition is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 45% by mass or less. By setting the content of the urethane resin (A) in this embodiment to the above range, a stereolithography curable resin composition with low shrinkage when cured can be obtained, as shown in the following examples. Furthermore, by setting the content of the urethane resin (A) in this embodiment to 20% by mass or more, the stereolithography curable resin composition can form optically three-dimensional objects that have both low shrinkage and heat resistance when cured, as shown in the following examples. In the stereolithography curable resin composition of this embodiment, the content of the α,β-unsaturated carbonyl compound (B) is preferably 20% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and even more preferably 20% by mass or more and 70% by mass or less. By setting the content of compound (B) in the stereolithography curable resin composition of this embodiment to the above range, a stereolithography curable resin composition having low shrinkage when cured is obtained, as shown in the following examples.

[0088] Furthermore, it is preferable that the content of the urethane resin (A) in the stereolithography curable resin composition of this embodiment is 20% by mass or more and 50% by mass or less, and the content of the α,β-unsaturated carbonyl compound (B) is 20% by mass or more and 80% by mass or less. It is more preferable that the content of the urethane resin (A) is 20% by mass or more and 45% by mass or less, and the content of the α,β-unsaturated carbonyl compound (B) is 20% by mass or more and 70% by mass or less. By setting the content of the urethane resin (A) and compound (B) in the stereolithography curable resin composition of this embodiment to the above ranges, the curable resin composition can form optically three-dimensional objects that have both low shrinkage and heat resistance when cured, as shown in the following examples.

[0089] In the stereolithography curable resin composition of this embodiment, the content of compound (D) having two or more (meth)acryloyl groups is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 45% by mass or less, and even more preferably 10% by mass or more and 40% by mass or less. By setting the content of compound (D) in the stereolithography curable resin composition of this embodiment to the above range, a stereolithography curable resin composition having low shrinkage when cured is obtained, as shown in the following examples.

[0090] (Second Embodiment) The photopolymerization curable resin composition of this embodiment comprises a urethane resin (A) having two (meth)acryloyl groups (sometimes simply referred to as "urethane resin (A)"), an α,β-unsaturated carbonyl compound (B), a urethane resin (C) having two or more (meth)acryloyl groups and not having an alicyclic structure, and a photopolymerization initiator. The urethane resin (A) is reacted using a polycarbonate diol (a1), a diisocyanate (a2), and a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials. The polycarbonate diol (a1) has an alicyclic structure. The α,β-unsaturated carbonyl compound (B) has a glass transition temperature (Tg) of 50°C or higher when used as a monomer polymer.

[0091] The stereochemical curable resin composition of this embodiment preferably further comprises a compound (D) having two or more (meth)acryloyl groups. The compound (D) having two or more (meth)acryloyl groups has a glass transition temperature (Tg) of 60°C or higher when it is used as a monomer polymer. It is preferable that the (meth)acryloyl group content of the urethane resin (A) is 0.6 mmol / g or more and 2.0 mmol / g or less.

[0092] Furthermore, the stereochemical curable resin composition of this embodiment may also contain other trifunctional or higher (meth)acrylic compounds (E) other than the α,β-unsaturated carbonyl compound (B) and / or the compound (D) having two or more (meth)acryloyl groups, as long as they do not impede the effects of the present invention. Furthermore, the stereochemical curable resin composition of this embodiment may also contain other additives such as photosensitizers, ultraviolet absorbers, polymerization inhibitors, and inorganic fillers, as needed.

[0093] [Urethane resin (A)] The urethane resin (A) used in this embodiment has the same meaning as [urethane resin (A)] in the first embodiment. Furthermore, the phrase "has the same meaning as the [configuration] of the first embodiment" in this invention means that it is the same as the description of the first embodiment, and therefore the description of the first embodiment is incorporated herein by reference.

[0094] [Compound (B)] The α,β-unsaturated carbonyl compound (B) used in this embodiment has the same meaning as [compound (B)] in the first embodiment.

[0095] [Urethane resin (C)] The urethane resin (C) used in this embodiment is a urethane resin having two or more (meth)acryloyl groups and not having an alicyclic structure (hereinafter sometimes referred to as "urethane resin (C)"). The urethane resin (C) may or may not have a polycarbonate structure.

[0096] "Urethane resin having a polycarbonate structure (C)" The urethane resin (C) having a polycarbonate structure may, for example, use a polycarbonate diol (a1x), a diisocyanate (a2), or a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials. The polycarbonate diol (a1x) does not have an alicyclic structure.

[0097] <Polycarbonate diol (a1x)> The polycarbonate diol (a1x) does not have an alicyclic structure. The term "alicyclic structure" has the same meaning as the "alicyclic structure" of the polycarbonate diol (a1) in the first embodiment. Specific examples of the aforementioned polycarbonate diol (a1x) include, but are not limited to, Kuraray Co., Ltd.'s polycarbonate diols Kuraray Polyol C-2050, C-2090, C-3050, C-3090; Asahi Kasei Corporation's polycarbonate diols Duranol T5651, T4671, T4691, G3450J, G3452; Ube Industries, Ltd.'s polycarbonate diols ETERNACOLL UH-50, PH-50, UHC50-100; and Daicel Corporation's PLACCEL CD205PL, CD220PL, etc.

