JP2017136739A - Filament and method for producing filament - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a raw material filament that is used for a three-dimensional printer of fused deposition modeling (FDM), wherein the raw material filament is a soft filament that resists bending during conveyance, and a method for producing a filament that allows the filament to be molded in any hardness.SOLUTION: A filament is used as raw materials for printed matter printed with a three-dimensional printer using fused deposition modeling (FDM), and comprises polylactic resin and thermoplastic elastomer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM) and a method for producing the filament.

  Conventionally, a three-dimensional printing apparatus has been used to create a three-dimensional model such as a prototype or a jig. The three-dimensional printing apparatus is also referred to as a 3D printer, and the three-dimensional printing apparatus can create a three-dimensional model using raw materials such as resin according to three-dimensional drawing data captured on a computer.

There are various methods for forming a three-dimensional model, and one of them is a hot melt lamination method (FDM). In the hot melt lamination method (FDM), a raw material filament such as a thermoplastic resin is discharged from a nozzle while being heated and melted by a heater provided in a head, and the nozzle is operated in a plane direction, for example, to form a first layer of a three-dimensional model. This is a method for obtaining a three-dimensionally shaped article by forming and then laminating the second layer and the third layer on the upper surface of the first layer.
Hot melt lamination (FDM) three-dimensional printing devices are cheaper and more widespread than three-dimensional printing devices that utilize a laser or powder sintering modeling method.

In such a conventional hot melt lamination (FDM) three-dimensional printing apparatus, for example, a hard resin having a large Shore A hardness, such as ABS resin or polylactic acid (PLA) resin, has a relatively low melting point. A three-dimensional model was printed using a filament made of the above resin.
On the other hand, if printing can be performed using a soft filament having a Shore A hardness smaller than that of a hard filament as a raw material filament, it becomes possible to produce a molded product such as a part that requires flexibility, and the range of use is further expanded. It becomes.

However, when a soft filament is used as a raw material filament of a general three-dimensional printing apparatus of the hot melt lamination method (FDM), the filament itself does not have rigidity, so that the filament is bent in the transport process to the head or in the head. There was a problem that the phenomenon of so-called jamming that would prevent conveyance was caused.
Conventionally, there has also been a hot melt lamination (FDM) three-dimensional printing device that can use soft filaments, but it becomes a dedicated machine for soft filaments and is not versatile and expensive. It was unsuitable for use.

As described above, the raw material filament of a general hot melt lamination method (FDM) three-dimensional printing apparatus has two main conditions: a melting point that can be melted by a heater, and a hardness that does not bend during transportation. It is necessary to satisfy.
However, in the conventional raw material filament, only a raw material consisting of a single component was selected and used. Therefore, filaments that satisfy the above two conditions are limited, and a molded product having an arbitrary hardness can be manufactured. I couldn't.
The applicant of the present patent has conducted a prior art search from such a viewpoint, but has not found a technique that can solve the above-mentioned problems.
JP-T-2006-501137

  The present invention is to solve the above-mentioned conventional problems, and the problem is a raw material filament used in a three-dimensional printing apparatus of a hot melt lamination method (FDM), An object of the present invention is to provide a soft filament that does not bend and a method for producing a filament that can be molded to an arbitrary hardness.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM), It contains a lactic acid resin and a thermoplastic elastomer.

“Polylactic acid (PLA) resin” is a synthetic resin produced by polymerizing lactic acid through an ester bond. The melting point is 170 ° C. and the Shore A hardness is 100 or more.
Here, the Shore A hardness is a hardness measured using a type A durometer in a method defined in JIS K 7215 (plastic) or JIS K 6253 (vulcanized rubber and thermoplastic rubber). There are various definitions of hard and soft in resins and rubbers. Here, those having a Shore A hardness of 95 or higher are called hard, and those having a Shore A hardness of 95 or lower are called soft.
The “thermoplastic elastomer” is a concept including an olefin elastomer and a styrene elastomer.
Olefin-based elastomers are thermoplastic elastomers in which polyethylene-polypropylene rubber (EPDM, EPM) is finely dispersed in polypropylene. They have flexibility and resilience like rubber at room temperature and have a large coefficient of friction. It is a synthetic resin that can be molded in the same way as general resins.
Styrenic elastomer is a thermoplastic elastomer obtained by block copolymerization of polystyrene and polyethylene-polybutylene. The polystyrene domain serves as a physical crosslinking point and plays a role corresponding to the crosslinking point of crosslinked rubber. Indicates. On the other hand, when the temperature reaches 140 to 230 ° C., the polystyrene part and the polyethylene / polybutylene part are both melted and exhibit flow characteristics as a thermoplastic resin.

The invention according to claim 2 is characterized in that the thermoplastic elastomer contains a styrene resin and a mineral oil plasticizer.
The “styrene resin” is a concept including a styrene elastomer.
“Plasticizer” is a general term for chemicals added to improve flexibility and weather resistance in addition to thermoplastic synthetic resins.
“Mineral oil” is also called mineral oil and is a general term for mixtures containing hydrocarbon compounds or impurities derived from underground resources such as petroleum (crude oil), natural gas, and coal. In general, mineral oils are classified as either paraffinic oils, naphthenic oils or higher fatty acids.

The invention according to claim 3 is characterized in that the thermoplastic elastomer contains an olefin resin and a mineral oil plasticizer.
The “olefin resin” is a concept including an olefin elastomer.

The invention according to claim 4 is a method for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM), which comprises polylactic acid resin and thermoplasticity Elastomers are mixed so that the total amount becomes 100% by weight, dissolved by heating, and filaments are produced by extrusion molding.
Therefore, a filament in which a polylactic acid resin and a thermoplastic elastomer are mixed at an arbitrary ratio is manufactured by extrusion molding.

  The invention according to claim 5 is characterized in that the thermoplastic elastomer contains a styrene resin and a mineral oil plasticizer.

  The invention according to claim 6 is characterized in that the thermoplastic elastomer contains an olefin resin and a mineral oil plasticizer.

Since the filament according to any one of claims 1 to 3 contains a polylactic acid having a high hardness and a thermoplastic elastomer having a low hardness, the hardness is continuously changed depending on the ratio of the polylactic acid and the thermoplastic elastomer. be able to.
On the other hand, in the filament according to claims 1 and 2, since the melting point of polylactic acid is substantially the same as the melting point of the thermoplastic elastomer, it is almost constant regardless of the ratio of polylactic acid to the thermoplastic elastomer. Shows melting point.
Accordingly, it is possible to provide a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer while the melting point is substantially constant.
As a result, filaments containing polylactic acid and thermoplastic elastomer that contain a certain percentage of polylactic acid having a high hardness are used as raw material filaments for a general three-dimensional printing apparatus of the hot melt lamination method (FDM). It is possible to provide a filament that satisfies two conditions of a melting point that can be dissolved by a heater and a certain hardness that does not bend during conveyance.

In the method for producing a filament according to any one of claims 4 to 6, a filament in which a polylactic acid resin having a high hardness and a thermoplastic elastomer having a low hardness are mixed at an arbitrary ratio is manufactured by extrusion molding. Depending on the ratio of polylactic acid and thermoplastic elastomer, it can be formed into a filament having any hardness between the hardness of polylactic acid and the hardness of thermoplastic elastomer.
On the other hand, in the method for producing a filament according to claims 3 and 4, since the melting point of polylactic acid is substantially the same as the melting point of the thermoplastic elastomer, regardless of the ratio of the polylactic acid and the thermoplastic elastomer, It can be formed into a filament having a substantially constant melting point.
As a result, it is possible to provide a method for producing a filament capable of forming a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of a thermoplastic elastomer while the melting point is substantially constant.

Moreover, in the manufacturing method of the filament of Claims 4-6, by manufacturing a filament by extrusion molding, the shape | molded filament is hard to deform | transform in an extrusion direction, and is in a direction orthogonal to an extrusion direction. It has the anisotropy of being easily deformed.
Therefore, when the filament formed by the filament manufacturing method according to any one of claims 4 to 6 is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), the conveying direction to the head is the filament. Since it coincides with the extrusion direction, the filament has rigidity in the conveyance direction to the head.
As a result, it is possible to prevent a phenomenon in which a so-called jamming phenomenon occurs in which the conveyance process to the head or the filament is bent in the head and the conveyance becomes impossible.

In general, when a filament is conveyed in a three-dimensional printing apparatus, the filament is fed and conveyed while being sandwiched between a drive gear having a groove and a roller.
At this time, when the filament formed by the filament manufacturing method according to any one of claims 4 to 6 is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), it is sandwiched between a drive gear and a roller. In this case, the filament is strongly pressed against the groove portion of the drive gear. However, since the pressing direction is a direction perpendicular to the extrusion direction of the filament, the filament is easily deformed as described above.
As a result, the filament is deformed in accordance with the groove portion of the drive gear and meshes with the groove portion of the drive gear, thereby preventing the filament from slipping.
Accordingly, the filament can be reliably conveyed by the drive gear, and the three-dimensional structure can be printed stably over a long period of time.

FIG. 1 shows the relationship between the content of a thermoplastic elastomer and the Shore A hardness when a polylactic acid resin and a thermoplastic elastomer are mixed to a total of 100% by weight in the filament according to the present embodiment. It is a graph. FIG. 2 (a) is a graph showing the relationship between elongation and tensile strength in a sheet sample extruded under the same conditions as the filament according to the present embodiment, and (b) is a graph in (a). It is the graph which expanded elongation the range of 0%-200%. FIG. 3 is a plan view of the sheet sample used in the measurements of FIGS. 2 (a) and 2 (b). 4A is a perspective view of a sheet sample extruded under the same conditions as the filament according to the present embodiment, and FIG. 4B is a vertical view of the sheet sample of FIG. 4A observed with a scanning electron microscope. (C) is a schematic diagram of (b), (d) is a flow direction sectional view of the sheet sample of (a) observed with a scanning electron microscope, and (e) is of (d). It is a schematic diagram.

Hereinafter, the present invention will be described in detail based on embodiments and examples.
[Filament manufacturing process]
The filament according to the present embodiment is manufactured by a general extruder.
Specifically, a 65φ extruder is used. Cylinder temperature is 150-180 degreeC of dice | dies, 160-200 degreeC of measurement parts, 160-200 degreeC of compression parts, and 150-180 degreeC of supply parts.
Further, the limit temperature is 240 ° C., the temperature of the cooling water in the cooling water tank is 8 to 15 ° C., the distance between the die and the sizer is 2 to 5 cm, the withdrawal rate is 0.87 to 0.92, and the sizing method is the driver vacuum.
In the filament according to the present embodiment, after mixing the polylactic acid resin (A) pellets and the thermoplastic elastomer (B) pellets to a total of 100% by weight, the mixture is added to the injection port of the extruder. The mixed pellets are put, and the screw is rotated while being heated, and the resin is sent out while being melted. The resin is extruded from the die at the tip, cooled and solidified in a cooling water tank, and manufactured as a filament having a diameter of 1.75 mm.

