KR101764237B1 - Crystallized polylactic acid filament, production method thereof, and method and fdm 3d printer for producing 3d output using the same - Google Patents

Abstract

A method of producing an output product using an FDM 3D printer according to the present invention includes: a filament manufacturing step of manufacturing a filament using a polylactic acid resin composition; A crystallization step of crystallizing the filament at 70 to 100 ° C to produce a crystallized filament; And an output step of outputting the three-dimensional output in an FDM 3D printer having an internal temperature of 70 to 110 DEG C by using the crystallized filament manufactured as described above.

Description

TECHNICAL FIELD [0001] The present invention relates to a crystallized polylactic acid filament, a method for producing the same, a method for producing an output product using the same, and an FDM 3D printer,

The present invention relates to a crystallized polylactic acid filament, a method for producing the same, a method for producing an output using the filament, and an FDM 3D printer.

Generally, in order to produce a three-dimensional model having a three-dimensional shape, there is a method of making a cooperative work by a manual operation depending on the drawing, and a manufacturing method by CNC milling. However, since the method of making the woodwork is by hand, elaborate numerical control is difficult and time-consuming, and the CNC milling method is capable of precise numerical control, but many shapes are difficult to process due to tool interference. Therefore, recently, a so-called three-dimensional printing method of producing prototypes of a three-dimensional shape using a computer storing data generated by three-dimensional modeling produced by product designers and designers has emerged.

3D printing refers to a method of manufacturing a three-dimensional solid object by a layer-by-layer method using design data of three-dimensional CAD and materials (polymer, metal, etc.) of various forms (liquid, powder, etc.). 3D printing is spreading to various fields and is being used by many manufacturers for making various models in the field of automobiles, medical manikin, toothbrush and razor.

In the 3D printing, a FDM (Fused Deposition Modeling) method in which a filament type thermoplastic material is melted and discharged in a nozzle, a low power and high density UV laser is projected in a water tank containing a melted photocurable resin, SLA (Stereo Lithography Apparatus) system, SLS (Selective Laser Sintering) method in which a powder applied on a bed is selectively irradiated with a laser to sinter and then powder is repeatedly laminated, an adhesive is applied by a laser beam A laminated object manufacturing (LOM) method in which the formed paper is cut to a desired cross section and laminated one upon another, and a ballistic particle manufacturing (BPM) method using an ink jet printer technology. Among them, the FDM method has the shortest output time, low manufacturing cost, and simple operation compared with other systems, making it the most popular for home and industrial use.

The filament, which is the raw material of the 3D printer of the FDM type, is formed by processing a thermoplastic resin into a thin thread form. The filament is wound around a spool. The filament wound on the spool is moved to a nozzle through a feeder The filaments injected into the nozzles are melted by the heat generated from the nozzles and injected out of the nozzle to accumulate in the bed for loading the output. The melted filaments form an image by the movement of the carrier and the bed, do.

Examples of filament materials include polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS), polyamide (PA), and thermoplastic urethane (TPU: Thermoplastic Urethane). The output of the 3D printer includes all advantages and disadvantages of each filament material. Accordingly, various improved filaments have been developed to overcome the disadvantages of each material.

At this time, acrylonitrile butadiene styrene is a non-decomposable resin derived from petroleum, easy to produce filament, excellent in physical properties of output and relatively easy to process, and has a large deformation of output. In producing filaments, harmful gas and fine dust are generated, Lt; / RTI >

Polylactic acid filaments are biodegradable resins derived from plants and have excellent interlaminar bond strength, low heat shrinkage at the time of output, and no harmful substances when filaments are produced. However, when heat resistance and impact strength are lower than acrylonitrile butadiene styrene, It breaks.

At present, the proportion of printing using polylactic acid filaments is increasing due to environmental friendliness and ease of output. However, due to the disadvantages inherent in polylactic acid itself, the application area is limited.

Accordingly, various FDM 3D printers and filaments having improved functionality have been developed to compensate for the disadvantages of such polylactic acid filaments and improve the output performance.