[0098] <Diisocyanate (a2)> The diisocyanate (a2) is the same as the diisocyanate (a2) in the first embodiment.

[0099] <Compounds having a hydroxyl group and a (meth)acryloyl group (a3)> The compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group is the same as the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group in the first embodiment.

[0100] "Urethane resin (C) that does not have a polycarbonate structure" Examples of urethane resins (C) that do not have a polycarbonate structure include urethane acrylates made of diols having a polyester skeleton, urethane acrylates made of diols having a polyether skeleton, aliphatic urethane acrylates, and urethane acrylates made of diols having a polycaprolactone skeleton. Specific examples of the polyester backbone diols mentioned above include, for example, the polyester diols Kuraray Polyol P-1012, P-2012, P-1050, P-2050, P-510, P-1010, P-2010, P-3010, P-4010, P-5010, and P-6010 manufactured by Kuraray Co., Ltd. Specific examples of diols having the aforementioned polyether skeleton include, for example, the poly(tetramethylene oxide) glycol PTMG series manufactured by Mitsubishi Chemical Corporation and the polypropylene glycol Sannix PP series manufactured by Sanyo Chemical Industries, Ltd. Specific examples of the aliphatic urethane acrylate include the product names "EBECRYL220", "EBECRYL4513", "EBECRYL4738", "EBECRYL4740", "EBECRYL8311", "EBECRYL9260", "EBECRYL8701", "KRM8667", "KRM8296", "EBECRYL4265", "EBECRYL4587", "EBECRYL4666", and "EBECRYL4701", all manufactured by Daicel Ornex Co., Ltd. Examples include "YL8210", "EBECRYL1290", "EBECRYL5129", "EBECRYL8301R", "KRM8200", "KRM8904", "KRM8451", "KRM9465", "EBECRYL230", "EBECRYL270", "EBECRYL4491", "EBECRYL4858", "EBECRYL8804", "EBECRYL8807", "EBECRYL8800", and MIWON brand names such as "MIRAMER PU340", "MIRAMER PU3450", "MIRAMER PU5000", "MIRAMER PU610", "MIRAMER PU6510", "MIRAMER PU9500", "MIRAMER PU9800", "MIRAMER SC2100", "MIRAMER SC2565", "MIRAMER PU370", and "MIRAMER PU640". Specific examples of diols containing a polycaprolactone skeleton include the Plaxel 200 series manufactured by Daicel Corporation.

[0101] If the urethane resin (C) is a urethane acrylate composed of a diol, the urethane acrylate composed of a diol may be obtained by using a compound (a3) ​​having a diol (c1), a diisocyanate (a2), a hydroxyl group, and a (meth)acryloyl group as reaction raw materials. The diol (c1) does not have an alicyclic structure. The urethane resin (C) used in this embodiment can be obtained by reacting the diol (c1), the diisocyanate (a2), and the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group.

[0102] <Polycarbonate diol (c1)> The polycarbonate diol (c1) does not have an alicyclic structure. The term "alicyclic structure" has the same meaning as the term "alicyclic structure" of the polycarbonate diol (a1) in the first embodiment. Examples of the diol (c1) include diols having a polyester structure, a polyether structure, and the like. Specific examples of the aforementioned diol (c1) include, but are not limited to, Kuraray Polyol P-2012, a polyester diol manufactured by Kuraray Co., Ltd., and PTMG3000, a poly(tetramethylene oxide) glycol manufactured by Mitsubishi Chemical Corporation.

[0103] <Diisocyanate (a2)> The diisocyanate (a2) is the same as the diisocyanate (a2) in the first embodiment.

[0104] <Compounds having a hydroxyl group and a (meth)acryloyl group (a3)> The compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group is the same as the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group in the first embodiment.

[0105] <Structure of urethane resin (C)> When the above-mentioned urethane resin (C) is obtained using the polycarbonate diol (a1x), the diisocyanate (a2), and the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials, the molar ratio [(a1x-1) / (a2-1) / (a3-1)] of the structure (a1x-1) derived from the polycarbonate diol (a1x) in the urethane resin (C), the structure (a2-1) derived from the diisocyanate (a2) in the urethane resin (C), and the structure (a3-1) derived from the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group in the urethane resin (C) may be 5-50 / 10-85 / 10-85, 10-45 / 15-75 / 15-75, or 10-40 / 20-70 / 20-70.