[3D printing device]
The three-dimensional printing apparatus according to this embodiment uses a hot melt lamination method (FDM), and includes a data processing unit and a printing unit that performs three-dimensional printing based on a control signal supplied from the data processing unit. It is composed of
The printing unit includes a head unit including a heater unit and a nozzle unit, and the head unit includes a drive gear for supplying a raw material filament to the nozzle unit and a roller. The drive gear is provided with a groove.
In the three-dimensional printing apparatus according to the present embodiment, the raw material filament is fed out while being sandwiched between the drive gear and the roller and conveyed to the head unit, and the filament melted by the heater unit is the nozzle. The printed matter is formed by being discharged from the section.

[raw materials]
A: Polylactic acid resin The polylactic acid resin (A) in the present invention has a purity of 95% or more, contains 5% or less of an additive, and has a melting point of 170 ° C. The polylactic acid resin (A) in the present invention is required to have a D-form content of 1.0 mol% or less or a D-form content of 99.0 mol% or more, 0.1 to 0.6 mol%, or 99.4 to 99.9 mol%.
When the D-form content is within this range, the crystal performance is excellent, so that the moldability is excellent (the molding cycle is shortened), and the obtained molded article has improved heat resistance.

B: Thermoplastic Elastomer The thermoplastic elastomer (B) in the present invention contains a styrene resin (C) and a mineral oil plasticizer (D). Specifically, the weight mixing ratio of (C) component and (D) component is (C) component / (D) component = 25 / 75-30 / 70, and melting | fusing point is 100-170 degreeC.

C: Styrene resin The styrene resin in the present invention has a polystyrene block as a hard segment and a conjugated diene polymer block as a soft segment. To show fluidity. Examples of the styrenic elastomer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene- Ethylene / propylene-styrene block copolymer (SEPS), partially hydrogenated styrene-ethylene / butylene-styrene block copolymer (partially hydrogenated SEBS), styrene / (ethylene-ethylene / propylene) -styrene block copolymer ( SEEPS) and the like. Desirable styrenic elastomers are SEBS and SEEPS. When SEBS or SEEPS is used, transparency is improved and excellent slip resistance is obtained.
The mass average molecular weight of the styrene elastomer in the present invention must be in the range of 100,000 to 200,000. When the mass average molecular weight is less than 100,000, mechanical strength such as tensile strength and tensile elongation at break is deteriorated. When the mass average molecular weight exceeds 200,000, transparency is deteriorated.

D: Mineral oil-based plasticizer In the present invention, a mineral oil-based plasticizer is used as the plasticizer in the thermoplastic elastomer. In the present invention, known mineral oils such as paraffinic oils and naphthenic oils can be used. It is preferable to use mineral oil which is hydrogen oil.

Based on the production method according to the present invention, filaments having different thermoplastic elastomer contents were produced by changing the ratio of the polylactic acid resin (A) and the thermoplastic elastomer (B). In addition, the filament concerning this Embodiment and the manufacturing method of a filament are not limited to a following example, A various change can be added in the range which does not deviate from the summary of this invention.
[Production Example 1] <Preparation of filament (1)>
In the filament (1) according to the present embodiment, the proportion of the thermoplastic elastomer (B) pellets is 1 part by weight (containing the thermoplastic elastomer) with respect to 10 parts by weight of the polylactic acid resin (A) pellets. The filament was produced by extrusion after mixing at a rate of 9.1%.
[Production Example 2] <Production of Filament (2)>
In the filament (2) according to the present embodiment, the ratio of 1 part by weight of the thermoplastic elastomer (B) pellets to 2 parts by weight of the polylactic acid resin (A) pellets (containing the thermoplastic elastomer) The filament was produced by extrusion after mixing at a rate of 33.3%.
[Production Example 3] <Production of Filament (3)>
In the filament (3) according to the present embodiment, the ratio of the pellets of the thermoplastic elastomer (B) to 1 part by weight of the pellets of the polylactic acid resin (A) (containing the thermoplastic elastomer) The filament is produced by extrusion after mixing at a rate of 50%).
[Production Example 4] <Production of Filament (4)>
In the filament (4) according to the present embodiment, a ratio of 2 parts by weight of the pellets of the thermoplastic elastomer (B) to 1 part by weight of the pellets of the polylactic acid resin (A) (containing the thermoplastic elastomer) The filament is produced by extrusion after mixing at a rate of 66.7%).
[Production Example 5] <Production of Filament (5)>
In the filament (5) according to the present embodiment, the proportion of the pellet of the thermoplastic elastomer (B) is 10 parts by weight of the pellet of the polylactic acid resin (A) (containing the thermoplastic elastomer). The filament is produced by extrusion after mixing at a rate of 90.9%).
[Production Examples 6 to 10] <Production of sheet samples (1) to (5)>
In the sheet samples (1) to (5) according to the present embodiment, the proportions of the polylactic acid resin (A) and the thermoplastic elastomer (B) are the filaments (1) to (5), respectively. It is the same and is a sheet sample manufactured by extrusion molding.
[Production Example 11] <Production of sheet sample (6)>
In the sheet sample (6) according to the present embodiment, a ratio of 7 parts by weight of the thermoplastic elastomer (B) pellets to 3 parts by weight of the polylactic acid resin (A) pellets (thermoplastic elastomer). It is a sheet sample manufactured by extrusion molding after mixing at a content rate of 70%.
[Comparative Example 1] <Filament (6)>
The filament (6) according to the present embodiment is a filament produced by extrusion molding only the polylactic acid resin (A) pellets (thermoplastic elastomer content 0%).
[Comparative Example 2] <Filament (7)>
The filament (7) according to the present embodiment is a filament produced by extrusion molding only thermoplastic elastomer (B) pellets (thermoplastic elastomer content 100%).
[Comparative Example 3] <Sheet sample (7)>
The sheet sample (7) according to the present embodiment is a sheet sample produced by extrusion molding only the polylactic acid resin (A) pellets (thermoplastic elastomer content 0%).
[Comparative Example 4] <Sheet sample (8)>
The sheet sample (8) according to the present embodiment is a sheet sample produced by extrusion molding only thermoplastic elastomer (B) pellets (thermoplastic elastomer content 100%).

<Test>
[Test procedure]

A hardness (sheet samples (1) to (5), (7) to (8))
The Shore A hardness was measured according to JIS K 7215 (plastic). Specifically, the test piece had a thickness of 5 mm, and was produced by punching from an extruded sheet. The test temperature is 23 ° C., and the test apparatus is a Shimadzu durometer A manufactured by Shimadzu Corporation.
When the Shore A hardness was 20 or less, the Shore E hardness was measured using a Shimadzu durometer E manufactured by Shimadzu Corporation in accordance with JIS K 6253 (vulcanized rubber and thermoplastic rubber). Other conditions are the same as those for the Shore A hardness measurement.

B Tensile strength and elongation (sheet sample (6))
It measured based on JISK6251: 2010. Specifically, the thickness of the test piece was 2 mm, and punching was performed from the extruded sheet to produce a dumbbell-shaped No. 3 shape (FIG. 3).
The tensile speed is 500 mm / min, the test temperature is 23 ° C., and the tester used is Strograph V10-D manufactured by Toyo Seiki Co., Ltd.

C Microscopic image (sheet sample (6))
It measured with the scanning electron microscope (SEM).

D Melting point (filaments (1) to (7))
A Du Pont thermal differential analyzer model 990 was used and measured at a temperature increase of 20 ° C./min to obtain a melting peak. When the melting temperature was not clearly observed, the melting point was defined as the temperature at which the polymer softened and started to flow (softening point) using a micro melting point measuring device (manufactured by Yanagimoto Seisakusho). Measurement was performed 5 times, and the average value was obtained.

E Printing with a three-dimensional printing device (filaments (1) to (2), (6))
Heater set temperature: 230 ° C
Processing speed (head speed): 20 to 40 mm / s
Stacking height (printing pitch): 0.1 mm
Continuous printing time: A three-dimensional printed material that takes about 30 minutes to 2 hours as a required printing time was printed a plurality of times.

[Test results]
A hardness (sheet samples (1) to (5), (7) to (8))
Table 1 shows the relationship between the content of the thermoplastic elastomer and the Shore A hardness in the sheet samples (1) to (5) and (7) to (8) prepared by the same extrusion molding as the filament according to the present embodiment. It is a table | surface which shows.
FIG. 1 shows the relationship between the content of the thermoplastic elastomer and the Shore A hardness when the polylactic acid resin and the thermoplastic elastomer are mixed to a total of 100% by weight in the filament according to the present embodiment. The data of Table 1 is plotted as a measurement error ± 5.
As shown in Table 1 and FIG. 1, it was found that when the content of the thermoplastic elastomer was increased, the Shore A hardness was decreased.

B Tensile strength and elongation (sheet sample (5))
FIG. 2 (a) is a graph showing the relationship between elongation and tensile strength in a sheet sample extruded under the same conditions as the filament according to the present embodiment, and (b) is a graph in (a). It is the graph which expanded elongation the range of 0%-200%.
FIG. 3 is a plan view of the sheet sample used in the measurements of FIGS. As shown in FIG. 3, a direction parallel to the extrusion direction is defined as a flow direction (MD: Machine direction), and a direction perpendicular to the extrusion direction is defined as a vertical direction (TD: Transverse direction). The elongation and tensile strength were also measured as reference values in the thickness direction of the sheet.
As shown in FIGS. 2 (a) and 2 (b), in the sheet sample according to the present embodiment, it begins to grow for the first time when 1.25 MPa is applied to the flow direction, and when it exceeds 2.22 MPa. It broke.
On the other hand, as shown in FIGS. 2 (a) and 2 (b), in the sheet sample according to the present embodiment, the sheet sample starts to stretch from the point where 0.1 MPa is applied to the vertical direction, and exceeds 1 MPa. It was a result that grew.
As described above, in the sheet sample according to the present embodiment, it is difficult to extend (i.e., not easily deformed) in a direction parallel to the extrusion direction, and to extend (easily deform) in a direction perpendicular to the extruding direction. It was found to have sex.
Note that, as shown in FIG. 2 (a), since the same elongation and tensile strength as in the vertical direction are exhibited in the thickness direction of the sheet, the results of this experiment do not depend on the shape of the sample. I can say that. Actually, filaments manufactured by the same extrusion molding have the same anisotropy.

