Container for stereolithography apparatus

Abstract

The present invention provides a container used in a stereolithography apparatus and having excellent transparency, shape accuracy, and durability. The present invention relates to a container for holding a photocurable composition (3), the container being used in a stereolithography apparatus comprising a container (2), an active energy beam irradiation apparatus (5), and an actuator (8), wherein the container (2) comprises a bottom (2′) and a wall, the bottom (2′) comprises a first layer (X) comprising a hard resin, a second layer (Y) comprising a soft resin, and a third layer (Z) comprising a fluorine resin, the second layer (Y) is laminated on the first layer (X) and the third layer (Z) is laminated on the second layer (Y), the pencil hardness measured according to JIS K 5600-5-4:1999 for the first layer (X) is 3 B or harder, the hardness measured for the second layer (Y) using a type A durometer compliant with JIS K 6253-3:2012 is 10 to 90, and the third layer (Z) has a thickness of 0.1 to 5.0 mm.

Claims

1. A container for holding a photocurable composition, wherein the container is used in a stereolithography apparatus, an active energy beam irradiation apparatus, and an actuator, wherein the container comprises a bottom and a wall, the bottom comprises a first layer comprising a hard resin, a second layer comprising a soft resin, and a third layer comprising a fluorine resin, the second layer is laminated on the first layer and the third layer is laminated on the second layer, the pencil hardness measured according to JIS K 5600-5-4:1999 for the first layer is 3B or harder, the hardness measured for the second layer using a type A durometer according to JIS K 6253-3:2012 is from 10 to 90, the third layer has a thickness of from 0.1 to 5.0 mm, and a ratio of an area expressed in cm.sup.2 of a bottom face on an inner face side of the container to a thickness expressed in cm of the bottom of the container is from 100 to 10000 cm.

2. The container according to claim 1, wherein the hard resin is at least one selected from the group consisting of acrylic, polycarbonate, polyester, polystyrene, polypropylene, polymethylpentene, and polycycloolefin.

3. The container according to claim 1, wherein the soft resin is at least one selected from the group consisting of a silicone, an acrylic elastomer, a polyolefin elastomer, and a styrene elastomer.

4. The container according to claim 1, wherein a thickness of the first layer is from 0.5 to 25 mm and a thickness of the second layer is from 0.01 to 25 mm.

5. The container according to claim 1, wherein the second layer is 0.1 to 5 times thicker than the first layer and the third layer is 0.01 to 5 times thicker than the second layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram showing an embodiment of a stereolithography apparatus (1) according to the present invention and a container (2) used in the apparatus.

(2) FIG. 2 is a schematic diagram relating to a method for producing three-dimensional objects using the stereolithography apparatus (1) and container (2) according to the present invention.

(3) FIG. 3 is an enlarged view of the container (2) shown in FIG. 1.

DESCRIPTION OF EMBODIMENTS

(4) A stereolithography apparatus in which a container of the present invention is used will be described with reference to an apparatus (1) shown in FIG. 1.

(5) In FIG. 1, a stereolithography apparatus (1) comprises a container (2) (the container of the present invention) for holding a photocurable composition (3) cured by irradiation of an active energy beam (4).

(6) The stereolithography apparatus (1) in which the container of the present invention is used comprises an active energy beam irradiation apparatus (5) emitting the active energy beam (4). In the vicinity of the bottom face (2′a) of the container (2), the active energy beam irradiation apparatus (5) can selectively irradiate the photocurable composition (3) held in the container (2) with the active energy beam (4) from the bottom (2′) side.

(7) As schematically shown in FIG. 2, irradiation of a portion (6) included in the photocurable composition (3) and located between the bottom (2′) and object production plate (7) with the active energy beam (4) forms a solidified layer (6′) at the irradiated portion (under the object production plate (7)).

(8) The stereolithography apparatus (1) also comprises an actuator (8) suitable for moving the solidified layer (6′) formed under the object production plate (7) with respect to the bottom (2′) of the container (2) along a direction W perpendicular to the bottom (2′).

(9) The object production plate (7) comprises a face (7a) facing the bottom (2′) of the container (2). The object production plate (7) supports the solidified layer (6′) at the face (7a).