Korean Patent No. 10-1451794 discloses a 3D printer capable of mixing and spinning various kinds of materials, and it is possible to melt extrusion and lamination by mixing a heterogeneous polymer and a color. However, compatibility problems of a heteropolymer and compatibility of a melt- There may be a problem of dispersibility of polymer material and color, and there is a limit of material mixing.

Korean Patent No. 10-1346704 discloses a nozzle body having a plurality of filament conveying portions for forming multicolor products and having a plurality of introduction holes into which the plurality of filaments are individually introduced, Discloses a technique for a 3D printer including a nozzle head having a single discharge hole formed therein and a controller for individually controlling the transferring operation of the plurality of filament transferring portions. In such a 3D printer, the color of the final output can be selectively output, but the improvement of the physical properties of the output can not be expected.

Korean Patent Registration No. 10-1350993 discloses a technique of adding melamine microcapsules made of a melamine resin to polylactic acid to improve heat resistance and flame retardancy of polylactic acid (PLA). However, the heat resistance and flame retardancy are improved, while the dimensional stability is weakened due to shrinkage due to the addition of melamine resin, which makes it difficult to manufacture precision parts.

The filament according to the above various techniques can improve the functionality by mixing or copolymerizing heterogeneous polymers, but the disadvantages of the filament can not be avoided. Therefore, new filament development is required.

Korean Registered Patent No. 10-1451794 (Three Di Korea Co., Ltd., Oct. 10, 2014) Korean Patent No. 10-1346704 (Ecole Biotech Co., Ltd., Dec. 24, 2013) Korean Patent No. 10-1350993 (Ecole Biotech Co., Ltd., 2014.01.07)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for producing a three-dimensional printed product by using the crystallized polylactic acid filament with improved heat resistance, And to improve fast crystallization, physical properties, post-processability and output properties.

In order to achieve the above object, the present invention provides a filament comprising a crystalline polylactic acid resin.

The present invention also provides a method for producing a filament, comprising: preparing a filament using a polylactic acid resin composition; And crystallizing the filament at 70 to 100 ° C to produce a crystallized filament.

The present invention also provides a method for producing a filament, comprising the steps of: preparing a filament using a polylactic acid resin composition; A crystallization step of crystallizing the filament at 70 to 100 ° C to produce a crystallized filament; And an output step of outputting a three-dimensional output in an FDM 3D printer having an internal temperature of 70 to 110 DEG C by using the crystallized filament manufactured as described above.

The present invention also provides a printer comprising: a bottom supporting an FDM 3D printer internal device; A wall portion extending from each corner of the bottom portion; A printer body including a ceiling portion parallel to the bottom portion and connected to the wall surface portion; A heat insulating material formed on inner surfaces of the ceiling part, the wall part and the bottom part, respectively; And a heat generating element formed on the inner surface of the heat insulating material and including an inner receiving space.

The FDM 3D printer according to the present invention has a temperature setting function and a constant temperature function. By producing the three-dimensional output using the crystallized filament, crystallization occurs simultaneously with the output, thereby making it possible to produce an output having excellent heat resistance by improving the molecular structure . In addition, it simplifies the crystallization step, eliminates the need for additional crystallization after printing, and ensures dimensional stability over the output of conventional FDM 3D printers.

In addition, durability, stability, flexibility, rigidity and physical properties can be ensured and output speed productivity can be improved.

1 is a perspective view of a 3D printer body.
2 is a sectional view of the 3D printer body.

Crystallized filament

The crystallized filament according to the present invention may be a polylactic acid composition. The filament composition according to the present invention may contain polylactic acid itself or a nucleating agent, and may further contain additives.