[0106] When the above-mentioned urethane resin (C) is obtained using the diol (c1), the diisocyanate (a2), and a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials, the molar ratio [(c1-1) / (a2-1) / (a3-1)] of the structure (c1-1) derived from the diol (c1) in the urethane resin (C), the structure (a2-1) derived from the diisocyanate (a2) in the urethane resin (C), and the structure (a3-1) derived from the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group in the urethane resin (C) may be 5-50 / 10-85 / 10-85, 10-45 / 15-75 / 15-75, or 10-40 / 20-70 / 20-70.

[0107] <Method for manufacturing urethane resin (C)> The method for producing the urethane resin (C) is not particularly limited and can be produced by any method. For example, the polycarbonate diol (a1x) or diol (c1) may be produced by reacting reaction materials containing the diisocyanate (a2) and the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group all at once, or by reacting the reaction materials separately in sequence. For example, the polycarbonate diol may be reacted with the reaction materials containing the polycarbonate diol (a1x) or diol (c1) and the diisocyanate (a2), and then the reactant may be reacted with the compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group. Alternatively, a reaction material containing the compound (a3) ​​having a meth)acryloyl group and the diisocyanate (a2) may be reacted, and then the reactant may be reacted with the polycarbonate diol (a1x) or diol (c1). Furthermore, since a curable resin composition is obtained that can form optically three-dimensional molded objects that have both low shrinkage and impact resistance when cured, the equivalent ratio [(OH-1+OH-2) / NCO] of the sum of the first hydroxyl group (OH-1) of the polycarbonate diol (a1x) or diol (c1) and the second hydroxyl group (OH-2) of the compound (a3) ​​having the hydroxyl group and (meth)acryloyl group, and the isocyanate group (NCO) of the diisocyanate (a2), is preferably in the range of 0.95 / 1.00 to 1.05 / 1.00, and more preferably 1 / 1. The equivalent ratio [OH-1 / OH-2] of the first hydroxyl group (OH-1) of the polycarbonate diol (a1x) or diol (c1) and the second hydroxyl group (OH-2) of the compound (a3) ​​having the hydroxyl group and (meth)acryloyl group is preferably in the range of 1.8 / 1.00 to 2.2 / 1.00, and more preferably 2 / 1.

[0108] In the production of urethane resin (C), for example, dibutyltin laurate or dibutyltin acetate can be used as a catalyst, and it can be produced under the conditions of a typical urethane reaction. Furthermore, if necessary, solvents such as ethyl acetate, butyl acetate, methyl isobutyl ketone, toluene, xylene, or radical polymerizable monomers that do not contain a site for reacting with isocyanates and do not contain hydroxyl or amino groups can also be used as solvents.

[0109] <Properties of urethane resin (C)> In this embodiment, the urethane resin (C) used preferably has a (meth)acryloyl group content of 0.2 mmol / g or more and 2.0 mmol / g or less, more preferably 0.2 mmol / g or more and 1.7 mmol / g or less, and even more preferably 0.3 mmol / g or more and 1.7 mmol / g or less. By incorporating a urethane resin (C) having a specific content of (meth)acryloyl groups into a curable resin composition, the curable resin composition can form optical three-dimensional objects that exhibit both low shrinkage and impact resistance when cured, as shown in the following examples. The content of (meth)acryloyl groups in urethane resin (C) is, for example, 1 The acryloyl group content can be determined by assigning each peak of the measurement sample and the internal standard using an HNMR analyzer and determining the integral ratio, or by creating a calibration curve from the ratio of the peak attributable to the acryloyl group to a specific peak of the standard substance using an IR analyzer and quantifying the result. In this application, the (meth)acryloyl group content of urethane resin (A) was calculated based on the (theoretical value) of the (meth)acryloyl group content of the raw material.

[0110] The number-average molecular weight (Mn) of the urethane resin (C) used in this embodiment is 1000 or more, preferably 1500 or more, and more preferably 2000 or more. The number-average molecular weight (Mn) of the urethane resin (A) may be 12000 or less, or 10000 or less. By setting the number-average molecular weight (Mn) of the urethane resin (C) used in the stereolithography curable resin composition of this embodiment to the above range, the curable resin composition can form optically three-dimensional objects that have both low shrinkage and impact resistance when cured, as shown in the following examples. The number-average molecular weight (Mn) of the (meth)acryloyl groups in the urethane resin (C) can be obtained, for example, by the measurement method described in the examples.

[0111] [Compound (D)] Compound (D) in this embodiment has the same meaning as [Compound (D)] in the first embodiment.

[0112] [Other (meth)acrylic compounds (E)] The other (meth)acrylic compound (E) in this embodiment has the same meaning as [other (meth)acrylic compound (E)] in the first embodiment.

[0113] [Photopolymerization initiator] The photopolymerization initiator in this embodiment has the same meaning as the [photopolymerization initiator] in the first embodiment.

[0114] [Other additives] Other additives in this embodiment have the same meaning as "other additives" in the first embodiment.