4A is a perspective view of a sheet sample extruded under the same conditions as the filament according to the present embodiment, and FIG. 4B is a scanning electron microscope (SEM) of the sheet sample of FIG. Observed vertical sectional view (200 times), (c) is a schematic diagram of (b), (d) is a sectional view in the flow direction of the sheet sample of (a) observed with a scanning electron microscope (SEM). (200 times) and (e) are schematic views of (d).
As shown in FIG. 4A, as in FIG. 3, the direction parallel to the extrusion direction is defined as the flow direction (MD: Machine direction), and the direction perpendicular to the extrusion direction is defined as the vertical direction (TD: Transverse direction). To do.
As shown in FIGS. 4B, 4C, 4D, and 4E, in the sheet sample according to the present embodiment, the molecular chain of polylactic acid (PLA) resin is parallel to the extrusion direction. It can be seen that it is oriented.
That is, the results shown in FIGS. 2 (a) and 2 (b) and the results shown in FIGS. 4 (b) and (c), (d) and (e) cause the molecular chains of the polylactic acid resin to be oriented. It has the anisotropy that it is difficult to stretch in the direction parallel to the direction (hard to deform), the molecular chain of the polylactic acid resin is not oriented, and easy to stretch in the direction perpendicular to the extrusion direction (easy to deform). I found out.
Therefore, it is determined that the anisotropy with respect to the deformation of the sheet sample according to the present embodiment is caused by the orientation of the molecular chain of the polylactic acid resin by extrusion molding.
In addition, since the anisotropy to the deformation of the sheet sample according to the present embodiment is due to the molecular chain orientation of the polylactic acid resin, regardless of the type of the thermoplastic elastomer, the polylactic acid resin and the thermoplastic elastomer It is inferred that the same anisotropy is developed if the filament or sheet sample is manufactured by mixing, heating and melting, and extrusion molding.

D Melting point (filaments (1) to (7))
Table 2 shows the results of measuring the melting points of the filaments (1) to (7) according to the present embodiment.
As shown in Table 2, the filaments (1) to (5) and (7) all started to soften at 100 ° C., except that the filament (6) of polylactic acid resin alone was 170 ° C. Melted in
In the filament according to the present embodiment, the rate of softening at 100 ° C. increased as the thermoplastic elastomer content increased, but the filament completely melted at 170 ° C.
As described above, since the melting point of the polylactic acid resin is 170 ° C. and the melting point of the thermoplastic elastomer is 100 to 170 ° C., the filament according to the present embodiment includes the polylactic acid resin and the thermoplastic elastomer. It is judged that they are sufficiently dispersed.

E 3D printing device (filaments (1) to (3), (6))
In the printing test using the filaments (1) to (3) and (6) according to the present embodiment, 100 or more three-dimensional prints that require about 30 minutes to 2 hours as printing time were printed. However, the phenomenon of so-called jamming, in which the filament is bent and cannot be transported in the transport process to the head or in the head, did not occur, and there was no defective filament supply or molding due to this phenomenon.
In the three-dimensional printing apparatus according to the present embodiment, the filaments (1) to (3) and (6) having different thermoplastic elastomer contents are used by setting the heater unit to 230 ° C. Even if it was, it could be used without changing the setting of the heater section.
Moreover, as shown in Table 1, the filaments (2) and (3) according to the present embodiment are soft filaments having Shore A hardness of 85 to 95 and 75 to 85, respectively. Since it was possible to print using a printer, it became possible to produce molded parts such as parts that required flexibility.

  Further, in the dual head type three-dimensional printing apparatus that can use two kinds of materials at the same time, when the filament according to the present embodiment is used as a support material for supporting an object, it is sufficient as a support. It has been found that the support material can be easily peeled from the object while having strength.

[Action / Effect]
As described above, since the filament according to the present embodiment contains polylactic acid with a high hardness and a thermoplastic elastomer with a low hardness, as shown in Table 1 and FIG. The hardness can be continuously changed depending on the ratio to the elastomer.
On the other hand, as shown in Table 2, in the filament according to the present embodiment, since the melting point of polylactic acid is almost the same as the melting point of the thermoplastic elastomer, it depends on the ratio between the polylactic acid and the thermoplastic elastomer. It shows an almost constant melting point.
Accordingly, it is possible to provide a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer while the melting point is substantially constant.
As a result, filaments containing polylactic acid and thermoplastic elastomer that contain a certain percentage of polylactic acid having a high hardness are used as raw material filaments for a general three-dimensional printing apparatus of the hot melt lamination method (FDM). It is possible to provide a filament that satisfies two conditions of a melting point that can be dissolved by a heater and a certain hardness that does not bend during conveyance.

As shown in Table 1 and FIG. 1, in the filament manufacturing method according to the present embodiment, a filament in which a polylactic acid resin having a high hardness and a thermoplastic elastomer having a low hardness are mixed in an arbitrary ratio. Can be formed into a filament having any hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer, depending on the ratio of polylactic acid and thermoplastic elastomer.
On the other hand, as shown in Table 2, in the filament manufacturing method according to the present embodiment, the melting point of polylactic acid is almost the same as the melting point of the thermoplastic elastomer. Regardless of the proportion, it can be formed into a filament having a substantially constant melting point.
As a result, it is possible to provide a method for producing a filament capable of forming a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of a thermoplastic elastomer while the melting point is substantially constant.

Moreover, in the manufacturing method of the filament which concerns on this Embodiment, as shown to FIG. 2 (a) and (b), the shape | molded filament is in an extrusion direction by manufacturing a filament by extrusion molding. It has an anisotropy that it is difficult to deform and is easily deformed in a direction perpendicular to the extrusion direction.
Therefore, when the filament formed by the filament manufacturing method according to the present embodiment is used as a raw material filament of a three-dimensional printing apparatus of the hot melt lamination method (FDM), the conveyance direction to the head is the filament extrusion direction. Therefore, the filament has rigidity in the transport direction to the head.
As a result, it is possible to prevent a phenomenon in which a so-called jamming phenomenon occurs in which the conveyance process to the head or the filament is bent in the head and the conveyance becomes impossible.

In general, when a filament is conveyed in a three-dimensional printing apparatus, the filament is fed and conveyed while being sandwiched between a drive gear having a groove and a roller.
At this time, when the filament formed by the filament manufacturing method according to the present embodiment is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), it is sandwiched between a drive gear and a roller. At this time, the filament is strongly pressed against the groove portion of the drive gear. However, since the direction in which the filament is pressed is perpendicular to the extrusion direction of the filament, the filament is easily deformed as described above.
As a result, the filament is deformed in accordance with the groove portion of the drive gear and meshes with the groove portion of the drive gear, thereby preventing the filament from slipping.

Therefore, in the three-dimensional printing apparatus using the hot melt lamination method (FDM), if the filament according to the present embodiment is used, a three-dimensional object can be printed stably over a long period of time.
As a result, a flexible large three-dimensional model and a high-precision three-dimensional model can be obtained by the filament according to the present embodiment.

Since the filament and the method for producing the filament according to the present invention can be widely used for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM) and the filament. Has industrial applicability.

  The present invention relates to a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM) and a method for producing the filament.

  Conventionally, a three-dimensional printing apparatus has been used to create a three-dimensional model such as a prototype or a jig. The three-dimensional printing apparatus is also referred to as a 3D printer, and the three-dimensional printing apparatus can create a three-dimensional model using raw materials such as resin according to three-dimensional drawing data captured on a computer.

There are various methods for forming a three-dimensional model, and one of them is a hot melt lamination method (FDM). In the hot melt lamination method (FDM), a raw material filament such as a thermoplastic resin is discharged from a nozzle while being heated and melted by a heater provided in a head, and the nozzle is operated in a plane direction, for example, to form a first layer of a three-dimensional model. This is a method for obtaining a three-dimensionally shaped article by forming and then laminating the second layer and the third layer on the upper surface of the first layer.
Hot melt lamination (FDM) three-dimensional printing devices are cheaper and more widespread than three-dimensional printing devices that utilize a laser or powder sintering modeling method.

In such a conventional hot melt lamination (FDM) three-dimensional printing apparatus, for example, a hard resin having a large Shore A hardness, such as ABS resin or polylactic acid (PLA) resin, has a relatively low melting point. A three-dimensional model was printed using a filament made of the above resin.
On the other hand, if printing can be performed using a soft filament having a Shore A hardness smaller than that of a hard filament as a raw material filament, it becomes possible to produce a molded product such as a part that requires flexibility, and the range of use is further expanded. It becomes.

However, when a soft filament is used as a raw material filament of a general three-dimensional printing apparatus of the hot melt lamination method (FDM), the filament itself does not have rigidity, so that the filament is bent in the transport process to the head or in the head. There was a problem that the phenomenon of so-called jamming that would prevent conveyance was caused.
Conventionally, there has also been a hot melt lamination (FDM) three-dimensional printing device that can use soft filaments, but it becomes a dedicated machine for soft filaments and is not versatile and expensive. It was unsuitable for use.

As described above, the raw material filament of a general hot melt lamination method (FDM) three-dimensional printing apparatus has two main conditions: a melting point that can be melted by a heater, and a hardness that does not bend during transportation. It is necessary to satisfy.
However, in the conventional raw material filament, only a raw material consisting of a single component was selected and used. Therefore, filaments that satisfy the above two conditions are limited, and a molded product having an arbitrary hardness can be manufactured. I couldn't.
The applicant of the present patent has conducted a prior art search from such a viewpoint, but has not found a technique that can solve the above-mentioned problems.
JP-T-2006-501137

  The present invention is to solve the above-mentioned conventional problems, and the problem is a raw material filament used in a three-dimensional printing apparatus of a hot melt lamination method (FDM), An object of the present invention is to provide a soft filament that does not bend and a method for producing a filament that can be molded to an arbitrary hardness.

In order to solve the above-mentioned problem, the invention according to claim 1 is a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM), Containing a lactic acid resin and a thermoplastic elastomer containing a styrene resin and a mineral oil plasticizer in an arbitrary ratio of 25:75 to 30:70 in an arbitrary ratio of 1: 1 to 10: 1. It is characterized by.

