JP6877017B2 - Optical three-dimensional modeling method - Google Patents

Description

The present invention is an optical three-dimensional modeling method capable of producing a three-dimensional model that does not cause an inappropriate optical phenomenon without optical phenomena such as a rainbow appearing or diffuse reflection depending on the viewing angle, and thus obtained. Regarding three-dimensional objects to be made.

In recent years, a method of three-dimensionally optically modeling a liquid photocurable resin composition based on three-dimensional data input to a computer has achieved good dimensional accuracy for a target three-dimensional model without producing a mold or the like. Since it can be manufactured in (for example, Patent Document 1, Patent Document 2, etc.).
As a typical example of the optical three-dimensional modeling method, light is selected on the surface of the resin composition for optical three-dimensional modeling housed in the modeling tank (modeling bath) based on the three-dimensional three-dimensional data stored in the computer. To form one layer of photocurable resin layer having a predetermined shape and pattern, and then supply one layer of uncured optical three-dimensional modeling resin composition to the photocurable resin layer. The next photo-curing resin layer having a predetermined shape / pattern is formed by selectively irradiating light based on the three-dimensional three-dimensional data stored in the computer, and the operation is repeated many times to achieve the desired three-dimensional modeling. A method of manufacturing a product can be mentioned. By this optical three-dimensional modeling method, it is possible to easily and relatively quickly produce a modeled object having a considerably complicated shape.

The three-dimensional model obtained by performing optical three-dimensional modeling using the resin composition for optical three-dimensional modeling is used to check the functionality of models and parts for verifying the appearance design of various industrial products during the design process. It is widely used as a model, a resin mold for making molds, a base model for making molds, etc. In recent years, for example, prototyping models of optical parts such as automobile and motorcycle lenses, works of art. It is also being used in applications that require uniform optical properties and high transparency, such as restoration, imitation and contemporary art, and arts and crafts fields such as design presentation models for glass-walled buildings. ..

Based on the three-dimensional three-dimensional data stored in the computer, the photocurable resin composition surface is selectively irradiated with light to form a photocurable resin layer, and the operation of laminating is repeated many times to manufacture a three-dimensional model. Conventionally, in the optical three-dimensional modeling technique, it has been generally practiced to form each photocurable resin layer at the same lamination pitch.
However, depending on the viewing angle, the three-dimensional model manufactured by such a conventional technique may have an inappropriate optical phenomenon such as a rainbow being visible or diffuse reflection occurring even though the rainbow is originally invisible. For applications such as prototype models of optical products such as automobile and motorcycle lenses, restoration of works of art, imitation and contemporary art, design presentation models of glass-walled buildings, improper optical phenomena such as rainbows and diffuse reflections. There is a demand for a three-dimensional model that does not occur.

On the other hand, there is known a method of producing a three-dimensional model by setting the lamination pitch of the photocurable resin layer to a large or small size and performing optical three-dimensional modeling (see Patent Documents 3 and 4). However, these conventional techniques employ a large lamination pitch (thickness of the photocurable resin layer) in the portion where the size and shape are the same or almost the same, and form and laminate the photocurable resin layer to increase the molding speed. In order to prevent deterioration of dimensional accuracy in parts where there is a difference in size and shape, a small stacking pitch (thickness of the photocurable resin layer) is adopted to form and laminate the photocurable resin layer at high speed. It is a technology to be manufactured, and is not intended to prevent the occurrence of inappropriate optical phenomena such as the generation of rainbows and diffused reflection depending on the viewing angle in a three-dimensional model.

Japanese Unexamined Patent Publication No. 3-227222 Japanese Unexamined Patent Publication No. 2000-62030 Japanese Unexamined Patent Publication No. 8-85155 Japanese Unexamined Patent Publication No. 8-156108

An object of the present invention is to provide a three-dimensional model that does not generate rainbows or the like even if the viewing angle is different, does not cause diffuse reflection, and does not cause an inappropriate optical phenomenon, and provides a method for manufacturing the same. is there.

In order to achieve the above object, the present inventors have studied, and in the process, the refractive index of the three-dimensional model obtained by the above-mentioned conventional technique for producing the three-dimensional model by adopting the same stacking pitch. investigated. As a result, as shown in the schematic view of FIG. 2, in a three-dimensional model having the same thickness of each photocurable resin layer manufactured by adopting the same lamination pitch, the refractive index in the surface 1 of the photocurable resin layer becomes high. Although there is almost no difference, a plurality of photocurable resin layers 2a, 2b, 2c, 2d, 2e, ... With the same thickness are laminated (2a = 2b = 2c = 2d = 2e = ...). in to have laminated section (side face of the three-dimensionally shaped object) 2, have a refractive index n ₂ of the refractive index n ₁ and the lower Y of the top X of the photocurable resin layer are different, in that state, the layers of the stacking pitch ( Reflecting the laminated structure that the thickness of each photo-curing resin layer is the same, the refractive index is n ₁ / n ₂ / n at equal intervals along the laminated cross section (side surface of the three-dimensional model). It was found that it has a periodic structure of ₁ / n ₂ / n ₁ / n ₂ / n ₁ / n _{2 / .... At that time, n 1} <n ₂ may be set depending on the type and component composition of the resin composition for optical three-dimensional modeling used, the type of light source used for light irradiation, the intensity of light, and the like. _In some cases, 1> n _2. In addition, the refractive index of the three-dimensional model _{gradually changes from n 1 to} n ₂ , but it may change linearly with respect to the depth (thickness) of the layer, or exponentially. It may change.

The present inventors cause optical phenomena such as diffraction of light due to the periodic structure of the above-mentioned difference in refractive index in the laminated cross section (side surface) of optical three-dimensional modeling, and thereby generate rainbows due to the difference in viewing angle, diffuse reflection, etc. I thought it might be caused.
Therefore, in producing a three-dimensional model by sequentially forming and laminating photocurable resin layers, the stacking pitch (thickness of the photocurable resin layer) of each photocurable resin layer is not made the same, but a predetermined stacking pitch (predetermined). When the formation pitch (lamination pitch) of the adjacent photocurable resin layers was changed within the range of thickness), the above-mentioned periodic structure of the refractive index disappeared, and rainbows and diffuse reflections due to the difference in viewing angle were observed. The present invention has been completed by finding that a three-dimensional model that does not occur and does not cause an inappropriate optical phenomenon can be obtained.

