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

Abstract

The present invention provides a curable resin composition for stereolithography that can form optically three-dimensional objects with sufficient toughness and heat resistance, a cured product thereof, and a three-dimensional object. [Solution] The photopolymerization curable 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 reacted using a polycarbonate diol (a1), a diisocyanate (a2), a compound (a3) ​​having a hydroxyl group and a (meth)acryloyl group as a reaction raw material. The polycarbonate diol (a1) has a branched or linear aliphatic 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. The urethane resin (A) has a number-average molecular weight (Mn) of 2000 or higher.

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 optical stereolithography method (stereolithography) has been actively developed because of its high shaping speed and accuracy (see, for example, Patent Documents 1 and 2). As a result, with the improvement of stereolithography machines and stereolithography materials, the application range of stereolithography is gradually expanding from prototypes to final products. However, in automotive parts, home appliance parts, etc., existing technologies have not been able to obtain an optically stereolithographed object that achieves both sufficient toughness and heat resistance as a final product.

[0005] Therefore, there has been a demand for a curable resin composition for stereolithography that can form an optically stereolithographed object with both sufficient toughness and heat resistance.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a curable resin composition for stereolithography, a cured product thereof, and a stereolithographed object that can form an optically stereolithographed object with both sufficient toughness and heat resistance.

Means for Solving the Problems

[0008] The present invention includes the following aspects. [1] A urethane resin (A) having two (meth)acryloyl groups, an α,β-unsaturated carbonyl compound (B), and a photopolymerization initiator, which is a curable resin composition for stereolithography, where the urethane resin (A) is made from 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 a branched or linear aliphatic 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. A curable resin composition for stereolithography, wherein the number average molecular weight (Mn) of the urethane resin (A) is 2000 or more. [2] Further comprising a compound (C) having two or more (meth)acryloyl groups, The photopolymerizable resin composition according to [1], wherein the compound (C) having two or more (meth)acryloyl groups has a glass transition temperature (Tg) of 60°C or higher when it is a monomer polymer. [3] The photopolymerizable resin composition according to [1] or [2], wherein the α,β-unsaturated carbonyl compound (B) is a compound having one (meth)acryloyl group. [4] The stereochemical curable resin composition for photopolymerization according to any one of [1] to [3], wherein the content of (meth)acryloyl groups in the urethane resin (A) is 0.3 mmol / g or more and 2.0 mmol / g or less. [5] The photopolymerizable resin composition according to any one of [1] to [4], wherein the content of the urethane resin (A) is 1% by mass or more and 50% by mass or less. [6] The photopolymerizable resin composition according to any one of [1] to [5], wherein the content of the α,β-unsaturated carbonyl compound (B) is 20% by mass or more and 90% by mass or less. [7] The photopolymerizable resin composition according to any one of [2] to [5], wherein the content of the compound (C) having two or more (meth)acryloyl groups is 1% by mass or more and 50% by mass or less. [8] The stereochemical curable resin composition for photopolymerization according to any one of [1] to [7], wherein the urethane resin (A) is a resin represented by the following formula (1). [ka] (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 -C2H4-, -C3H6-, -C4H8-, or -C2H4O(COC5H 10 )(s = 1 to 4), s where R 3 and R 5 each independently represents -C5H<​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​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 a branched or linear aliphatic structure. The number average molecular weight (Mn) of the urethane resin (A) is 2000 or more. 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.

[0011] The stereochemical curable resin composition of this embodiment preferably further comprises a compound (C) having two or more (meth)acryloyl groups. The compound (C) 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 0.3 mmol / g or more and 2.0 mmol / g or less.

[0012] Furthermore, the stereochemical curable resin composition of this embodiment may also contain other trifunctional or higher (meth)acrylic compounds other than the α,β-unsaturated carbonyl compound (B) and / or the compound (C) having two or more (meth)acryloyl groups, to the extent that it does not impair 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.

[0013] [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.

[0014] <Polycarbonate diol (a1)> The polycarbonate diol (a1) has a branched or linear aliphatic structure. The branched or linear aliphatic structure is preferably a branched or linear aliphatic structure having 2 to 12 carbon atoms, more preferably a branched or linear aliphatic structure having 3 to 10 carbon atoms, and even more preferably a branched or linear aliphatic structure having 3 to 9 carbon atoms. Examples of linear aliphatic structures with 2 to 12 carbon atoms include -(CH2)s-(s=2~12). Examples of branched aliphatic structures with 2 to 12 carbon atoms include -(CH2)s-CH(CH3)―(CH2)t-(s and t may be 0, and s+t=0 to 10) and -(CH2)s-CH(C2H4)―(CH2)t-(s and t may be 0, and s+t=0 to 9).