The polylactic acid according to the present invention is classified into a crystalline polylactic acid (c-PLA) and an amorphous polylactic acid (a-PLA), and a crystalline polylactic acid and an amorphous polylactic acid may be appropriately mixed. In case of mixed use, the polylactic acid composition may comprise more than 0% by weight to 30% by weight of amorphous polylactic acid. In addition, the polylactic acid composition may contain at least 70% by weight of crystalline polylactic acid. When a mixture of amorphous polylactic acid and crystalline polylactic acid is used, weak heat resistance, processability, and mechanical properties of the amorphous polylactic acid can be compensated. In the case of crystalline polylactic acid, the bleeding phenomenon of the plasticizer flowing into the sheet surface can be prevented have. When polylactic acid alone is used as the filament composition, it is preferable to use crystalline polylactic acid rather than amorphous polylactic acid. In the case of crystalline polylactic acid, a sufficient processing efficiency can be increased alone without addition of a nucleating agent.

The polylactic acid may be obtained by polymerizing L-lactic acid, D-lactic acid, racemic mixture thereof, or the like. The molecular weight of the polylactic acid may be 10,000 to 1,000,000.

The nucleating agent according to the present invention is used for improving the crystallization rate or promoting crystallization during the molding of the polylactic acid composition, and has a melting or softening point of 80 to 300 ° C and a melting entropy of 10 to 100 cal / K / mol .

The nucleating agent may include at least one member selected from the group consisting of inorganic particles, sorbitol derivatives, amide compounds and phosphorus compound metal salts.

Examples of the inorganic particle nucleus agent include clay such as calcium silicate filler (wollastonite), mica, talc (granular talc using powdered talc or rosin as a binder), kaolin, potassium titanate whisker, boron nitride and layered silicate, And carbon fibers. The inorganic particles preferably have a particle diameter of 0.01 to 5 탆, more preferably 1.5 to 3.0 탆, and more preferably have a particle diameter of 1.5 to 2.0 탆 in order to facilitate dispersion in the composition. .

Examples of the sorbitol derivative nucleus agent include bis (p-methylbenzylidene) sorbitol, bis (p-ethylbenzylidene) sorbitol, bis (n-propylbenzylidene) sorbitol, bis (p-isopropylbenzylidene) sorbitol, bis Bis (2,4-dimethylbenzylidene) sorbitol, bis (2,4,5-trimethylbenzylidene) sorbitol, bis (2,4-dimethylbenzylidene) sorbitol, bis 4,6-trimethylbenzylidene) sorbitol and bis (4-biphenylbenzylidene) sorbitol, and the like. It is preferable that the sorbitol derivative particles have a particle diameter of 0.01 to 5 탆 in order to facilitate dispersion in the composition.

As the phosphorus compound metal salt nucleus, a phenylphosphoric acid metal salt may be used. The metal salt may be a lithium salt, a sodium salt, a potassium salt, a magnesium salt, a calcium salt, a barium salt, an iron salt, a cobalt salt, . More specifically, the present invention relates to a lithium salt of phenylphosphonic acid, a sodium salt of phenylphosphonic acid, a salt of potassium phenylphosphonate, a salt of magnesiumphosphoric acid, a salt of calciumphosphonate, a salt of bismethoxyphosphonic acid, a salt of ironphosphonate, , A copper salt of phenylphosphoric acid, a manganese salt of phenylphosphonic acid and a zinc salt of phenylphosphonic acid, and the like. The phosphorus compound metal salt is preferably 0.01 to 5 mu m in particle diameter to facilitate dispersion in the composition.

The nucleating agent preferably comprises 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polylactic acid composition.

When the content of the nucleating agent is within the above range, the nucleating agent in the polylactic acid composition can be easily mixed and dispersed, and the heat resistance, durability and physical properties can be improved, the crystallization rate can be improved, and the productivity can be improved.

The polylactic acid composition may further include a functional additive or a physical additive, if necessary.

The functional additive may be added to impart a specific function to the filament. By using the functional additive in combination, the filament according to the present invention can further improve properties such as heat resistance, durability, flexibility and tensile strength.

