JPH02145616A - Resin composition for optical stereo modeling - Google Patents

Abstract

PURPOSE: To provide an optical three-dimensional molding resin composition minimized in deformation with low viscosity and capable of providing a tough hardened matter by containing a fine particle having a specified apparent specific gravity difference with a liquid hardening resin, and the hardening resin.

CONSTITUTION: This composition contains (A) a liquid hardening tesin and (B) a fine particle having an apparent specific gravity difference with the component A less than 0.2. As the component B, a polymer or copolymer of monofunctional monomer having one ethylenic unsaturated group such as isobornyl (meth)acrylate or the like is used, and it is manufactured by suspension polymerization with a particle size of 1-25 μm and an apparent specific gravity of 0.9-1.2. As the component A, a polyether polyol such as polyoxyethylene diol or the like may be used.

COPYRIGHT: (C)1990,JPO

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a resin composition for optical three-dimensional modeling, and in particular to an optical three-dimensional modeling resin composition that has a low viscosity, exhibits little deformation during curing, and is capable of producing a tough cured product. The present invention relates to a resin composition for three-dimensional modeling.

[Prior Art] Recently, Japanese Unexamined Patent Publication No. 60-247515 has proposed a method for forming a three-dimensional object of a desired shape by selectively supplying light energy necessary for curing to a photocurable liquid material. Ta. Similar methods or improved techniques thereof are also disclosed in U.S. Pat. A typical example of this optical three-dimensional modeling method is to selectively irradiate the surface of a liquid photocurable resin placed in a container with, for example, an ultraviolet laser so as to obtain a cured layer with a desired pattern. Next, one layer of photocurable resin is supplied on top of the cured layer, and then light is selectively irradiated in the same manner as above to perform a lamination operation to obtain a cured layer continuous with the above cured layer. By repeating the process, a desired three-dimensional object is finally obtained.

This optical three-dimensional modeling method is attracting attention because even when the shape of the object to be manufactured is complex, it is possible to easily obtain the desired object in a short time.

Conventionally, examples of photocurable liquid substances used in this optical three-dimensional modeling method include modified polyurethane methacrylate, oligoester acrylate, urethane acrylate, epoxy acrylate, photosensitive polyimide, and amino alkyd. (Japanese Unexamined Patent Publication No. 60-247515).

[Problem to be solved by the invention]

By the way, in the above-mentioned optical three-dimensional modeling method, the viscosity of the resin is low from the viewpoint of ease of handling, modeling speed, modeling accuracy, etc., and deformation due to volumetric shrinkage during curing is small (it is possible to form a modeled object with high dimensional accuracy). It is required that the strength of the molded object obtained is sufficiently high.

However, none of the conventional liquid photocurable resins had these properties in a well-balanced manner, and were not satisfactory.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a resin composition for optical three-dimensional modeling that has a low viscosity, exhibits little deformation due to volumetric shrinkage during curing, etc., and is capable of producing a modeled object having sufficiently high strength. It is in.

[Means to solve the problem]

The present invention solves the above problem, and the difference in apparent specific gravity between the liquid curable resin and the liquid curable resin is 0.2.
The object of the present invention is to provide a resin composition for optical stereolithography, which includes microparticles that are less than or equal to 100%.

In the present invention, the optical three-dimensional modeling method in which the above-mentioned resin composition is used is a method in which the liquid curable resin is selectively irradiated with light to specific locations to supply the energy necessary for curing, thereby creating a three-dimensional shape of a desired shape. Refers to the method of obtaining a modeled object. The liquid curable resin used here may be a photocurable resin that is cured by ultraviolet rays, visible light, etc., or a thermosetting resin that is cured by infrared rays. Therefore, as described above, examples of the light used for irradiation include ultraviolet light, visible light, infrared light, and the like. Furthermore, the method of selectively irradiating light onto a specific location of the liquid curable resin is not limited, and examples include methods of irradiating a specific location with focused light obtained using a laser beam, a lens, a mirror, etc.; Examples include a method in which light is irradiated only to specific locations by irradiating the liquid curable resin through a mask with a certain pattern. Furthermore, the specific location that is irradiated with light may be the surface of the liquid curable resin contained in the container, the surface in contact with the side wall or bottom wall of the container, or even in the liquid. To irradiate the liquid surface of the liquid curable resin or the surface in contact with the container wall, it is sufficient to irradiate the light from the outside directly or through the transparent container wall.To irradiate light to a specific point in the liquid, , for example by means of a light guide such as an optical fiber.