[0015] Examples of the branched aliphatic structure having 2 to 12 carbon atoms include the skeleton of isosorbide, the skeleton of cyclohexanedimethanol, the skeleton of 3-methylpentanediol (3MPD), and the skeleton of 2-methyloctanediol (MOD). In this specification, "diol skeleton" refers to the structure of a diol after the -OH group has been removed.

[0016] The polycarbonate diol (a1) is preferably a diol represented by the following formula (2).

[0017] H(O-R4-OC(=O)) n -O-R4-OH (2)

[0018] In equation (2), R4 may consist of one or more types, and at least one substituent is a branched or linear aliphatic alkylene group. R4 may consist of one or more types, and may be an aliphatic, alicyclic, or aliphatic / alicyclic alkylene group. The number of carbon atoms of at least one branched or linear aliphatic alkylene group in R4 is 2 to 12, preferably 4 to 10, and more preferably 4 to 9. n is an integer between 2 and 100. R4 may be one or more types, at least one of which is -CH2CH2CH(CH3)CH2CH2-, -(CH2)6-, or -(CH2)4-, preferably a combination of -CH2CH2CH(CH3)CH2CH2- and -(CH2)6-.

[0019] 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 (C) having two or more (meth)acryloyl groups. For example, the number-average molecular weight (Mn) of the polycarbonate diol (a1) may be 1200 or more, 1500 or more, or 2000 or more. The larger the number-average molecular weight, the longer the distance between crosslinking points becomes, and the impact resistance improves. On the other hand, the viscosity increases and the molding accuracy deteriorates, so it may be 10,000 or less, or 8,000 or less.

[0020] Specific examples of the aforementioned polycarbonate diol (a1) include, but are not limited to, those commercially available from Kuraray Co., Ltd. under the trade name "Kuraray Polyol". Specifically, examples of these include C-2050, C-3050, C-3090, C-2015N, C-2065N, etc., which contain branched aliphatic structures. Another example is G3452, which contains linear aliphatic structures. The content of the polycarbonate diol (a1) skeleton in the urethane resin (A) 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, 80% by mass or less, or 70% by mass or less. For example, in 100 parts by mass of the total mass of raw materials used to synthesize the urethane resin (A), the content of polycarbonate diol (a1) may be 10 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more. It may also be 90 parts by mass or less, 80 parts by mass or less, or 70 parts 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.

[0021] <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. The diisocyanate (a2) is preferably, for example, hexamethylene diisocyanate (HDI), 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or 2,2,4-trimethylhexamethylene diisocyanate (TMDI), or hydrogenated diphenylmethane diisocyanate. Any combination of the above is also acceptable. It is more preferable that the diisocyanate (a2) is isophorone diisocyanate (IPDI). The content of the diisocyanate (a2) skeleton in the urethane resin (A) 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, 80% by mass or less, or 70% by mass or less. Furthermore, in 100 parts by mass of the total mass of raw materials used to synthesize the urethane resin (A), the content of diisocyanate (a2) may be 10 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more. It may also be 90 parts by mass or less, 80 parts by mass or less, or 70 parts 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.

[0022] <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.

[0023] The compound (a3) ​​having the hydroxyl group and (meth)acryloyl group described above can be used alone or in combination of two or more.

[0024] The content of the hydroxyl group and (meth)acryloyl group-containing compound (a3) ​​skeleton in the urethane resin (A) 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, 80% by mass or less, or 70% by mass or less. Furthermore, in 100 parts by mass of the total mass of raw materials used to synthesize the urethane resin (A), the content of the hydroxyl group and (meth)acryloyl group-containing compound (a3) ​​may be 10 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more. It may also be 90 parts by mass or less, 80 parts by mass or less, or 70 parts 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.

[0025] The above-mentioned urethane resin (A) is preferably a resin represented by the following formula (1).