(10) The stereolithography apparatus (1) also comprises a logic circuit control (9) operationally connected to the active energy beam irradiation apparatus (5) and actuator (8). With the use of the logic circuit control (9), irradiation of the portion (6) included in the photocurable composition (3) and located between the bottom (2′) and object production plate (7) with the active energy beam is controlled from the bottom (2′) side.

(11) An exemplary motion of the stereolithography apparatus (1) in which the container of the present invention is used will be described below. First, as a first positioning motion, the face (7a) of the object production plate (7) is moved to the vicinity of the bottom (2′) of the container (2) by means of the actuator (8). Next, when the face (7a) reaches a position at which there is a given distance from the bottom face (2′a) on the inner face side of the container (2), the portion (6) of the photocurable composition (3) is irradiated with the active energy beam (4) by the active energy beam irradiation apparatus (5) to form a first solidified layer (6′) at the irradiated portion. Subsequently, the actuator (8) moves the first solidified layer (6′) away from the bottom (2′) of the container (2) by an upward motion. In order to form a continuously solidified layer, the first solidified layer (6′) is moved to the vicinity of the bottom (2′) of the container (2) by a second positioning motion same as the first positioning motion. By the above upward motion and second positioning motion, the photocurable composition (3) is provided between the first solidified layer (6′) and bottom (2′). The portion included in the photocurable composition (3) and located between the first solidified layer (6′) and bottom (2′) is irradiated with the active energy beam (4) in the same manner as above to form a second solidified layer at the irradiated portion. The second solidified layer is supported by the face of the first solidified layer (6′) which has already been solidified and faces the bottom (2′). Further, the second solidified layer is moved away from the bottom (2′) of the container (2) as the first solidified layer (6′) was. Subsequently, the second solidified layer is moved to the vicinity of the bottom (2′) of the container (2) by a third positioning motion. The above motions are repeated likewise. A three-dimensional object in which solidified layers form a continuous layer can be obtained by a constrained surface method as described above. Another embodiment of the present invention is a method for producing three-dimensional objects using the container (2).

(12) The container (2) of the present invention will be described with reference to FIG. 3.

(13) In an embodiment shown in FIG. 3, the container (2) of the present invention used in a stereolithography apparatus comprises the bottom (2′) having a three-layered flat laminate structure. The bottom (2′) comprises, from the side irradiated with the active energy beam, a first layer (X) comprising a hard resin, a second layer (Y) laminated on the first layer (X) and comprising a soft resin, and a third layer (Z) laminated on the second layer (Y) and comprising a fluorine resin. The liquid, photocurable composition (3) is held in the container (2). The material of a wall portion jointed to the bottom (2′) of the container (2) is not especially limited, and is preferably the same as that of the first layer (X) in terms of ease of production.

(14) First Layer (X) Comprising Hard Resin

(15) A hard resin that is transparent and not flexible is suitably used as the material composing the first layer (X) of the bottom (2′) of the container (2) of the present invention. Specific examples of the hard resin used as the first layer (X) include acrylic (such as polymethyl methacrylate), polycarbonate, polyester (such as polyethylene terephthalate), polystyrene, polypropylene, polymethylpentene, and polycycloolefin. Among these, acrylic and polycarbonate are preferred in terms of the transparency, strength, and durability. One of these hard resins may be used alone, or two or more thereof may be used in combination.

(16) The scratch hardness (which is herein referred to as “pencil hardness”) measured according to JIS K 5600-5-4:1999 (pencil method) for the first layer (X) needs to be 3 B or harder and is preferably 2 B or harder, more preferably 1 B or harder, and even more preferably F or harder, so as to maintain the shape as a container.

(17) The thickness of the first layer (X) is preferably 0.5 to 25 mm, more preferably 0.75 to 10 mm, even more preferably 0.75 to 7.5 mm, and the most preferably 1.0 to 5.0 mm, in terms of the durability, strength, and transparency.