That is, the present invention
(1) The surface or bottom surface of the optical three-dimensional modeling resin composition housed in the modeling tank is selectively irradiated with light based on the three-dimensional three-dimensional data stored in the computer to have a predetermined shape / pattern. One layer of photocurable resin layer is formed, and then one layer of uncured optical three-dimensional modeling resin composition is supplied to the photocurable resin layer based on the three-dimensional three-dimensional data stored in the computer. To selectively irradiate light to form the next photocurable resin layer having a predetermined shape and pattern, and to repeat the operation of laminating on or under the photocurable resin layer to produce a three-dimensional modeled object. It is an optical three-dimensional modeling method;
Adjacent photo-curing resin layers are arranged from 0.3 × D (mm) to 3.0 × D (mm) [In the formula, D is a stacking pitch that forms the basis preset in the computer for forming the photo-curing resin layer. (Mm) is shown. ], While adopting the stacking pitch within the range of], they are formed with different stacking pitches;
It is an optical three-dimensional modeling method characterized by this.

And the present invention
(2) The optical three-dimensional modeling method according to (1) above, wherein the difference between the stacking pitch of one of the adjacent photocurable resin layers and the stacking pitch of the other is 1.5 mm or less.
(3) The optical three-dimensional modeling method according to (1) or (2) above, wherein the photocurable resin layer is formed and laminated so that the lamination pitch is random along the lamination direction of the photocurable resin layer;
(4) The photocurable resin layers are formed and laminated so that the ratio of the same lamination pitch is 20% or less of the total number of the photocurable resin layers constituting the three-dimensional model. Either optical three-dimensional modeling method; and
(5) The above-mentioned (1) to (4) in which the basic lamination pitch D (mm) set in the computer for forming the photocurable resin layer is a constant value within the range of 0.01 to 2.0 mm. ) Any one of the optical three-dimensional modeling methods;
Is.

Furthermore, the present invention
(6) It is a three-dimensional model composed of a plurality of laminated photocurable resin layers, and the thicknesses of adjacent photocurable resin layers are different from each other, and the thicknesses of the adjacent photocurable resin layers are all 0. 3 × D (mm) to 3.0 × D (mm) [In the formula, D indicates the basic design thickness (mm) for forming the photocurable resin layer. ], And the thickness of each photocurable resin layer constituting the three-dimensional model is random along the laminating direction of the photocurable resin layer. ..

And the present invention
(7) The three-dimensional model according to (6) above, wherein the difference between the thickness of one photocurable resin layer and the thickness of the other photocurable resin layer in the adjacent photocurable resin layer is within the range of 1.5 mm or less; and,
(8) The three-dimensional model according to (6) or (7) above, wherein the proportion of the photocurable resin layers having the same thickness is 20% or less of the total number of laminated photocurable resin layers constituting the three-dimensional model;
Is.

By performing the optical three-dimensional modeling method of the present invention, it is possible to smoothly produce a three-dimensional object that does not cause an inappropriate optical phenomenon without the generation of a rainbow due to a difference in viewing angle or optical abnormalities such as diffused reflection. Can be done.
Therefore, the optical three-dimensional modeling method of the present invention is, for example, a prototyping model for optical products such as automobile and motorcycle lenses, restoration of works of art, imitation and contemporary art, and art such as design presentation models for glass-walled buildings. It is extremely effective as a manufacturing technique for three-dimensional objects that are required not to cause inappropriate optical phenomena such as rainbow generation and diffused reflection in the field of crafts.

FIG. 1 schematically shows a laminated structure of a three-dimensional model obtained by the optical three-dimensional modeling method of the present invention in which adjacent photocurable resin layers are formed and laminated at different lamination pitches to produce a three-dimensional model. It is a figure. FIG. 2 is a diagram schematically showing a laminated structure of a three-dimensional model obtained by forming and laminating a photocurable resin layer using the same laminating pitch.

The present invention will be described in detail below.
In the present invention, in the production of a three-dimensional object, light is selected on the surface or bottom surface of the optical three-dimensional modeling resin composition housed in the modeling tank (modeling bath) based on the three-dimensional three-dimensional data stored in the computer. To form one layer of photocurable resin layer having a predetermined shape and pattern, and then supply one layer of uncured optical three-dimensional modeling resin composition to the photocurable resin layer. Light is selectively irradiated based on the three-dimensional three-dimensional data stored in the computer to form the next photocurable resin layer having a predetermined shape and pattern, and the next photocurable resin layer is laminated on or below the photocurable resin layer. An optical three-dimensional modeling method (hereinafter, "optical three-dimensional modeling" may be referred to as "optical modeling") is adopted in which a three-dimensional model is manufactured by repeating the operations.