[0115] [Characteristics of curable resin compositions for stereolithography] In the stereolithography curable resin composition of this embodiment, it is preferable that the content of the urethane resin (A) is 5% by mass or more and 25% by mass or less, the content of the α,β-unsaturated carbonyl compound (B) is 10% by mass or more and 50% by mass or less, and the content of the urethane resin (C) is 20% by mass or more and 60% by mass or less. In the stereolithography curable resin composition of this embodiment, it is more preferable that the content of the urethane resin (A) is 5% by mass or more and 25% by mass or less, the content of the α,β-unsaturated carbonyl compound (B) is 10% by mass or more and 40% by mass or less, and the content of the urethane resin (C) is 20% by mass or more and 50% by mass or less. By adjusting the content of the urethane resin (A), compound (B), and urethane resin (C) in the stereochemical curable resin composition of this embodiment to the above range, the curable resin composition can form optically three-dimensional objects that exhibit both low shrinkage and impact resistance when cured, as shown in the following examples. Furthermore, when the stereochemical curable resin composition for stereolithography of this embodiment contains the compound (D) having two or more (meth)acryloyl groups, its content is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 45% by mass or less, and even more preferably 10% by mass or more and 40% by mass or less. By setting the content of compound (D) in the stereochemical curable resin composition for stereolithography of this embodiment to the above range, the curable resin composition can form optically three-dimensional objects that have low shrinkage and impact resistance as well as heat resistance when cured, as shown in the following examples.

[0116] (cured product) The cured product of one embodiment of the present invention is a cured reaction product of the above-mentioned curable resin composition for stereolithography. The cured product of this embodiment can be obtained by irradiating the curable resin composition for stereolithography with active energy rays. Examples of active energy rays include ionizing radiation such as ultraviolet rays, electron beams, alpha rays, beta rays, and gamma rays. When ultraviolet rays are used as the active energy rays, irradiation may be carried out under an inert gas atmosphere such as nitrogen gas, or under an air atmosphere, in order to efficiently carry out the curing reaction by ultraviolet rays.

[0117] For practical and economic reasons, ultraviolet lamps are commonly used as sources of ultraviolet light. Specifically, these include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, sunlight, and LEDs.

[0118] The integrated amount of active energy rays is not particularly limited, but is generally between 50 and 5,000 mJ / cm². 2 Preferably, the concentration is 300-1,000 mJ / cm². 2 It is more preferable that the cumulative light intensity is within the above range, as this can prevent or suppress the occurrence of uncured areas.

[0119] (3D model) A three-dimensional object according to one embodiment of the present invention is made of the above-mentioned cured material. The three-dimensional object according to this embodiment can be manufactured by the above-mentioned known optical three-dimensional manufacturing method.

[0120] Examples of optical three-dimensional modeling methods include stereolithography (SLA), digital light processing (DLP), and inkjet.

[0121] Stereolithography (SLA) is a method of creating three-dimensional objects by irradiating a tank of liquid, curable resin composition with active energy rays, such as laser beams, at a single point, and curing each layer while moving the build stage.

[0122] The Digital Light Processing (DLP) method is a technique that involves irradiating a tank of liquid, curable resin composition with active energy rays, such as those from an LED, and curing it layer by layer while moving the build stage to create a three-dimensional object.

[0123] Inkjet photopolymerization is a method in which minute droplets of a photopolymerizable resin composition are ejected from a nozzle to create a predetermined shape pattern, and then cured into a thin film by irradiating with ultraviolet light.

[0124] Among these optical 3D printing methods, the DLP method is preferred because it allows for high-speed printing using surfaces.

[0125] While there are no particular restrictions on DLP-based 3D printing methods, as long as they utilize a DLP stereolithography system, the printing conditions should ideally be such that the layer thickness is in the range of 0.01 to 0.2 mm, the irradiation wavelength is in the range of 350 to 410 nm, and the light intensity is in the range of 0.5 to 50 mW / cm² to achieve good printing accuracy. 2 This range includes an integrated light intensity of 1 to 100 mJ / cm² per layer. 2 The following conditions must be met, and in particular, to achieve even better accuracy in creating three-dimensional objects, the layer thickness for stereolithography should be in the range of 0.02 to 0.1 mm, the irradiation wavelength in the range of 380 to 410 nm, and the light intensity should be in the range of 5 to 15 mW / cm². 2 The range is such that the cumulative light intensity per layer is 5-15 mJ / cm². 2 It is preferable that it be within the range of [specify range].

[0126] The three-dimensional object produced by the present invention is a cured product of a photopolymerizable resin composition having low shrinkage when cured. Furthermore, the three-dimensional object produced by a preferred embodiment of the present invention is an optically produced object with impact resistance or heat resistance, and can therefore be suitably used for, for example, automobile parts, aerospace-related parts, electrical and electronic components, home appliances, building materials, etc. [Examples]

[0127] The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to these examples.

[0128] The materials used in the following synthesis examples and examples are as follows:

[0129] "Polycarbonate diol (a1)" BENEBiOL HS0830B is a polycarbonate diol manufactured by Mitsubishi Chemical Corporation. It is a copolymer of isosorbide and butanediol. Mn ≈ 800 Isosorbide: Represented by the following formula (ISB).