The functional additive may be one selected from the group consisting of wood powder, metal powder (bronze powder, stainless powder, iron powder, copper powder, aluminum powder), carbon fiber, inorganic material, plasticizer, pigment, antioxidant, colorant, Or more. However, the functional additives according to the present invention can use functional additives known in the art without particular limitation.

The functional additive may include 0.1 to 500 parts by weight based on 100 parts by weight of the polylactic acid composition. When the content of the functional additive is within the above range, the dispersion in the thermoplastic resin becomes uniform and the mixing is facilitated, thereby enhancing the stability of the filament, improving durability and flexibility, and securing the stability of the output.

The physical additive may be added to improve the properties of the filament. By mixing the above-mentioned physical property additive, the filament according to the present invention can further improve various properties such as stability, heat resistance, durability, oxidation resistance,

The physical property additive may be at least one selected from the group consisting of plasticizers, impact modifiers, heat stabilizers, light stabilizers, light absorbers, lubricants, inorganic fillers, antioxidants, flame retardants, fillers, biodegradable resins and combinations thereof .

At this time, the physical property additive may include 0.1 to 10 parts by weight based on 100 parts by weight of the polylactic acid composition. At this time, when the content of the physical additive is within the above range, the function is sufficiently exhibited to improve the physical properties of the filament and ensure the stability of the output product.

The filament according to the present invention can be formed by applying a technique generally used in the related art, and the filament can be formed by selecting an appropriate molding method and molding condition required by the FDM 3D printer to be used, It is possible to design and produce filaments having physical properties and specifications. At this time, the molded product may be formed using a general-purpose plastic processing apparatus such as a single extruder or a twin extruder. The present invention does not limit the form or molding process of the molded product.

Crystallization filament manufacturing method

The crystallization filament preparation step can be crystallized at 70 to 100 ° C. At this time, the crystallization can proceed in hot wind or hot water.

In the FDM 3D printer according to the present invention, filaments can not be fed when an output is produced using amorphous polylactic acid filaments. Therefore, ensuring the heat resistance by crystallization of the filament is a necessary step for feeding the filament at the output.

After the polylactic acid composition is injected from the extruder in the filament manufacturing step, the filament can be obtained by drying and crystallizing the polylactic acid composition with hot air using a hot air dryer.

At this time, the temperature of the hot air is preferably 70 to 100 DEG C, more preferably 80 to 95 DEG C, higher than 53 DEG C, which is the thermal deformation temperature of polylactic acid. By subjecting the crystallized filament to hot air drying in the temperature range described above, it is possible to have a crystallization speed suitable for improving the durability, stability, flexibility and heat resistance of the crystallized filament, and to reduce the occurrence of defects and increase the production efficiency.

When the crystallization of the polylactic acid is carried out by using a hot water, a liquid medium in which the polylactic acid is not substantially dissolved can be used as the hot water.

FDM 3D Printer

1 and 2, an FDM 3D printer according to the present invention includes a bottom supporting an FDM 3D printer internal device; A wall portion extending from each corner of the bottom portion;

A printer body including a ceiling portion parallel to the bottom portion and connected to the wall surface portion;

A heat insulating material formed on inner surfaces of the ceiling part, the wall part and the bottom part, respectively; And a heat generating element formed on the inner surface of the heat insulating material and including an internal space.

 The printer body 101 may include a top portion 110, a wall portion 120 and a bottom portion 130. The bottom portion 130 may be formed in a shape that is in contact with the wall portion 120, And the wall portion 120 may be erected on the wall 130. FIG.

The printer body 101 keeps the generated heat in the inside of the printer body 101 at a predetermined temperature and prevents contact with the outside air to prevent heat from being lost from the outside.

The material of the printer body 101 may be selected from the group consisting of metal, synthetic resin, wood, stone, glass, and the like.

By using such a material, durability and rigidity are improved, and the ability to support the FDM 3D printer apparatus can be improved.

The thickness of the printer body 101 is preferably 1 to 4 cm, more preferably 2 to 3 cm. When the thickness of the printer body 101 is within the above range, the FDM 3D printer can be easily supported and fixed, and heat generated from the outside can be prevented from entering the inside of the printer body 101.