(18) Second Layer (Y) Comprising Soft Resin

(19) A transparent soft resin is suitably used as the material composing the second layer (Y) of the bottom (2′) of the container (2) of the present invention. Specific examples of the soft resin used as the second layer (Y) include a silicone, an acrylic elastomer, a polyolefin elastomer, and a styrene elastomer. Among these, a silicone is preferred in terms of the transparency and pliability. One of these soft resins may be used alone, or two or more thereof may be used in combination.

(20) The hardness measured for the second layer (Y) using a type A durometer compliant with JIS K 6253-3:2012 needs to be 10 to 90 and is preferably 20 to 80 and more preferably 30 to 70.

(21) The thickness of the second layer (Y) is preferably 0.01 to 25 mm, more preferably 0.1 to 10 mm, even more preferably 0.25 to 7.5 mm, and most preferably 0.5 to 5.0 mm, in terms of the pliability and transparency.

(22) Third Layer (Z) Comprising Fluorine Resin

(23) A transparent fluorine resin is suitably used as the material composing the third layer (Z) of the bottom (2′) of the container (2) of the present invention. Specific examples of the fluorine resin used as the third layer (Z) include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxy resins (PFA), tetrafluoroethylene-hexafluoropropylene copolymers (FEP), ethylene-tetrafluoroethylene copolymers (ETFE), and ethylene-chlorotrifluoroethylene copolymers (ECTFE). Among these, in terms of the transparency and releasability, polytetrafluoroethylene (PTFE), perfluoroalkoxy resins (PFA), tetrafluoroethylene-hexafluoropropylene copolymers (FEP), and ethylene-tetrafluoroethylene copolymers (ETFE) are preferred and tetrafluoroethylene-hexafluoropropylene copolymers (FEP) and ethylene-tetrafluoroethylene copolymers (ETFE) are more preferred. One of these fluorine resins may be used alone, or two or more thereof may be used in combination.

(24) The thickness of the third layer (Z) needs to be 0.1 to 5.0 mm not only in terms of the pliability and transparency but also in terms of the shape accuracy and durability. The container of the present invention has excellent shape accuracy in spite of the relatively large thickness of the third layer (Z). The thickness of the third layer (Z) is preferably 0.15 to 2.5 mm, more preferably 0.2 to 1.5 mm, and even more preferably 0.25 to 1.0 mm.

(25) For the bottom (2′) of the container (2) of the present invention, it is preferable that the second layer (Y) is 0.1 to 5 times thicker than the first layer (X) and the third layer (Z) is 0.01 to 5 times thicker than the second layer (Y), it is more preferable that the second layer (Y) is 0.1 to 5 times thicker than the first layer (X) and the third layer (Z) is 0.01 to 1 times thicker than the second layer (Y), and it is even more preferable that the second layer (Y) is 0.2 to 4 times thicker than the first layer (X) and the third layer (Z) is 0.02 to 0.8 times thicker than the second layer (Y), in terms of obtaining objects with good shape accuracy.

(26) [The area (cm.sup.2) of a bottom face (2′a) on an inner face side of the container (2) of the present invention]/[the thickness (cm) of the bottom (2′)] is preferably 100 to 10000 cm, more preferably 200 to 8000 cm, even more preferably 300 to 6000 cm, and, in terms of better shape accuracy and better durability, particularly preferably 400 to 3000 cm.

(27) The bottom (2′) of the container (2) of the present invention may comprise an additional layer other than the first layer (X), second layer (Y), and third layer (Z) without departing from the spirit of the present invention. Examples of the additional layer include an adhesive layer for imparting the adhesiveness to its neighboring layer and a coating layer for preventing the outer face of the first layer (X) from being scratched. The thickness of each of these additional layers is preferably 0.1 mm or less, more preferably 0.05 mm or less, and even more preferably 0.01 mm or less.

(28) The bottom (2′) of the container (2) of the present invention has the three-layered structure described above. As long as the photocurable composition (3) can be held in the container (2), the shape, size, and the like of the container (2) are not especially limited, and can be decided depending on the intended use thereof.

