Method for manufacturing a shape

Abstract

A granular body for a hot melt type 3D printer capable of manufacturing soft objects with high precision is provided. According to the present invention, a granular body for a hot melt type 3D printer composed of a thermoplastic elastomer is provided, wherein the thermoplastic elastomer, when measured using a rotational rheometer under the conditions of a parallel plate of 20 mmφ, a measuring gap of 1.3 mm, and a frequency of 1 Hz, has a loss tangent tanδ of 0.40 or more at at least one point in a measuring temperature of 120 to 270°C, and a loss modulus G″ of 11000 Pa or less.

Description

Technical Field

[0001] The present invention relates to a granular body for a hot-melt three-dimensional printer, a method for manufacturing a shaped object, and a filament. Background Art

[0002] (First point of view)

[0003] Patent document 1 discloses a method for forming a shaped object, which comprises supplying a filament as a forming material to an extrusion head, then melting the filament with a liquefier mounted on the extrusion head, and extruding the molten filament through a nozzle onto a base.

[0004] In this manufacturing method, the filament is generally transported directly to the front end of the nozzle by means of gear engagement, but when the filament is made of a highly soft thermoplastic elastomer, the gear will bite the filament, making it impossible for the filament to be supplied to the front end of the nozzle.

[0005] In Patent Document 2, the above-mentioned problem is solved by using a filament having a linear reinforcement portion provided on a part of the outer peripheral surface of a core material containing a thermoplastic elastomer.

[0006] (Second point of view)

[0007] Patent Document 3 discloses a filament containing a shape memory polymer and an inorganic filler.

[0008] Prior art documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent Publication No. 2009-500194

[0011] Patent Document 2: Japanese Patent Application Publication No. 2017-177497

[0012] Patent Document 3: Japanese Patent Application Publication No. 2018-122466 Summary of the invention

[0013] (Problems to be solved by the invention)

[0014] (First point of view)

[0015] Since the linear reinforcement part is formed together in the method of Patent Document 2, in order to obtain a shape composed only of an elastomer, the linear reinforcement part has to be dissolved using water or an organic solvent after the 3D printer is used for shaping. This treatment process is not only troublesome, but also causes the problem of reduced quality of the shape.

[0016] In particular, when the flexibility of a thermoplastic elastomer is to be improved, the intervals between the lines constituting the object need to be widened. However, depending on the material used, the shape of the object may be easily lost, making it difficult to form with high precision.

[0017] The present invention has been developed in view of the above circumstances, and provides a granular body for a hot-melt type three-dimensional printer capable of manufacturing a soft object with high precision.

[0018] (Second point of view)

[0019] In Patent Document 1, although the restoring force of the shaped object is improved by adding an inorganic filler to the shape memory polymer, it is desired to further improve the restoring force.

[0020] The present invention has been developed in view of the above situation, and provides a filamentous body capable of forming a shaped object with high resilience.

[0021] (Technical solutions to solve problems)

[0022] (First point of view)

[0023] According to the present invention, a granular body is provided, which is a granular body for a hot melt 3D printer composed of a thermoplastic elastomer. When the thermoplastic elastomer is measured using a rotational rheometer with a parallel plate of 20 mmφ, a measuring gap of 1.3 mm, and a frequency of 1 Hz, the loss tangent tanδ at at least one point in the measuring temperature of 120 to 270°C is greater than 0.40, and the loss modulus G'' is less than 11000 Pa.

[0024] The first feature of the first viewpoint is that it is not a filament but a granular body. The granular body of the present invention can be melted by using a screw extruder and extruded from a nozzle, so there is no need to use the linear reinforcement part in Patent Document 2, and there is no need to have a process of dissolving the linear reinforcement part from the shaped object.

[0025] The second feature of the first aspect is that the thermoplastic elastomer has a specific viscoelasticity. By using a thermoplastic elastomer having a viscoelasticity within the range specified in the present invention, a soft object can be manufactured with high precision by adjusting the molding temperature.

[0026] Various embodiments of the present invention are described below. The embodiments described below can be combined with each other.

[0027] In the granular body, it is preferred that the loss tangent tanδ of the thermoplastic elastomer at at least one point in a measurement temperature of 120 to 230° C. is 0.40 or more, and the loss modulus G″ is 8000 Pa or less.

[0028] In the granular body, the loss modulus G″ is preferably 600 to 4500 Pa at at least one point at a measurement temperature of 120 to 230°C.

[0029] A granular body, wherein the thermoplastic elastomer preferably has a Shore A hardness of 0 to 10.

[0030] A method for producing a shaped object preferably comprises a scanning step of scanning a strand obtained by melting the granular body in a screw extruder and extruding the strand from a nozzle.