“Polylactic acid (PLA) resin” is a synthetic resin produced by polymerizing lactic acid through an ester bond. The melting point is 170 ° C. and the Shore A hardness is 100 or more.
Here, the Shore A hardness is a hardness measured using a type A durometer in a method defined in JIS K 7215 (plastic) or JIS K 6253 (vulcanized rubber and thermoplastic rubber). There are various definitions of hard and soft in resins and rubbers. Here, those having a Shore A hardness of 95 or higher are called hard, and those having a Shore A hardness of 95 or lower are called soft .
The “styrene resin” is a concept including a styrene elastomer.
The scan styrene-based elastomer, polystyrene and polyethylene - a polybutylene and the block copolymer is a thermoplastic elastomer were, to serve the domain of polystyrene corresponding to the cross point of the crosslinked rubber becomes physical crosslinking point, as an elastic body Show properties. On the other hand, when the temperature reaches 140 to 230 ° C., the polystyrene part and the polyethylene / polybutylene part are both melted and exhibit flow characteristics as a thermoplastic resin.
“Plasticizer” is a general term for chemicals added to improve flexibility and weather resistance in addition to thermoplastic synthetic resins.
“Mineral oil” is also called mineral oil and is a general term for mixtures containing hydrocarbon compounds or impurities derived from underground resources such as petroleum (crude oil), natural gas, and coal. In general, mineral oils are classified as either paraffinic oils, naphthenic oils or higher fatty acids.

The invention according to claim 2 is a method for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM), comprising a polylactic acid resin and styrene And 100% by weight of a thermoplastic elastomer containing a thermoplastic resin and a mineral oil plasticizer in an arbitrary ratio of 25:75 to 30:70 in an arbitrary ratio of 1: 1 to 10: 1 It mixes, heats and melt | dissolves, The filament is manufactured by extrusion molding, It is characterized by the above-mentioned.
Therefore, the polylactic acid resin and the thermoplastic elastomer containing the styrene resin and the mineral oil plasticizer in any ratio from 25:75 to 30:70 are in any ratio from 1: 1 to 10: 1. Mixed filaments are produced by extrusion.

In the filament according to claim 1 , since it contains polylactic acid having a high hardness and a thermoplastic elastomer having a low hardness, the hardness can be continuously changed depending on the ratio of the polylactic acid and the thermoplastic elastomer. it can.
On the other hand, in the filament according to claim 1 , since the melting point of polylactic acid is substantially the same as the melting point of the thermoplastic elastomer, it has a substantially constant melting point regardless of the ratio of the polylactic acid and the thermoplastic elastomer. Show.
Accordingly, it is possible to provide a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer while the melting point is substantially constant.
As a result, filaments containing polylactic acid and thermoplastic elastomer that contain a certain percentage of polylactic acid having a high hardness are used as raw material filaments for a general three-dimensional printing apparatus of the hot melt lamination method (FDM). It is possible to provide a filament that satisfies two conditions of a melting point that can be dissolved by a heater and a certain hardness that does not bend during conveyance.

In the method for producing a filament according to claim 2 , a filament in which a polylactic acid resin having a high hardness and a thermoplastic elastomer having a low hardness are mixed at an arbitrary ratio of 1: 1 to 10: 1 is provided. Since it is manufactured by extrusion molding, it can be formed into a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of thermoplastic elastomer depending on the ratio of polylactic acid and thermoplastic elastomer.
On the other hand, in the method for producing a filament according to claim 2 , since the melting point of polylactic acid is substantially the same as the melting point of the thermoplastic elastomer, it is substantially constant regardless of the ratio of the polylactic acid and the thermoplastic elastomer. Can be formed into a filament having a melting point of.
As a result, it is possible to provide a method for producing a filament capable of forming a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of a thermoplastic elastomer while the melting point is substantially constant.

In the method for producing a filament according to claim 2 , by producing the filament by extrusion molding, the formed filament is hardly deformed in the extrusion direction and deformed in a direction perpendicular to the extrusion direction. Anisotropy is easy.
Therefore, when the filament formed by the method for producing a filament according to claim 2 is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), the conveyance direction to the head is the extrusion direction of the filament. Therefore, the filament has rigidity in the conveyance direction to the head.
As a result, it is possible to prevent a phenomenon in which a so-called jamming phenomenon occurs in which the conveyance process to the head or the filament is bent in the head and the conveyance becomes impossible.

In general, when a filament is conveyed in a three-dimensional printing apparatus, the filament is fed and conveyed while being sandwiched between a drive gear having a groove and a roller.
At this time, when the filament formed by the filament manufacturing method according to claim 2 is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), it is sandwiched between a drive gear and a roller. At this time, the filament is strongly pressed against the groove portion of the drive gear. However, since the direction in which the filament is pressed is perpendicular to the extrusion direction of the filament, the filament is easily deformed as described above.
As a result, the filament is deformed in accordance with the groove portion of the drive gear and meshes with the groove portion of the drive gear, thereby preventing the filament from slipping.
Accordingly, the filament can be reliably conveyed by the drive gear, and the three-dimensional structure can be printed stably over a long period of time.

FIG. 1 shows the relationship between the content of a thermoplastic elastomer and the Shore A hardness when a polylactic acid resin and a thermoplastic elastomer are mixed to a total of 100% by weight in the filament according to the present embodiment. It is a graph. FIG. 2 (a) is a graph showing the relationship between elongation and tensile strength in a sheet sample extruded under the same conditions as the filament according to the present embodiment, and (b) is a graph in (a). It is the graph which expanded elongation the range of 0%-200%. FIG. 3 is a plan view of the sheet sample used in the measurements of FIGS. 2 (a) and 2 (b). 4A is a perspective view of a sheet sample extruded under the same conditions as the filament according to the present embodiment, and FIG. 4B is a vertical view of the sheet sample of FIG. 4A observed with a scanning electron microscope. (C) is a schematic diagram of (b), (d) is a flow direction sectional view of the sheet sample of (a) observed with a scanning electron microscope, and (e) is of (d). It is a schematic diagram.

Hereinafter, the present invention will be described in detail based on embodiments and examples.
[Filament manufacturing process]
The filament according to the present embodiment is manufactured by a general extruder.
Specifically, a 65φ extruder is used. Cylinder temperature is 150-180 degreeC of dice | dies, 160-200 degreeC of measurement parts, 160-200 degreeC of compression parts, and 150-180 degreeC of supply parts.
Further, the limit temperature is 240 ° C., the temperature of the cooling water in the cooling water tank is 8 to 15 ° C., the distance between the die and the sizer is 2 to 5 cm, the withdrawal rate is 0.87 to 0.92, and the sizing method is the driver vacuum.
In the filament according to the present embodiment, after mixing the polylactic acid resin (A) pellets and the thermoplastic elastomer (B) pellets to a total of 100% by weight, the mixture is added to the injection port of the extruder. The mixed pellets are put, and the screw is rotated while being heated, and the resin is sent out while being melted. The resin is extruded from the die at the tip, cooled and solidified in a cooling water tank, and manufactured as a filament having a diameter of 1.75 mm.

[3D printing device]
The three-dimensional printing apparatus according to this embodiment uses a hot melt lamination method (FDM), and includes a data processing unit and a printing unit that performs three-dimensional printing based on a control signal supplied from the data processing unit. It is composed of
The printing unit includes a head unit including a heater unit and a nozzle unit, and the head unit includes a drive gear for supplying a raw material filament to the nozzle unit and a roller. The drive gear is provided with a groove.
In the three-dimensional printing apparatus according to the present embodiment, the raw material filament is fed out while being sandwiched between the drive gear and the roller and conveyed to the head unit, and the filament melted by the heater unit is the nozzle. The printed matter is formed by being discharged from the section.

[raw materials]
A: Polylactic acid resin The polylactic acid resin (A) in the present invention has a purity of 95% or more, contains 5% or less of an additive, and has a melting point of 170 ° C. The polylactic acid resin (A) in the present invention is required to have a D-form content of 1.0 mol% or less or a D-form content of 99.0 mol% or more, 0.1 to 0.6 mol%, or 99.4 to 99.9 mol%.
When the D-form content is within this range, the crystal performance is excellent, so that the moldability is excellent (the molding cycle is shortened), and the obtained molded article has improved heat resistance.

B: Thermoplastic Elastomer The thermoplastic elastomer (B) in the present invention contains a styrene resin (C) and a mineral oil plasticizer (D). Specifically, the weight mixing ratio of (C) component and (D) component is (C) component / (D) component = 25 / 75-30 / 70, and melting | fusing point is 100-170 degreeC.

C: Styrene resin The styrene resin in the present invention has a polystyrene block as a hard segment and a conjugated diene polymer block as a soft segment. To show fluidity. Examples of the styrenic elastomer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene- Ethylene / propylene-styrene block copolymer (SEPS), partially hydrogenated styrene-ethylene / butylene-styrene block copolymer (partially hydrogenated SEBS), styrene / (ethylene-ethylene / propylene) -styrene block copolymer ( SEEPS) and the like. Desirable styrenic elastomers are SEBS and SEEPS. When SEBS or SEEPS is used, transparency is improved and excellent slip resistance is obtained.
The mass average molecular weight of the styrene elastomer in the present invention must be in the range of 100,000 to 200,000. When the mass average molecular weight is less than 100,000, mechanical strength such as tensile strength and tensile elongation at break is deteriorated. When the mass average molecular weight exceeds 200,000, transparency is deteriorated.

D: Mineral oil-based plasticizer In the present invention, a mineral oil-based plasticizer is used as the plasticizer in the thermoplastic elastomer. In the present invention, known mineral oils such as paraffinic oils and naphthenic oils can be used. It is preferable to use mineral oil which is hydrogen oil.