(29) A method for producing the container (2) of the present invention is not especially limited, and one example thereof is as follows. First, hard resin sheets each having a desired shape are cut out of a sheet-shaped hard resin and bonded together with an adhesive to produce a frame of the container (2). Alternatively, a frame of the container (2) can be produced by press molding. The first layer (X) forming the bottom (2′) of the container (2) and comprising a hard resin can thus be obtained. Next, the second layer comprising a soft resin is laminated on the first layer (X). For example, when a silicone resin is used as the soft resin, a method in which a two-component curable material is mixed, poured into the above frame, and allowed to be cured, a method in which a soft resin layer is formed by solution casting, or the like can be employed. Finally, the third layer (Z) comprising a fluorine resin is laminated on the second layer (Y). For this lamination, for example, a method in which a film-shape fluorine resin is cut to have a desired size and the resultant fluorine resin film is bonded onto the second layer (Y) can be employed. Additionally, entry of the photocurable composition (3) can be prevented by coating the edge of the film with a soft resin.

(30) Any known light source may be used in stereolithographic modeling using the stereolithography apparatus (1) and container (2) according to the present invention. Among the known light sources, an active energy beam is used in the present invention as the energy used to cure the photocurable composition (3). The term “active energy beam” means an energy beam capable of curing the photocurable composition (3), and examples of the active energy beam include ultraviolet light, an electron beam, X-ray, radiant ray, and high-frequency electromagnetic wave. For example, the active energy beam may be ultraviolet light having a wavelength of 300 to 400 nm. Examples of the light source of the active energy beam include: lasers such as an Ar laser and He—Cd laser; and lighting devices such as a halogen lamp, xenon lamp, metal halide lamp, LED light, mercury lamp, and fluorescent lamp. Lasers are particularly preferred. The use of a laser as the light source makes it possible to reduce the modeling time by increasing the energy level and also to obtain accurately modeled three-dimensional objects by taking advantage of a desirable convergence of a laser beam.

(31) The present invention encompasses embodiments obtainable by combining the above features in various manners within the technical scope of the present invention as long as the effect of the present invention can be obtained.

EXAMPLES

(32) Hereinafter, the present invention will be described in more detail by way of examples. The present invention is by no means limited by these examples and can be modified in various ways by those ordinarily skilled in the art within the technical scope of the invention. The materials of the containers according to Examples or Comparative Examples used in a stereolithography apparatus will be described hereinafter along with abbreviations of the materials.

(33) [First Layer (X) Comprising Hard Resin]

(34) PMMA: polymethyl methacrylate, PARAPET GH-S (manufactured by KURARAY CO., LTD.)

(35) PC: polycarbonate, Iupilon S2000 (manufactured by Mitsubishi Engineering-Plastics Corporation)

(36) [Second Layer (Y) Comprising Soft Resin]

(37) Silicone 1: two-component curable silicone resin, KE-103/CAT-103 (manufactured by Shin-Etsu Chemical Co., Ltd.)

(38) Silicone 2: two-component curable silicone resin, KE 1603A/B (manufactured by Shin-Etsu Chemical Co., Ltd.)

(39) [Third Layer (Z) Comprising Fluorine Resin]

(40) FEP: tetrafluoroethylene-hexafluoropropylene copolymer (manufactured by DAIKIN INDUSTRIES, LTD.)

(41) ETFE: ethylene-tetrafluoroethylene copolymer (manufactured by DAIKIN INDUSTRIES, LTD.)

Example 1

(42) A 33-mm-high and 244-mm-square PMMA container whose bottom face has a thickness of 1.0 mm and an area of 484 cm.sup.2 was produced from a 12-mm-thick and 30-mm-wide PMMA prism and a 1.0-mm-thick and 244-mm-square PMMA sheet (the pencil hardness measured according to JIS K 5600-5-4:1999 was 3H).

(43) Next, into a polypropylene disposable cup were put 100 g of KE-103 and 5.0 g of CAT-103, which were manually stirred for 1 minute using a spatula to obtain a silicone 1. An amount of 25 g of the silicone 1 was poured into the above PMMA container, spread over the entire bottom face thereof with a spatula, left for 24 hours, and then heated at 70° C. for 6 hours to form a soft resin layer. The hardness measured using a type A durometer (ASKER Durometer Type A manufactured by KOBUNSHI KEIKI CO., LTD.) compliant with JIS K 6253-3:2012 for the soft resin layer was 50. The thickness of the soft resin layer was 0.5 mm.