[0130] [ka]

[0131] BENEBiOL HS0840H is a polycarbonate diol manufactured by Mitsubishi Chemical Corporation. It is a copolymer of isosorbide and hexanediol. Mn ≈ 800 ETERNACOLL UM-90(1 / 1) is a polycarbonate diol manufactured by Ube Industries, Ltd. It is a copolymer of cyclohexanedimethanol and hexanediol (1 / 1 ratio). Molecular weight: approximately 900. Cyclohexanedimethanol: Represented by the following formula (CHDM).

[0132] [ka]

[0133] ETERNACOLL UM-90 (1 / 3) is a polycarbonate diol manufactured by Ube Industries, Ltd. It is a copolymer of cyclohexanedimethanol and hexanediol (1 / 3 ratio). Molecular weight: approximately 900. ETERNACOLL UM-90(3 / 1) is a polycarbonate diol manufactured by Ube Industries, Ltd. It is a copolymer of cyclohexanedimethanol / hexanediol = 3 / 1. Molecular weight: approximately 900.

[0134] "Diol (c1)" • PTMG3000, manufactured by Mitsubishi Chemical Corporation, poly(tetramethylene oxide) glycol, number average molecular weight 3000. • Kuraray Polyol P-2012: A polyester diol manufactured by Kuraray Co., Ltd. A copolymer of 3-methylpentanediol / adipic acid / isophthalic acid. Mw ≈ 2,000

[0135] "Urethane resin (C)" MIRAMER PU340, manufactured by MIWON, is a trifunctional aliphatic urethane acrylate oligomer with a weight-average molecular weight of 2400.

[0136] "Polycarbonate diol (C1)" • Duranol T5651: A polycarbonate diol manufactured by Asahi Kasei Corporation. A copolymer of pentanediol and hexanediol (C6). Mn = 1,000

[0137] "Diisocyanate (a2)" • Isophorone diisocyanate (IPDI): A diisocyanate represented by the following formula (a2-1) [ka]

[0138] • Sumijool N3300: An isocyanurate-type hexamethylene diisocyanate (HDI-nurate) represented by the following formula (a2-2). [ka] (a2-2)

[0139] "A compound having a hydroxyl group and a (meth)acryloyl group (a3)" • Praxel FA4DT: Caprolactone 4mol-added 2-hydroxyethyl acrylate (ε-lactone-modified HEA) represented by the following formula (a3-1), hydroxyl value: 98.1 KOH mg / g

[0140] [ka] (a3-1)

[0141] "Compound (B)" • ACMO: Acryloylmorpholine represented by the following formula (B-1) (manufactured by KJ Chemicals Co., Ltd.), Tg 145℃, 1 functional group

[0142] [ka]

[0143] IBXA: Isobornyl acrylate represented by the following formula (B-2) (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Tg 97℃, 1 functional group

[0144] [ka]

[0145] IBXMA: Isobornyl methacrylate represented by the following formula (B-3) (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Tg 97℃, 1 functional group

[0146] [ka]

[0147] GMEC: (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, represented by the following formula (B-4) (Osaka Organic Chemical), Tg 212℃, 1 functional group [ka] AOMA: Methyl 2-allyloxymethyl acrylate cyclopolymerizable monomer represented by the following formula (B-5) (Nippon Shokubai Co., Ltd.), Tg 78℃

[0148] [ka]

[0149] "Monomers other than those listed above" • MIRAMER M1130 Trimethylcyclohexyl acrylate represented by the following formula (B-6) (manufactured by Miwon), Tg □43℃, 1 functional group

[0150] [ka]

[0151] "Compound (D)" • MIRAMER M262: Tricyclodecanedimethanol diacrylate represented by the following formula (D-1) (manufactured by MIWON), Tg 110℃, 2 functional groups

[0152] [ka] • NK Ester DCP: Tricyclodecanedimethanol dimethacrylate represented by the following formula (D-2) (manufactured by Shin-Nakamura Chemical Co., Ltd.), Tg 112℃, 2 functional groups

[0153] [ka]

[0154] • Arronix M-2545: Isosorbide diacrylate represented by the following formula (D-3) (manufactured by Toagosei Co., Ltd.), Tg 174℃, 2 functional groups

[0155] [ka]

[0156] • Epoxy ester 3000A (manufactured by Kyoeisha Chemical Co., Ltd.) is bisphenol A diglycidyl ether diacrylate represented by the following formula (C-4), Tg 79°C, and has 2 functional groups.

[0157] [ka]

[0158] • MIRAMER PE250: Bisphenol A diglycidyl ether dimethacrylate represented by the following formula (D-5) (manufactured by MIWON), Tg 122℃, 2 functional groups

[0159] [ka]

[0160] "Initiator" • TPO(1108): Runtecure1108 (manufactured by Runtec Chemical Co., Ltd.)