In this optical three-dimensional modeling method, after curing a desired specific area, the irradiation position is moved continuously or stepwise from the cured area to the adjacent uncured area, so that the cured area is cured. can be grown into a desired three-dimensional shape. Various methods are possible for moving the irradiation position.
For example, methods include moving one or more of the light source, the container, and the curing part, or adding uncured liquid curable resin to the container.

The above-mentioned optical three-dimensional modeling method includes, for example, Japanese Patent Application Laid-open No. 60247.
No. 515, No. 62-101408, No. 62-3596
In addition to the method described in No. 6, "Kold Technology", Vol. 2, No. 9, pages 72-73, all methods included in the above definition are included.

The resin composition of the present invention is used as a liquid curable resin in the above-mentioned optical three-dimensional modeling method.

The fine particles contained in the resin composition of the present invention are not particularly limited, and include, for example, a polymer or copolymer of a monomer having a polymerizable ethylenically unsaturated group, polyamide, epoxy resin, phenol resin, benzoguanamine. Examples include resin particles made of resin, silicone resin, and the like.

The above monomer having a polymerizable ethylenically unsaturated group has at least one ethylenically unsaturated group,
Even a monofunctional monomer having one ethylenically unsaturated group,
It may be a polyfunctional monomer having two or more ethylenically unsaturated groups, or a combination thereof. In particular, when a monofunctional monomer is used as the main component, it is preferable to use a polyfunctional monomer in combination.

Examples of the monofunctional monomer having one ethylenically unsaturated group include isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, bornyl (meth)acrylate, and isobornyloxyethyl (meth)acrylate.
Acrylate, dicyclopentenyloxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethyldiethylene glycol (meth) Acrylate, 2-ethylhexyl (meth)acrylate, phenoxyethyl (meth)acrylate, dicyclopentadiene (meth)acrylate, polyethylene glycol (meth)acrylate, diethylaminoethyl (meth)acrylate, 7-amino-3
, 7 monofunctional (meth)acrylic monomers such as dimethylocdyl (meth)acrylate, acrylamide, isobutoxymethylacrylamide, diacetone acrylamide, N,N-dimethylacrylamide; or N-vinylpyrrolidone, N-vinylcaprolactam, Examples include vinylphenol, vinyl acetate, vinyl ether, styrene, acrylonitrile, ethylene, propylene, and the like.

Furthermore, examples of the polyfunctional monomer having two or more ethylenically unsaturated groups include polyfunctional (meth)acrylic monomers, divinylbenzene, and the like. This polyfunctional (meth)acrylic monomer has at least two (meth)acryloyl groups, and includes, for example, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. (meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4 butanediol di(meth)acrylate, 1.6 hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dicyclopentadiene(meth)acrylate, ) acrylate, polyester di(meth)acrylate, bisphenol A glycidyl ether (meth)acrylic acid adduct at both ends, pentaerythritol tetra(meth)acrylate, and the like.

Resin particles made of the various raw materials mentioned above can be produced by a known method using a suspension polymerization method or an emulsion polymerization method. These resin particles can also be obtained as commercial products, such as Eposter S manufactured by Nippon Shokubai Kagaku Co., Ltd.
MP1000 manufactured by Soken Chemical Co., Ltd., XC9 manufactured by Toshiba Silicone Corporation
1-501, Fine Pearl 3000SP manufactured by Sumitomo Chemical Co., Ltd.
, Toshisha 5P-500, EP-13, Kanebo Co., Ltd. Bell Pearl, Daikin Co., Ltd. Lubron L-5, Tetsu Kagaku Co., Ltd. Flow Beads LE-1080, Flow Beads CL-2080
, Flowbeads EA-209, Flowene UF and the like can be mentioned.

Fine particles made of these polymers or copolymers can be used alone or in combination of two or more. Moreover, the particle shape is not particularly limited.

