JP7374861B2 - Manufacturing method of resin mold - Google Patents

Description

Embodiments of the present invention relate to a method for manufacturing a resin mold.

In three-dimensional modeling technology called additive manufacturing technology or three-dimensional printing, stereolithography technology (stereolithography) is known, which creates three-dimensional objects by laminating resins that are cured by light such as ultraviolet rays or radiation. (See Patent Documents 1 to 3). In stereolithography technology, the process of supplying photocurable resin layer by layer by coating or other methods and curing the photocurable resin of each layer by irradiating light onto an area according to the shape of the object is repeated. It will be done. In the stereolithography technology, by repeating this process and stacking the cured layers, a shaped article having a desired shape is generated. Stereolithography techniques include free liquid level method, regulated liquid level method, etc. On the other hand, a method of discharging and supplying a photocurable resin as droplets using an inkjet method is not included in the stereolithography technology in this specification.

For example, stereolithography technology is used to create resin molds used in injection molding (molding) and the like. This makes it possible to obtain an injection molded product (or a prototype thereof) in a shorter period of time than, for example, when injection molding is performed using a metal mold.

Japanese Patent Application Publication No. 2004-130529 JP2020-037245A International Publication No. 2018/175739 Japanese Patent Application Publication No. 2000-94471 JP2006-076822A

However, in resin mold modeling using stereolithography technology, modeling accuracy and production efficiency are in a trade-off relationship with each other, and it is difficult to achieve both. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a resin mold having excellent toughness and achieving both molding accuracy and production efficiency.

In order to solve the above-mentioned problems and achieve the objects, the present invention provides a resin for stereolithography using a stereolithographic resin composed of a photocurable resin composition containing a photocurable component, organic particles, and inorganic particles. A mold manufacturing method, wherein among a plurality of contour irradiation lines through which light is irradiated to cure the contour portion of the resin mold, the contour irradiation lines located on the inner side, the contour irradiation lines located on the outer side. The method of manufacturing a resin mold includes irradiating the light with a width larger than the width of the line.

The present invention also provides a method for manufacturing a resin mold by a stereolithography method using a stereolithographic resin composed of a photocurable resin composition containing a photocurable component, organic particles, and inorganic particles, the method comprising: forming a weir-shaped resin mold; A method of manufacturing a resin mold includes forming a cured film inside the weir shape.

According to the present invention, it is possible to provide a method for manufacturing a resin mold with excellent toughness, which achieves both modeling accuracy and production efficiency.

FIG. 1 is a diagram showing a configuration example of a stereolithography apparatus 100 according to an embodiment. FIG. 2 is a diagram illustrating an example of the first manufacturing method according to the embodiment. FIG. 3 is a diagram showing a comparative example in which the first manufacturing method is not applied. FIG. 4 is a diagram illustrating an example of the second manufacturing method according to the embodiment. FIG. 5 is a diagram showing a comparative example in which the second manufacturing method is not applied. FIG. 6 is a plan view showing resin molds for evaluation according to Examples and Comparative Examples.

Hereinafter, a method for manufacturing a resin mold according to an embodiment will be described with reference to the accompanying drawings. Note that the embodiments described below are not limited to the following description. The embodiment described below can be combined with other embodiments or conventional techniques as long as there is no inconsistency in the configuration.

Note that the configuration illustrated below is not limited to the illustrated content. For example, the dimensions and angles of each part illustrated below can be changed as appropriate within a range that does not significantly impair modeling accuracy and production efficiency.

(Embodiment)
(Configuration of stereolithography device 100)
A configuration example of a stereolithography apparatus 100 according to an embodiment will be described using FIG. 1. FIG. 1 is a diagram showing a configuration example of a stereolithography apparatus 100 according to an embodiment. The stereolithography apparatus 100 illustrated in FIG. 1 is an example of an apparatus that executes the resin mold manufacturing method according to the embodiment. In FIG. 1, the Z direction is a direction perpendicular to a liquid surface 104 (irradiation plane) of a liquid composition 103 (described later), the X direction is an arbitrary direction on the irradiation plane, and the Y direction is a direction perpendicular to the X direction on the irradiation plane. Corresponds to each. That is, FIG. 1 corresponds to a cross-sectional view of the stereolithography apparatus 100 on the YZ plane.

As shown in FIG. 1, the stereolithography apparatus 100 includes a container 101 and a support stand 102. The container 101 contains a liquid composition 103 (stereolithography resin). The support stand 102 is arranged below the liquid level 104 of the liquid composition 103 (that is, in the liquid composition 103). Further, the stereolithography apparatus 100 irradiates the liquid surface 104 with laser light 105 for curing the stereolithography resin from above. The laser beam 105 has enough energy, such as ultraviolet rays or radiation, to harden the stereolithography resin. The stereolithography apparatus 100 cures an arbitrary position with an arbitrary irradiation line width by controlling the beam diameter and irradiation position of the laser beam 105 using a lens, an aperture, or the like.

The process of curing the first hardened layer 106 will be explained using the upper part of FIG. 1 . First, the stereolithography apparatus 100 places the support base 102 in the liquid composition 103. At this time, the stereolithography apparatus 100 adjusts the position (height) of the support base 102 so that the distance between the upper surface of the support base 102 and the liquid level 104 matches the thickness of the cured layer 106. The stereolithography apparatus 100 then applies the liquid composition 103 to the upper surface of the support base 102 using a recoater. Then, the stereolithography apparatus 100 irradiates the liquid composition 103 applied to the upper surface of the support base 102 with laser light 105 to harden the liquid composition 103. Thereby, the stereolithography apparatus 100 hardens the first hardened layer 106.