In the present invention, the surface of the resin composition for optical three-dimensional modeling housed in the modeling tank (modeling bath) is selectively irradiated with light based on the three-dimensional three-dimensional data stored in the computer to form a predetermined shape. A photo-curable resin layer for one layer having a pattern is formed, and then one layer of an uncured resin composition for optical three-dimensional modeling is supplied to the photo-curable resin layer, and the three-dimensional solid is stored in a computer. A three-dimensional model is manufactured by repeating the operation of selectively irradiating light based on the data to form the next photocurable resin layer having a predetermined shape and pattern and laminating on the above-mentioned photocurable resin layer. A method in which a photocurable resin layer (a laminate of photocurable resin layers) formed by light irradiation is lowered by one layer below the molding tank, and a layer of the photocurable resin composition is supplied onto the photocurable resin layer. Is preferably adopted.
Further, in the present invention, the bottom surface of the optical three-dimensional modeling resin composition housed in the modeling tank (modeling bath) is selectively irradiated with light based on the three-dimensional three-dimensional data stored in the computer (from the bottom surface side). Then, one layer of a photocurable resin layer having a predetermined shape and pattern is formed, and then one layer of an uncured resin composition for three-dimensional modeling is supplied to the photocurable resin layer and stored in a computer. The operation of selectively irradiating light based on the three-dimensional three-dimensional data to form the next photo-curable resin layer having a predetermined shape / pattern and laminating under the above-mentioned photo-curable resin layer is repeated. In manufacturing a three-dimensional model, a photo-curing resin layer is formed by irradiating light from the bottom surface using a modeling tank having a light-transmitting bottom surface. Then, the photocurable resin layer (laminate of photocurable resin layer) is raised by one layer above the modeling tank, and between the bottom surface of the modeling tank and the bottom surface of the photocurable resin layer (laminate of photocurable resin layer). A method of forming the next photocurable resin layer by supplying one layer of the photocurable resin composition to the material is preferably adopted.
In the optical three-dimensional modeling, any of the conventionally known optical three-dimensional modeling methods and devices can be adopted as long as it is of the above-mentioned type, and is not particularly limited.

As the photocurable resin composition, a photocurable resin composition that is liquid at a temperature at which optical three-dimensional modeling is performed and is capable of forming a transparent three-dimensional model is preferably adopted.
As the light for curing the photocurable resin composition, γ-rays, X-rays, ultraviolet rays, visible rays, infrared rays and the like can be used, but ultraviolet rays are preferably used. Among them, ultraviolet rays having a wavelength of 300 to 400 nm are more preferably used from an economical point of view. The light sources at that time include ultraviolet lasers (for example, semiconductor-pumped solid-state lasers, Ar lasers, He-Cd lasers, etc.), high-pressure mercury lamps, ultra-high pressure mercury lamps, low-pressure mercury lamps, xenon lamps, halogen lamps, metal halide lamps, and ultraviolet LEDs. (Light emitting diode), ultraviolet fluorescent lamp, etc. can be mentioned.

In irradiating the molding surface made of the resin composition for optical three-dimensional molding with active energy rays to form each cured resin layer having a predetermined shape pattern, light rays focused in dots such as laser light are emitted. It may be used to form a cured resin layer by stippling or line drawing, or it is modeled through a planar drawing mask formed by arranging multiple micro-optical shutters such as a liquid crystal shutter or a digital micromirror shutter (DMD). A modeling method may be adopted in which the surface is irradiated with active energy rays in a planar manner to form a cured resin layer.

In the present invention, the surface or bottom surface of the resin composition for optical three-dimensional modeling housed in the modeling tank is selectively irradiated with light based on the three-dimensional three-dimensional data stored in the computer to obtain a predetermined shape / pattern. A photo-curable resin layer for one layer is formed, and then one layer of an uncured resin composition for optical three-dimensional modeling is supplied to the photo-curable resin layer, and three-dimensional three-dimensional data stored in a computer. A three-dimensional model is formed by repeating the operation of selectively irradiating light based on the above to form the next photo-curable resin layer having a predetermined shape and pattern and laminating on or under the above-mentioned photo-curable resin layer. In manufacturing, the adjacent photocurable resin layer is 0.3 × D (mm) to 3.0 × D (mm) [in the formula, D is a basic preset in the computer for forming the photocurable resin layer. The stacking pitch (mm) is shown. ], While adopting the stacking pitch within the range of], they are formed with different stacking pitches.

Among them, it is preferable to form the adjacent photocurable resin layers in the range of 0.5 × D (mm) to 2.0 × D (mm) at different stacking pitches, and 0.75 × D (mm). ) To 1.5 × D (mm), it is more preferable to form the layers at different stacking pitches.
Here, the above-mentioned "D" is not the actual thickness of the photocurable resin layer formed by photocuring, but the basic lamination pitch (mm) set in the computer in order to form the photocurable resin layer. (Set value on the computer).
Also, the "lamination pitch" when forming each photo-curing resin layer is not the actual thickness of the photo-curing resin layer formed by photo-curing, but on the computer for forming each photo-curing resin layer. The set pitch.
The actual thickness of the photocurable resin layer formed by irradiation with light is usually almost the same as the stacking pitch set in the computer, but in some cases, the type and physical properties of the photocurable resin composition (for example, Flattening the upper surface of the photocurable resin composition for one layer supplied to the surface of the photocurable resin layer formed by light irradiation, the shape of the modeled object, the shape of the thin layer to be formed, etc. The thickness of the photocurable resin layer actually formed may be slightly increased or decreased from the value of the lamination pitch set in the computer depending on the number of times and the speed of the operation). It allows an increase or decrease.

In optical three-dimensional modeling, a three-dimensional solid for the purpose of manufacturing is formed by selectively irradiating one layer of a photocurable resin composition with light to form a photocurable resin layer having a predetermined shape and pattern. A large number of tomographic data obtained by slicing a modeled object at predetermined intervals are stored in a computer, and stereolithography is performed based on the tomographic data. The three-dimensional model is manufactured by the optical three-dimensional modeling method of the present invention. As a specific method for doing so, for example, the following methods << 1 >> to << 3 >> can be mentioned. However, the method is not limited to the following methods << 1 >> to << 3 >>.

<< 1 >> Determine a fixed stacking pitch that forms the basis, calculate the actual thickness for forming each photocured resin layer based on the stacking pitch that forms the basis, using random numbers, etc., and then random numbers, etc. The tomographic data of each layer according to the actual thickness calculated by the above is input and stored in the computer, and each photocured resin layer is sequentially formed based on the tomographic data input and stored in the computer to form a three-dimensional structure. A method of manufacturing a modeled object.
<< 2 >> Set a constant stacking pitch (slice pitch) on the computer (for example, set the slice pitch to 0.1 mm on the computer), and use random numbers or the like based on the constant stacking pitch to actually perform a predetermined layer. The stacking pitch of the predetermined layer is determined, and the tomographic data of the predetermined layer is determined on a computer by the interpolation method according to the stacking pitch of the layers before and after the predetermined layer. A method for producing a three-dimensional model by sequentially forming the photocured resin layers.
<< 3 >> A constant stacking pitch (slice pitch) (for example, 0.1 mm) is stored as tomographic data on a computer, and the actual stacking pitch is obtained on the computer using random numbers or the like based on the tomographic data. A method for producing a three-dimensional model by sequentially forming photocured resin layers according to the actual stacking pitch obtained above.