[0161] In this example, the number-average molecular weight (Mn) was measured using gel permeation chromatography (GPC) under the following conditions.

[0162] Measuring device; HLC-8220, manufactured by Tosoh Corporation. Column; Guard Column H manufactured by Tosoh Corporation XL -H + TSKgel G5000HXL manufactured by Tosoh Corporation + TSKgel G4000HXL manufactured by Tosoh Corporation + TSKgel G3000HXL manufactured by Tosoh Corporation + TSKgel G2000HXL manufactured by Tosoh Corporation Detector; RI (Differential Refractometer) Data processing: Tosoh Corporation SC-8010 Measurement conditions: Column temperature 40℃ Solvent: tetrahydrofuran Flow rate 1.0ml / min Standard; polystyrene Sample: 100 μl of a tetrahydrofuran solution containing 0.4% by mass (based on resin solids content) filtered through a microfilter.

[0163] (Synthesis Example 1: Synthesis of Urethane (Meth)acrylate (A1)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (148 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Mitsubishi Chemical Corporation's HS0830B (270 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (80 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (A1) having an acryloyl group. The content of (meth)acryloyl groups per gram of urethane (meth)acrylate (A1), calculated from the theoretical acryloyl group content of the raw materials, was 1.33 mmol (as shown in Table 1 below. The content of (meth)acryloyl groups in each urethane (meth)acrylate obtained in the synthesis examples below is also shown in Table 1).

[0164] (Synthesis Example 2: Synthesis of Urethane (Meth)acrylate (A2)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (147 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Mitsubishi Chemical Corporation's HS0840H (271 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (80 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (A2) having an acryloyl group.

[0165] (Synthesis Example 3: Synthesis of Urethane (Meth)acrylate (A3)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (141 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Ube Industries, Ltd.'s UM-90 (1 / 1) (281 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (77 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (A3) having an acryloyl group.

[0166] (Synthesis Example 4: Synthesis of Urethane (Meth)acrylate (A4)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (140 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Ube Industries, Ltd.'s UM-90 (1 / 3) (283 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (76 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (A4) having an acryloyl group.

[0167] (Synthesis Example 5: Synthesis of Urethane (Meth)acrylate (A5)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (137 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Ube Industries, Ltd.'s UM-90 (3 / 1) (287 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (75 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (A5) having an acryloyl group.

[0168] (Synthesis Example 6: Synthesis of Urethane (Meth)acrylate (C1)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (59 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Polytetramethylene ether glycol glycol (number average molecular weight 3000) (407 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (32 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (C1) having an acryloyl group.

[0169] (Synthesis Example 7: Synthesis of Urethane (Meth)acrylate (C2)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (80 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added, and the temperature was raised to 70°C. Kuraray Polyol P-2012 (375 parts by mass), manufactured by Kuraray Co., Ltd., was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (44 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding a urethane resin (C2) having an acryloyl group.

[0170] The compositions and evaluation results of the urethane resins obtained in Synthesis Examples 1-7 are shown in Tables 1 and 2 below.

[0171] (Comparative synthesis example 1: Synthesis of urethane (meth)acrylate (L1)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (IPDI) (131 parts by mass), tert-butylhydroxytoluene (1.0 part by mass), methoxyhydroquinone (0.1 part by mass), and dibutyltin diacetate (0.1 part by mass) were added. The temperature was raised to 70°C, and Asahi Kasei Corporation's T5651 (297 parts by mass) was added in installments over 1 hour. After the reaction was allowed to proceed at 70°C for 3 hours, hydroxyethyl acrylate (HEA) (71 parts by mass) was added dropwise over 1 hour. After the dropwise addition, the mixture was heated to 2250 cm², which shows the isocyanate group. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding urethane (meth)acrylate (L1). The number-average molecular weight (Mn) of the urethane resin (L1) was 1,700. The amount of (meth)acryloyl groups per gram of urethane (meth)acrylate (L1), calculated from the theoretical acryloyl group content of the raw materials, was 1.19 mmol (as shown in Table 3 below. The amount of (meth)acryloyl groups in each urethane (meth)acrylate obtained in the synthesis examples below is also shown in Table 3).

[0172] (Comparative synthesis example 2: Synthesis of urethane (meth)acrylate (L2)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, 224 parts by mass of Praxel FA4DT (ε-lactone-modified HEA represented by formula (a3-1) above), manufactured by Daicel Corporation, 0.6 parts by mass of tert-butylhydroxytoluene, 0.06 parts by mass of methoxyhydroquinone, and 0.06 parts by mass of dibutyltin diacetate were added. The temperature was raised to 70°C, and 75 parts by mass of Sumijule N3300 (HDI nurate represented by formula (a2-2) above), manufactured by Sumika Bayer Urethane Co., Ltd., were added in stages over 1 hour. After charging, the mixture was heated to 2250 cm², which exhibits isocyanate groups. -1 The reaction was carried out at 70°C until the infrared absorption spectrum disappeared, yielding urethane (meth)acrylate (L2). The number-average molecular weight (Mn) of the urethane resin (L2) was 2,300.