Next, the process of curing the second hardened layer 107 will be explained using the lower part of FIG. The stereolithography apparatus 100 lowers the position of the support base 102 so that the distance between the upper surface of the cured layer 106 and the liquid level 104 matches the thickness of the cured layer 107. The stereolithography apparatus 100 then applies the liquid composition 103 onto the upper surfaces of the support base 102 and the cured layer 106 using a recoater. Then, the stereolithography apparatus 100 irradiates a desired position of the liquid composition 103 applied to the upper surface of the support base 102 and the cured layer 106 with a laser beam 105 to match the shape of the intended object. The liquid composition 103 is cured. Thereby, the stereolithography apparatus 100 hardens the second hardened layer 107. By repeating this process, the stereolithography apparatus 100 stacks the cured layers on the support base 102, thereby modeling an object having a desired shape.

Note that the content described in FIG. 1 is just an example, and is not limited to the content shown in the figure. For example, the resin mold manufacturing method according to the present embodiment is not limited to the stereolithography apparatus 100 using the free liquid level method shown in FIG. It is widely applicable to known stereolithography techniques such as the stereolithography technique described in 1. Furthermore, regarding the composition of the resin for stereolithography, known components used in the production of resin molds can be appropriately applied. Note that the composition of the stereolithography resin will be described later.

Here, the stereolithography apparatus 100 executes two manufacturing methods (a first manufacturing method and a second manufacturing method) described below as resin mold manufacturing methods that achieve both molding accuracy and production efficiency. Either one of the first manufacturing method and the second manufacturing method may be performed alone, or both methods may be used in combination. Hereinafter, the first manufacturing method and the second manufacturing method will be explained in order.

(First manufacturing method: contour drawing control)
The first manufacturing method according to the embodiment will be described using FIGS. 2 and 3. FIG. 2 is a diagram illustrating an example of the first manufacturing method according to the embodiment. FIG. 3 is a diagram showing a comparative example in which the first manufacturing method is not applied. 2 and 3 show the irradiation line of light irradiated to harden the edge 10 of the object to be modeled in the irradiation plane (XY plane) seen from the irradiation direction (Z direction) of the light (laser light 105). exemplify.

Here, the "irradiation line" is a path along which the laser beam 105 having a desired beam diameter, which is focused by a lens, a diaphragm, etc., is scanned (moved) on the support base 102 (irradiation plane). The laser beam 105 is scanned by adjusting the beam diameter and laser output over time to match the width and position of the irradiation line. For example, the irradiation line is set in advance according to the shape of the object to be modeled. In other words, the stereolithography apparatus 100 hardens the stereolithography resin of each layer by moving the focal point of light collected by a lens, an aperture, or the like on the irradiation plane along the irradiation line. Note that the setting of the irradiation line may be automatically performed by the stereolithography apparatus 100, or may be performed manually by the operator. The irradiation line is also called a "drawing line."

The irradiation lines include two types: "internal drawing lines" and "contour drawing lines." The "internal drawing line" is an irradiation line where light is irradiated mainly to harden the inside of the object to be modeled (the inside in the XY plane). In order to improve production efficiency (curing speed), internal drawing lines are often set thicker than outline drawing lines and are laser scanned at high speed. Further, the "outline drawing line" is an irradiation line where light is irradiated mainly to harden the outline part (the outline part in the XY plane) of the object to be modeled. In the first manufacturing method, a plurality of outline drawing lines are provided. The lower limit of the number of outline drawing lines is preferably two, and more preferably three. The upper limit of the number of contour drawing lines is preferably 7 lines, more preferably 6 lines, and particularly preferably 5 lines. By setting the number of contour drawing lines within these ranges, it is possible to obtain a modeled object with both modeling accuracy and production efficiency. Since the outline drawing line greatly affects the surface properties of the resin mold in the Z direction (layered steps), it is often set thinner than the internal drawing line and precisely scanned (drawn) with a laser. Note that the surface properties of the resin mold also greatly affect the surface properties of the molded product.

For example, the semicircular shape at the end of the internal drawing line may cause unevenness on the surface of the object to be modeled (resin mold). Therefore, in order to prevent the internal drawing line from affecting the surface of the object to be modeled, the range drawn according to the internal drawing line (internal drawing range) is generally fixed from the end (edge 10) of the object to be modeled. A distance (approximately 100 to 200 μm) to the inside. Further, the remaining range (outline drawing range 11) included within a certain distance from the end of the object to be modeled is precisely drawn according to the outline drawing line.

In the example shown in FIG. 2, four internal drawing lines 21, 22, 23, 24 and three outline drawing lines 31, 32, 33 are set in order to harden the edge 10 of the object to be modeled. Note that the internal drawing lines 21, 22, 23, and 24 are also called "internal irradiation lines." Further, the contour drawing lines 31, 32, and 33 are also called "contour irradiation lines."