[0026] [ka]

[0027] In the above formula (1), R 1 , R7 Each of these independently represents either a hydrogen atom or a methyl group. R 2 , R 6 This is the skeleton of compound (a3) ​​having the hydroxyl group and the (meth)acryloyl group, and is preferably a divalent substituent derived from HEA or HEMA, HPA or HPMA, or 4-HBA lactone-modified HEA / HEMA. The skeleton of compound (a3) ​​having the hydroxyl group and the (meth)acryloyl group is a divalent substituent obtained by removing the hydroxyl group and the (meth)acryloyloxy group from compound (a3). R 3 ,R 5 This is the skeleton of the diisocyanate (a2), and is 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).

[0028] R 4 This is the skeleton of the polycarbonate diol (a1) represented by formula (2) above. It has the same meaning as R4 of the polycarbonate diol (a1) represented by formula (2) above. R4 has at least one substituent that is a branched or linear aliphatic alkylene group. R4 is also an aliphatic, alicyclic, or aliphatic / alicyclic alkylene group. 4 The number of carbon atoms in at least one branched or linear aliphatic alkylene group is 2 to 12, preferably 4 to 10, and more preferably 4 to 9. n is an integer between 2 and 100. R4 may be one or more types, at least one of which is -CH2CH2CH(CH3)CH2CH2-, -(CH2)6-, or -(CH2)4-, preferably a combination of -CH2CH2CH(CH3)CH2CH2- and -(CH2)6-.

[0029] The above urethane resin (A) is preferably a resin represented by the above formula (1), wherein each substituent in formula (1) is as follows. R1 , R 7 Each of these independently represents either a hydrogen atom or a methyl group. R 2 , R 6 These are, independently, -C2H4-, -C3H6-, -C4H8-, or -C2H4O(COC5H 10 ) represents s - (s = 1 to 4), R 3 , R 5 Each of these is independently -C5H 10 -, -C6H 12 -, -C 10 H 18 -, or -C9H 18 - represents, R 4 It may be one type or two or more types, and it is more preferable that at least one substituent is a branched or linear aliphatic structure having 2 to 12 carbon atoms, more preferably a branched or linear aliphatic structure having 3 to 10 carbon atoms, and even more preferably a branched or linear aliphatic structure having 4 to 9 carbon atoms. 4 It may be one type or two or more types, more preferably a branched or linear aliphatic structure having 2 to 12 carbon atoms, more preferably a branched or linear aliphatic structure having 3 to 10 carbon atoms, and even more preferably a branched or linear aliphatic structure having 4 to 9 carbon atoms. R 4 R4 may consist of one or more types, and at least one substituent represents an aliphatic structure having 2 to 12 carbon atoms, an isosorbide skeleton, a cyclohexanedimethanol skeleton, a 3-methylpentanediol (3MPD) skeleton, or a 2-methyloctanediol (MOD) skeleton. R4 may consist of one or more types, and represents an aliphatic structure having 2 to 12 carbon atoms, an isosorbide skeleton, a cyclohexanedimethanol skeleton, a 3-methylpentanediol (3MPD) skeleton, or a 2-methyloctanediol (MOD) skeleton. Examples of linear aliphatic structures having 2 to 12 carbon atoms include -(CH2)s-(s=2 to 12). Examples of linear aliphatic structures having 3 to 10 carbon atoms include -(CH2)s-(s=3 to 10). Examples of branched aliphatic structures having 2 to 12 carbon atoms include -(CH2)s-CH(CH3)―(CH2)t-(s and t may be 0, s+t=0 to 10) and -(CH2)s-CH(C2H4)―(CH2)t-(s and t may be 0, s+t=0 to 9). Examples of branched aliphatic structures having 3 to 10 carbon atoms include -(CH2)s-CH(CH3)―(CH2)t-(s and t may be 0, s+t=1 to 8) and -(CH2)s-CH(C2H4)―(CH2)t-(s and t may be 0, s+t=1 to 7). R4 is -(CH2) s -(s=2~12), and -(CH2)s-CH(CH3)-(CH2) t It is preferable to represent one or more divalent groups selected from the group consisting of -(s and t may be 0, and s+t=0 to 10).

[0030] <Structure of urethane resin (A)> The above-mentioned urethane resin (A) uses 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 5-90 / 5-90 / 5-90, 10-80 / 10-80 / 10-80, or 15-70 / 15-70 / 15-70.

[0031] <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 is obtained that can form optically three-dimensional molded objects that have sufficient toughness and heat resistance, 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.

[0032] 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.