In the method of << 1 >> above, a fixed stacking pitch that forms the basis is determined, and the actual thickness for forming each photocured resin layer is calculated based on the stacking pitch that forms the basis by random numbers or the like. Since it is necessary to input and store the tomographic data of each layer according to the actual thickness calculated by random numbers or the like in a computer, it is possible to obtain a three-dimensional model having excellent modeling accuracy, although it is a little complicated.
The method of << 2 >> is simpler than the method of << 1 >>, and a three-dimensional model having excellent modeling accuracy can be obtained.
The method of << 3 >> has an advantage that it is simpler than the methods of << 1 >> and << 2 >> because it is not necessary to change the tomographic data stored in the computer. However, the modeling accuracy may not be sufficient depending on the shape of the three-dimensional modeled object.

In the present invention, for example, a random number generator, a random number generation algorithm, or the like can be used to make the stacking pitch between the photocurable resin layers different (set the stacking pitch to random number). Here, the algorithm for generating random numbers may be any algorithm as long as the thicknesses of adjacent layers are different. Specifically, for example, it may be selected from a random number table, or a pseudo-random number generation algorithm such as a square sampling method or a linear congruential method may be used.

Further, when a random number is used, the distribution of the stacking pitch may be partially biased (for example, when the set value on the computer is 0.1 mm, the actual stacking pitch value is 0.085 →. When it becomes less than 0.1 in succession like 0.092 → 0.079 → 0.090, or conversely, in the case of 0.12 → 0.15 → 0.13 → 0.11 in succession, 0. (For example, when it exceeds 1), in that case, partial distortion may occur in the shape and physical properties of the three-dimensional model obtained by performing the optical three-dimensional modeling.
Therefore, in order to prevent the occurrence of partial distortion of the shape and physical properties of the three-dimensional model, for example,
(A) Alternately add or subtract according to the value of the random number (for example, when the random number from 0 to an appropriate value is Rand, and the set value is 0.1 mm, 0.1 + Rand, 0.1-Rand, 0. Method such as 1 + Rand ...);
(B) When determining the actual thickness, add not only random numbers but also correction values that prevent deviations from the set values (although it is not a random number in a narrow sense, the random number in the present invention is a sequence of irregular numbers. (Used);
(C) Introduce a correction coefficient so that the thickness of the previous layer and the thickness of the next layer are different;
(D) If the thickness obtained by a random number method is adopted when performing the process of determining the stacking pitch, a partial distribution may be biased, or between adjacent or adjacent layers and the layer for determining the thickness. If the difference in thickness is small, the decision is made, the stacking pitch is rejected, and a new stacking pitch is selected;
You may perform processing such as.

In the present invention, 90% or more of the total photocurable resin layers constituting the three-dimensional object, particularly all the photocurable resin layers are in the range of 0.3 × D (mm) to 3.0 × D (mm). It is preferable that the film is formed at a stacking pitch because it is a three-dimensional object that does not cause inappropriate optical phenomena such as rainbow generation and diffused reflection.
If the stacking pitch when forming the photocurable resin layer constituting the three-dimensional model is smaller than 0.3 × D (mm), it takes a long time to manufacture the three-dimensional model, or when recoating. A uniform photocurable resin composition layer cannot be obtained, or the irradiation energy becomes higher than the energy required for curing, so that yellowing or warpage deformation of the three-dimensional model is likely to occur. On the other hand, if the stacking pitch when forming the photocurable resin layer constituting the stereolithographic object exceeds 3.0 × D (mm), the dimensional accuracy and strength of the stereolithographic object obtained by stereolithography are lowered. Since the light irradiation energy is lower than the energy required for curing, the photocurable resin layer (cured thin layer) is likely to peel off, and the energy required for curing increases exponentially with respect to the thickness of the layer. In the local overexposure state, problems such as yellowing and warpage deformation of the three-dimensional model are likely to occur.

In the present invention, the difference between the stacking pitch of one of the adjacent photocurable resin layers and the stacking pitch of the other layer is 1.5 mm or less, further 1.0 mm or less, particularly 0.5 mm or less. It is preferable to form and laminate the resin layer.
If the difference between the stacking pitch of one of the adjacent photocurable resin layers and the stacking pitch of the other is too large, the mechanical properties and other physical properties of the obtained three-dimensional model are likely to deteriorate. On the other hand, if the difference between the stacking pitch and the other stacking pitch is too small, the photocurable resin layer constituting the three-dimensional model becomes almost the same as the conventional technique formed by almost the same stacking pitch, and the laminated cross section of the three-dimensional model is formed. On the (side surface), a periodic structure such as _{n 1} / n ₂ / n ₁ / n ₂ / n ₁ / n ₂ / n ₁ / n _{2 / ...} It tends to cause inappropriate optical phenomena.

In the present invention, in the production of a three-dimensional model, the same stacking pitch (for example, stacking) is alternately performed along the entire or substantially the entire laminated cross section of the three-dimensional model along the laminated cross section (lamination direction of the photocurable resin layer). Laminated structure such as pitch A / laminated pitch B / laminated pitch A / laminated pitch B / laminated pitch A / laminated pitch B / ..., laminated pitch A / laminated pitch B / laminated pitch C / laminated pitch A / It is preferable to form and laminate the photocurable resin layer so as not to have a laminated structure (lamination pitch B / lamination pitch C / lamination pitch A / lamination pitch B / lamination pitch C / ...).
In particular, in the present invention, in the production of the three-dimensional model, the photocurable resin layer is formed and laminated so that the lamination pitch is random along the lamination cross section (the direction in which the photocurable resin layer is laminated) of the three-dimensional model. This is preferable because it does not cause an inappropriate optical phenomenon of the three-dimensional model.
In the present invention, when manufacturing a three-dimensional model, the ratio of the same stacking pitch is 20% or less, further 10% or less, particularly 5% or less of the total number of laminated photocurable resin layers constituting the three-dimensional model. It is preferable to form and laminate the photocurable resin layer in this way from the viewpoint of obtaining a three-dimensional object that does not cause inappropriate optical phenomena such as rainbow generation and diffused reflection.
Random stacking pitches for forming the photocurable resin layer constituting the three-dimensional model, and lowering the ratio of the same stack pitch are, for example, input three-dimensional data related to the production of the three-dimensional model. This can be done by generating a (pseudo) random number on your computer.