For example, in the first manufacturing method, the internal drawing range can be drawn first, and then the outline drawing range 11 (outline part) can be drawn. Preferably, the internal drawing line 21, the internal drawing line 22, the internal drawing line 23, and the internal drawing line 24 are irradiated with light in this order. Thereafter, light is irradiated to the outline drawing line 31, the outline drawing line 32, and the outline drawing line 33 in this order. Note that the order of light irradiation is not limited to this, and the outline drawing line may be drawn before the internal drawing line, and for multiple outline drawing lines, the outer outline drawing line is drawn first. You can also draw it. The order of light irradiation can be arbitrarily changed depending on the size and shape of the object to be modeled. The method described above as a preferable irradiation order is particularly preferable in achieving both modeling accuracy and production efficiency.

Here, the contour drawing line 33 for drawing the surface of the object to be modeled (the part in contact with the edge 10 of the object to be modeled; also referred to as the "decorative surface") is drawn with a thin (small) width, and draws the inside from the surface. The contour drawing lines 31 and 32 are drawn with a width that becomes thicker (larger) as the distance from the surface increases. That is, among the plurality of contour drawing lines, the innermost contour drawing line is set to have a larger width than the outermost contour drawing line. This makes it possible to achieve both modeling accuracy and production efficiency. In addition, when there are three or more outline drawing lines, the width of the outline drawing line for drawing the cosmetic surface among the plurality of outline drawing lines need only be smaller than the width of the innermost outline drawing line, It is not necessary that all contour lines have different widths. For example, it is possible to provide a plurality of contour drawing lines that are larger than the width of the contour drawing line for drawing the decorative surface and have uniform widths.

Note that "inside"/"outside" described with respect to the outline drawing line is intended to mean "inside"/"outside" of the object to be modeled. In other words, the "outer contour drawing line" is a drawing line located close to the surface of the object to be printed, and the "inner contour irradiation line" is the drawing line located away from the surface of the object. It is a certain drawing line.

Here, the effects of the first manufacturing method will be explained with reference to FIG. In the example of FIG. 3 to which the first manufacturing method is not applied, one outline drawing line 41 is set in the outline drawing range 11. Alternatively, instead of the single outline drawing line shown in FIG. 3, a plurality of thin outline drawing lines having a uniform width may be set. Therefore, if the first manufacturing method is not applied, multiple laser scans are required to harden the outline drawing range 11 depending on the thin outline drawing line. For this reason, it is difficult to achieve high production efficiency.

On the other hand, in the first manufacturing method shown in FIG. By setting the width of the contour drawing lines 31 and 32 to be larger than the width of the contour drawing line 33 while maintaining the same level of modeling accuracy as in the example, a fixed area of the contour drawing range 11 is hardened with three laser scans. can be done. Therefore, according to the first manufacturing method, it is possible to achieve both modeling accuracy and production efficiency.

Furthermore, in the first manufacturing method, the overlapping area between adjacent outline drawing lines is reduced. For example, assuming a comparative example (not shown) in which a plurality of contour drawing lines 42, 43, 44, and 45 having equal widths are provided, the overlapping area is between the contour drawing lines 42 and 43, and the contour drawing lines 43 and 44, and between outline drawing lines 44 and 45. In contrast, in the first manufacturing method, there are two overlapping regions: between the contour drawing lines 31 and 32 and between the contour drawing lines 32 and 33. Since two laser scans are performed on this superimposed area, it is difficult to accurately adjust the cumulative amount of energy of the laser beam irradiated, and if more energy than necessary is irradiated, This excess energy turns into heat, which causes deformation such as curing shrinkage and shaving. In the first manufacturing method, since the overlapping area between adjacent contour drawing lines is reduced, the factors of deformation can be reduced, and therefore, it is expected that the modeling accuracy will be improved.

In addition, in the first manufacturing method, it is preferable that the output (laser power) and scanning speed of the laser light are set to such an extent that a sufficient curing depth can be obtained even with the thickest contour drawing line (contour drawing line 31). It is. For example, when the thickness of each layer is 100 μm, it is preferable to set the output and scanning speed so that the curing depth at the outline drawing line 31 is about 130 to 150 μm.

Further, the laser power may be constant or may be changed depending on the drawing line. For example, the laser power may be different between the contour drawing line and the internal drawing line. Further, the laser power may be different for each of the plurality of contour drawing lines. It is preferable to increase the laser power as the width of the drawn line increases.

Furthermore, the scanning speeds of the contour drawing lines 31, 32, and 33 can be set arbitrarily, and may be the same or different. However, if the laser power is constant, the thicker the drawing line width (beam diameter), the shallower the curing depth, so it is preferable to slow down the scanning speed. On the other hand, since the thinner the drawing line is, the deeper the curing depth becomes, so it is preferable to increase the scanning speed. That is, among the plurality of contour drawing lines 31, 32, and 33, it is preferable that the contour irradiation line 31 located on the inside is irradiated at a scanning speed slower than the scanning speed of the contour irradiation line 33 located on the outside. By setting an appropriate scanning speed according to the thickness of each contour drawing line 31, 32, 33, production efficiency can be improved.

Further, the width of the outline drawing line is preferably 80 to 700 μm, more preferably 100 to 600 μm, and still more preferably 200 to 400 μm. In the first manufacturing method, since the width varies depending on the position of the contour drawing line, the width of the outermost contour drawing line is preferably 80 to 400 μm, more preferably 100 to 300 μm, and still more preferably is 200 to 250 μm. Further, the width of the innermost contour drawing line is preferably 200 to 700 μm, more preferably 300 to 600 μm, and still more preferably 350 to 400 μm.