Furthermore, hollow particles made of inorganic material can also be used as the microparticles in the present invention.

The particle size of the microparticles used in the composition of the present invention is usually 0.1 to 50t! m, preferably 0.5 to 35 μm,
Particularly preferably, it is 1 to 25 μm, and the apparent specific gravity is
Usually, it is 0.9 to 1.2. If the particle size is too small, the viscosity of the resulting optical three-dimensional modeling resin composition will increase, resulting in poor productivity and modeling accuracy of the three-dimensional model, while if the particle size is too large, the modeling accuracy of the three-dimensional model will be poor. or a sufficiently smooth surface may not be obtained.

In the composition of the present invention, the difference in apparent specific gravity between the microparticles and the liquid curable resin is preferably as small as possible from the viewpoint of storage stability of the composition, and is less than 0.2, preferably less than 0.1, Particularly preferably less than 0.05. If this difference in apparent specific gravity exceeds 0.1, the microparticles and the liquid curable resin will separate during storage.

Furthermore, when it is desired to obtain a transparent three-dimensional object using the composition of the present invention, the difference between the refractive index of the microparticles used and the refractive index of the liquid curable resin after curing should be kept as small as possible. For example, the absolute value of the difference in refractive index between the two may be 0.2 or less.

The content of microparticles in the composition of the present invention is usually
5 to 45% by weight, preferably 8 to 40% by weight, particularly preferably 10 to 35% by weight. If the content of microparticles is too low, the effect of adding the microparticles will not be sufficiently obtained, and if the content is too high, the viscosity of the resulting composition will increase,
There is a possibility that the handleability of the composition, the molding speed of the three-dimensional object, the molding accuracy, etc. may deteriorate.

The liquid curable resin used in the composition of the present invention is not particularly limited as long as it has the property of being cured by light, heat, etc., and examples thereof include those comprising the following components.

(A) Oligomer having two or more (meth)acryloyl groups (B) (B-1) Monofunctional monomer having an ethylenically unsaturated group and/or (B-2) having an ethylenically unsaturated group Polyfunctional monomer and (C) polymerization initiator The oligomer having two or more (meth)acryloyl groups, which is the (^) component of the specific example of the liquid curable resin listed above, has an ester skeleton, a urethane skeleton, etc. and an epoxy ring-opened structure skeleton, preferably an oligomer having a urethane skeleton. Specifically, polyol compounds such as polyether polyols, polyester polyols, polycaprolactone polyols, and polycarbonate polyols, preferably polyol compounds having an average of about 2 to 5 hydroxyl groups in one molecule, diisocyanate compounds, and (meth) A urethane (meth)acrylate oligomer obtained by reacting a compound having an acryloyl group; an ester (meth)acrylate oligomer obtained by an esterification reaction between a similar polyol compound and a compound having a (meth)acryloyl group; It is an epoxy (meth)acrylate compound obtained by an addition reaction between an epoxy compound and a compound having a (meth)acryloyl group.

Here, examples of the polyether polyol include polyoxyethylene diol, polyoxypropylene diol, polyoxytetramethylene diol, and the like.

Examples of polyester polyols include dihydric alcohols such as (poly)ethylene glycol, (poly)propylene glycol, (poly)tetramethylene glycol, 1,6-hexanediol, neopentyl glycol, and 1,4-cyclohexane dimetatool. , phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, and other dibasic acids.

Examples of polycaprolactone polyols include ε-caprolactone and divalent diols such as (poly)ethylene glycol, (poly)tetramethylene glycol, 1°6-hexanediol, neopentyl glycol, and 1,4-butanediol. Examples include those obtained by reaction.

In addition, as polycarbonate polyols, for example, commercially available products include DN-980, DN-981, and DN-982.
, DN-983 (manufactured by Nippon Polyurethane), PC
-8000 (manufactured by PPG, USA) and the like.

Preferred among these polyol compounds are polyester diols.