[0033] <Properties of urethane resin (A)> In this embodiment, the urethane resin (A) used preferably has a (meth)acryloyl group content of 0.3 mmol / g or more and 2.0 mmol / g or less, more preferably 0.5 mmol / g or more and 1.7 mmol / g or less, and even more preferably 0.5 mmol / g or more and 1.7 mmol / g or less. By incorporating a urethane resin (A) having a specific content of (meth)acryloyl groups into a curable resin composition, the curable resin composition can form optical three-dimensional objects that possess both sufficient toughness and heat resistance, 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.

[0034] The number-average molecular weight (Mn) of the urethane resin (A) used in this embodiment is 2000 or more, preferably 2500 or more, and more preferably 3000 or more. Furthermore, the number-average molecular weight (Mn) of the urethane resin (A) may be 30000 or less, or 1500 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, the curable resin composition can form optically three-dimensional objects that possess both sufficient toughness and heat resistance, 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.

[0035] [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).

[0036] 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 is 60°C or higher.

[0037] 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.

[0038] [ka]

[0039] 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.

[0040] 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.

[0041] [Compound (C)] The stereochemical curable resin composition of this embodiment preferably further contains two or more compounds (C) having (meth)acryloyl groups (sometimes simply referred to as "compound (C)"). The compound (C) 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. Preferably, the glass transition temperature (Tg) of the compound (C) when it is used as a monomer polymer is 70°C or higher, and more preferably 75°C or higher. It may also be 250°C or lower. Examples of the compound (C) 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 (C) can be used individually or in combination of two or more. Furthermore, among the compounds (C) 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.

[0042] Furthermore, when two or more of the above-mentioned compound (C) are used 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.

[0043] Furthermore, the α,β-unsaturated carbonyl compound (B) and the compound (C) 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.

[0044] <Other (meth)acrylic compounds (D)> 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 (D) such as trifunctional or higher (meth)acrylic compounds (sometimes simply referred to as "compound (D)") in addition to the α,β-unsaturated carbonyl compound (B) and the compound (C) 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 (D) used in combination is 40°C or higher.

[0045] 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;

[0046] Tetrafunctional (meth)acrylates such as ditrimethylolpropanetetraacrylate, pentaerythritol ethoxytetraacrylate, and pentaerythritol tetraacrylate;

[0047] Pentafunctional (meth)acrylates such as dipentaerythritol hydroxypentaacrylate and alkyl-modified dipentaerythritol pentaacrylate;

[0048] 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.

[0049] [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.

[0050] 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.

[0051] The amount of photopolymerization initiator added is preferably in the range of 1 to 20% by mass in the photopolymerization curable resin composition.

[0052] <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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Examples of polymerization inhibitors include hydroquinone, methoquinone, di-t-butylhydroquinone, p-methoxyphenol, butylhydroxytoluene, and nitrosamine salts.

[0057] 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.

[0058] 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.

[0059] 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;

[0060] Epoxy-based silane coupling agents such as diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane;

[0061] Styrene-based silane coupling agents such as p-styryltrimethoxysilane;

[0062] (Meth)acryloxy-based silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane;

[0063] 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;

[0064] Ureidopropyltriethoxysilane and other ureidopropyl silane coupling agents;

[0065] Chloropropyl silane coupling agents such as 3-chloropropyltrimethoxysilane;

[0066] Mercaptopropyl silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoquinsilane;

[0067] Sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide;

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Examples of organic fillers include solvent-insoluble substances derived from plants, such as cellulose, lignin, and cellulose nanofibers.

[0074] Examples of inorganic fillers include glass (particles), silica (particles), alumina silicate, talc, mica, aluminum hydroxide, alumina, calcium carbonate, and carbon nanotubes.

[0075] 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.

[0076] Examples of defoaming agents include oligomers containing fluorine or silicon atoms, or oligomers such as higher fatty acids or acrylic polymers.

[0077] Examples of coloring agents include pigments and dyes.

[0078] As pigments, commonly known and conventional inorganic pigments and organic pigments can be used.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] [Characteristics of curable resin compositions for stereolithography] In the stereolithography curable resin composition of this embodiment, the content of the urethane resin (A) is preferably 1% by mass or more and 60% by mass or less, more preferably 5% by mass or more and 55% by mass or less, and even more preferably 10% by mass or more and 50% by mass or less. By setting the content of the urethane resin (A) 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 sufficient toughness and heat resistance, 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 25% by mass or more and 80% by mass or less, and even more preferably 30% by mass or more and 75% by mass or less. By setting the content of compound (B) 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 sufficient toughness and heat resistance, as shown in the following examples. In the stereolithography curable resin composition of this embodiment, the content of compound (C) having two or more (meth)acryloyl groups is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less. By setting the content of compound (C) 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 sufficient toughness and heat resistance, as shown in the following examples.