Based on the production method according to the present invention, filaments having different thermoplastic elastomer contents were produced by changing the ratio of the polylactic acid resin (A) and the thermoplastic elastomer (B). In addition, the filament concerning this Embodiment and the manufacturing method of a filament are not limited to a following example, A various change can be added in the range which does not deviate from the summary of this invention.
[Production Example 1] <Preparation of filament (1)>
In the filament (1) according to the present embodiment, the proportion of the thermoplastic elastomer (B) pellets is 1 part by weight (containing the thermoplastic elastomer) with respect to 10 parts by weight of the polylactic acid resin (A) pellets. The filament was produced by extrusion after mixing at a rate of 9.1%.
[Production Example 2] <Production of Filament (2)>
In the filament (2) according to the present embodiment, the ratio of 1 part by weight of the thermoplastic elastomer (B) pellets to 2 parts by weight of the polylactic acid resin (A) pellets (containing the thermoplastic elastomer) The filament was produced by extrusion after mixing at a rate of 33.3%.
[Production Example 3] <Production of Filament (3)>
In the filament (3) according to the present embodiment, the ratio of the pellets of the thermoplastic elastomer (B) to 1 part by weight of the pellets of the polylactic acid resin (A) (containing the thermoplastic elastomer) The filament is produced by extrusion after mixing at a rate of 50%).
[Production Example 4] <Production of Filament (4)>
In the filament (4) according to the present embodiment, a ratio of 2 parts by weight of the pellets of the thermoplastic elastomer (B) to 1 part by weight of the pellets of the polylactic acid resin (A) (containing the thermoplastic elastomer) The filament is produced by extrusion after mixing at a rate of 66.7%).
[Production Example 5] <Production of Filament (5)>
In the filament (5) according to the present embodiment, the proportion of the pellet of the thermoplastic elastomer (B) is 10 parts by weight of the pellet of the polylactic acid resin (A) (containing the thermoplastic elastomer). The filament is produced by extrusion after mixing at a rate of 90.9%).
[Production Examples 6 to 10] <Production of sheet samples (1) to (5)>
In the sheet samples (1) to (5) according to the present embodiment, the proportions of the polylactic acid resin (A) and the thermoplastic elastomer (B) are the filaments (1) to (5), respectively. It is the same and is a sheet sample manufactured by extrusion molding.
[Production Example 11] <Production of sheet sample (6)>
In the sheet sample (6) according to the present embodiment, a ratio of 7 parts by weight of the thermoplastic elastomer (B) pellets to 3 parts by weight of the polylactic acid resin (A) pellets (thermoplastic elastomer). It is a sheet sample manufactured by extrusion molding after mixing at a content rate of 70%.
[Comparative Example 1] <Filament (6)>
The filament (6) according to the present embodiment is a filament produced by extrusion molding only the polylactic acid resin (A) pellets (thermoplastic elastomer content 0%).
[Comparative Example 2] <Filament (7)>
The filament (7) according to the present embodiment is a filament produced by extrusion molding only thermoplastic elastomer (B) pellets (thermoplastic elastomer content 100%).
[Comparative Example 3] <Sheet sample (7)>
The sheet sample (7) according to the present embodiment is a sheet sample produced by extrusion molding only the polylactic acid resin (A) pellets (thermoplastic elastomer content 0%).
[Comparative Example 4] <Sheet sample (8)>
The sheet sample (8) according to the present embodiment is a sheet sample produced by extrusion molding only thermoplastic elastomer (B) pellets (thermoplastic elastomer content 100%).

<Test>
[Test procedure]

A hardness (sheet samples (1) to (5), (7) to (8))
The Shore A hardness was measured according to JIS K 7215 (plastic). Specifically, the test piece had a thickness of 5 mm, and was produced by punching from an extruded sheet. The test temperature is 23 ° C., and the test apparatus is a Shimadzu durometer A manufactured by Shimadzu Corporation.
When the Shore A hardness was 20 or less, the Shore E hardness was measured using a Shimadzu durometer E manufactured by Shimadzu Corporation in accordance with JIS K 6253 (vulcanized rubber and thermoplastic rubber). Other conditions are the same as those for the Shore A hardness measurement.

B Tensile strength and elongation (sheet sample (6))
It measured based on JISK6251: 2010. Specifically, the thickness of the test piece was 2 mm, and punching was performed from the extruded sheet to produce a dumbbell-shaped No. 3 shape (FIG. 3).
The tensile speed is 500 mm / min, the test temperature is 23 ° C., and the tester used is Strograph V10-D manufactured by Toyo Seiki Co., Ltd.

C Microscopic image (sheet sample (6))
It measured with the scanning electron microscope (SEM).

D Melting point (filaments (1) to (7))
A Du Pont thermal differential analyzer model 990 was used and measured at a temperature increase of 20 ° C./min to obtain a melting peak. When the melting temperature was not clearly observed, the melting point was defined as the temperature at which the polymer softened and started to flow (softening point) using a micro melting point measuring device (manufactured by Yanagimoto Seisakusho). Measurement was performed 5 times, and the average value was obtained.

E Printing with a three-dimensional printing device (filaments (1) to (2), (6))
Heater set temperature: 230 ° C
Processing speed (head speed): 20 to 40 mm / s
Stacking height (printing pitch): 0.1 mm
Continuous printing time: A three-dimensional printed material that takes about 30 minutes to 2 hours as a required printing time was printed a plurality of times.

[Test results]
A hardness (sheet samples (1) to (5), (7) to (8))
Table 1 shows the relationship between the content of the thermoplastic elastomer and the Shore A hardness in the sheet samples (1) to (5) and (7) to (8) prepared by the same extrusion molding as the filament according to the present embodiment. It is a table | surface which shows.
FIG. 1 shows the relationship between the content of the thermoplastic elastomer and the Shore A hardness when the polylactic acid resin and the thermoplastic elastomer are mixed to a total of 100% by weight in the filament according to the present embodiment. The data of Table 1 is plotted as a measurement error ± 5.
As shown in Table 1 and FIG. 1, it was found that when the content of the thermoplastic elastomer was increased, the Shore A hardness was decreased.

B Tensile strength and elongation (sheet sample (5))
FIG. 2 (a) is a graph showing the relationship between elongation and tensile strength in a sheet sample extruded under the same conditions as the filament according to the present embodiment, and (b) is a graph in (a). It is the graph which expanded elongation the range of 0%-200%.
FIG. 3 is a plan view of the sheet sample used in the measurements of FIGS. As shown in FIG. 3, a direction parallel to the extrusion direction is defined as a flow direction (MD: Machine direction), and a direction perpendicular to the extrusion direction is defined as a vertical direction (TD: Transverse direction). The elongation and tensile strength were also measured as reference values in the thickness direction of the sheet.
As shown in FIGS. 2 (a) and 2 (b), in the sheet sample according to the present embodiment, it begins to grow for the first time when 1.25 MPa is applied to the flow direction, and when it exceeds 2.22 MPa. It broke.
On the other hand, as shown in FIGS. 2 (a) and 2 (b), in the sheet sample according to the present embodiment, the sheet sample starts to stretch from the point where 0.1 MPa is applied to the vertical direction, and exceeds 1 MPa. It was a result that grew.
As described above, in the sheet sample according to the present embodiment, it is difficult to extend (i.e., not easily deformed) in a direction parallel to the extrusion direction, and to extend (easily deform) in a direction perpendicular to the extruding direction. It was found to have sex.
Note that, as shown in FIG. 2 (a), since the same elongation and tensile strength as in the vertical direction are exhibited in the thickness direction of the sheet, the results of this experiment do not depend on the shape of the sample. I can say that. Actually, filaments manufactured by the same extrusion molding have the same anisotropy.

4A is a perspective view of a sheet sample extruded under the same conditions as the filament according to the present embodiment, and FIG. 4B is a scanning electron microscope (SEM) of the sheet sample of FIG. Observed vertical sectional view (200 times), (c) is a schematic diagram of (b), (d) is a sectional view in the flow direction of the sheet sample of (a) observed with a scanning electron microscope (SEM). (200 times) and (e) are schematic views of (d).
As shown in FIG. 4A, as in FIG. 3, the direction parallel to the extrusion direction is defined as the flow direction (MD: Machine direction), and the direction perpendicular to the extrusion direction is defined as the vertical direction (TD: Transverse direction). To do.
As shown in FIGS. 4B, 4C, 4D, and 4E, in the sheet sample according to the present embodiment, the molecular chain of polylactic acid (PLA) resin is parallel to the extrusion direction. It can be seen that it is oriented.
That is, the results shown in FIGS. 2 (a) and 2 (b) and the results shown in FIGS. 4 (b) and (c), (d) and (e) cause the molecular chains of the polylactic acid resin to be oriented. It has the anisotropy that it is difficult to stretch in the direction parallel to the direction (hard to deform), the molecular chain of the polylactic acid resin is not oriented, and easy to stretch in the direction perpendicular to the extrusion direction (easy to deform). I found out.
Therefore, it is determined that the anisotropy with respect to the deformation of the sheet sample according to the present embodiment is caused by the orientation of the molecular chain of the polylactic acid resin by extrusion molding.
In addition, since the anisotropy to the deformation of the sheet sample according to the present embodiment is due to the molecular chain orientation of the polylactic acid resin, regardless of the type of the thermoplastic elastomer, the polylactic acid resin and the thermoplastic elastomer It is inferred that the same anisotropy is developed if the filament or sheet sample is manufactured by mixing, heating and melting, and extrusion molding.

D Melting point (filaments (1) to (7))
Table 2 shows the results of measuring the melting points of the filaments (1) to (7) according to the present embodiment.
As shown in Table 2, the filaments (1) to (5) and (7) all started to soften at 100 ° C., except that the filament (6) of polylactic acid resin alone was 170 ° C. Melted in
In the filament according to the present embodiment, the rate of softening at 100 ° C. increased as the thermoplastic elastomer content increased, but the filament completely melted at 170 ° C.
As described above, since the melting point of the polylactic acid resin is 170 ° C. and the melting point of the thermoplastic elastomer is 100 to 170 ° C., the filament according to the present embodiment includes the polylactic acid resin and the thermoplastic elastomer. It is judged that they are sufficiently dispersed.

E 3D printing device (filaments (1) to (3), (6))
In the printing test using the filaments (1) to (3) and (6) according to the present embodiment, 100 or more three-dimensional prints that require about 30 minutes to 2 hours as printing time were printed. However, the phenomenon of so-called jamming, in which the filament is bent and cannot be transported in the transport process to the head or in the head, did not occur, and there was no defective filament supply or molding due to this phenomenon.
In the three-dimensional printing apparatus according to the present embodiment, the filaments (1) to (3) and (6) having different thermoplastic elastomer contents are used by setting the heater unit to 230 ° C. Even if it was, it could be used without changing the setting of the heater section.
Moreover, as shown in Table 1, the filaments (2) and (3) according to the present embodiment are soft filaments having Shore A hardness of 85 to 95 and 75 to 85, respectively. Since it was possible to print using a printer, it became possible to produce molded parts such as parts that required flexibility.

  Further, in the dual head type three-dimensional printing apparatus that can use two kinds of materials at the same time, when the filament according to the present embodiment is used as a support material for supporting an object, it is sufficient as a support. It has been found that the support material can be easily peeled from the object while having strength.

[Action / Effect]
As described above, since the filament according to the present embodiment contains polylactic acid with a high hardness and a thermoplastic elastomer with a low hardness, as shown in Table 1 and FIG. The hardness can be continuously changed depending on the ratio to the elastomer.
On the other hand, as shown in Table 2, in the filament according to the present embodiment, since the melting point of polylactic acid is almost the same as the melting point of the thermoplastic elastomer, it depends on the ratio between the polylactic acid and the thermoplastic elastomer. It shows an almost constant melting point.
Accordingly, it is possible to provide a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer while the melting point is substantially constant.
As a result, filaments containing polylactic acid and thermoplastic elastomer that contain a certain percentage of polylactic acid having a high hardness are used as raw material filaments for a general three-dimensional printing apparatus of the hot melt lamination method (FDM). It is possible to provide a filament that satisfies two conditions of a melting point that can be dissolved by a heater and a certain hardness that does not bend during conveyance.