[0173] [Table 1]

[0174] [Table 2]

[0175] [Table 3]

[0176] (Example 1: Preparation of photocurable resin composition (M1)) In a four-necked flask equipped with a stirrer, thermometer, and condenser, 30 parts by mass of urethane (meth)acrylate (A1) obtained in Synthesis Example 1, 35 parts by mass of ACMO manufactured by KJ Chemicals Co., Ltd., 35 parts by mass of MIRAMER M262 manufactured by MIWON, and 2 parts by mass of Omnirad TPO manufactured by BASF were charged. The mixture was then stirred at a temperature of 60°C or lower until uniform dissolution was achieved to obtain a photocurable resin composition (M1).

[0177] (Examples 2-10: Preparation of curable resin compositions for stereolithography (M2)-(10)) In Example 1, the urethane resin (A), compound (B), and compound (D) were changed to the compositions and amounts shown in Table 4, except that the same method was used to obtain the stereopolymerizable resin compositions (M2) to (M10).

[0178] (Example 11: Preparation of a curable resin composition for stereolithography (M11)) In a four-necked flask equipped with a stirrer, thermometer, and condenser, 15 parts by mass of urethane (meth)acrylate (A1) obtained in Synthesis Example 1, 40 parts by mass of MIRAMER PU340, 30 parts by mass of ACMO manufactured by KJ Chemicals Co., Ltd., 30 parts by mass of MIRAMER M210 manufactured by MIWON, and 2 parts by mass of Omnirad TPO manufactured by BASF were charged. The mixture was then stirred at a temperature of 60°C or below until uniformly dissolved to obtain a photocurable resin composition (M7).

[0179] (Examples 12 to 20: Preparation of curable resin compositions (M12) to (20) for optical molding) In Example 11, curable resin compositions (M12) to (M20) for optical molding were obtained in the same manner as in Example 11, except that the urethane resin (A), compound (B), and compound (D) were changed to the compositions and blending amounts shown in Table 5.

[0180] (Comparative Examples 1 to 4: Preparation of curable resin compositions (cM1) to (cM4) for optical molding) In Example 1, curable resin compositions (cM1) to (cM4) for optical molding were obtained in the same manner as in Example 1, except that the urethane resin (A), compound (B), and compound (D) were changed to the compositions and blending amounts shown in Table 4.

[0181] (Comparative Examples 5 to 8: Preparation of curable resin compositions (cM5) to (cM8) for optical molding) In Example 11, curable resin compositions (cM5) to (cM8) for optical molding were obtained in the same manner as in Example 11, except that the urethane resin (A), urethane resin (C), compound (B), and compound (D) were changed to the compositions and blending amounts shown in Table 5.

[0182] Using the curable resin compositions obtained in the above Examples 1 to 20 and Comparative Examples 1 to 8, the following evaluations were conducted.

[0183] [Measurement of viscosity] Using an E-type viscometer ("TV-22" manufactured by Toki Sangyo Co., Ltd.), the viscosity at 25°C of the curable resin compositions obtained in each example and comparative example was measured.

[0184] [Preparation of test pieces] Using an optical molding 3D printer ("Vittro P100" manufactured by 3DLight), test pieces for the load deflection temperature test and test pieces for the Izod impact test (conforming to ASTM D256, width 3.2 mm) were prepared. The optical molding was 2.5 mW / cm per layer 2It was carried out at an illuminance of

[0185] [Method for measuring load deflection temperature (heat resistance)] In accordance with ASTM D648, using the test piece 1, a load deflection temperature test (HDT) was performed with a "HDT test device (model: 6M-2)" manufactured by Toyo Seiki Seisaku-sho, Ltd.

[0186] [Method for measuring shrinkage rate] Using a precision balance ("XS204" manufactured by METTLER TOLEDO), the densities at 25°C of the curable resin compositions and their cured products obtained in each example and comparative example were measured respectively. The ratio of the density of the cured product to the density of the curable resin composition was calculated as the shrinkage rate.

[0187] [Method for measuring Izod impact strength (impact resistance)] Based on ASTM D256, using the test piece 2, an Izod impact strength was measured with a "1.0 J hammer" using an "Izod impact tester" manufactured by Toyo Seiki Seisaku-sho, Ltd.

[0188] The compositions and evaluation results of the curable resin compositions obtained in Examples 1 to 20 and Comparative Examples 1 to 8 are shown in Tables 4 and 5 below.