[0083] (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.

[0084] 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.

[0085] 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.

[0086] (3D object) 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.

[0087] Examples of optical three-dimensional modeling methods include stereolithography (SLA), digital light processing (DLP), and inkjet.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Among these optical 3D printing methods, the DLP method is preferred because it allows for high-speed printing using surfaces.

[0092] 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 integrated light intensity per layer is 5-15 mJ / cm². 2 It is preferable that it be within the range of [specify range].

[0093] The three-dimensional object of this embodiment is an optically manufactured object that achieves both sufficient toughness and heat resistance, and can therefore be suitably used in applications such as automobile parts, aerospace-related parts, electrical and electronic components, home appliances, and building materials. [Examples]

[0094] 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.

[0095] The materials used in the following synthesis examples and examples are as follows: "Polycarbonate diol (a1)" C-2050 is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 3-methylpentanediol (3MPD) and hexanediol (C6) in a 50 / 50 molar ratio. Mw = 2,000 C-2090 is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 3-methylpentanediol (3MPD) and hexanediol (C6) in a molar ratio of 90 / 10. Mw = 2,000 C-3050 is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 3-methylpentanediol (3MPD) and hexanediol (C6) in a 50 / 50 molar ratio. Mw = 3,000 C-3090 is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 3-methylpentanediol (3MPD) and hexanediol (C6) in a molar ratio of 90 / 10. Mw = 3,000 C-2015N is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 2-methyloctanediol (MOD) and nonanediol (C9) in a molar ratio of 85 / 15. Mw = 2,000 C-2065N is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 2-methyloctanediol (MOD) and nonanediol (C9) in a molar ratio of 65 / 35. Mw = 2,000 C-1090 is a polycarbonate diol manufactured by Kuraray Co., Ltd. It is a copolymer of 3-methylpentanediol (3MPD) and hexanediol (C6) in a molar ratio of 90 / 10. Mw = 1,000 Duranol G3450J is a polycarbonate diol manufactured by Asahi Kasei Corporation. It is a copolymer of propanediol (C3) and butanediol (C4) in a molar ratio of approximately 50 / 50. Mn = 800 • Duranol G3452: A polycarbonate diol manufactured by Asahi Kasei Corporation. A copolymer of propanediol (C3) and butanediol (C4) ≈ 50 / 50 (molar ratio). Mn = 2,000 • Duranol T5651: A polycarbonate diol manufactured by Asahi Kasei Corporation. A copolymer of pentanediol / hexanediol (C6) ≈ 50 / 50 (molar ratio). Mn = 1,000

[0096] "Diisocyanate (a2)" • Isophorone diisocyanate (IPDI): A diisocyanate represented by the following formula (a2-1)

[0097] [ka]

[0098] • Sumijool N3300: An isocyanurate-type hexamethylene diisocyanate (HDI-nurate) represented by the following formula (a2-2).

[0099] [ka]

[0100] "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

[0101] [ka]

[0102] "Compound (B)" • ACMO: Acryloylmorpholine represented by the following formula (B-1) (manufactured by KJ Chemicals Co., Ltd.), Tg 145℃, 1 functional group

[0103] [ka]

[0104] IBXA: Isobornyl acrylate represented by the following formula (B-2) (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Tg 97℃, 1 functional group

[0105] [ka]

[0106] IBXMA: Isobornyl methacrylate represented by the following formula (B-3) (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Tg 97℃, 1 functional group

[0107] [ka]

[0108] AOMA: Methyl 2-allyloxymethyl acrylate cyclopolymerizable monomer represented by the following formula (B-4) (Nippon Shokubai Co., Ltd.), Tg 78℃.