Examples of the diisocyanate compound to be reacted with these polyol compounds include 2,4-toluene diisocyanate, 2,6-)toluene diisocyanate, and 1,3-toluene diisocyanate.
Xylene diisocyanate, 1.4-xylene diisocyanate, 1. 5-naphthalene diisocyanate, p
-phenylene diisocyanate, 3,3'-dimethyl-
4,4' diphenylmethane diisocyanate, 4,4'
Diphenylmethane diisocyanate, 3.3' dimethylphenylene diisocyanate, 4,4' biphenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, methylene bis(4-cyclohexyl isocyanate), hydrogenated diphenylmethane diisocyanate, 2. Examples include 2.4-) dimethylhexamethylene diisocyanate, bis(2-isocyanatoethyl) fumarate, 6-isoprobyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, and lysine diisocyanate.

Examples of the compound having a (meth)acryloyl group to be reacted with the polyol compound include (meth)acrylic compounds having a hydroxyl group. Specific examples of this (meth)acrylic compound having a hydroxyl group include:
2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxyoctyl (meth)acrylate, pentaerythritol (
meth)acrylate, glycerin di(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, ■, 4-butanediol mono(meth)acrylate, 4-hydroxycyclohexyl(meth)acrylate, 1゜6-hexanediol mono (meth)acrylate, neopentyl glycol mono(meth)
Acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane di(meth)acrylate, etc., and further alkyl glycidyl ether,
Examples include compounds obtained by an addition reaction between a glycidyl group-containing compound such as aryl glycidyl ether and glycidyl acrylate and (meth)acrylic acid.

Epoxy compounds include, for example, glycidyl ether obtained by reacting bisphenol A or its alkylene oxide adduct with epichlorohydrin; glycidyl ether obtained by reacting hydrogenated bisphenol A or its alkylene oxide adduct with epichlorohydrin, and phenol novolak. Polyglycidyl ether, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin,
Triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol; diglycidyl ether of polyether diol obtained by adding alkylene oxide such as ethylene oxide or propylene oxide to aliphatic dihydric alcohol such as propylene glycol or glycerin. diglycidyl esters of aliphatic long-chain dibasic acids; monoglycidyl ethers of phenol, butylphenol, cresol, or polyether alcohols obtained by adding alkylene oxides to these; glycidyl esters of higher fatty acids; diglycidyl phthalate esters; glycidyl Acrylate, polyglycidyl acrylate; 3,4
-Epoxycyclohexane carboxylate and the like.

Furthermore, commercially available products can also be used as the component (A), such as Ebecry 1204 manufactured by UCB, Ebe
cry 1205, Ebecry 1210, Eb
ecry 1220, Ebecry 1240, Eb
ecry 1254, Ebecry 1264, Eb
ecry 1265, ebecry 1270, E
becry 1284, ebecry 1285, E
becry 1600, ebecry 1601, E
becry 1604, ebecry 1605,
Ebecry 1608, Ebecry 1616,
Ebecry 160B, Ebecry 12608
, Ebecry 1860; A CH made by RCO
EML INK3000, CHEMLINK 500
0, CHEMLINK 9503, CHEMLINK
9504, CHEMLINK 9505; Toagosei Kagaku Co., Ltd. Aronix M-6100, Aronix M
-6250, Aronix M-6300, Aronix M-6500, Aronix M-8030, Aronix M-8060i UV ITH manufactured by Morton Thiokol
ANE893; Shell EPON100L, EPO
Examples include N82B.

The content of these components (A) in the composition is usually 5 to 5.
It is 35% by weight, preferably 10-35% by weight, more preferably 10-30% by weight. If the content of component (A) is too small, the volumetric shrinkage rate of the obtained composition during curing will increase, the curing speed will decrease, and the mechanical properties of the cured product will deteriorate (or if the content is too high) If it is too high, the viscosity of the resulting composition may increase, the production speed of the three-dimensional object may be reduced, and the surface smoothness of the cured object may be impaired.

Among components (B), (B-1) the monofunctional monomer having an ethylenically unsaturated group is the monofunctional monomer having one ethylenically unsaturated group as exemplified above as a raw material for the microparticles. Among these, preferred are monofunctional (meth)acrylic monomers, vinylpyrrolidone and vinylcaprolactam.