Also, the width of the outermost contour drawing line is the ratio of the width of the innermost contour drawing line (the width of the outermost contour drawing line divided by the width of the innermost contour drawing line). It can also be specified by This ratio is preferably 0.1 to 0.9, more preferably 0.2 to 0.5.

Further, the width of the outline drawing line can also be defined by a ratio to the width of the internal drawing line (a value obtained by dividing the width of the outline drawing line by the width of the internal drawing line). The ratio of the width of the outermost contour drawing line to the width of the inner drawing line is preferably 0.1 to 0.9, more preferably 0.2 to 0.5. Further, the ratio of the width of the innermost contour drawing line to the width of the internal drawing line is preferably 0.5 to 1.5, more preferably 0.9 to 1.1.

Further, the width of the internal drawing line can be set arbitrarily, but is preferably 200 to 600 μm, more preferably 300 to 500 μm. This is because if the width of the internal drawing line is less than 200 μm, the production efficiency decreases, and if it is 600 μm or more, the modeling accuracy decreases.

Note that the content described in FIG. 2 is just an example, and is not limited to the content shown in the figure. For example, the position, number, and width of the outline drawing lines shown in FIG. 2 can be arbitrarily set depending on the size and shape of the object to be modeled. Further, the position, number, and width of the internal drawing lines shown in FIG. 2 can be arbitrarily set depending on the size and shape of the object to be modeled.

(Second manufacturing method: film formation)
Next, a second manufacturing method according to the embodiment will be described using FIGS. 4 and 5. FIG. 4 is a diagram illustrating an example of the second manufacturing method according to the embodiment. FIG. 5 is a diagram showing a comparative example in which the second manufacturing method is not applied. 4 and 5 illustrate cross-sectional views of the stereolithography apparatus 100 in the YZ plane.

In the example shown in FIG. 4, the stereolithography apparatus 100 repeats the process described in FIG. 1 to stack the cured layers on the support base 102, thereby forming a mold that is the object to be modeled 110. Here, the object to be modeled 110 has a trap shape. The "trap shape" is a concave shape whose bottom (lower part) is closed and whose upper part is open with respect to the above-mentioned Z direction. It can also be said that the shape has a concave portion toward the top in the Z direction. The trap shape is a container-like shape that can contain a liquid or the like, and is also called a "weir shape." In the stereolithography technique using the free liquid level method, liquid (liquid composition 103) accumulates inside the trap shape. As will be described later in the explanation of FIG. 5, the surface tension of the liquid accumulated inside the trap shape causes the liquid level to rise (rise), which affects the modeling. The term "inside the trap shape" refers to the internal space of the recess that constitutes the trap shape, and is a hollow portion of the resulting molded article.

Therefore, in the second manufacturing method, a film-like cured product (cured film) is formed inside the trap shape in modeling a resin mold having a trap shape. In the example shown in FIG. 4, four cured films 111, 112, 113, and 114 are formed at predetermined intervals along the irradiation plane (XY plane).

Specifically, in the second manufacturing method, when molding a resin mold having a trap shape, the laser beam 105 is not irradiated to a range (hole) corresponding to the inside of the trap shape, thereby forming a cured layer having a hole. formed and laminated one layer at a time. For example, in the step of forming a cured layer including the cured film 111, the laser beam 105 is also irradiated inside the area corresponding to the trap shape, thereby forming a cured layer without holes (in a state where the holes are filled). hardened layer). In other words, the cured layer formed at this stage has a cured film 111 formed inside the hole corresponding to the trap shape. The cured film may be formed as a single-layer cured layer layered by stereolithography, or may be formed as a cured layer consisting of a plurality of consecutive laminated layers. When forming a plurality of continuous cured layers, the number of continuous layers is not particularly limited, but in order to easily remove the cured film after forming the resin mold, it is necessary to prevent the liquid level from rising 120. It is preferable not to form a thick cured film. For this reason, the cured film is preferably one cured layer or two to three continuous cured layers, and more preferably one or two cured layers, which are layered in the stereolithography method. , a single hardened layer is particularly preferred. By intentionally forming cured films at predetermined intervals in this manner, four cured films 111, 112, 113, and 114 are formed at predetermined intervals.

That is, each cured film 111, 112, 113, 114 is cured on the same surface (same layer) as the surrounding cured layer. Therefore, at the stage when each cured film 111, 112, 113, 114 is formed, the rise in the liquid level that has occurred up to that point can be suppressed. Therefore, by forming the four cured films 111, 112, 113, and 114 at predetermined intervals, it is possible to model the object 110 while suppressing the rise in the liquid level that occurs during the trap-shaped modeling process at predetermined intervals. can.

Here, the effects of the second manufacturing method will be explained with reference to FIG. If the second manufacturing method is not applied, as shown in FIG. 5, a liquid level rise 120 may occur due to surface tension, and the liquid (liquid composition 103) may rise on the edge of the trap shape. When these raised portions are irradiated with laser light 105, they are hardened into partial raised portions 121 and 122. These partial protuberances 121 and 122 may lead to phenomena such as a decrease in precision of the PL (Parting Line) surface, inability to clamp the mold, or generation of burrs when molding a resin mold.