[0031] A method for manufacturing a shaped object, wherein the strand preferably has a loss tangent tanδ of greater than 0.40 and a loss modulus G'' of less than 11000 Pa when measured using a rotational rheometer under the conditions of a parallel plate of 20 mmφ, a measuring gap of 1.3 mm, a frequency of 1 Hz and a forming temperature, wherein the forming temperature is the temperature of the strand just extruded from the nozzle.

[0032] In a method for manufacturing a shaped object, it is preferred that the loss modulus G″ of the wire material at the forming temperature is 600 to 4500 Pa.

[0033] A method for manufacturing a shaped object, preferably forming a stacked structure by stacking single-layer structures formed by the scanning process, wherein the single-layer structures each have a plurality of parallel line portions spaced apart from each other, and two of the single-layer structures adjacent in the upper and lower directions in the stacked structure are arranged so that the plurality of parallel line portions intersect each other.

[0034] In a method for manufacturing a shaped object, it is preferred that a pitch ratio defined by a ratio of a pitch of the parallel line portions to a line width of the parallel line portions is 1.5 to 6.

[0035] (Second point of view)

[0036] According to the present invention, a filament containing continuous reinforcing fibers and a shape memory polymer is provided.

[0037] The inventors have found through careful studies that a shaped object made by using a filament containing continuous reinforcing fibers and a shape memory polymer has high restoring force, thereby arriving at the present invention.

[0038] Various embodiments of the present invention are described below. The embodiments described below can be combined with each other.

[0039] A filamentous body preferably includes a continuous fiber bundle as a bundle of continuous fibers, wherein the continuous fiber bundle contains the continuous reinforcing fibers as the continuous fibers.

[0040] It is preferred that the filament body includes a covering layer covering the continuous fiber bundle, and the covering layer contains the shape-memory polymer.

[0041] It is preferable that the continuous fiber bundle of the filamentous body contains continuous resin fibers as the continuous fibers.

[0042] It is preferred that the continuous resin fibers of the filament contain the shape-memory polymer.

[0043] It is preferable that the continuous reinforcing fibers of the filaments are carbon fibers and are filaments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] exist Figure 1 middle, Figure 1 A represents the shape of the granular body according to one embodiment of the first aspect. Figure 1 B is Figure 1 A is a cross-sectional view along line AA.

[0045] Figure 2 This is a schematic diagram showing a state where granular bodies 1 are put into an extruder 2 of a hot melt type three-dimensional printer usable in the first aspect to form strands 4 .

[0046] Figure 3 A network-like laminated structure 5 is shown, wherein Figure 3 A is a stereogram, Figure 3 B is a top view.

[0047] Figure 4 represents a single-layer structure 6, wherein Figure 4 A is a stereogram, Figure 4 B is a top view.

[0048] Figure 5 represents a single-layer structure 7, wherein Figure 5 A is a stereogram, Figure 5 B is a top view.

[0049] Figure 6 represents a single-layer structure 8, wherein Figure 6 A is a stereogram, Figure 6 B is a top view.

[0050] exist Figure 7 middle, Figure 7 A is a perspective view of the filament 11 according to the first embodiment in the second viewpoint. Figure 7 B is from Figure 7 A is a three-dimensional cross-sectional view after a portion of the cover layer 13 is cut away.

[0051] Figure 8 It is a three-dimensional diagram of the shape 17.

[0052] Fig. 9It is a perspective view of a head 14 for heating the filament 11 to form a molten filament 11 a and a cutter 15 for cutting the molten filament 11 a .

[0053] Fig.10 This is an end view of the filament 11 according to the second embodiment in the second viewpoint.

[0054] exist Fig.11 middle, Fig.11 A is a three-dimensional diagram of the original shape of the sample 17a used to measure the restoring force. Fig.11 B is a perspective view showing a state in which the dynamometer 16 is brought into contact with the upper surface of the sample 17 a deformed into a flat shape to measure the restoring force. DETAILED DESCRIPTION

[0055] Next, embodiments of the present invention will be described. Various features shown in the embodiments shown below can be combined with each other, and each feature can independently constitute the present invention.

[0056] (Implementation of the First Aspect)

[0057] 1. Granular body for hot melt 3D printer

[0058] exist Figure 1 The granular body 1 for hot melt type 3D printer according to one embodiment of the present invention shown in is composed of a thermoplastic elastomer. When measured using a rotational rheometer under the conditions of parallel plate 20 mmφ, measurement gap 1.3 mm, and frequency 1 Hz, the loss tangent tanδ of the thermoplastic elastomer at at least one point in the measurement temperature of 120 to 270°C is greater than 0.40, and the loss modulus G'' is less than 11000 Pa. Next, it is described in detail.