The ceiling portion 110 may be opened and closed by being connected to the wall portion 120 and may be used as a passage for taking out a completed output. At this time, the ceiling 110 may include a heating element 103 formed inside the printer body 110 and a heat insulating material 102 formed inside the heating element 103.

 The wall portion 120 may be connected to the bottom portion 130 or may be formed on the upper surface of the bottom portion 130, or may be formed to be openable and closable. A hole 104 is formed on one surface of the wall 120 to connect a separate supply unit 105 for supplying the crystallized filament to the FDM 3D printer output unit 106 through the hole 104. The wall 120 may include a heating element 103 formed on the inner side of the printer body 110 and a thermal insulator 102 formed on the inner side of the heating element 103.

The bottom part 130 may have a rectangular shape and may include a heating element 103 formed inside the printer body 110 and a heat insulating material 102 formed inside the heating element 103.

The heat insulating material 102 is in the form of a planar sheet and is joined to the inside of the printer body 101 in a planar manner so as to block the heat or cool air remaining after the external heat or cool air is primarily blocked by the printer body 101, The generated heat can be trapped inside and can serve as a constant temperature.

 The material of the heat insulating material 102 may be at least one selected from the group consisting of styrofoam, cotton, air cap, synthetic resin, synthetic fiber, glass fiber and inorganic material.

By using such a material as described above, it is possible to improve the stability in accordance with the temperature change.

 The thickness of the heat insulator 102 is preferably 1 to 4 cm, more preferably 2 to 3 cm. When the thickness of the heat insulator 102 is in the above range, the heat insulator 102 can be kept warm and kept warm.

The heating element 103 is in the form of a flat sheet and is joined to the inside of the heat insulating material 102 in a planar manner to generate heat in the printer body 101 and to adjust the temperature.

 At this time, the heating element 103 can generate heat at 60 to 120 ° C, and the temperature of the output space can be controlled so that heat generation and circulation in the printer body 101 can be uniformly performed.

The heating element 103 may be a heat generating material used in the related art, and may include at least one selected from the group consisting of a sheet containing a heating coil, a conductive sheet containing a carbon material, and a combination thereof. However,

The thickness of the heating element 103 is preferably 1 to 3 cm, more preferably 1.5 to 2.5 cm. When the thickness of the heating element 103 is in the above range, it is possible to uniformly generate heat as a whole, and the temperature can be easily adjusted.

The FDM 3D printer according to the present invention may include a temperature control unit on the ceiling 110, the wall 120, and the bottom 130.

The temperature control device may be installed in the ceiling 110, the wall 120 and the bottom 130 to sense the temperature inside the printer body 101 and adjust the operation of the heating element to maintain the set temperature .

The temperature control device can use a device commonly used in the related art, and it is possible to set the temperature inside the printer body 101 and to maintain the set temperature, thereby enhancing the durability, stability and completeness of the 3D output.

Manufacturing method of output using FDM 3D printer

In the FDM 3D printer output step according to the present invention, the three-dimensional output is output from the inside of the printer body 101 having a temperature of 70 to 110 ° C by using the crystallized filament, and then the final product is manufactured through the crystallization step inside . At this time, the heat resistance of the final product can be improved by improving the molecular structure by rapid crystallization at a temperature higher than the thermal deformation temperature of polylactic acid (53 ° C), and since the deformation of the final product is less than the process of further crystallization after output, can do.

The method for producing a three-dimensional output product using the FDM 3D printer and the crystallized filament of the present invention can be used for manufacturing a three-dimensional output product ensuring heat resistance and dimensional stability within the scope of the technical idea of the present invention.

≪ Example 1 >

To the polylactic acid composition was added 1 part by weight of unsubstituted zinc phosphates (Ecopromot) manufactured by Nissan Chemical Industries, Ltd. as a nucleating agent, based on 100 parts by weight of the polylactic acid composition, and then melted and mixed to prepare a filament having a diameter of 1.75 mm by an extruder . The filament was dried in a hot air drier at 90 DEG C for 30 minutes to prepare a crystallized filament.