In addition, when adjusting the refractive index of the composition, a compound having a high refractive index, such as the following formula (
I): [In the formula, R1 and R2 may be the same or different and are a hydrogen atom or a methyl group, and R3 is a linear or branched alkylene group having 2 to 16 carbon atoms substituted or unsubstituted with a hydroxyl group. , X is a halogen atom, m is an integer from 0 to 6, and n is an integer from 1 to 5].

Specific examples of the compound represented by the above formula (1) include tribromophenyl (meth)acrylate, tetrabromophenyl (meth)acrylate, and tetrachlorophenyl (
meth)acrylate, pentabromophenyl (meth)acrylate, pentachlorophenyl (meth)acrylate, 2-trichlorophenoxyethyl (meth)acrylate, 2-trichlorophenoxyethyl (meth)acrylate, 2-tetrachlorophenoxyethyl (meth)acrylate, Examples include 2-tetrabromophenoxyethyl (meth)acrylate.

The (B-2) polyfunctional monomer having an ethylenically unsaturated group in the component (B) is a polyfunctional monomer having two or more ethylenically unsaturated groups as exemplified above as a raw material for microparticles. Monomers and other polyfunctional monomers having an ethylenically unsaturated group can be mentioned, and among these, polyfunctional (meth)acrylic monomers are preferred.

These (B) components are usually contained in the composition in an amount of 15 to 75
It is contained in an amount of % by weight, preferably 20 to 75% by weight, particularly preferably 30 to 75% by weight. If this content is too large, the curing shrinkage rate of the resulting composition tends to increase and the curing speed decreases.

Moreover, the type of polymerization initiator of component (C) is not particularly limited, and various photopolymerization initiators and thermal polymerization initiators can be used, and the following compounds can be exemplified.

Photoinitiator: acetophenone, benzophenone, xanthone, fluorenone, anthraquinone, carbazole, 4-chlorobenzophenone, 33-dimethyl-4-methoxybenzophenone, 4°4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, pen Zoin ether, benzoin propyl ether, acetophenone diethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-
2-methylpropan-1one, 2-methyl-1-(4-
(Methylthio)phenyl)-2morpholinopropan-1-one, 1-hydroxycyclohexylphenyl ketone, benzyldimethylketal, 2,4.6-trimethylbenzoyldiphenylphosphine oxide, thioxanthone compound, 3.3' , 4.4'-tetra (t-
Butylperoxycarbonyl)benzophenone (BTT
B), and BTTB and xanthine, thioxanthin,
Combinations of coumarin, ketocoumarin and other dye sensitizers such as camphorquinone and fluorescein.

Thermal polymerization initiator: benzoin peroxide, L-butyl peroxybenzoate, dicumyl panioxide, 2.4
-dichlorobenzoyl peroxide, butyl peroxide, azobisisobutyronitrile.

These (C) components are used alone or in combination of two or more, and in the case of a photopolymerization initiator, a sensitizer, an amine compound, etc. are optionally added to effectively utilize the light from the light source. It is also possible to use an auxiliary agent.

The content of component (C) in the composition is usually 0.03 to 1
It is 0% by weight, preferably 0.1 to 8% by weight. (C)
If the content of the component is too small, the curability of the composition obtained tends to decrease, and if the content is too large, the mechanical strength of the cured product obtained tends to decrease.

The composition of the present invention may contain leveling agents, surfactants, organosilicon compounds, inorganic fillers, pigments, dyes, and the like, if necessary.

2 The composition of the present invention is made by mixing the above-mentioned microparticles and a liquid curable resin, or by adding other components as necessary, but the method of mixing these components is not particularly limited. .

The viscosity of the composition of the present invention is usually 100 to 2000 cl.
'is.

The light used when obtaining a model by optical stereolithography using the composition of the present invention is selected depending on whether the composition is photocurable or thermosetting. , ultraviolet rays,
Visible light, infrared light, etc. are used, but it is preferable to use ultraviolet light.

More specific embodiments of the optical stereolithography method using the composition of the present invention include the following examples.

■After the first cured layer is formed, additionally supplying the uncured composition for the next cured surface onto the obtained first cured layer,
A method of repeating the process of further irradiating light to form the next hardened layer.