[0059] The granular body 1 of this embodiment is not in the form of a filament like a filament, but in the form of a granule that can be easily put into a screw extruder. Figure 1 As shown, when the length of the longest part of the particles constituting the granular body is L and the diameter of the largest circumscribed circle 1a on the plane perpendicular to the longest part is D, L / D is, for example, 1 to 10, preferably 1 to 5. Among them, L is, for example, 0.5 to 10 mm, preferably 1 to 6 mm, and more preferably 2 to 4 mm. L / D is specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and can also be a range between any two of the numerical values ​​exemplified here. L is specifically, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm, and can also be a range between any two of the numerical values ​​exemplified here.

[0060] The thermoplastic elastomer constituting the granular body 1 may be exemplified by styrene elastomer, olefin elastomer or acrylic elastomer. The thermoplastic elastomer preferably contains a styrene elastomer. This is because the styrene elastomer has high flexibility, and by including a styrene elastomer in the thermoplastic elastomer, the flexibility of the thermoplastic elastomer can be improved. The proportion of the styrene elastomer in the thermoplastic elastomer is preferably 50 to 100 mass%, more preferably 80 to 100 mass%, and specifically, for example, 50, 60, 70, 80, 90, 100 mass%, and may also be a range between any two of the numerical values ​​exemplified herein.

[0061] Styrene elastomers are thermoplastic elastomers having styrene units, and specifically include styrene copolymers (e.g., styrene-ethylene-styrene block copolymers (SES), styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene rubber (SBR), etc.), hydrogenated styrene copolymers (e.g., styrene-ethylene-styrene block copolymers (SES), styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene rubber (SBR), etc.), Propylene-styrene block copolymer (SEPS), styrene-ethylene Butylene-styrene block copolymer (SEBS), styrene-butylene butadiene-styrene block copolymer (SBBS), hydrogenated styrene-butadiene rubber (HSBR), etc.) or a mixture of two or more thereof.

[0062] The Shore A hardness of the thermoplastic elastomer is preferably 0 to 10, and specifically can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or a range between any two of the values ​​exemplified herein. As long as the Shore A hardness is within this range, a shaped object with better flexibility can be obtained. The Shore A hardness is measured based on JIS K6253.

[0063] The viscoelasticity of thermoplastic elastomers is measured according to JIS K 7244-10. Regarding viscoelastic properties, specifically, the loss modulus G'' (Pa) at a measurement temperature of 120 to 270°C is measured using a rotational rheometer under the conditions of parallel plates of 20 mm φ, a measurement gap of 1.3 mm, and a frequency of 1 Hz, while heating to 40 to 280°C at a heating rate of 2°C / min, and the loss tangent tanδ (=G'' / G') calculated from the loss modulus G'' (Pa) and the storage modulus G' (Pa).

[0064] As will be described later, when the loss tangent tanδ at the molding temperature is greater than 0.40 and the loss modulus G'' is less than 11000Pa, the hot melt 3D printer can still manufacture the molded object with high precision even if the intervals between the line portions constituting the molded object are wide. In addition, the molding temperature of the hot melt 3D printer is generally 120 to 270°C. Therefore, when the loss tangent tanδ and the loss modulus G'' of the thermoplastic elastomer meet the above conditions, a high-precision molded object can be manufactured by appropriately adjusting the molding temperature. In one embodiment, the energy storage modulus G' may also be considered.

[0065] In addition, since molding is easy when the molding temperature is relatively low, molding is preferably performed at 120 to 230° C. Therefore, when the loss modulus G'' at a molding temperature of 120 to 230° C. is 8000 Pa or less, such as 600 to 4500 Pa, and particularly 700 to 2000 Pa, a molded object can be manufactured with particularly high precision at a relatively low temperature, so the loss modulus G'' of the thermoplastic elastomer is preferably 8000 Pa or less at at least one point in the measurement temperature of 120 to 230° C., more preferably 600 to 4500 Pa, and particularly preferably 700 to 2000 Pa.

[0066] The measurement temperature is specifically, for example, 120, 125, 130, 135, 140, 145, 150, 155, 158, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, or 270° C. and may be a range between any two of the values ​​exemplified here. In one embodiment, the loss tangent tanδ is, for example, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, or 7.0, or a range between any two of the values ​​exemplified herein. Specific examples of the loss modulus G″ include 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, 10500, and 11000 Pa, and may be a range between any two of the values ​​exemplified here.

[0067] The temperature range in which the loss tangent tanδ and the loss modulus G'' are within the above range is preferably 10°C or more, more preferably 20°C or more. In this case, the setting of the molding temperature becomes easy. The temperature range is, for example, 10 to 50°C, and specifically, it can be, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50°C, or a range between any two of the values ​​exemplified here.