For this reason, when the second manufacturing method is not applied, a waiting time may be set until the liquid level rise 120 subsides and the modeling process is stopped, but this countermeasure will reduce production efficiency. Another countermeasure is to change the shape or the printing direction (layering direction) of the object to be printed to avoid the trap shape, but the trap shape cannot be avoided in order to print the desired shape of the object. There are many cases where there is no. Further, even if the trap shape can be avoided, the modeling direction is not necessarily optimal for production efficiency, and production efficiency will decrease.

On the other hand, in the second manufacturing method shown in FIG. 4, by forming the cured films 111, 112, 113, and 114 inside the trap shape, the object 110 is printed while suppressing the liquid level rise 120. can do. Therefore, in the second manufacturing method, the occurrence of protuberance near the edge of the trap shape is suppressed, so that the modeling accuracy can be improved. In addition, in the second manufacturing method, even when printing a resin mold having a trap shape, there is no need to set a waiting time or change the shape or the printing direction (layering direction) of the object to be printed. Decrease in production efficiency can be suppressed. Therefore, according to the first manufacturing method, it is possible to achieve both modeling accuracy and production efficiency.

Note that in the second manufacturing direction, the cured film is removed after the stereolithography process is completed. For example, after the modeling of the object 110 is completed, the cured films 111, 112, 113, and 114 formed inside the trap shape are removed. The method for removing the cured film 110 is not particularly limited, and may be removed manually, or may be removed using a blasting device (a device that polishes by spraying powder), etc., as long as it does not damage the obtained mold. . The cured film has the same thickness as each layer stacked in the stereolithography method, so it can be easily removed.

Further, the cured film may have a network structure or other pores. The number, size, and shape of the holes are not particularly limited as long as the rise in the liquid level can be substantially suppressed. For example, a plurality of holes may be formed along the inside of the contour of the trap shape. Further, for example, a plurality of holes may be formed in a mesh shape (in the X direction and the Y direction) inside the trap shape. Since it is not necessary to irradiate the position corresponding to the hole with the laser beam 105, production efficiency can be improved. Furthermore, by forming the holes, the cured film can be removed more easily.

Further, it is preferable that the interval at which the cured films are provided is changed depending on the size of the trap-shaped opening. Hereinafter, the size of the opening will be explained as the opening diameter, but if the opening is in a shape other than circular, for example rectangular, the diagonal length of the opening will be used. It can be read as the longest dimension across. For example, when the cured film has a trap shape with an opening diameter of 50 mm or more, the liquid level rise is relatively small, so if the trap shape is formed at intervals of 5 mm to 20 mm in depth, the liquid level rise 120 can be substantially suppressed. can be suppressed to Furthermore, when the trap-shaped opening diameter is 10 mm or more and less than 50 mm, the cured film is preferably formed at intervals of 5 mm to 15 mm in depth of the trap shape. Further, when the trap-shaped opening diameter is 5 mm or more and less than 10 mm, the cured film is preferably formed at intervals of 5 mm to 10 mm in depth of the trap shape. In addition, when the opening diameter of the trap shape is less than 5 mm, the cured film may not be formed because the rise in the liquid level is small and the influence on the modeling accuracy is limited. Further, the cured film is preferably formed on the top layer of the trap shape.

(modeling resin)
The stereolithography resin used in the present invention is composed of a photocurable resin composition containing a "photocurable component", "organic particles" and "inorganic particles". Each component will be explained in order below.

The "photocurable component" is not particularly limited as long as it is a component that has photocurability. As the photocurable component used in resin mold stereolithography, a component that is cured by short wavelength (high energy) light such as ultraviolet rays or radiation is suitable, for example. Preferred photocurable components include radical curing components and cationic curing components.

As the radical curing component, a compound having a (meth)acryloyl group is generally used. As the cationic curing component, a compound having a glycidyl group such as an epoxy group or an oxetanyl group is generally used.

As the photocurable component, only one of the radical curing component and the cationic curing component may be used, or both may be used in combination. As the photocurable component, one type or two or more types of compounds can be used for each of the radical curing component and the cationic curing component.

"Organic particles" are particles made of organic polymers. The organic polymer is not particularly limited, but particles having a core-shell structure are particularly preferred since they can produce shaped articles with excellent impact resistance. As the organic particles, one type or two or more types of organic particles can be used. The organic particles may be organic particles with a crosslinked structure or organic particles without a crosslinked structure, but organic particles with a crosslinked structure are preferable from the viewpoint of the physical strength of the particles. .

The average particle diameter of the organic particles is preferably 10 to 500 μm, more preferably 100 to 300 μm. When the average particle size is within this range, it is possible to produce a shaped article with excellent impact resistance. As the organic particles, organic particles having one type or two or more types of average particle diameter can be used. By using two or more types of organic particles having different average particle sizes, it is possible to produce a shaped article with excellent impact resistance and toughness. The average particle size of the organic particles is the number average particle size in terms of polystyrene particles measured by an optical particle size measuring device such as a light scattering type or a light blocking type.

"Inorganic particles" are particles made of inorganic material. Examples of inorganic particles include, but are not limited to, metal particles, metal oxide particles, glass particles, silica particles, and the like. As the inorganic particles, one or more types of inorganic particles can be used.