Depending on the value (large or small) of the lamination pitch so that the photocurable resin layer that is sufficiently and uniformly photocured is formed even if the lamination pitch for forming the photocurable resin layer constituting the three-dimensional model changes. The thickness, light irradiation intensity (laser intensity), laser scanning speed, laser irradiation frequency, etc. of the uncured optical three-dimensional modeling resin composition supplied onto the surface of the photocurable resin layer are automatically controlled by a computer. However, the light irradiation amount may be controlled. In addition, the amount of light irradiation in optical three-dimensional modeling is to strengthen the adhesion between layers by using light that is slightly stronger than the thickness of the object to be cured (stacking pitch) so that a thicker layer can be cured. Therefore, it is possible to cope with an increase in the cured film thickness to some extent. Therefore, it is possible to easily cure the light irradiation amount corresponding to the set pitch on the computer while keeping it constant.

In the present invention, the basic lamination pitch D (mm) set in the computer for forming the photocurable resin layer is preferably a constant value within the range of 0.01 to 2.0 mm, and 0. It is preferably a constant value within the range of 01 to 1.0 mm, more preferably a constant value within the range of 0.02 to 0.5 mm, and a constant value within the range of 0.025 to 0.3 mm. Is more preferable, and a constant value within the range of 0.05 to 0.15 mm is particularly preferable.
If the value of the stacking pitch D is too small, the stacking pitch for forming each photocurable resin layer is also too small, and it tends to take time for stereolithography. On the other hand, if the value of the stacking pitch D is too large, The stacking pitch for forming each photocurable resin layer also becomes large, and the dimensional accuracy and strength of the three-dimensional model obtained by stereolithography are likely to decrease.

According to the above-mentioned optical three-dimensional modeling method of the present invention, it is a three-dimensional model formed by laminating a plurality of photocurable resin layers, and the thicknesses of adjacent photocurable resin layers are different from each other to form a three-dimensional model. A three-dimensional model is produced in which the thickness of each photocurable resin layer is random or substantially random along the laminated cross section of the three-dimensional model (the direction in which the photocurable resin layers are laminated). This three-dimensional model has a characteristic that an inappropriate optical phenomenon is unlikely to occur because an optical phenomenon such as a rainbow appearing or diffuse reflection occurs depending on the viewing angle does not occur.
In the three-dimensional model obtained by the present invention, the thicknesses of the adjacent photocurable resin layers are all 0.3 × D (mm) to 3.0 × D (based on the optical three-dimensional modeling method of the present invention). It is preferable that the values within the range of mm) are different from each other and are random along the laminating direction of the photocurable resin layer (the laminating cross section of the three-dimensional model).
At that time, the difference between the thickness of one photocurable resin layer and the thickness of the other photocurable resin layer of the adjacent photocurable resin layers is 1.5 mm or less, further 1.0 mm or less, particularly 0. It is preferably 5 mm or less.
In the three-dimensional model obtained by the present invention, the proportion of the photocurable resin layers having the same thickness is 20% or less, further 10% or less, particularly 5 of the total number of laminated photocurable resin layers constituting the three-dimensional model. % Or less is preferable.
Here, the thickness of the photocurable resin layer constituting the three-dimensional model obtained by the optical three-dimensional modeling method of the present invention can be measured by measuring the refractive index or the like on the laminated cross section of the three-dimensional model.

Although not limited in any way, an example of the laminated structure of the photocurable resin layer in the three-dimensional model obtained by the present invention is schematically shown in FIG.
As shown in FIG. 1, in the three-dimensional model obtained by the optical three-dimensional modeling method of the present invention, the thickness of the adjacent photocurable resin layer is different (2a ≠ 2b ≠ 2c ≠ 2d ≠ 2e ≠ ... -), Because there is no regularity or little regularity, a periodic structure of refractive index is not formed along the laminating direction of the photocurable resin layer in the three-dimensional model. Therefore, phenomena such as diffraction and interference do not occur or even if they do occur, the degree is small. As a result, it is presumed that the generation of rainbows and diffused reflections due to the difference in viewing angle will not occur, and inappropriate optical phenomena will be less likely to occur.

In the present invention, as a resin composition for optical three-dimensional modeling for producing a three-dimensional model, << 1 >> a photocurable resin composition containing a radically polymerizable organic compound and a photosensitive radical polymerization initiator, << 2 >>. A photocurable resin composition containing a cationically polymerizable organic compound and a photosensitive cationic polymerization initiator, or << 3 >> radically polymerizable organic compound, a cationically polymerizable organic compound, a photosensitive radical polymerization initiator and a photosensitive cationic polymerization initiator. Any photocurable resin composition containing the agent may be used.
Among them, the photocurable resin composition of << 3 >> is preferably used because it has a high stereolithography speed when manufacturing a three-dimensional model and can obtain a three-dimensional model having excellent mechanical properties and modeling accuracy. Be done.

The radically polymerizable organic compound used in the photocurable resin compositions of << 1 >> and << 3 >> causes a polymerization reaction and / or a cross-linking reaction when irradiated with light in the presence of a photosensitive radical polymerization initiator. Any of the compounds can be used, and typical examples thereof include (meth) acrylate compounds, unsaturated polyester compounds, allyl urethane compounds, polythiol compounds, etc., and one of the above-mentioned radically polymerizable organic compounds or Two or more types can be used. Among them, a compound having at least one (meth) acrylic group in one molecule is preferably used, and specific examples thereof include a reaction product of an epoxy compound and (meth) acrylic acid, and (meth) acrylic of alcohols. Examples thereof include acid esters, urethane (meth) acrylates, polyester (meth) acrylates, and polyether (meth) acrylates.