[0068] 2. Method for manufacturing the object

[0069] like Figure 2 As shown, the method for producing a shaped object according to one embodiment of the present invention includes a scanning step of melting the granular body 1 in a screw extruder 2 and scanning a strand 4 extruded from a nozzle 2c. The strand 4 is extruded in a molten state and directly scanned.

[0070] The extruder 2 includes a hopper 2a, a cylinder 2b, and a nozzle 2c. The granular material 1 is put into the cylinder 2b from the hopper 2a, and is heated and melted in the cylinder 2b to become a molten material. The molten material is pushed toward the front end of the cylinder 2b by the rotation of the screw arranged in the cylinder 2b, and is extruded from the nozzle 2c provided at the front end of the cylinder 2b to form a strand 4. By various means, even a highly flexible material such as a thermoplastic elastomer can be easily formed into a strand 4.

[0071] The wire material 4 is in a linear shape and has a diameter of, for example, 0.5 to 6.0 mm, preferably 1.0 to 4.0 mm. The diameter is specifically 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0 mm, or may be a range between any two of the values ​​exemplified here.

[0072] The wire material 4 can be scanned in such a way as to form a desired object, and the object can be manufactured by cooling and solidifying the wire material 4 after scanning. The cooling can be natural cooling or forced cooling.

[0073] The temperature of the strand 4 just extruded from the nozzle 2c is defined as the molding temperature. The molding temperature is preferably 120 to 270°C. In this case, the strand 4 is easily fully hardened during cooling and is not easily degraded by heating of the molding material. The loss tangent tanδ of the strand 4 at the molding temperature is preferably greater than 0.40, and the loss modulus G'' is less than 11000 Pa. When the molding temperature is a relatively low temperature such as 120 to 230°C, the loss modulus G'' of the strand 4 is more preferably less than 8000, further preferably 600 to 4500 Pa, and particularly preferably 700 to 2000 Pa. As shown in the embodiments to be described later, when the loss tangent tanδ and the loss modulus G'' at the molding temperature are within this range, the molding accuracy is particularly high.

[0074] The above-mentioned molding temperature is specifically, for example, 120, 125, 130, 135, 140, 145, 150, 155, 158, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270°C, and may be a range between any two of the values ​​exemplified here. In one embodiment, the loss tangent tanδ is, for example, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, or 7.0, or may be a range between any two of the values ​​exemplified herein. Specific examples of the loss modulus G″ include 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, 10500, and 11000 Pa, and may be a range between any two of the values ​​exemplified here.

[0075] Figure 3 The figure shows a structure composed of a mesh-shaped layered structure 5. The layered structure 5 is formed by laminating the single-layer structures 6, 7, and 8 formed by the above-mentioned scanning step.

[0076] Figure 4The single-layer structure 6 shown has an outer peripheral line portion 6a and an inner line portion 6b. The outer peripheral line portion 6a and the inner line portion 6b are respectively formed by cooling the wire material 4, and the line width thereof is substantially equal to the diameter of the wire material 4. The inner line portion 6b is arranged in the area surrounded by the outer peripheral line portion 6a. The outer peripheral line portion 6a and the inner line portion 6b are fused to each other. The outer peripheral line portion 6a and the inner line portion 6b are each preferably formed in one stroke by the extrusion action of the wire material 4 without stopping, and it is more preferable to form the entire single-layer structure 6 in one stroke. In this way, the number of stops of the extruded wire material 4 in the scanning process can be reduced, thereby improving the forming accuracy and productivity.

[0077] The inner line portion 6b includes a plurality of parallel line portions 6b1 spaced apart from each other and a connecting line portion 6b2 connecting adjacent parallel line portions 6b1. Figure 4 As shown in FIG. 1B , the ratio of the pitch P of the parallel line portion 6b1 to the line width W of the parallel line portion 6b1, i.e., the pitch ratio P / W, is preferably 1.5 to 6, and more preferably 2.0 to 5.0. If the pitch ratio is too small, the flexibility of the formed object is insufficient, and if the pitch ratio is too large, the forming is difficult. The pitch ratio is specifically, for example, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, and may also be a range between any two of the values ​​exemplified here.

[0078] like Figure 5 The single-layer structure 7 shown has an outer peripheral line portion 7a and an inner line portion 7b. The inner line portion 7b has a plurality of parallel line portions 7b1 and a connecting line portion 7b2. The single-layer structure 7 has the same structure as the single-layer structure 6, except that the extension direction of the parallel line portion 7b1 is different from that of the parallel line portion 6b1. The parallel line portion 7b1 is formed to intersect with a plurality of parallel line portions 6b1. The larger the above-mentioned spacing ratio, the greater the distance (bridging distance) that the parallel line portion 7b1 spans between two parallel line portions 6b1, and the bending forming accuracy of the parallel line portion 7b1 is likely to be reduced. In this embodiment, if the loss tangent tanδ and the loss modulus G'' at the forming temperature are set within the above-mentioned range, the problem of reduced forming accuracy caused by the bending of the parallel line portion can be suppressed.