[0109] [ka]

[0110] "Monomers other than those listed above" • MIRAMER M1130 Trimethylcyclohexyl acrylate represented by the following formula (B-5) (manufactured by Miwon), Tg 43℃, 1 functional group [ka]

[0111] "Compound (C)" • MIRAMER M262: Tricyclodecanedimethanol diacrylate represented by the following formula (C-1) (manufactured by MIWON), Tg 110℃, 2 functional groups [ka]

[0112] • NK Ester DCP: Tricyclodecanedimethanol dimethacrylate represented by the following formula (C-2) (manufactured by Shin-Nakamura Chemical Co., Ltd.), Tg 112℃, 2 functional groups

[0113] [ka]

[0114] • Arronix M-2545: Isosorbide diacrylate represented by the following formula (C-3) (manufactured by Toagosei Co., Ltd.), Tg 174℃, 2 functional groups [ka]

[0115] • 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.

[0116] [ka]

[0117] • MIRAMER PE250: Bisphenol A diglycidyl ether dimethacrylate represented by the following formula (C-5) (manufactured by MIWON), Tg 122℃, 2 functional groups

[0118] [ka]

[0119] "Initiator" • TPO(1108): Runtecure1108 (manufactured by Runtec Chemical Co., Ltd.)

[0120] In this example, the number-average molecular weight (Mn) was measured using gel permeation chromatography (GPC) under the following conditions.

[0121] 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°C 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.

[0122] (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 (IPDI) (83 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 C-2050 (370 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 (HEA) (45 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, and urethane (meth)acrylate (A1) was obtained as the "urethane resin (A) having two (meth)acryloyl groups" according to this embodiment. The (meth)acryloyl group content per gram of urethane (meth)acrylate (A1), calculated from the theoretical acryloyl group content of the raw materials, was 0.75 mmol (see Table 1 below). The (meth)acryloyl group content of each urethane (meth)acrylate obtained in the synthesis examples below is also listed in Table 1. The number-average molecular weight (Mn) of urethane (meth)acrylate (A1) was 2,700 (see Table 1 below). The number-average molecular weight (Mn) of each urethane (meth)acrylate obtained in the synthesis examples below is also listed in Table 1.

[0123] (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 (IPDI) (83 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 C-2090 (370 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 (HEA) (45 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 (A2). The number-average molecular weight (Mn) of the urethane resin (A2) was 2,700.

[0124] (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 (IPDI) (58 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 Kuraray Polyol C-3050 (410 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 (HEA) (31 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 (A3). The number-average molecular weight (Mn) of the urethane resin (A3) was 3,900.

[0125] (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 (IPDI) (61 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 C-3090 (405 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 (HEA) (33 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 (A4). The number-average molecular weight (Mn) of the urethane resin (A4) was 3,700.

[0126] (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 (IPDI) (82 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 C-2015N (373 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 (HEA) (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 urethane (meth)acrylate (A5). The number-average molecular weight (Mn) of the urethane resin (A5) was 2,700.

[0127] (Synthesis Example 6: Synthesis of Urethane (Meth)acrylate (A6)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (IPDI) (83 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 C-2065N (371 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 (HEA) (45 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 (A6). The number-average molecular weight (Mn) of the urethane resin (A6) was 2,700.

[0128] (Synthesis Example 7: Synthesis of Urethane (Meth)acrylate (A7)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (IPDI) (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. The temperature was raised to 70°C, and Asahi Kasei Corporation's G3452 (376 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) (43 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 (A7). The number-average molecular weight (Mn) of the urethane resin (A6) was 2,800.

[0129] (Synthesis Example 8: Synthesis of Urethane (Meth)acrylate (B1)) 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, and the temperature was raised to 70°C. Kuraray Polyol C-1090 (297 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 (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 (B1). The number-average molecular weight (Mn) of the urethane resin (B1) was 1,700.

[0130] (Synthesis Example 9: Synthesis of Urethane (Meth)acrylate (B2)) In a 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer, isophorone diisocyanate (IPDI) (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. The temperature was raised to 70°C, and Asahi Kasei Corporation's G3450J (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 (HEA) (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 urethane (meth)acrylate (B2). The number-average molecular weight (Mn) of the urethane resin (B2) was 1,500.

[0131] (Synthesis Example 10: Synthesis of Urethane (Meth)acrylate (B3)) 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 (B3). The number-average molecular weight (Mn) of the urethane resin (B3) was 1,700.

[0132] (Synthesis Example 11: Synthesis of Urethane (Meth)acrylate (B4)) 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 Sumijoule N3300 (HDI nurate represented by formula (a2-2) above), manufactured by Sumika Bayer Urethane Co., Ltd., were added in stages over 1 hour. After the addition, the reaction was carried out at 70°C until the infrared absorption spectrum at 2250 cm-1, indicating an isocyanate group, disappeared, yielding urethane (meth)acrylate (B4). The number-average molecular weight (Mn) of the urethane resin (B4) was 2,300.