The reaction product of the above-mentioned epoxy compound and (meth) acrylic acid is obtained by reacting an aromatic epoxy compound, an alicyclic epoxy compound and / or an aliphatic epoxy compound with (meth) acrylic acid (meth). ) Acrylic reaction products can be mentioned. Specific examples of the (meth) acrylate-based reaction product obtained by the reaction of an aromatic epoxy compound with (meth) acrylic acid include a bisphenol compound such as bisphenol A or bisphenol F or an alkylene oxide adduct thereof and an epoxy such as epichlorohydrin. (Meta) acrylate obtained by reacting glycidyl ether obtained by reaction with an agent with (meth) acrylic acid, (meth) acrylate-based reaction generation obtained by reacting epoxy novolac resin with (meth) acrylic acid You can mention things.

Further, as the (meth) acrylic acid ester of the above-mentioned alcohols, aromatic alcohols having at least one hydroxyl group in the molecule, fatty alcohols, alicyclic alcohols and / or their alkylene oxide adducts, and ( Examples thereof include (meth) acrylate obtained by reacting with meta) acrylic acid.

Further, examples of the urethane (meth) acrylate described above include (meth) acrylate obtained by reacting a hydroxyl group-containing (meth) acrylic acid ester with an isocyanate compound. As the hydroxyl group-containing (meth) acrylic acid ester, a hydroxyl group-containing (meth) acrylic acid ester obtained by an esterification reaction between an aliphatic dihydric alcohol and (meth) acrylic acid is preferable, and as a specific example, 2-hydroxy Ethyl (meth) acrylate and the like can be mentioned. Further, as the isocyanate compound, a polyisocyanate compound having two or more isocyanate groups in one molecule such as tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like is preferable.

Further, examples of the polyester (meth) acrylate described above include polyester (meth) acrylate obtained by reacting a hydroxyl group-containing polyester with (meth) acrylic acid.
Further, examples of the above-mentioned polyether (meth) acrylate include a polyether acrylate obtained by reacting a hydroxyl group-containing polyether with acrylic acid.

Examples of the cationically polymerizable organic compound that can be used in the photocurable resin compositions of << 2 >> and << 3 >> include epoxy compounds such as <1> alicyclic epoxy resin, aliphatic epoxy resin, and aromatic epoxy resin. <2> Cyclic ether or cyclic acetal compounds (oxetan compounds, oxolane compounds such as tetrahydrofuran, 2,3-dimethyltetrahydrofuran, trioxane, 1,3-dioxolane, 1,3,6-trioxanecyclooctane, etc.); <3 > Cyclic lactone compounds (β-propiolactone, ε-caprolactone, etc.); <4> Thiirane compounds (ethylene sulfide, thioepichlorohydrin, etc.); <5> Thietan compounds (1,3-propine sulfide, 3, 3-Dimethylthietan, etc.); <6> Vinyl ether compounds [ethylene glycol divinyl ether, alkyl vinyl ether, 3,4-dihydropyran-2-methyl (3,4-dihydropyran-2-carboxylate), triethylene glycol di Vinyl ether and the like]; <7> Spiroorthoester compound obtained by reacting an epoxy compound with lactone; <8> Ethylene unsaturated compounds such as vinylcyclohexane, isobutylene, and polybutadiene can be mentioned.

Among the above, as the cationically polymerizable organic compound, an epoxy compound [particularly, a polyepoxy compound having two or more epoxy groups in one molecule (epoxy resin)] is preferably used, and the epoxy compound and the oxetane compound are used in combination. Is more preferable. In particular, when an alicyclic polyepoxy compound (aliphatic epoxy resin) having two or more epoxy groups in one molecule and an oxetane compound are used in combination, the viscosity of the photocurable resin composition becomes low and the molding becomes smooth. Moreover, the cationic polymerization rate, the thick film curability, the resolution, the ultraviolet transmittance, and the like are improved, and the volume shrinkage rate of the obtained three-dimensional model is reduced.

As the above-mentioned alicyclic epoxy resin (alicyclic polyepoxy compound), polyglycidyl ether of a polyhydric alcohol having at least one alicyclic ring, or a cyclohexene or cyclopentene ring-containing compound is hydrogenated or peracid. Cyclohexene oxide or a cyclopentene oxide-containing compound obtained by epoxidation with an appropriate oxidizing agent such as the above can be mentioned.

Examples of the above-mentioned aliphatic epoxy resin include polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers of glycidyl acrylates and glycidyl methacrylates, and copolymers. And so on.

Further, examples of the above-mentioned aromatic epoxy resin include monovalent or polyhydric phenol having at least one aromatic nucleus or mono or polyglycidyl ether of an alkylene oxide adduct thereof, and specifically, for example. Monoglycidyl ether of glycidyl ether, epoxy novolac resin, phenol, cresol, butylphenol obtained by reaction of bisphenol A or bisphenol F or its alkylene oxide adduct with epichlorohydrin, or monoglycidyl ether of a polyether alcohol obtained by adding alkylene oxide to these. And so on.

Further, as the above-mentioned oxetane compound, one or more of a monooxetane compound (OXm) having one oxetane group in the molecule and a polyoxetane compound (OXp) having two or more oxetane groups in the molecule are used. be able to.
As the monooxetane compound (OXm), any compound having one oxetane group in one molecule can be used. For example, trimethylene oxide, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane, 3 −Methyl-3-phenoxymethyloxetane, monooxetane monoalcohol having one oxetane group and one alcoholic hydroxyl group in the molecule, etc. can be mentioned, among which the reactivity, the viscosity of the photocurable resin composition, etc. From this point of view, a monooxetane monoalcohol compound is preferably used.
As the polyoxetane compound (OXp), any compound having two or more oxetane groups, for example, a compound having two, three or four or more oxetane groups can be used, and among them, a compound having two oxetane groups can be used. A dioxetane compound is preferably used.