[0079] Figure 6 The single-layer structure 8 shown in FIG. 1 has an outer peripheral line portion 8a and an inner line portion 8b. The inner line portion 8b has a plurality of parallel line portions 8b1 and a connecting line portion 8b2. The single-layer structure 8 has the same structure as the single-layer structure 6 except that the parallel line portion 8b1 extends in a direction different from the parallel line portion 6b1.

[0080] The laminated structure 5 is formed by repeatedly laminating the single-layer structures 6, 7, and 8 in this order. The parallel line portions 6b1, 7b1, and 8b1 are not parallel to each other, and the parallel line portions of two single-layer structures adjacent in the vertical direction intersect each other. In this embodiment, since the parallel line portions 6b1, 7b1, and 8b1 are offset by 60 degrees and have the same pitch, in the laminated structure 5, Figure 3 As shown in the top view of FIG. 1B , the parallel line portions 6b1 , 7b1 , and 8b1 can form a regular triangle-shaped gap S. The larger the pitch ratio, the larger the gap S, thereby improving the flexibility of the object.

[0081] (Implementation of the Second Aspect)

[0082] 1. First Implementation Method

[0083] 1-1. Structure of the filament 11 and its manufacturing method

[0084] like Figure 7 As shown in FIG. 1 , the filament 11 according to the first embodiment of the present invention includes a continuous fiber bundle 12 and a covering layer 13 covering the fiber bundle 12 .

[0085] The continuous fiber bundle 12 is a bundle of continuous fibers 12a. The so-called continuous fibers 12a refer to fibers that extend continuously in the long side direction of the filament 11. The fiber length of the continuous fibers 12a is preferably 3 cm or more, more preferably 10 cm or more, and further preferably 1 m or more. Unless otherwise specified, the fiber length in the present invention refers to the arithmetic mean fiber length. The continuous fibers 12a are preferably arranged over the entire length of the filament 11. The number of continuous fibers 12a contained in the continuous fiber bundle 12 is preferably 10 or more, more preferably 100 or more, further preferably 1000 or more, and most preferably 10,000 or more. The number of continuous fibers 12a is, for example, less than 1,000,000. Each continuous fiber 12a may be composed of one continuous fiber, or may be a bundle formed by bundling a plurality of thin continuous fibers.

[0086] The continuous fiber bundle 12 includes continuous reinforcing fibers 12a1 which can be continuous fibers 12a. The continuous reinforcing fibers 12a1 are continuous fibers that do not melt during molding and that enhance the rigidity of the filament 11.

[0087] The continuous reinforcing fibers 12a1 may include inorganic fibers such as glass fibers, carbon fibers, plant fibers (including kenaf, bamboo fibers, etc.), alumina fibers, boron fibers, ceramic fibers, metal fibers (steel fibers, etc.), and organic fibers such as aramid fibers, polyoxymethylene fibers, aromatic polyamide fibers, poly(p-benzobisoxazole) fibers, and ultra-high molecular weight polyethylene fibers. The continuous reinforcing fibers 12a1 may consist of only inorganic fibers or only organic fibers, or may contain both inorganic fibers and organic fibers. The continuous reinforcing fibers 12a1 preferably contain at least one of carbon fibers and glass fibers, and more preferably contain carbon fibers.

[0088] The covering layer 13 is formed of a shape memory material including a shape memory polymer. The shape memory material is a material having shape memory properties, which has the property of being able to return to its original shape through elasticity when heated to a predetermined recovery temperature or above. Although the shape memory material preferably contains only shape memory polymers, it may also contain other components without affecting its shape memory characteristics. Components other than shape memory polymers may include polyolefin resins such as polyethylene and polypropylene, and fillers. The proportion of the shape memory polymer in the shape memory material is, for example, 50 to 100% by mass, and specifically, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100% by mass, and may also be a range between any two of the values ​​exemplified here. The recovery temperature of the shape memory material is usually the same as the glass transition temperature of the shape memory polymer.

[0089] Shape memory polymers have the property of being able to restore their original shape through elasticity when heated to a temperature exceeding Tg. Tg is, for example, 35 to 100°C, preferably 40 to 75°C, and specifically, for example, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100°C, or may be a range between any two of the values ​​exemplified herein.