As shown in Table 1 and FIG. 1, in the filament manufacturing method according to the present embodiment, a filament in which a polylactic acid resin having a high hardness and a thermoplastic elastomer having a low hardness are mixed in an arbitrary ratio. Can be formed into a filament having any hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer, depending on the ratio of polylactic acid and thermoplastic elastomer.
On the other hand, as shown in Table 2, in the filament manufacturing method according to the present embodiment, the melting point of polylactic acid is almost the same as the melting point of the thermoplastic elastomer. Regardless of the proportion, it can be formed into a filament having a substantially constant melting point.
As a result, it is possible to provide a method for producing a filament capable of forming a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of a thermoplastic elastomer while the melting point is substantially constant.

Moreover, in the manufacturing method of the filament which concerns on this Embodiment, as shown to FIG. 2 (a) and (b), the shape | molded filament is in an extrusion direction by manufacturing a filament by extrusion molding. It has an anisotropy that it is difficult to deform and is easily deformed in a direction perpendicular to the extrusion direction.
Therefore, when the filament formed by the filament manufacturing method according to the present embodiment is used as a raw material filament of a three-dimensional printing apparatus of the hot melt lamination method (FDM), the conveyance direction to the head is the filament extrusion direction. Therefore, the filament has rigidity in the transport direction to the head.
As a result, it is possible to prevent a phenomenon in which a so-called jamming phenomenon occurs in which the conveyance process to the head or the filament is bent in the head and the conveyance becomes impossible.

In general, when a filament is conveyed in a three-dimensional printing apparatus, the filament is fed and conveyed while being sandwiched between a drive gear having a groove and a roller.
At this time, when the filament formed by the filament manufacturing method according to the present embodiment is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), it is sandwiched between a drive gear and a roller. At this time, the filament is strongly pressed against the groove portion of the drive gear. However, since the direction in which the filament is pressed is perpendicular to the extrusion direction of the filament, the filament is easily deformed as described above.
As a result, the filament is deformed in accordance with the groove portion of the drive gear and meshes with the groove portion of the drive gear, thereby preventing the filament from slipping.

Therefore, in the three-dimensional printing apparatus using the hot melt lamination method (FDM), if the filament according to the present embodiment is used, a three-dimensional object can be printed stably over a long period of time.
As a result, a flexible large three-dimensional model and a high-precision three-dimensional model can be obtained by the filament according to the present embodiment.

Since the filament and the method for producing the filament according to the present invention can be widely used for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM) and the filament. Has industrial applicability.

  The present invention relates to a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM) and a method for producing the filament.

  Conventionally, a three-dimensional printing apparatus has been used to create a three-dimensional model such as a prototype or a jig. The three-dimensional printing apparatus is also referred to as a 3D printer, and the three-dimensional printing apparatus can create a three-dimensional model using raw materials such as resin according to three-dimensional drawing data captured on a computer.

There are various methods for forming a three-dimensional model, and one of them is a hot melt lamination method (FDM). In the hot melt lamination method (FDM), a raw material filament such as a thermoplastic resin is discharged from a nozzle while being heated and melted by a heater provided in a head, and the nozzle is operated in a plane direction, for example, to form a first layer of a three-dimensional model. This is a method for obtaining a three-dimensionally shaped article by forming and then laminating the second layer and the third layer on the upper surface of the first layer.
Hot melt lamination (FDM) three-dimensional printing devices are cheaper and more widespread than three-dimensional printing devices that utilize a laser or powder sintering modeling method.

In such a conventional hot melt lamination (FDM) three-dimensional printing apparatus, for example, a hard resin having a large Shore A hardness, such as ABS resin or polylactic acid (PLA) resin, has a relatively low melting point. A three-dimensional model was printed using a filament made of the above resin.
On the other hand, if printing can be performed using a soft filament having a Shore A hardness smaller than that of a hard filament as a raw material filament, it becomes possible to produce a molded product such as a part that requires flexibility, and the range of use is further expanded. It becomes.

However, when a soft filament is used as a raw material filament of a general three-dimensional printing apparatus of the hot melt lamination method (FDM), the filament itself does not have rigidity, so that the filament is bent in the transport process to the head or in the head. There was a problem that the phenomenon of so-called jamming that would prevent conveyance was caused.
Conventionally, there has also been a hot melt lamination (FDM) three-dimensional printing device that can use soft filaments, but it becomes a dedicated machine for soft filaments and is not versatile and expensive. It was unsuitable for use.

As described above, the raw material filament of a general hot melt lamination method (FDM) three-dimensional printing apparatus has two main conditions: a melting point that can be melted by a heater, and a hardness that does not bend during transportation. It is necessary to satisfy.
However, in the conventional raw material filament, only a raw material consisting of a single component was selected and used. Therefore, filaments that satisfy the above two conditions are limited, and a molded product having an arbitrary hardness can be manufactured. I couldn't.
The applicant of the present patent has conducted a prior art search from such a viewpoint, but has not found a technique that can solve the above-mentioned problems.
JP-T-2006-501137

  The present invention is to solve the above-mentioned conventional problems, and the problem is a raw material filament used in a three-dimensional printing apparatus of a hot melt lamination method (FDM), An object of the present invention is to provide a soft filament that does not bend and a method for producing a filament that can be molded to an arbitrary hardness.

In order to solve the above-mentioned problem, the invention according to claim 1 is a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM), and acid resin, 1 part by weight of a thermoplastic elastomer containing in any ratio of a styrene resin and a mixing ratio by weight of the mineral oil plasticizer is from 25:75 to mixing weight ratio of 30:70: 1 part by weight 10 parts by weight : 1 part by weight

“Polylactic acid (PLA) resin” is a synthetic resin produced by polymerizing lactic acid through an ester bond. The melting point is 170 ° C. and the Shore A hardness is 100 or more.
Here, the Shore A hardness is a hardness measured using a type A durometer in a method defined in JIS K 7215 (plastic) or JIS K 6253 (vulcanized rubber and thermoplastic rubber). There are various definitions of hard and soft in resins and rubbers. Here, those having a Shore A hardness of 95 or higher are called hard, and those having a Shore A hardness of 95 or lower are called soft.
The “styrene resin” is a concept including a styrene elastomer.
Styrenic elastomer is a thermoplastic elastomer obtained by block copolymerization of polystyrene and polyethylene-polybutylene. The polystyrene domain serves as a physical crosslinking point and plays a role corresponding to the crosslinking point of crosslinked rubber. Indicates. On the other hand, when the temperature reaches 140 to 230 ° C., the polystyrene part and the polyethylene / polybutylene part are both melted and exhibit flow characteristics as a thermoplastic resin.
“Plasticizer” is a general term for chemicals added to improve flexibility and weather resistance in addition to thermoplastic synthetic resins.
“Mineral oil” is also called mineral oil and is a general term for mixtures containing hydrocarbon compounds or impurities derived from underground resources such as petroleum (crude oil), natural gas, and coal. In general, mineral oils are classified as either paraffinic oils, naphthenic oils or higher fatty acids.

The invention according to claim 2 is a method for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM), comprising a polylactic acid resin and styrene 1 part by weight : 1 part by weight to 10 parts by weight : 1 part by weight of a thermoplastic elastomer containing a base resin and a mineral oil plasticizer in an arbitrary ratio of a weight mixing ratio of 25:75 to a weight mixing ratio of 30:70 It mixes so that it may become a total of 100 weight% in arbitrary ratios to a weight part , it melt | dissolves by heating, A filament is manufactured by extrusion molding, It is characterized by the above-mentioned.
Accordingly, a polylactic acid resin, a thermoplastic elastomer is 1 part by weight, containing in any ratio of a styrene resin and a mixing ratio by weight of the mineral oil plasticizer is from 25:75 to mixing weight ratio of 30:70: 1 Filaments mixed at an arbitrary ratio from parts by weight to 10 parts by weight : 1 part by weight are produced by extrusion.

In the filament according to claim 1, since it contains polylactic acid having a high hardness and a thermoplastic elastomer having a low hardness, the hardness can be continuously changed depending on the ratio of the polylactic acid and the thermoplastic elastomer. it can.
On the other hand, in the filament according to claim 1, since the melting point of polylactic acid is substantially the same as the melting point of the thermoplastic elastomer, it has a substantially constant melting point regardless of the ratio of the polylactic acid and the thermoplastic elastomer. Show.
Accordingly, it is possible to provide a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer while the melting point is substantially constant.
As a result, filaments containing polylactic acid and thermoplastic elastomer that contain a certain percentage of polylactic acid having a high hardness are used as raw material filaments for a general three-dimensional printing apparatus of the hot melt lamination method (FDM). It is possible to provide a filament that satisfies two conditions of a melting point that can be dissolved by a heater and a certain hardness that does not bend during conveyance.

Further, in the method for producing a filament according to claim 2, greater polylactic acid resin and the small thermoplastic elastomer hardness is 1 part by weight of hardness: 1 10 parts by weight parts: 1 Any up parts Since the filament mixed at the ratio of is produced by extrusion molding, it is formed into a filament having an arbitrary hardness between the hardness of the polylactic acid and the hardness of the thermoplastic elastomer depending on the ratio of the polylactic acid and the thermoplastic elastomer be able to.
On the other hand, in the method for producing a filament according to claim 2, since the melting point of polylactic acid is substantially the same as the melting point of the thermoplastic elastomer, it is substantially constant regardless of the ratio of the polylactic acid and the thermoplastic elastomer. Can be formed into a filament having a melting point of.
As a result, it is possible to provide a method for producing a filament capable of forming a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of a thermoplastic elastomer while the melting point is substantially constant.

In the method for producing a filament according to claim 2, by producing the filament by extrusion molding, the formed filament is hardly deformed in the extrusion direction and deformed in a direction perpendicular to the extrusion direction. Anisotropy is easy.
Therefore, when the filament formed by the method for producing a filament according to claim 2 is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), the conveyance direction to the head is the extrusion direction of the filament. Therefore, the filament has rigidity in the transport direction to the head.
As a result, it is possible to prevent a phenomenon in which a so-called jamming phenomenon occurs in which the conveyance process to the head or the filament is bent in the head and the conveyance becomes impossible.