■ Submerge the bottom plate in the composition to the depth of the first hardened layer,
After the first cured layer is formed, the bottom plate is further sunk to a depth of one layer, thereby allowing -layers of uncured composition to flow onto the first cured layer and further irradiated with light. A method of repeating the process to form the next hardened layer.

■ A box with a transparent bottom plate is submerged in the composition placed in a container, and the composition layer formed in the gap between the bottom plate and the bottom of the container is made to have the same thickness as the first cured layer. , the composition layer is irradiated with light through the transparent bottom plate of the box, and the first
After forming a cured layer, the case is raised to allow the composition to flow into the gap between the first cured layer and the transparent bottom plate of the case,
A method of repeating the process of irradiating light in the same way to form the next hardened layer.

■ Submerge the plate in the composition placed in a container with a transparent bottom, and make the composition layer formed in the gap between the shaking plate and the bottom of the container the same thickness as the first cured layer. After irradiating the composition layer with light through the transparent bottom of the container to form a first cured layer, one layer of uncured composition is added by raising the plate by one layer thickness. A method of repeating the operation of causing a material to flow into the gap between the first hardened layer and the plate, and then irradiating light in the same manner as described above to form the next hardened layer.

The three-dimensional structure formed by the methods (1) to (4) above is taken out from the container used for the reaction, and after removing the unreacted composition remaining on the surface of the three-dimensional structure, the three-dimensional structure is washed as necessary. As the cleaning agent used for cleaning, organic solvents such as alcohols such as isopropyl alcohol, and low-viscosity resins such as thermosetting or photocuring resins having a viscosity of 200 cP or less can be used. When it is desired to impart transparency to a three-dimensional object, it is preferable to use the above-mentioned low-viscosity thermosetting or photosetting resin for cleaning. Furthermore, in this case, it is necessary to post-cure with heat or light after cleaning, depending on the type of resin used for cleaning. This post-cure not only cures the uncured resin on the surface, but also cures any unreacted composition that may remain inside the three-dimensional object, so even if it is cleaned with an organic solvent. It is preferable to do so.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these.

Example 1 A reaction vessel equipped with a stirrer was charged with 180 g of polyester urethane acrylate oligomer (Uvisan 893 manufactured by Morton Thiokol ■), 60 g of trimethylolpropane triacrylate, and 60 g of vinylpyrrolidone, and heated at 50°C for 1 hour without stirring. Heating resulted in a mixture. (Hereinafter referred to as "Mixture I") Next, in a sealable container with an internal volume of 250 ml, 136.4 g of the above mixture and 48 g of isobornyl acrylate were added.
゜6g, the difference in apparent specific gravity with the polyester urethane acrylate oligomer is 0.1, and the average particle size is a3
Molar ratio of μm divinylhenzene and styrene 80:20
15g of copolymer particles, photopolymerization initiator (Jiha Geigy a
6.0 g of Irgacure 184) manufactured by Irgacure Co., Ltd. and 80 mρ of stainless steel balls with particle size of 3 plates were charged and mixed for 1.5 hours using a paint shaker. The resulting mixture was filtered through a 200 MSO nylon filter to remove the stainless steel spheres to obtain a resin composition for optical three-dimensional modeling.
It was designated as "Composition A".

The viscosity of the obtained composition was measured, and the shrinkage rate, gel content, and Young's modulus of the cured product were measured according to the following methods, and the appearance of the cured product was observed. The results are shown in Table-1.

Curing: A focused He-Cd laser beam (output 20m, wavelength 3250m) is applied from a direction perpendicular to the surface of the composition.
Irradiation was carried out to obtain a rectangle of 30mm x 30non x O, 4m+++. Density of the cured composition (D
I) and the density (D2) of the composition before curing were measured, and the shrinkage rate of the cured product was calculated from the following formula.

Shrinkage rate (%) = 100 x ((1/D2) - (1/D
+))/(1/DZ) The composition was cured under the same conditions as for measuring the shrinkage rate of the cured product, and the weight of the obtained cured product was measured at 23°C. After that, it was immersed in 100 ml of methyl ethyl ketone at 23°C for 1 hour. After that, take out the cured product and store it at 70°C under normal pressure.
After drying for 1 hour at 23°C, the weight was measured and the gel content was calculated.