[0090] When a secondary shape is formed by applying an external force at a temperature exceeding Tg, and after being cooled to a temperature below Tg while maintaining the external force, the secondary shape is fixed. At a temperature below Tg, it will not return to its original shape even if the external force is removed. In contrast, when a shape memory polymer that has been formed into a secondary shape is heated and made to exceed the temperature of Tg and is in a state where no external force is applied, it will return to its original shape due to elasticity. The original shape can be set by melting the shape memory polymer and forming it into a desired shape. Shape memory polymers can include polymers with rubber elasticity, specifically polynorbornene, trans-polyisoprene, styrene-butadiene copolymer, and polyurethane.

[0091] The diameter of the filament 11 is, for example, 0.5 to 3 mm, preferably 1 to 2.5 mm, and specifically, for example, 0.5, 1, 1.5, 1.75, 2, 2.5, 3 mm, and may be a range between any two of the values ​​exemplified here. Let the diameter of the filament 11 be D1, and the diameter of the continuous fiber bundle 12 be D2, D2 / D1 is preferably 0.1 to 0.9, and more preferably 0.2 to 0.5. D2 / D1 is, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and may be a range between any two of the values ​​exemplified here.

[0092] The ratio of the continuous fiber bundle 12 in the filament 11 is, for example, 1 to 90% by mass, preferably 5 to 30% by mass. The ratio is specifically, for example, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90% by mass, and may be a range between any two of the values ​​exemplified here.

[0093] The filament 11 may be manufactured in a manner of coating the continuous fiber bundle 12 with the shape memory material at the outlet of an extruder that extrude the shape memory material to form a covering layer 13 .

[0094] 1-2. Method of using the filament 11

[0095] The filament 11 can be used to print using a hot melt 3D printer and in the following manner: Figure 8 The object 17 shown is manufactured into a desired shape.

[0096] In one example, if Fig. 9 As shown, the filament 11 is inserted into the head 14 from the opening 14a provided on the upper side of the head 14, and the filament 11 is heated in the head 14, so that the resin component contained in the filament 11 can be melted, thereby forming a molten filament 11a in a molten state, and finally extruded from the lower side of the head 14. The object 17 can be formed by moving the head 14 relative to the forming surface (not shown) on which the object is formed. Figure 8 The object 17 is formed by moving the head 14 in a circular manner repeatedly to form the molten filament 11a into a spiral shape and to fuse the molten resin of the tobacco oil in the molten filament 11a. The forming temperature is, for example, 130 to 270°C, specifically, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270°C, and may be a range between any two of the values ​​exemplified here.

[0097] A cutter 15 is provided directly below the head 14, and the molten filament 11a (particularly the continuous reinforcing fiber 12a1 contained in the molten filament 11a) can be cut by the cutter 15. In one example, the cutter 15 is configured to cut the molten filament 11a by clamping the molten filament 11a with a pair of blades 15a.

[0098] When the temperature of the object 17 is above Tg, the elastic modulus of the shape memory polymer is significantly reduced, so that it can be freely deformed into a secondary shape. When the object 17 is cooled to a temperature below Tg while maintaining its shape, its shape is maintained.

[0099] Then, after the secondary shape shaped object 17 is heated to a temperature above Tg, the shape 17 will return to its original shape due to the elasticity of the shape memory polymer. At this time, the greater the restoring force, the higher the restorability of the shape 17, so it is preferred. In addition, since the greater the restoring force, the less the amount of shape memory polymer required for restoration, the thinner the shape 17 can be. The shape 17 involved in this embodiment is formed by using the filament 11 containing the continuous reinforcing fiber 12a1, so the restoring force is high (refer to the embodiments and comparative examples to be described later).

[0100] 2. Second Implementation Method

[0101] use Fig.10 A filament 11 according to a second embodiment of the present invention will be described. This embodiment is similar to the first embodiment, but differs mainly in the structure of the continuous fiber bundle 12. The following description will focus on this difference.

[0102] In this embodiment, the continuous fiber bundle 12 contains continuous resin fibers 12a2 in addition to the continuous reinforcing fibers 12a1 as the continuous fibers 12a. The continuous resin fibers 12a2 are composed of resin that melts during shaping. When the continuous fiber bundle 12 contains the continuous resin fibers 12a2, the molten resin obtained by melting the continuous resin fibers 12a2 during shaping causes the continuous reinforcing fibers 12a1 to be connected to each other, thereby increasing the strength of the shaped object 17.

[0103] The resin constituting the continuous resin fibers 12a2 includes polyolefins such as polyethylene and polypropylene, aliphatic polyamides such as nylon 6 and nylon 66, semi-aromatic polyamides such as nylon 6T / 66, and the above-mentioned shape memory polymers. When the continuous resin fibers 12a2 contain shape memory polymers, the restoring force is enhanced.