(44) Furthermore, a 0.25-mm-thick and 215-mm-square FEP sheet was placed on the soft resin layer in such a manner that air is not trapped therebetween. The silicone 1 was applied to the edge of the FEP sheet and cured so that a photocurable composition would not enter under the FEP sheet. A container was thus obtained.

Example 2

(45) A container was produced in the same manner as in Example 1, except that the thickness of the PMMA sheet, namely, the thickness of the first layer (X) was changed to 5.0 mm, the amount of the silicone 1 poured into the PMMA container was changed to 250 g, and the thickness of the FEP sheet was changed to 0.5 mm. The hardness measured using a type A durometer compliant with JIS K 6253-3:2012 for the soft resin layer was 50. The thickness of the soft resin layer was 5.0 mm.

Example 3

(46) A container was produced in the same manner as in Example 1, except that PMMA was changed to PC (the pencil hardness measured according to JIS K 5600-5-4:1999 for the PC sheet was F), the thickness of the first layer (X) was changed to 3.0 mm, the silicone 1 was changed to the silicone 2, the amount of the silicone 2 poured into the PC container was changed to 50 g, and the 0.25-mm-thick FEP sheet was changed to a 0.75-mm-thick ETFE sheet. The hardness measured using a type A durometer compliant with JIS K 6253-3:2012 for the soft resin layer was 60. The thickness of the soft resin layer was 1.0 mm.

Comparative Example 1

(47) A PMMA container as produced in Example 1 was used directly and not provided with the second layer (soft resin layer) and third layer.

Comparative Example 2

(48) A container was produced in the same manner as in Example 1, except that no FEP sheet was attached.

Comparative Example 3

(49) A container was produced in the same manner as in Example 1, except that no coating of the silicone 1 was provided.

Comparative Example 4

(50) A container was produced in the same manner as in Example 1, except that PMMA was changed to an acrylic elastomer, KURARITY L2250 (manufactured by KURARAY CO., LTD.) (the pencil hardness measured according to JIS K 5600-5-4:1999 for a sheet made of the acrylic elastomer was softer than 3 B, and the thickness of the acrylic elastomer sheet was 1.0 mm). The hardness measured using a type A durometer compliant with JIS K 6253-3:2012 for the soft resin layer was 50. The thickness of the soft resin layer was 0.5 mm.

(51) [Photocurable Compositions]

(52) Photocurable compositions obtained by the following production methods were used for evaluation of the shape accuracy and durability.

(53) Photocurable Composition 1:

(54) In a sample bottle were put 50 g of 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.), 50 g of N-acryloylmorpholine (manufactured by KJ Chemicals Corporation), 2.0 g of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by Wako Pure Chemical Industries, Ltd.), and 0.05 g of 3,5-di-t-butyl-4-hydroxytoluene (manufactured by Wako Pure Chemical Industries, Ltd.), which were stirred at 40° C. for 24 hours to obtain a photocurable composition 1.

(55) Photocurable Composition 2:

(56) In a sample bottle were put 70 g of 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (manufactured by Shin-Nakamura Chemical Co., Ltd.), 30 g of dodecyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd.), 2.0 g of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by Wako Pure Chemical Industries, Ltd.), and 0.05 g of 3,5-di-t-butyl-4-hydroxytoluene (manufactured by Wako Pure Chemical Industries, Ltd.), which were stirred at 40° C. for 24 hours to obtain a photocurable composition 2.

(57) <Transparency>

(58) The transparency ΔL was measured for the bottom faces of the containers according to Examples and Comparative Examples shown in Table 1 using a spectrophotometer (SE 2000 (compliant with JIS Z 8722:2009) manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.; 0 to 45° post dispersive; illuminant D65). The transparency ΔL is defined by the following formula.
ΔL=L*W−L*B
(In the formula, L*W represents the lightness L* in the L*a*b* color system as measured against a white background according to JIS Z 8781-4:2013, and L*B represents the lightness L* in the L*a*b* color system as measured against a black background according to JIS Z 8781-4:2013.)