The photocurable resin compositions of << 2 >> and << 3 >> have two or more epoxy groups in one molecule based on the mass of the cationically polymerizable organic compound contained in the photocurable resin composition. It is preferable that the polyepoxy compound (epoxy resin) is contained in an amount of 30% by mass or more, more preferably 40% by mass or more, and particularly preferably 50% by mass or more.
When the photocurable resin compositions of << 2 >> and << 3 >> contain an oxetane compound as a part of the cationically polymerizable organic compound, the content of the oxetane compound is the mass of the cationically polymerizable organic compound. It is preferably 1 to 70% by mass, and more preferably 1 to 60% by mass.
Further, in the photocurable resin composition of << 3 >> above, the content ratio of the radically polymerizable organic compound: the cationically polymerizable organic compound is preferably 9: 1 to 1: 9 in terms of mass ratio, and 8: It is more preferably 2 to 2: 8.

The photosensitive radical polymerization initiator (hereinafter referred to as “photoradical polymerization initiator”) contained in the photocurable resin compositions of << 1 >> and << 3 >> is a radical-polymerizable organic compound when irradiated with light. Any polymerization initiator capable of initiating radical polymerization can be used, for example, a phenylketone compound such as 1-hydroxy-cyclohexylphenylketone, a benzyl or a dialkylacetal thereof such as benzyldimethylketal and benzyl-β-methoxyethyl acetal. Examples thereof include a compound, a benzoin or an alkyl ether-based compound thereof, a benzophenone-based compound, and a thioxanthone-based compound.

The photocurable resin compositions of << 1 >> and << 3 >> preferably contain a photoradical polymerization initiator in a proportion of 0.5 to 10% by mass based on the mass of the photocurable resin composition. , 1 to 5% by mass, more preferably.

The photosensitive cationic polymerization initiator (hereinafter referred to as “photocationic polymerization initiator”) contained in the photocurable resin compositions of << 2 >> and << 3 >> is a cationically polymerizable organic compound when irradiated with light. Any polymerization initiator capable of initiating cationic polymerization can be used, for example, triphenylphenacilphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate, bis. -[4- (Diphenylsulfonio) phenyl] sulfide bisdihexafluoroantimonate, bis- [4- (di4'-hydroxyethoxyphenylsulfonio) phenyl] sulfide bisdihexafluoroantimonate, diphenyl-4 -Thiophenoxyphenyl sulfonium hexafluorophosphate, bis- [4- (diphenyl sulfonio) phenyl] sulfide bis dihexafluorophosphate, diphenyliodonium tetrafluoroborate, diphenyl-4-thiophenoxyphenyl sulfonium tris (pentafluoroethyl) ) Trifluorophosphate and the like can be mentioned, and one or more of these can be used.

Further, for the purpose of improving the reaction rate, a photosensitizer such as benzophenone, benzoin alkyl ether, thioxanthone, dialkoxyanthracene and the like may be used together with the cationic polymerization initiator, if necessary.

The photocurable resin compositions of << 2 >> and << 3 >> preferably contain a photocationic polymerization initiator in a proportion of 1 to 10% by mass based on the mass of the photocurable resin composition. More preferably, it is contained in a proportion of ~ 6% by mass.

The resin composition for optical three-dimensional molding (photocurable resin composition) used for manufacturing the three-dimensional molding is, if necessary, a discoloring agent such as a dye, a defoaming agent, a leveling agent, a thickener, a flame retardant, and the like. It can contain one or more kinds of antioxidants, reforming resins and the like in an appropriate amount.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the Examples.
In the following example, the viscosity of the resin composition for optical three-dimensional modeling is determined by adjusting the temperature of the resin composition for optical three-dimensional modeling to 25 ° C in a constant temperature bath at 25 ° C. LVDV2T ”) was used for measurement.

<< Example 1 >>
(1) 3,4-Epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarboxylate ("Ceroxide 2021P" manufactured by Daicel Co., Ltd.) 13.0 parts by mass, 2- [4- (2,3-epoxypropoxy) Phenyl] -2- [4- [1,1-bis [4- ([2,3-epoxypropoxy] phenyl] ethyl] phenyl] propane (VG3101L described above) 24.0 parts by mass, polytetramethylene glycol diglycidyl Ether ("Epogosei PT" manufactured by Yokkaichi Synthetic Co., Ltd., number of bonds of tetramethylene oxide unit ≒ 9, average molecular weight ≒ 780) 1.9 parts by mass, 3-ethyl-3-hydroxymethyloxetane (manufactured by Toa Synthetic Co., Ltd. " OXT-101 ”) 4.5 parts by mass, bis (3-ethyl-3-oxetanylmethyl) ether (“OXT-221” manufactured by Toa Synthetic Co., Ltd.) 12.0 parts by mass, dipentaerythritol polyacrylate (Shin-Nakamura Kagaku) "A-9550W" manufactured by Kogyo Co., Ltd., 8.0 parts by mass of pentaacrylate and hexaacrylate), polytetramethylene glycol diacrylate ("A-PTMG-65" manufactured by Shin-Nakamura Chemical Industry Co., Ltd., average molecular weight ≈650 ) 10.0 parts by mass, polypropylene glycol monoacrylate ("Blemmer AP-150" manufactured by Nippon Oil & Fats Co., Ltd. 6.0 parts by mass, tricyclodecanedimethanol diacrylate ("A-DCP" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)) 12.0 parts by mass, cationic polymerization initiator (“CPI-200K” manufactured by San-Apro Co., Ltd.) 3.0 parts by mass, 1-hydroxy-cyclohexylphenylketone (“Irgacure 184” manufactured by BASF) (radical polymerization initiator) 3 .0 parts by mass, polytetramethylene ether glycol (2.0 parts by mass of "PTG-850SN" manufactured by Hodoya Chemical Industry Co., Ltd., 0.020 parts by mass of 2-naphthalenethiol and 0.3 parts by mass of distilled water are well mixed. A resin composition for optical three-dimensional modeling was prepared. The viscosity of this resin composition for optical three-dimensional modeling was 370 MPa · s (25 ° C.).