[0133] The composition and evaluation results of the urethane resins obtained in Synthesis Examples 1 to 11 are shown in Table 1 below.

[0134] [Table 1]

[0135] (Example 1: Preparation of curable resin composition (M1)) In a four-necked flask equipped with a stirrer, thermometer, and condenser, 25 parts by mass of urethane (meth)acrylate (A1) obtained in Synthesis Example 1, 75 parts by mass of IBXA manufactured by Osaka Organic Chemical Industry Co., Ltd., 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 curable resin composition (M1).

[0136] (Examples 2-14: Preparation of curable resin compositions for stereolithography (M2)-(14)) In Example 1, the urethane resin (A), compound (B), and compound (C) were changed to the compositions and amounts shown in Table 1 or Table 2, except that the same method was used to obtain the stereopolymerizable resin compositions (M2) to (M14).

[0137] (Comparative Examples 1-7: Preparation of curable resin compositions for stereolithography (cM1)-(cM7)) In Example 1, the urethane resin (A), compound (B), and compound (C) were changed to the compositions and amounts shown in Table 2, except that the same method was used to obtain the stereopolymerizable resin compositions (cM1) to (cM7).

[0138] The following evaluations were performed using the stereolithography curable resin compositions obtained in Examples 1 to 14 and Comparative Examples 1 to 7 described above.

[0139] [Viscosity measurement] The viscosity of the curable resin compositions obtained in each example and comparative example at 25°C was measured using an E-type viscometer (TV-22, manufactured by Toki Sangyo Co., Ltd.).

[0140] [Preparation of test specimens] Using a stereolithography 3D printer (3DLight "Vittro P100"), test specimens for load deflection temperature testing and test pieces for Izod impact testing (compliant with ASTM D256, 3.2 mm wide) were fabricated. The stereolithography process was performed at 2.5 mW / cm² per layer. 2The irradiation was performed at the specified illuminance for a duration of 10 seconds and with a z-axis (height direction) pitch of 100 μm. Next, the test specimens for load deflection temperature testing and the Izod impact testing obtained by stereolithography were washed with isopropyl alcohol, dried at room temperature for 1 hour, and then, as a post-curing step, both sides were irradiated for 10 minutes each with an LED at a wavelength of 385 nm using a Multicure180 manufactured by XYZ Printing, to obtain test specimen 1 (test specimen for load deflection temperature testing) and test specimen 2 (test piece for Izod impact testing).

[0141] [Method for measuring temperature deflection under load (heat resistance)] In accordance with ASTM D648, a temperature deflection test (HDT) was performed using the aforementioned test specimen 1 with an HDT test apparatus (model: 6M-2) manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0142] [Method for measuring Izod impact strength (impact resistance)] In accordance with ASTM D256, the Izod impact strength was measured using the aforementioned test piece 2 with an Izod impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd., using a 1.0 J hammer.

[0143] The compositions and evaluation results of the curable resin compositions obtained in Examples 1-14 and Comparative Examples 1-7 are shown in Table 2 below.

[0144] [Table 2]

[0145] (Discussion) 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 molding machine. Furthermore, the load deflection temperature of the molded object should be 45°C or higher from the viewpoint of heat resistance, and higher is better. The Izod impact strength should be 45 J / m or higher from the viewpoint of impact resistance, and higher is better. In the compositions of Examples 1-2, which combine the urethane resin (A) and the α,β-unsaturated carbonyl compound (B), it can be seen that high impact resistance is maintained while also ensuring heat resistance. Furthermore, in the compositions of Examples 3-14, which combine the compound (C) having two or more (meth)acryloyl groups, it can be seen that high heat resistance and impact resistance are achieved simultaneously. In addition, by comparing Example 4 with Comparative Example 5 and Example 11 with Comparative Example 7, it can be seen that the larger the molecular weight of the polycarbonate diol used as a raw material for the urethane resin, the higher the impact resistance while maintaining heat resistance. The results shown in Table 2 above confirm that the curable resin composition of this embodiment can form optically three-dimensional objects that possess both sufficient toughness and heat resistance. The curable resin composition of this embodiment can be effectively used for stereolithography.

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