(59) A transparency (ΔL) of 95 or more is defined as acceptable to ensure high modeling performance. Table 1 shows the results.

(60) <Shape Accuracy>

(61) Cubic objects 10.0 mm on a side were produced from the photocurable compositions 1 and 2 using the containers according to Examples and Comparative Examples shown in Table 1 and a stereolithography apparatus (DigitalWax (registered trademark) 028J-Plus manufactured by DWS). Each object was washed with methanol to remove unpolymerized monomers and was then measured for dimensions (unit: mm) using a micrometer. A shape error was calculated using the following formula.
Shape error (%)=100×(|(measured dimensions)−10.0|)/10.0

(62) When the shape error of the object is 5.0% or less, the shape accuracy thereof is acceptable. When the shape error is 4.0% or less, the shape accuracy is better. When the shape error is 3.5% or less, the shape accuracy is much better.

(63) <Durability>

(64) Cubic objects 10.0 mm on a side were produced from the photocurable compositions 1 and 2 using the containers according to Examples and Comparative Examples shown in Table 1 and a stereolithography apparatus (DigitalWax (registered trademark) 028J-Plus manufactured by DWS). After the completion of the modeling, the objects were removed. Modeling was carried out repeatedly under the same conditions until the bottom faces of the containers were damaged. The greater the number of times modeling can be completed is, the better the durability is.

(65) TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 1 2 3 4 Container Material of first layer (X) PMMA PMMA PC PMMA PMMA PMMA Elastomer Material of second layer (Y) Silicone Silicone Silicone Silicone Silicone 1 1 2 1 1 Material of third layer (Z) FEP FEP ETFE FEP FEP Thickness (mm) of first layer (X) 1.0 5.0 3.0 1.0 1.0 1.0 1.0 Thickness (mm) of second layer (Y) 0.5 5.0 1.0 0.5 0.5 Thickness (mm) of third layer (Z) 0.25 0.5 0.75 0.25 0.25 Area (cm.sup.2) of bottom 2765 460 1020 4840 3230 3870 2765 face/thickness (cm) of bottom Properties Transparency ΔL 99 97 99 99 99 99 98 Shape error (%) Photocurable 2.2 3.2 2.2 Modeling 8.4 12.3 11.4 composition 1 not completed Photocurable 2.4 3.5 2.4 11.8 Modeling 14.5 13.2 composition 2 not completed Durability Photocurable 28 32 28 0 1 1 1 Number of times composition 1 modeling can be Photocurable 31 33 31 1 0 1 1 completed composition 2

(66) As shown in Table 1, the containers according to Examples 1 to 3 had excellent transparency, were able to reduce penetration of the photocurable compositions into the containers and sticking of the photocurable compositions to the containers, were reusable, and had excellent durability. Moreover, the objects were modeled with high accuracy with the use of the containers and had excellent shape accuracy. On the other hand, the objects were clung to the containers according to Comparative Examples 1 to 4. The bottoms of the containers were torn and modeling could not be completed, or modeling could not be completed with the same containers two or more times. Even in the case where modeling could be completed, the shape accuracy was inferior. Additionally, according to the present invention, the types of photocurable compositions usable for modeling are not limited, unlike Comparative Examples 1 and 2, and stereolithographic modeling can be carried out with the container according to the present invention capable of holding various types of photocurable compositions including, for example, photocurable compositions containing a relatively-low-molecular-weight (for example, a molecular weight of 2000 or less) polymerizable monomer and photocurable compositions containing a silicone resin.

INDUSTRIAL APPLICABILITY

(67) Having excellent transparency, shape accuracy, and durability, the container of the present invention is useful as a container used in a stereolithography apparatus.

DESCRIPTION OF REFERENCE NUMERALS

(68) 1 Stereolithography apparatus 2 Container 2′ Bottom 2′a Bottom face 3 Photocurable composition 4 Active energy beam 5 Active energy beam irradiation apparatus 6 Portion included in photocurable composition and located between bottom (2′) and object production plate (7) 7 Object production plate 8 Actuator 9 Logic circuit control