(2) Using the resin composition for optical three-dimensional modeling obtained in (1) above, using a semiconductor laser (rated output 200 mW; wavelength 355 nm; manufactured by Spectraphysics), liquid surface irradiation energy 50 to 150 mJ. Under the condition of / cm ² , the basic stacking pitch D is set to 0.1 mm, and the stacking pitch for forming each photocurable resin layer is randomly set within the numerical range of 0.075 to 0.125 mm. By changing, a rectangular parallelepiped three-dimensional model having a length × width × thickness = 5 mm × 40 mm × 30 mm was produced. The obtained three-dimensional model was irradiated with ultraviolet rays (metal halide lamp, wavelength 365 nm, intensity 3.0 mW / cm ² ) for 20 minutes and then cured.
(3) When visually observing the straight-shaped three-dimensional object obtained in (2) above from the directions of its six faces, the directions of its twelve sides, and the directions of its eight vertices, which one Even when viewed from the direction, there were no optical phenomena such as rainbow generation and diffused reflection, and it had the property of not causing inappropriate optical phenomena and high transparency.

<< Comparative Example 1 >>
(1) Using the same resin composition for optical three-dimensional modeling prepared in (1) of Example 1, a semiconductor laser (rated output 200 mW; wavelength 355 nm; manufactured by Spectraphysics), liquid surface irradiation energy 100 mJ. Under the condition of / cm ² , all the photocurable resin layers were formed at a stacking pitch of 0.10 mm to produce a rectangular parallelepiped three-dimensional object having a length × width × thickness = 5 mm × 40 mm × 30 mm. The obtained three-dimensional model was irradiated with ultraviolet rays (metal halide lamp, wavelength 365 nm, intensity 3.0 mW / cm ² ) for 20 minutes and then cured.
(2) When the straight body-shaped three-dimensional object obtained in (1) above was visually observed from the directions of its six faces, the directions of its twelve sides, and the directions of its eight vertices, it was found to be lateral. When viewed from the direction of (30 mm × 40 mm), rainbows were generated, diffused reflection occurred, and inappropriate optical phenomena did not occur, and transparency was insufficient.

By performing the optical three-dimensional modeling method of the present invention, it is possible to smoothly produce a three-dimensional model without optical abnormalities such as rainbow generation due to a difference in viewing angle and diffused reflection. Therefore, the optical of the present invention Three-dimensional modeling methods are inappropriate optics such as prototyping models for optical products such as automobile and motorcycle lenses, restoration of fine arts, imitation and contemporary art, and arts and crafts fields such as design presentation models for glass-walled buildings. It is extremely effective as a method for manufacturing a three-dimensional model that does not cause a phenomenon.

1 Surface of photocurable resin layer in optical three-dimensional modeling 2 Laminated cross section (side surface) of optical three-dimensional modeling
X Upper part of photo-curing resin layer Y Lower part of photo-curing resin layer

Claims (10)

One layer having a predetermined shape / pattern by selectively irradiating the front surface or bottom surface of the optical three-dimensional modeling resin composition housed in the modeling tank with light based on the three-dimensional three-dimensional data stored in the computer. The photocurable resin layer is formed, and then one layer of uncured optical three-dimensional modeling resin composition is supplied to the photocurable resin layer to emit light based on the three-dimensional three-dimensional data stored in the computer. A solid having a total light transmittance of 85% or more by repeating the operation of selectively irradiating to form the next photocurable resin layer having a predetermined shape / pattern and laminating on or under the photocurable resin layer described above. It is an optical three-dimensional modeling method for manufacturing a target model;
Adjacent photo-curing resin layers are arranged from 0.3 × D (mm) to 3.0 × D (mm) [In the formula, D is a stacking pitch that forms the basis preset in the computer for forming the photo-curing resin layer. (Mm) is shown. ], While adopting stacking pitches within the range of], they are formed at different stacking pitches; an optical three-dimensional modeling method. The optical three-dimensional modeling method according to claim 1, wherein the total light transmittance of the three-dimensional model is 88% or more. The optical three-dimensional modeling method according to claim 1 or 2 , wherein the difference between the stacking pitch of one of the adjacent photocurable resin layers and the stacking pitch of the other is 1.5 mm or less. The optical three-dimensional modeling method according to any one of claims 1 to 3, wherein the photocurable resin layer is formed and laminated so that the lamination pitch is random along the lamination direction of the photocurable resin layer. According to any one of claims 1 to 4 , the photocurable resin layer is formed and laminated so that the ratio of the same lamination pitch is 20% or less of the total number of laminated photocurable resin layers constituting the three-dimensional model. The optical three-dimensional modeling method described. Any one of claims 1 to 5 , wherein the basic lamination pitch D (mm) set in the computer for forming the photocurable resin layer is a constant value within the range of 0.01 to 2.0 mm. The optical three-dimensional modeling method described in. It is a three-dimensional model composed of a plurality of laminated photocurable resin layers having a total light transmittance of 85% or more, and the thicknesses of adjacent photocurable resin layers are different from each other. The thicknesses are all 0.3 × D (mm) to 3.0 × D (mm) [In the formula, D indicates the basic design thickness (mm) for forming the photocurable resin layer. ], And the thickness of each photocurable resin layer constituting the three-dimensional model is random along the laminating direction of the photocurable resin layer. The three-dimensional model according to claim 7, wherein the total light transmittance of the three-dimensional model is 88% or more. The three-dimensional model according to claim 7 or 8 , wherein the difference between the thickness of one photocurable resin layer and the thickness of the other photocurable resin layer in the adjacent photocurable resin layer is within the range of 1.5 mm or less. The three-dimensional model according to any one of claims 7 to 9, wherein the ratio of the photocurable resin layers having the same thickness is 20% or less of the total number of laminated photocurable resin layers constituting the three-dimensional model.

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