The average particle size of the inorganic particles is preferably 5 nm to 500 μm, more preferably 10 nm to 300 μm. When the average particle size is within this range, sufficient hardness can be obtained and a shaped article with excellent impact resistance can be manufactured. As the inorganic particles, organic particles having one or more types of average particle diameter can be used. By using two or more types of inorganic particles having different average particle sizes, it is possible to produce a shaped article with excellent impact resistance. Within the above average particle size range, inorganic particles with an average particle size of 5 nm to 100 nm (also called "nano inorganic particles", and in the case of silica particles, "nano silica particles") and 1 μm average particle size By using inorganic particles with a diameter of ~500 μm (also called "micro inorganic particles", and in the case of silica particles, it is also called "micro silica particles"), it is possible to manufacture objects with even better impact resistance. can.

In addition, the modeling resin can contain a "polymerization initiator" and other arbitrary components as non-essential components to the extent that they do not inhibit the curing of the present invention. By including a polymerization initiator, photocurability is improved and a shaped article with excellent shape accuracy can be manufactured.

Examples of the "polymerization initiator" include "radical polymerization initiators" and "photoacid generators." A "radical polymerization initiator" is a component that absorbs light and promotes polymerization of a photocurable component. A "photoacid generator" is a component that absorbs light and promotes polymerization of organic particles.

That is, the manufacturing method according to the present embodiment is a method for manufacturing a resin mold by stereolithography using a stereolithography resin made of a photocurable resin composition containing a photocurable component, organic particles, and inorganic particles.

(Other embodiments)
In addition to the embodiments described above, the present invention may be implemented in various different forms. For example, in the above embodiment, a case has been described in which the first manufacturing method and the second manufacturing method are applied simultaneously, but either one may be applied individually. Even when either one of the first manufacturing method and the second manufacturing method is applied, it is possible to achieve both modeling accuracy and production efficiency.

[Example]
EXAMPLES The present invention will be described in more detail below based on Examples, but the present invention is not limited thereto. In this example, the effects of the manufacturing methods corresponding to Examples 1 to 3 and Comparative Examples 1 to 8 shown in Tables 1 and 2 were verified (evaluated).

1. Preparation of stereolithography resins The following four types of stereolithography resins were prepared.
[Resin 1]
A radical curing component and a cation curing component as photocurable components, a radical polymerization initiator and a photoacid generator as polymerization initiators, a mixture of nanosilica particles and microsilica particles as inorganic particles, and organic particles with an average particle diameter of 200 μm as organic particles. A photocurable resin composition was prepared by mixing the following, and was designated as Resin 1.
[Resin 2]
A stereolithography resin was prepared in the same manner as stereolithography resin 1 except that no inorganic particles were blended, and it was designated as resin 2.
[Resin 3]
A stereolithography resin was prepared in the same manner as stereolithography resin 1 except that no organic particles were blended, and it was designated as resin 3.
[Resin 4]
A resin for stereolithography was prepared in the same manner as resin for stereolithography 1 except that neither inorganic particles nor organic particles were blended, and it was designated as resin 4.

2. Manufacturing of evaluation objects [stereolithography device]
As the stereolithography device, BeamArt BA45S (semiconductor laser with a wavelength of 355 nm) manufactured by D-Mec was used. In all Examples and Comparative Examples, the stacking pitch was 100 μm.

[Preparation and evaluation method of laminate level difference evaluation molded object]
A rectangular parallelepiped shaped object for evaluation with dimensions of 40 mm in length (X direction) x 10 mm in width (Y direction) x 100 mm in height (Z direction) was produced.
Table 1 shows whether or not contour drawing control, which is the first manufacturing method, was used in each example and comparative example.
The conditions for contour drawing control, which is the first manufacturing method, were as follows. The width of the internal drawing line used for drawing the inside of the resin mold was set to 400 μm. Three outline drawing lines were provided for drawing the outline portion, and the width of each outline drawing line was set to 150 μm, 200 μm, and 300 μm, respectively, in order from the outside. The order of drawing was to irradiate laser light along the internal drawing line, then irradiate the three outline drawing lines with laser light sequentially from the inside, and finally irradiate the outermost outline drawing line with laser light.
The conditions for the case where the contour drawing control, which is the first manufacturing method, was not performed were as follows. The width of the internal drawing line was set to 400 μm. One outline drawing line was provided for drawing the outline, and the width of the outline drawing line was set to 300 μm. The drawing order was such that the laser beam was irradiated along the internal drawing line and then the outline drawing line was irradiated with the laser beam.
Since the evaluation molded article of the stacked step difference did not have a weir shape, the second manufacturing method, film formation, was not used.
The evaluation molded articles obtained in each of the Examples and Comparative Examples were evaluated by measuring the level difference for each layer on the side surface (the surface in the Z direction) of the evaluation molded article. If the average value of the measured step difference was 10 μm or more and less than 100 μm, it was evaluated as “◎”, if it was 100 μm or more and less than 200 μm, it was evaluated as “○”, and if it was 200 μm or more, it was evaluated as “x”.