In general, when a filament is conveyed in a three-dimensional printing apparatus, the filament is fed and conveyed while being sandwiched between a drive gear having a groove and a roller.
At this time, when the filament formed by the filament manufacturing method according to claim 2 is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), it is sandwiched between a drive gear and a roller. At this time, the filament is strongly pressed against the groove portion of the drive gear. However, since the direction in which the filament is pressed is perpendicular to the extrusion direction of the filament, the filament is easily deformed as described above.
As a result, the filament is deformed in accordance with the groove portion of the drive gear and meshes with the groove portion of the drive gear, thereby preventing the filament from slipping.
Accordingly, the filament can be reliably conveyed by the drive gear, and the three-dimensional structure can be printed stably over a long period of time.

FIG. 1 shows the relationship between the content of a thermoplastic elastomer and the Shore A hardness when a polylactic acid resin and a thermoplastic elastomer are mixed to a total of 100% by weight in the filament according to the present embodiment. It is a graph. FIG. 2 (a) is a graph showing the relationship between elongation and tensile strength in a sheet sample extruded under the same conditions as the filament according to the present embodiment, and (b) is a graph in (a). It is the graph which expanded elongation the range of 0%-200%. FIG. 3 is a plan view of the sheet sample used in the measurements of FIGS. 2 (a) and 2 (b). 4A is a perspective view of a sheet sample extruded under the same conditions as the filament according to the present embodiment, and FIG. 4B is a vertical view of the sheet sample of FIG. 4A observed with a scanning electron microscope. (C) is a schematic diagram of (b), (d) is a flow direction sectional view of the sheet sample of (a) observed with a scanning electron microscope, and (e) is of (d). It is a schematic diagram.

Hereinafter, the present invention will be described in detail based on embodiments and examples.
[Filament manufacturing process]
The filament according to the present embodiment is manufactured by a general extruder.
Specifically, a 65φ extruder is used. Cylinder temperature is 150-180 degreeC of dice | dies, 160-200 degreeC of measurement parts, 160-200 degreeC of compression parts, and 150-180 degreeC of supply parts.
Further, the limit temperature is 240 ° C., the temperature of the cooling water in the cooling water tank is 8 to 15 ° C., the distance between the die and the sizer is 2 to 5 cm, the withdrawal rate is 0.87 to 0.92, and the sizing method is the driver vacuum.
In the filament according to the present embodiment, after mixing the polylactic acid resin (A) pellets and the thermoplastic elastomer (B) pellets to a total of 100% by weight, the mixture is added to the injection port of the extruder. The mixed pellets are put, and the screw is rotated while being heated, and the resin is sent out while being melted. The resin is extruded from the die at the tip, cooled and solidified in a cooling water tank, and manufactured as a filament having a diameter of 1.75 mm.

[3D printing device]
The three-dimensional printing apparatus according to this embodiment uses a hot melt lamination method (FDM), and includes a data processing unit and a printing unit that performs three-dimensional printing based on a control signal supplied from the data processing unit. It is composed of
The printing unit includes a head unit including a heater unit and a nozzle unit, and the head unit includes a drive gear for supplying a raw material filament to the nozzle unit and a roller. The drive gear is provided with a groove.
In the three-dimensional printing apparatus according to the present embodiment, the raw material filament is fed out while being sandwiched between the drive gear and the roller and conveyed to the head unit, and the filament melted by the heater unit is the nozzle. The printed matter is formed by being discharged from the section.

[raw materials]
A: Polylactic acid resin The polylactic acid resin (A) in the present invention has a purity of 95% or more, contains 5% or less of an additive, and has a melting point of 170 ° C. The polylactic acid resin (A) in the present invention is required to have a D-form content of 1.0 mol% or less or a D-form content of 99.0 mol% or more, 0.1 to 0.6 mol%, or 99.4 to 99.9 mol%.
When the D-form content is within this range, the crystal performance is excellent, so that the moldability is excellent (the molding cycle is shortened), and the obtained molded article has improved heat resistance.

B: Thermoplastic Elastomer The thermoplastic elastomer (B) in the present invention contains a styrene resin (C) and a mineral oil plasticizer (D). Specifically, the weight mixing ratio of (C) component and (D) component is (C) component / (D) component = 25 / 75-30 / 70, and melting | fusing point is 100-170 degreeC.

C: Styrene resin The styrene resin in the present invention has a polystyrene block as a hard segment and a conjugated diene polymer block as a soft segment. To show fluidity. Examples of the styrenic elastomer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene- Ethylene / propylene-styrene block copolymer (SEPS), partially hydrogenated styrene-ethylene / butylene-styrene block copolymer (partially hydrogenated SEBS), styrene / (ethylene-ethylene / propylene) -styrene block copolymer ( SEEPS) and the like. Desirable styrenic elastomers are SEBS and SEEPS. When SEBS or SEEPS is used, transparency is improved and excellent slip resistance is obtained.
The mass average molecular weight of the styrene elastomer in the present invention must be in the range of 100,000 to 200,000. When the mass average molecular weight is less than 100,000, mechanical strength such as tensile strength and tensile elongation at break is deteriorated. When the mass average molecular weight exceeds 200,000, transparency is deteriorated.

D: Mineral oil-based plasticizer In the present invention, a mineral oil-based plasticizer is used as the plasticizer in the thermoplastic elastomer. In the present invention, known mineral oils such as paraffinic oils and naphthenic oils can be used. It is preferable to use mineral oil which is hydrogen oil.

Based on the production method according to the present invention, filaments having different thermoplastic elastomer contents were produced by changing the ratio of the polylactic acid resin (A) and the thermoplastic elastomer (B). In addition, the filament concerning this Embodiment and the manufacturing method of a filament are not limited to a following example, A various change can be added in the range which does not deviate from the summary of this invention.
[Production Example 1] <Preparation of filament (1)>
In the filament (1) according to the present embodiment, the proportion of the thermoplastic elastomer (B) pellets is 1 part by weight (containing the thermoplastic elastomer) with respect to 10 parts by weight of the polylactic acid resin (A) pellets. The filament was produced by extrusion after mixing at a rate of 9.1%.
[Production Example 2] <Production of Filament (2)>
In the filament (2) according to the present embodiment, the ratio of 1 part by weight of the thermoplastic elastomer (B) pellets to 2 parts by weight of the polylactic acid resin (A) pellets (containing the thermoplastic elastomer) The filament was produced by extrusion after mixing at a rate of 33.3%.
[Production Example 3] <Production of Filament (3)>
In the filament (3) according to the present embodiment, the ratio of the pellets of the thermoplastic elastomer (B) to 1 part by weight of the pellets of the polylactic acid resin (A) (containing the thermoplastic elastomer) The filament is produced by extrusion after mixing at a rate of 50%).
[Production Example 4] <Production of Filament (4)>
In the filament (4) according to the present embodiment, a ratio of 2 parts by weight of the pellets of the thermoplastic elastomer (B) to 1 part by weight of the pellets of the polylactic acid resin (A) (containing the thermoplastic elastomer) The filament is produced by extrusion after mixing at a rate of 66.7%).
[Production Example 5] <Production of Filament (5)>
In the filament (5) according to the present embodiment, the proportion of the pellet of the thermoplastic elastomer (B) is 10 parts by weight of the pellet of the polylactic acid resin (A) (containing the thermoplastic elastomer). The filament is produced by extrusion after mixing at a rate of 90.9%).
[Production Examples 6 to 10] <Production of sheet samples (1) to (5)>
In the sheet samples (1) to (5) according to the present embodiment, the proportions of the polylactic acid resin (A) and the thermoplastic elastomer (B) are the filaments (1) to (5), respectively. It is the same and is a sheet sample manufactured by extrusion molding.
[Production Example 11] <Production of sheet sample (6)>
In the sheet sample (6) according to the present embodiment, a ratio of 7 parts by weight of the thermoplastic elastomer (B) pellets to 3 parts by weight of the polylactic acid resin (A) pellets (thermoplastic elastomer). It is a sheet sample manufactured by extrusion molding after mixing at a content rate of 70%.
[Comparative Example 1] <Filament (6)>
The filament (6) according to the present embodiment is a filament produced by extrusion molding only the polylactic acid resin (A) pellets (thermoplastic elastomer content 0%).
[Comparative Example 2] <Filament (7)>
The filament (7) according to the present embodiment is a filament produced by extrusion molding only thermoplastic elastomer (B) pellets (thermoplastic elastomer content 100%).
[Comparative Example 3] <Sheet sample (7)>
The sheet sample (7) according to the present embodiment is a sheet sample produced by extrusion molding only the polylactic acid resin (A) pellets (thermoplastic elastomer content 0%).
[Comparative Example 4] <Sheet sample (8)>
The sheet sample (8) according to the present embodiment is a sheet sample produced by extrusion molding only thermoplastic elastomer (B) pellets (thermoplastic elastomer content 100%).

<Test>
[Test procedure]

A hardness (sheet samples (1) to (5), (7) to (8))
The Shore A hardness was measured according to JIS K 7215 (plastic). Specifically, the test piece had a thickness of 5 mm, and was produced by punching from an extruded sheet. The test temperature is 23 ° C., and the test apparatus is a Shimadzu durometer A manufactured by Shimadzu Corporation.
When the Shore A hardness was 20 or less, the Shore E hardness was measured using a Shimadzu durometer E manufactured by Shimadzu Corporation in accordance with JIS K 6253 (vulcanized rubber and thermoplastic rubber). Other conditions are the same as those for the Shore A hardness measurement.

B Tensile strength and elongation (sheet sample (6))
It measured based on JISK6251: 2010. Specifically, the thickness of the test piece was 2 mm, and punching was performed from the extruded sheet to produce a dumbbell-shaped No. 3 shape (FIG. 3).
The tensile speed is 500 mm / min, the test temperature is 23 ° C., and the tester used is Strograph V10-D manufactured by Toyo Seiki Co., Ltd.

C Microscopic image (sheet sample (6))
It measured with the scanning electron microscope (SEM).

D Melting point (filaments (1) to (7))
A Du Pont thermal differential analyzer model 990 was used and measured at a temperature increase of 20 ° C./min to obtain a melting peak. When the melting temperature was not clearly observed, the melting point was defined as the temperature at which the polymer softened and started to flow (softening point) using a micro melting point measuring device (manufactured by Yanagimoto Seisakusho). Measurement was performed 5 times, and the average value was obtained.

E Printing with a three-dimensional printing device (filaments (1) to (2), (6))
Heater set temperature: 230 ° C
Processing speed (head speed): 20 to 40 mm / s
Stacking height (printing pitch): 0.1 mm
Continuous printing time: A three-dimensional printed material that takes about 30 minutes to 2 hours as a required printing time was printed a plurality of times.