[0104] It should be noted that when the continuous resin fibers 12a2 contain a shape memory polymer, the cover layer 13 may be composed of a resin that does not contain a shape memory polymer. In this case, the cover layer 13 may be composed of the above-mentioned polyolefin, aliphatic or semi-aromatic polyamide, etc. In addition, if it is not necessary to have the cover layer 13 on the shaped object 17, the cover layer 13 may be omitted.

[0105] [Example]

[0106] (Example of the first aspect)

[0107] Table 1 shows the Shore A hardness of the granular body composed of the thermoplastic elastomer, and the maximum and minimum values ​​of each measured value related to viscoelasticity measured at 120 to 270°C. Table 2 shows the Shore A hardness of the granular body composed of the thermoplastic elastomer (same as Table 1), and the maximum and minimum values ​​of each measured value related to viscoelasticity measured at 120 to 230°C.

[0108] Viscoelasticity was measured according to JIS K 7244-10. First, a sheet of about 100 mm × 100 mm × 1 mm (vertical × horizontal × thickness) was made by compression molding (device: hydraulic molding machine 26 tons, manufactured by Toho Press Manufacturing Co., Ltd.), and then a test piece of 20 mm × 20 mm (vertical × horizontal) was cut out. The gauge pressure during compression molding was 5 MPa, and the press temperatures of AR-SC-0, AR-815C, G1645MO, AR-SC-5, JS20N, and CJ103 were 130°C, 230°C, 230°C, 150°C, 170°C, and 230°C, respectively.

[0109] The measurement conditions are as follows:

[0110] Geometry: Parallel plate 20mmφ

[0111] Temperature: 40~280℃

[0112] Heating rate: 2℃ / min

[0113] Frequency: 1Hz (6.28rad / s)

[0114] Gap: 1.3~1.4mm

[0115] Set strain: 0.01

[0116] Number of measurements: n=1

[0117] Measuring device: MARSIII

[0118]

Table 1

[0119]

[0120]

Table 2

[0121]

[0122] Table 3 shows the evaluation of viscoelasticity and formability at various temperatures. The evaluation of formability was performed by using these granules as materials and using a 3D printer with a screw extruder at the temperatures shown in Table 3 to produce a 3D printer having a screw extruder. Figure 3 The evaluation was performed in the manner of a shaped object composed of the laminated structure 5 shown in Table 3. The temperature in Table 3 is the temperature of the strand 4 just after it was extruded from the nozzle 2c, which was measured using a thermal imager (manufactured by Nippon Avionics Co., Ltd., infrared thermal imager camera Thermo GEAR, model: G120EX). The diameter of the strand 4 is 2 mm, the moving speed of the nozzle 2c is 50 mm / s, and the spacing of the parallel line portions is 6.5 mm. The line width of the parallel line portion is 2.0 mm. Therefore, the spacing ratio is 3.25.

[0123] The obtained shaped objects were visually observed, and the shapeability was evaluated according to the following criteria.

[0124] ◎: No shape collapse was observed.

[0125] ○: Slight collapse of the shape was observed (for example, the corners of the shape were lifted).

[0126] △: Although some collapse of the shape was observed, no significant collapse was observed.

[0127] ×: The strands were torn or not fixed on the molding table, or the molding collapsed significantly.

[0128] As shown in Table 3, when the loss tangent tanδ at the molding temperature is 0.40 or more and the loss modulus G'' is 11000Pa or less, the molding property is good. Among them, the molding property is good at a relatively low molding temperature of 120-230°C and when the loss modulus G'' is 8000Pa or less. The molding property is better at 600-4500Pa, and the molding property is particularly good when the loss modulus G'' is 700-2000Pa.

[0129]

Table 3

[0130]

[0131] The details of the thermoplastic elastomers in the table are as follows:

[0132] CJ103: Made by Kuraray Co., Ltd., Earneston

[0133] JS20N: Made by Kuraray Co., Ltd., earneston

[0134] AR-SC-0: Made by Aronkasei Co., Ltd.

[0135] AR-SC-5: Made by Aronkasei Co., Ltd.

[0136] AR-815C: Made by Aronkasei Co., Ltd.

[0137] G1645MO: Made by Kraton Polymer Japan Co., Ltd.

[0138] (Example of the Second Aspect)

[0139] 1. Production of Filament 11

[0140] ・Example 1

[0141] At the outlet of an extruder for extruding a shape memory polymer (manufactured by SMP Technologies, Inc., model: MM5520), a carbon fiber (density 1.79 g / cm) as a continuous reinforcing fiber was coated with a shape memory polymer. 3 A covering layer 13 is formed around a continuous fiber bundle 12 having a tensile strength of 4.12 GPa and a tensile elastic modulus of 235 GPa) to form a filament 11 having a diameter of 1.75 mm. The ratio of the continuous fiber bundle 12 in the filament 11 is set to 9.5% by mass.