<Experimental Example 1, Comparative Experimental Example 1 and Comparative Experimental Example 2>

Using the above-mentioned crystallized filament according to the present invention and an FDM 3D printer, specimens having dimensions of 127 mm in length, 12.7 mm in height, 3.2 mm in height and 100% in filling were produced according to ASTM D648 test conditions under the conditions shown in Table 1 below.

(1) Evaluation of dimensional stability

The crystallized filaments prepared in Experimental Example 1, Comparative Experimental Example 1 and Comparative Experimental Example 2 were compared with dimensions of 127 mm x 12.7 mm x 3.2 mm, which is the standard size of the ASTM D648 test, and the results are shown in Table 1 below .

(2) Evaluation of heat resistance

According to the ASTM D648 test method, the crystallized filaments prepared in Experimental Example 1, Comparative Experimental Example 1 and Comparative Experimental Example 2 were put into oil, and the temperature at which constant strain occurred was measured by applying a bending stress to the specimen. The results are shown in Table 1 below.

division 3D
printer
Internal temperature
(° C) Add
crystallization Appearance
observe Dimension measurement
(mm) Thermal deformation
Temperature
(° C) horizontal Vertical Height Experimental Example
One 75 - Mold deformation
none 126.88 12.69 3.2 101 (-0.094%) (-0.079%) (-0.000%) Comparative Experimental Example
One 25 - Mold deformation
none 127.03 12.71 3.21 53 (0.024%) (0.079%) (0.312%) Comparative Experimental Example
2 25 100 ℃ hot water
60 seconds Weak bend
Occur 124.34 12.67 3.19 98 (-2.094%) (-0.236%) (-0.313%)

As shown in Table 1, Experimental Example 1, in which the internal temperature of the printer body was set to 75 ° C and no further crystallization was performed, showed dimensional deformation of less than 0.1% in length and width, no external deformations, and heat distortion temperature of 101 ° C Was higher than that of Comparative Experimental Example 1 and Comparative Experimental Example 2, confirming that heat resistance and dimensional stability were obtained. On the other hand, in Comparative Experiment Example 1 in which the internal temperature of the printer body was set at 25 캜 and no further crystallization was carried out, the deformation of the dimensions of the output after molding was smaller than that of Comparative Example 2, It was found that the heat resistance was not improved. Comparative Example 2, in which the internal temperature of the printer body was set at 25 ° C and crystallization was added, showed high dimensional stability due to high external deformations and dimensional changes although the heat distortion temperature was high.

Therefore, by setting the printing temperature conditions suitable for the thermoplastic resin to be used with the FDM 3D printer for producing the crystallized filament and the three-dimensional heat-resistant polylactic acid output according to the present invention, it is possible to improve the physical properties of the three- .

The functional filament for a 3D printer according to the present invention can be utilized in various fields such as automobile industry, medical human body model, and household product field.

The present invention relates to an FDM 3D printer, and more particularly, to an image forming apparatus,

Claims (9)

delete delete delete delete Producing a 3D printer filament using a polylactic acid resin composition;
Crystallizing the filament at 70 to 100 占 폚 to produce a crystallized filament; And
And outputting the three-dimensional output inside the FDM 3D printer body having an internal temperature of 70 to 110 DEG C by feeding the crystallized filament to a 3D printer. [5] The method according to claim 1, As a result,
Wherein the polylactic acid resin composition comprises a crystallized polylactic acid or an amorphous polylactic acid. 6. The method of claim 5,
The polylactic acid resin composition
Wherein the method comprises the steps of: The method according to claim 6,
The nucleating agent
Wherein at least one selected from the group consisting of inorganic particles, sorbitol derivative nucleating agent, amide compound nucleating agent and phosphorus compound metal salt nucleating agent is used. delete delete

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