[0189]

Table 4

[0190]

Table 5

[0191] (Consideration) The viscosity of the curable resin composition should be 15,000 mPa·s or less, preferably 10,000 mPa·s or less, from the viewpoint of moldability and load on the 3D printer. Furthermore, the load deflection temperature of the molded object should be 50°C or higher, and a higher temperature is preferable, from the viewpoint of heat resistance. A lower shrinkage rate is preferable from the viewpoint of preventing molding defects such as the molded object detaching from the platform during molding and the dimensional accuracy of the cured object. In addition, the Izod impact strength should be 30 J / m or higher, and a higher temperature is preferable, from the viewpoint of impact resistance. In the composition of the example, which combines the urethane resin (A) and compound (B), it can be seen that high heat resistance is achieved while keeping the shrinkage rate low. Furthermore, in the composition of Examples 1 to 5 which further combines compound (D) having two or more (meth)acryloyl groups, it can be seen that both high heat resistance and low shrinkage rate are achieved. In addition, comparing Comparative Example 1 with the Examples, it can be seen that high heat resistance and low shrinkage rate are achieved simultaneously despite the same double bond concentration, which is due to the introduction of a rigid alicyclic structure into the urethane resin. In the compositions of Examples 11-20, which further incorporated compound (D), comparison with Comparative Example 5 revealed that, despite having the same double bond concentration in the curable resin composition, it exhibited low shrinkage while maintaining heat resistance. Furthermore, it was found that introducing a rigid alicyclic polycarbonate skeleton into the urethane acrylate resulted in good impact resistance. From the results in Table 4 above, it was confirmed that the curable resin composition of the first embodiment can form optically three-dimensional objects that exhibit both low shrinkage and heat resistance when cured. From the results in Table 5 above, it was confirmed that the curable resin composition of the second embodiment can form optically three-dimensional objects that exhibit both low shrinkage and impact resistance when cured. The curable resin compositions of these embodiments can be effectively used for stereolithography.

Claims

1. A urethane resin (A) having two (meth)acryloyl groups, α,β-unsaturated carbonyl compound (B), A photopolymerization initiator and a curable resin composition for photopolymerization, The urethane resin (A) is reacted using a polycarbonate diol (a1), a diisocyanate (a2), a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as reaction raw materials. The polycarbonate diol (a1) has an alicyclic structure, The α,β-unsaturated carbonyl compound (B) is a curable resin composition for photopolymerization, wherein the glass transition temperature (Tg) when it is a monomer polymer is 50°C or higher.

2. Furthermore, the photopolymerization curable resin composition according to claim 1, comprising a urethane resin (C) having two or more (meth)acryloyl groups and not having an alicyclic structure.

3. The photopolymerization curable resin composition according to claim 1, wherein the α,β-unsaturated carbonyl compound (B) is a compound having one (meth)acryloyl group.

4. The compound (D) further comprises two or more (meth)acryloyl groups, The stereochemical curable resin composition for photopolymerization according to any one of claims 1 to 3, wherein the compound (D) having two or more (meth)acryloyl groups has a glass transition temperature (Tg) of 60°C or higher when it is used as a monomer polymer.

5. The photopolymerization curable resin composition according to any one of claims 1 to 3, wherein the content of (meth)acryloyl groups in the urethane resin (A) is 0.6 mmol / g or more and 2.0 mmol / g or less.

6. The photopolymerization curable resin composition according to claim 1, wherein the content of the urethane resin (A) is 20% by mass or more and 50% by mass or less, the content of the α,β-unsaturated carbonyl compound (B) is 20% by mass or more and 80% by mass or less, and the total of the urethane resin (A) and the α,β-unsaturated carbonyl compound (B) is 100% by mass or less.

7. The photopolymerization curable resin composition according to claim 2, wherein the content of the urethane resin (A) is 5% by mass or more and 25% by mass or less, the content of the α,β-unsaturated carbonyl compound (B) is 10% by mass or more and 50% by mass or less, the content of the urethane resin (C) is 20% by mass or more and 60% by mass or less, and the total of the urethane resin (A), the α,β-unsaturated carbonyl compound (B), and the urethane resin (C) is 100% by mass or less.

8. The photopolymerization curable resin composition according to claim 2, wherein the content of the compound (D) having two or more (meth)acryloyl groups is 1% by mass or more and 50% by mass or less.

9. The stereochemical curable resin composition for photopolymerization according to any one of claims 1 to 3, wherein the urethane resin (A) is a resin represented by the following formula (1). 【Chemistry 1】 (In the above formula (1), R １ , R ７ Each of these independently represents either a hydrogen atom or a methyl group. R ２ and R ６ each independently represents —C ２ H ４ —, —C ３ H ６ —, —C ４ H ８ —, or —C ２ H ４ O(COC ５ H １０ )(s = 1 to 4), ｓ ​ R ３ , R ５ Each of these is independently -C ５ H １０ -, -C ６ H １２ -, -C １０ H １８ -, or -C ９ H １８ - represents, R ４ This can be one or more types, and represents an alicyclic structure with 3 to 10 carbon atoms. n represents an integer between 2 and 50.

10. A cured product which is a cured reaction product of a stereochemical curable resin composition for stereolithography according to any one of claims 1 to 3.

11. A three-dimensional object made of the cured product according to claim 10.

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