[0142] ・Comparative Example 1

[0143] A shape memory polymer (manufactured by SMP Technologies, Inc., model: MM5520) was extruded from an extruder to produce a filament 11 having a diameter of 1.75 mm.

[0144] ・Comparative Example 2

[0145] 9.5 mass % of carbon fibers (density 1.79 g / cm2) with a fiber length of 6 mm were added to a shape memory polymer (manufactured by SMP Technologies, Inc., model: MM5520) extruded from an extruder. 3 , tensile strength 4.12 GPa, tensile elastic modulus 235 GPa) to form a filament 11 with a diameter of 1.75 mm.

[0146] 2. Preparation of samples for measuring resilience

[0147] Using the filaments 11 of the embodiment and the comparative example, at a molding temperature of 210°C, the following Figure 8 The shape of the object 17 (diameter 50mm, height 20mm, spiral pitch 1.5mm) is cut into two halves to make a shape as shown in FIG. Fig.11A sample 17a for measuring the restoring force having the shape shown in FIG.

[0148] 3. Determination of resilience

[0149] After the sample 17a was immersed in hot water at 67°C to soften it, the sample 17a was deformed into the following Fig.11 B shows the flattened shape. Then, Fig.11 As shown in B, the sample 17a was immersed in hot water at 67°C, and a dynamometer 16 (manufactured by Imada Co., Ltd., model: DS2-50N) was brought into contact with the upper surface of the sample 17a to measure the restoring force of the sample 17a. The results are shown below.

[0150] Example 1: 1.0N

[0151] Comparative Example 1: 0.3N

[0152] Comparative Example 2: 0.8N

[0153] The results show that the shaped object 17 made by using the filament 11 containing continuous reinforcing fibers and shape memory polymer has high restoring force.

[0154] Explanation of symbols

[0155] 1: Granular body for hot melt 3D printer, 1a: circumscribed circle, 2: screw extruder, 2a: hopper, 2b: cylinder, 2c: nozzle, 4: wire, 5: laminated structure, 6: single layer structure, 6a: outer peripheral line, 6b: inner line, 6b1: parallel line, 6b2: connecting line, 7: single layer structure, 7a: outer peripheral line, 7b: inner line, 7b1: parallel line, 7b2: connecting line, 8: single layer structure, 8a: outer peripheral line Circumferential line portion, 8b: inner line portion, 8b1: ​​parallel line portion, 8b2: connecting line portion, P: spacing, S: gap, W: line width, 11: filament, 11a: molten filament, 12: continuous fiber bundle, 12a: continuous fiber, 12a1: continuous reinforcing fiber, 12a2: continuous resin fiber, 13: covering layer, 14: head, 14a: opening, 15: tool, 15a: blade, 16: dynamometer, 17: shape, 17a: sample.

Claims

1. A method for producing a shaped object, comprising a scanning step of scanning a strand, wherein the strand is formed by melting a granular body in a screw extruder and extruding the granular body from a nozzle, The granular body is a granular body for a hot melt type 3D printer composed of a thermoplastic elastomer. The thermoplastic elastomer has a loss tangent tanδ of 0.40 or more and a loss modulus G″ of 2000 Pa or less at at least one point in a measurement temperature of 120 to 190° C. when measured using a rotational rheometer at a set strain of 0.01 mm and a frequency of 1 Hz.

2. The method for manufacturing a shaped object according to claim 1, wherein: The Shore A hardness of the thermoplastic elastomer is 0-10.

3. The method for manufacturing a shaped object according to claim 1, wherein: When the strand is measured using a rotational rheometer under the conditions of set strain of 0.01 mm, frequency of 1 Hz and forming temperature, the loss tangent tanδ is greater than 0.40 and the loss modulus G'' is less than 2000 Pa, wherein the forming temperature is the temperature of the strand just after being extruded from the nozzle.

4. The method for manufacturing a shaped object according to claim 3, wherein: The loss modulus G″ of the wire material at the molding temperature is 600 to 2000 Pa.

5. The method for producing a shaped object according to any one of claims 1 to 4, wherein: The single-layer structure formed by the scanning step is stacked to form a stacked structure. The single-layer structures each include a plurality of parallel line portions spaced apart from each other, Two of the single-layer structures adjacent to each other in the vertical direction of the stacked structure are provided so that the plurality of parallel line portions intersect each other.

6. The method for manufacturing a shaped object according to claim 5, wherein: A pitch ratio defined by a ratio of a pitch of the parallel line portions to a line width of the parallel line portions is 1.5-6.

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