[Preparation of molded object for evaluation of top plate smoothness and evaluation method]
Vertical (X direction) 50 x horizontal with a prismatic recess (trap (weir)) measuring 30 mm vertical (X direction) x 30 mm horizontal (Y direction) x 50 mm height (depth in this case, Z direction) in the center. A prismatic block-shaped evaluation object measuring 50 mm (in the Y direction) and 60 mm in height (in the Z direction) was produced.
Table 2 shows whether or not the first manufacturing method, contour drawing control, and the second manufacturing method, film formation, were used in each of the Examples and Comparative Examples.
The conditions for the contour drawing control, which is the first manufacturing method, are the same as those for manufacturing the evaluation molded article of the stacked level difference.
The conditions for film formation in the second manufacturing method were set so that one layer of cured film was formed every 10 mm in the Z direction (corresponding to 100 laminated layers). When the second manufacturing method was not applied, modeling was performed without forming a cured film.
The evaluation molded articles obtained in each of the Examples and Comparative Examples were evaluated by measuring the height around the trap opening. After the modeling was completed, the cured film was removed, and the smoothness around the opening of the trap was measured using a digital scanner (KEYENCE 3D shape measuring machine, VR-5200). Using the outer periphery of the prismatic block as a reference plane, if the height around the trap opening was less than ±100 μm, it was evaluated as “◎”, if it was 100 μm or more and less than 200 μm, it was evaluated as “○”, and if it was 200 μm or more, it was evaluated as “×”.

[Preparation and evaluation method of molded object for toughness (brittleness) evaluation]
A mold having the shape shown in FIG. 6 was produced. The length of the resin mold in FIG. 6 in the horizontal direction is 95 mm, the length in the vertical direction is 110 mm, and the height at the highest part is 95 mm. The left figure in FIG. 6 shows the male type, and the right figure shows the female type. The female mold has three locations: cylindrical recesses (diameter 8 mm, depth 10 mm) at the upper left and lower right, and rectangular recess at the center (30 mm wide, 100 mm long, and 15 mm deep, including the shallow part). There is a weir shape.
Table 2 shows whether or not the first manufacturing method, contour drawing control, and the second manufacturing method, film formation, were used in each of the Examples and Comparative Examples.
The conditions for contour drawing control in the first manufacturing method and film formation in the second manufacturing method are the same as those for manufacturing the shaped article for evaluating the flatness of the top plate.
Regarding the evaluation molded articles obtained in each example and comparative example, "frittleness during molding" and "frittleness as shape" were evaluated.

"Fragility during molding" is an indicator of the toughness of the resin mold.The resin mold shown in Figure 6 was manufactured, and the resulting resin mold was used to mold polycarbonate resin (Teijin: Panlite L-1225L(N)). was injection molded. The injection molding conditions were 290° C. and a pressure of 30 MPa. Injection molding is performed for 50 shots, and if no cracks or chips occur in the resin mold after 50 shots, it is considered to have excellent toughness, and if even one crack or chip occurs, it is considered to have sufficient toughness. It was evaluated as "x" because it was not.

"Fragility as a shape" was evaluated by a bending resistance test. First, the preparation of the test piece used in the bending resistance test will be explained. A coating film with a thickness of 200 μm is formed by applying the composition onto a glass plate using an applicator, and the surface of the coating film is irradiated with ultraviolet rays using a conveyor curing device equipped with a metal halide lamp. 0.5 J/cm2) to produce a semi-cured resin film. Next, the semi-cured resin film was peeled off from the glass plate, placed on a release paper, and irradiated with ultraviolet rays from the side opposite to the side that was first irradiated with ultraviolet rays (irradiation dose: 0.5 J/cm2) to cure the resin. A film was prepared as a test piece.

Next, measurements in the bending resistance test will be explained. The cured resin film produced by the above method was left standing in a constant temperature and humidity chamber at a temperature of 23°C and a relative humidity of 50% for 24 hours, and then tested at a constant weight of 100 g using an MIT (Massachusetts Institute of Technology) type bending tester. A bending test was repeated at a bending rate of 60 times/second while applying a load, and the number of times until the test piece broke at the bending position was measured. Those that broke at the bending position 30 times or more were judged to be passed, and those that broke less than 30 times were judged to be rejected.

"Contour drawing control" indicates whether or not the first manufacturing method (technique 1) described above is applied as the manufacturing method. "○" indicates that the first manufacturing method was applied, and "-" indicates that the first manufacturing method was not applied.

"Cured film" indicates whether or not the second manufacturing method (technique 2) described above was applied as the manufacturing method. "○" indicates that the second manufacturing method was applied, and "-" indicates that the second manufacturing method was not applied.

Example 1 and Example 2 using Resin 1: The evaluation result of the manufacturing method of Example 1 using the first manufacturing method was that the stacking level difference was "◎". In addition, the evaluation results of the manufacturing method of Example 2 using the first manufacturing method and the second manufacturing method are: top surface smoothness "◎", brittleness during molding "◎", and brittleness as a shape "◎". The manufacturing methods of Example 1 and Example 2 yielded the best results compared to the manufacturing methods of other Examples and Comparative Examples.

Example 3 using Resin 1: The evaluation results of the manufacturing method of Example 3, in which the first manufacturing method was used but the second manufacturing method was not used, were that the top surface smoothness was "○" and the brittleness during molding was "◎". ”, and the brittleness as a shape was rated “◎”. From this result, by comparing the results of Example 2 and Example 3, it was suggested that the second manufacturing method contributes to the top surface smoothness.

Comparative Example 1 and Comparative Example 5 using Resin 2: The evaluation result of the manufacturing method of Comparative Example 1 was that the stacking level difference was "○". Moreover, the evaluation results of the manufacturing method of Comparative Example 5 were that the top surface smoothness was "○", the brittleness during molding was "x", and the brittleness as a shape was "◎". This result suggested that the presence of inorganic particles greatly contributed to the strength during molding, and also contributed to the stacking level difference and top surface smoothness.