[Test results]
A hardness (sheet samples (1) to (5), (7) to (8))
Table 1 shows the relationship between the content of the thermoplastic elastomer and the Shore A hardness in the sheet samples (1) to (5) and (7) to (8) prepared by the same extrusion molding as the filament according to the present embodiment. It is a table | surface which shows.
FIG. 1 shows the relationship between the content of the thermoplastic elastomer and the Shore A hardness when the polylactic acid resin and the thermoplastic elastomer are mixed to a total of 100% by weight in the filament according to the present embodiment. The data of Table 1 is plotted as a measurement error ± 5.
As shown in Table 1 and FIG. 1, it was found that when the content of the thermoplastic elastomer was increased, the Shore A hardness was decreased.

B Tensile strength and elongation (sheet sample (5))
FIG. 2 (a) is a graph showing the relationship between elongation and tensile strength in a sheet sample extruded under the same conditions as the filament according to the present embodiment, and (b) is a graph in (a). It is the graph which expanded elongation the range of 0%-200%.
FIG. 3 is a plan view of the sheet sample used in the measurements of FIGS. As shown in FIG. 3, a direction parallel to the extrusion direction is defined as a flow direction (MD: Machine direction), and a direction perpendicular to the extrusion direction is defined as a vertical direction (TD: Transverse direction). The elongation and tensile strength were also measured as reference values in the thickness direction of the sheet.
As shown in FIGS. 2 (a) and 2 (b), in the sheet sample according to the present embodiment, it begins to grow for the first time when 1.25 MPa is applied to the flow direction, and when it exceeds 2.22 MPa. It broke.
On the other hand, as shown in FIGS. 2 (a) and 2 (b), in the sheet sample according to the present embodiment, the sheet sample starts to stretch from the point where 0.1 MPa is applied to the vertical direction, and exceeds 1 MPa. It was a result that grew.
As described above, in the sheet sample according to the present embodiment, it is difficult to extend (i.e., not easily deformed) in a direction parallel to the extrusion direction, and to extend (easily deform) in a direction perpendicular to the extruding direction. It was found to have sex.
Note that, as shown in FIG. 2 (a), since the same elongation and tensile strength as in the vertical direction are exhibited in the thickness direction of the sheet, the results of this experiment do not depend on the shape of the sample. I can say that. Actually, filaments manufactured by the same extrusion molding have the same anisotropy.

4A is a perspective view of a sheet sample extruded under the same conditions as the filament according to the present embodiment, and FIG. 4B is a scanning electron microscope (SEM) of the sheet sample of FIG. Observed vertical sectional view (200 times), (c) is a schematic diagram of (b), (d) is a sectional view in the flow direction of the sheet sample of (a) observed with a scanning electron microscope (SEM). (200 times) and (e) are schematic views of (d).
As shown in FIG. 4A, as in FIG. 3, the direction parallel to the extrusion direction is defined as the flow direction (MD: Machine direction), and the direction perpendicular to the extrusion direction is defined as the vertical direction (TD: Transverse direction). To do.
As shown in FIGS. 4B, 4C, 4D, and 4E, in the sheet sample according to the present embodiment, the molecular chain of polylactic acid (PLA) resin is parallel to the extrusion direction. It can be seen that it is oriented.
That is, the results shown in FIGS. 2 (a) and 2 (b) and the results shown in FIGS. 4 (b) and (c), (d) and (e) cause the molecular chains of the polylactic acid resin to be oriented. It has the anisotropy that it is difficult to stretch in the direction parallel to the direction (hard to deform), the molecular chain of the polylactic acid resin is not oriented, and easy to stretch in the direction perpendicular to the extrusion direction (easy to deform). I found out.
Therefore, it is determined that the anisotropy with respect to the deformation of the sheet sample according to the present embodiment is caused by the orientation of the molecular chain of the polylactic acid resin by extrusion molding.
In addition, since the anisotropy to the deformation of the sheet sample according to the present embodiment is due to the molecular chain orientation of the polylactic acid resin, regardless of the type of the thermoplastic elastomer, the polylactic acid resin and the thermoplastic elastomer It is inferred that the same anisotropy is developed if the filament or sheet sample is manufactured by mixing, heating and melting, and extrusion molding.

D Melting point (filaments (1) to (7))
Table 2 shows the results of measuring the melting points of the filaments (1) to (7) according to the present embodiment.
As shown in Table 2, the filaments (1) to (5) and (7) all started to soften at 100 ° C., except that the filament (6) of polylactic acid resin alone was 170 ° C. Melted in
In the filament according to the present embodiment, the rate of softening at 100 ° C. increased as the thermoplastic elastomer content increased, but the filament completely melted at 170 ° C.
As described above, since the melting point of the polylactic acid resin is 170 ° C. and the melting point of the thermoplastic elastomer is 100 to 170 ° C., the filament according to the present embodiment includes the polylactic acid resin and the thermoplastic elastomer. It is judged that they are sufficiently dispersed.

E 3D printing device (filaments (1) to (3), (6))
In the printing test using the filaments (1) to (3) and (6) according to the present embodiment, 100 or more three-dimensional prints that require about 30 minutes to 2 hours as printing time were printed. However, the phenomenon of so-called jamming, in which the filament is bent and cannot be transported in the transport process to the head or in the head, did not occur, and there was no defective filament supply or molding due to this phenomenon.
In the three-dimensional printing apparatus according to the present embodiment, the filaments (1) to (3) and (6) having different thermoplastic elastomer contents are used by setting the heater unit to 230 ° C. Even if it was, it could be used without changing the setting of the heater section.
Moreover, as shown in Table 1, the filaments (2) and (3) according to the present embodiment are soft filaments having Shore A hardness of 85 to 95 and 75 to 85, respectively. Since it was possible to print using a printer, it became possible to produce molded parts such as parts that required flexibility.

  Further, in the dual head type three-dimensional printing apparatus that can use two kinds of materials at the same time, when the filament according to the present embodiment is used as a support material for supporting an object, it is sufficient as a support. It has been found that the support material can be easily peeled from the object while having strength.

[Action / Effect]
As described above, since the filament according to the present embodiment contains polylactic acid with a high hardness and a thermoplastic elastomer with a low hardness, as shown in Table 1 and FIG. The hardness can be continuously changed depending on the ratio to the elastomer.
On the other hand, as shown in Table 2, in the filament according to the present embodiment, since the melting point of polylactic acid is almost the same as the melting point of the thermoplastic elastomer, it depends on the ratio between the polylactic acid and the thermoplastic elastomer. It shows an almost constant melting point.
Accordingly, it is possible to provide a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer while the melting point is substantially constant.
As a result, filaments containing polylactic acid and thermoplastic elastomer that contain a certain percentage of polylactic acid having a high hardness are used as raw material filaments for a general three-dimensional printing apparatus of the hot melt lamination method (FDM). It is possible to provide a filament that satisfies two conditions of a melting point that can be dissolved by a heater and a certain hardness that does not bend during conveyance.

As shown in Table 1 and FIG. 1, in the filament manufacturing method according to the present embodiment, a filament in which a polylactic acid resin having a high hardness and a thermoplastic elastomer having a low hardness are mixed in an arbitrary ratio. Can be formed into a filament having any hardness between the hardness of polylactic acid and the hardness of the thermoplastic elastomer, depending on the ratio of polylactic acid and thermoplastic elastomer.
On the other hand, as shown in Table 2, in the filament manufacturing method according to the present embodiment, the melting point of polylactic acid is almost the same as the melting point of the thermoplastic elastomer. Regardless of the proportion, it can be formed into a filament having a substantially constant melting point.
As a result, it is possible to provide a method for producing a filament capable of forming a filament having an arbitrary hardness between the hardness of polylactic acid and the hardness of a thermoplastic elastomer while the melting point is substantially constant.

Moreover, in the manufacturing method of the filament which concerns on this Embodiment, as shown to FIG. 2 (a) and (b), the shape | molded filament is in an extrusion direction by manufacturing a filament by extrusion molding. It has an anisotropy that it is difficult to deform and is easily deformed in a direction perpendicular to the extrusion direction.
Therefore, when the filament formed by the filament manufacturing method according to the present embodiment is used as a raw material filament of a three-dimensional printing apparatus of the hot melt lamination method (FDM), the conveyance direction to the head is the filament extrusion direction. Therefore, the filament has rigidity in the transport direction to the head.
As a result, it is possible to prevent a phenomenon in which a so-called jamming phenomenon occurs in which the conveyance process to the head or the filament is bent in the head and the conveyance becomes impossible.

In general, when a filament is conveyed in a three-dimensional printing apparatus, the filament is fed and conveyed while being sandwiched between a drive gear having a groove and a roller.
At this time, when the filament formed by the filament manufacturing method according to the present embodiment is used as a raw material filament of a three-dimensional printing apparatus of a hot melt lamination method (FDM), it is sandwiched between a drive gear and a roller. At this time, the filament is strongly pressed against the groove portion of the drive gear. However, since the direction in which the filament is pressed is perpendicular to the extrusion direction of the filament, the filament is easily deformed as described above.
As a result, the filament is deformed in accordance with the groove portion of the drive gear and meshes with the groove portion of the drive gear, thereby preventing the filament from slipping.

Therefore, in the three-dimensional printing apparatus using the hot melt lamination method (FDM), if the filament according to the present embodiment is used, a three-dimensional object can be printed stably over a long period of time.
As a result, a flexible large three-dimensional model and a high-precision three-dimensional model can be obtained by the filament according to the present embodiment.

Since the filament and the method for producing the filament according to the present invention can be widely used for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM) and the filament. Has industrial applicability.

Claims (6)

A filament used as a raw material for printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM),
A filament comprising a polylactic acid resin and a thermoplastic elastomer.   The filament according to claim 1, wherein the thermoplastic elastomer contains a styrene resin and a mineral oil plasticizer.   The filament according to claim 1, wherein the thermoplastic elastomer contains an olefin resin and a mineral oil plasticizer. A method for producing a filament used as a raw material of a printed matter printed by a three-dimensional printing apparatus using a hot melt lamination method (FDM),
A method for producing a filament, characterized in that a polylactic acid resin and a thermoplastic elastomer are mixed so that the total amount becomes 100% by weight, melted by heating, and produced by extrusion.   The method for producing a filament according to claim 4, wherein the thermoplastic elastomer contains a styrene resin and a mineral oil plasticizer. The method for producing a filament according to claim 4, wherein the thermoplastic elastomer contains an olefin resin and a mineral oil plasticizer.