Focused 1le-Cd laser beam (output 20mW,
wavelength 3250) from perpendicular to the surface of the composition,
Irradiation was carried out to obtain a 4 mm rectangle using 50 nus x 3 mm Xo. The cured composition was heated to 23°C 1 relative humidity 5
Conditions were adjusted for 24 hours at 0% and used as test pieces. The Young's modulus of this test piece was measured using a tensile testing machine at a temperature of 23° C. and a relative humidity of 50%, a tensile speed of 10 mm/min, and a distance between gauge lines of 15 mm.

The composition was cured under the same conditions as in the curing process and the measurement of the shrinkage rate of the cured product, and the resulting cured product was used as an ultraviolet curing type cleaning resin with a viscosity of 80 cP [Japan Hojo (m''J-KAYARADDPCA-
12,020 parts by weight, 74 parts by weight of vinylpyrrolidone, photopolymerization initiator Nilgacure 184 (manufactured by Ciba Geigy Qη)
4 parts by weight and photopolymerization initiator: 2 parts by weight of benzophenone] with gentle stirring, and the surface was washed. Next, using a 300 kW high-pressure mercury lamp, the cleaned composition was irradiated with ultraviolet rays for 30 seconds from a distance of 20 cm to cure the cleaning resin, and the surface of the resulting cured product was visually observed.

Example 2 Instead of copolymer particles of divinylbenzene and styrene with an average particle size of 3 μm, polydivinyl with an apparent specific gravity difference of 0.07 from the polyester urethane acrylate oligomer and an average particle size of 0.3 μm was used. A resin composition for optical three-dimensional modeling was obtained in the same manner as in Example 1, except that particles made of benzene were used, and designated as "composition B".

The viscosity of the obtained composition B was measured, and the shrinkage rate, gel content, and Young's modulus of the cured product were also measured, and the appearance of the cured product was observed. The results are shown in Table-1.

Example 3 Instead of copolymer particles of divinylbenzene and styrene with an average particle size of 3 μm, low-density polyamide particles with an average particle size of 5 μm and a difference in apparent specific gravity from the polyester urethane acrylate oligomer of 0.09 were used. A resin composition for optical three-dimensional modeling was obtained in the same manner as in Example 1, except that the following was used, and designated as "Composition C".

The viscosity of the resulting composition C was measured, and the shrinkage rate, gel content, and Young's modulus of the cured product were also measured, and the appearance of the cured product was observed. The results are shown in Table-1.

Example 4 Instead of copolymer particles of divinylbenzene and styrene with an average particle size of 3 μm, polyamide particles with an average particle size of 7 μm and a difference in apparent specific gravity from the polyester urethane acrylate oligomer of 0.13 were used. Except for the above, a resin composition for optical three-dimensional modeling was obtained in the same manner as in Example 1, and designated as "Mi composition D".

The viscosity of the obtained composition was measured, the shrinkage rate, gel content and Young's modulus of the cured product were measured, and the appearance of the cured product was observed. The results are shown in Table-1.

Comparative Example 1 142.9 g of the mixture obtained in Example 1 and 57.1 g of isobornyl acrylate were placed in a reaction vessel equipped with a stirrer.
and photopolymerization initiator (Irgacure 1 manufactured by Chiha Geigy)
84) 6.0 g was charged and heated at 50°C for 1 hour while stirring to obtain a resin composition for optical three-dimensional modeling, which was designated as "Composition E". The viscosity of this composition was measured, and the shrinkage rate, gel content and Young's modulus of the cured product were measured in the same manner as in Example 1, and the appearance of the cured product was observed. The results are shown in Table-1.

〔Effect of the invention〕

Since the resin composition for optical three-dimensional modeling of the present invention has a low viscosity and a small volumetric shrinkage rate during curing, it is possible to obtain objects with good modeling accuracy and high productivity by optical three-dimensional modeling. . Furthermore, after curing, a shaped article having sufficiently high strength can be obtained.

Claims (1)

[Claims] A resin composition for optical three-dimensional modeling, comprising a liquid curable resin and microparticles having an apparent specific gravity difference of less than 0.2 with the liquid curable resin.