Comparative Example 2 and Comparative Example 6 using Resin 3: The evaluation result of the manufacturing method of Comparative Example 2 was that the stacking level difference was "◎". Moreover, the evaluation results of the manufacturing method of Comparative Example 6 were that the top surface smoothness was "◎", the brittleness during molding was "x", and the brittleness as a shape was "x". This result suggested that the presence of organic particles greatly contributed to the strength during molding and the strength as a shape.

Comparative Example 3 and Comparative Example 7 using Resin 1: In Comparative Example 3 and Comparative Example 7, neither the first manufacturing method nor the second manufacturing method was used. The evaluation result of the manufacturing method of Comparative Example 3 was that the stacking level difference was "x". Furthermore, the evaluation results for the manufacturing method of Comparative Example 7 were that the top surface smoothness was "x", the brittleness during molding was "◎", and the brittleness as a shape was "◎". This result suggested that the first manufacturing method and the second manufacturing method greatly contributed to the stacking level difference and the top surface smoothness.

Comparative Example 4 and Comparative Example 8 using Resin 4: The evaluation result of the manufacturing method of Comparative Example 4 was that the stacking level difference was "○". Moreover, the evaluation results of the manufacturing method of Comparative Example 8 were that the top surface smoothness was "◎", the brittleness during molding was "x", and the brittleness as a shape was "x". This result suggested that the presence of inorganic particles and organic particles contributes to the layered level difference, and also greatly contributes to the strength during molding and the strength as a shape.

The above examples suggest that the first manufacturing method and the second manufacturing method contribute to achieving both modeling accuracy and production efficiency. Although not shown as an example, as a result of manufacturing an evaluation model using Resin 1 and using the second manufacturing method without using the first manufacturing method, the results showed that the stacking level difference was "x", the ceiling was The surface smoothness was rated "◎", the brittleness during molding was "◎", and the brittleness as a shape was "◎".

For example, according to the present embodiment (first manufacturing method) that employs stereolithography, molding with particularly excellent smoothness (small stacking level difference) and excellent toughness on the Z plane (side surface) of the resin mold can be achieved. You can get the mold. According to another embodiment (second manufacturing method), a mold having particularly excellent smoothness in the XY plane of the resin mold and excellent toughness can be obtained. Furthermore, according to the present embodiment (combination of the first manufacturing method and the second manufacturing method), a mold is obtained that suppresses the layered step difference, has particularly excellent smoothness in the XY plane, and has excellent toughness. be able to. Therefore, it is possible to provide a mold manufacturing method that achieves both molding accuracy and production efficiency. Furthermore, the surface of the molded product injection-molded using the resin mold (the surface corresponding to the XY plane of the resin mold) is excellent in smoothness, and a surface rich in gloss can be obtained.

On the other hand, as a three-dimensional modeling technique for manufacturing resin molds, an inkjet printing method is also known. In a resin mold manufactured using an inkjet method, the surface smoothness of the resin mold is inferior to that of a stereolithography method due to the nature of injecting and curing the resin using an inkjet method. For this reason, the surface smoothness of the molded product injection-molded using the resin mold is also poor, resulting in a matte surface lacking luster. Therefore, in the case of a molded product requiring transparency, the stereolithography method is more suitable than the inkjet method because the higher the surface smoothness, the higher the transparency.

10 Edge 11 Contour drawing range 21, 22, 23, 24 Internal drawing line 31, 32, 33 Outline drawing line 41, 42, 43, 44, 45 Outline drawing line 100 Stereolithography device 101 Container 102 Support stand 103 Liquid composition 104 Liquid level 105 Laser light 106, 107 Cured layer 110 Modeling object 111, 112, 113, 114 Cured film 120 Liquid level rise 121, 122 Uplift

Claims (7)

A resin mold formed by a stereolithography method using a photocurable resin composition containing a photocurable component, organic particles, and inorganic particles is irradiated with light in order to harden the inside of the resin mold. A manufacturing method using a plurality of internal irradiation lines and a plurality of contour irradiation lines through which light is irradiated to cure the contour portion of the resin mold,
A method for producing a resin mold, the method comprising: irradiating the light with a width that is larger for the inner contour irradiation lines than the outer contour irradiation lines among the plurality of contour irradiation lines. . The number of the plurality of contour irradiation lines is 2 or more and 7 or less,
A method for manufacturing a resin mold according to claim 1. Among the plurality of contour irradiation lines, the inner contour irradiation lines are irradiated with laser light at a scanning speed slower than the scanning speed of the outer contour irradiation lines.
A method for manufacturing a resin mold according to claim 1 or 2. The width of the plurality of contour irradiation lines is 80 to 700 μm,
A method for manufacturing a resin mold according to any one of claims 1 to 3. The ratio of the width of the outermost contour drawing line to the width of the internal drawing line among the plurality of contour irradiation lines is 0.1 to 0.9.
A method for manufacturing a resin mold according to any one of claims 1 to 4. Among the plurality of contour irradiation lines, the ratio of the width of the outermost contour drawing line to the width of the innermost contour irradiation line is 0.1 to 0.9.
A method for manufacturing a resin mold according to any one of claims 1 to 5. The irradiation position of the internal irradiation line is set so that the end shape of the internal irradiation line to be irradiated does not affect the surface properties of the resin mold,
The contour irradiation line is set outside the internal irradiation line of the resin mold,
A method for manufacturing a resin mold according to any one of claims 1 to 6.

Images