KR101715865B1 - Polymer for 3D printing and printing method by use of it - Google Patents

Abstract

The present invention relates to a method for manufacturing a polymer for 3D printing and a 3D printing method using the same. According to the present invention, a polymer in a blend form, which can be applied for 3D printing, can be manufactured, so a polymer having excellent thermal properties such as the glass transition temperature, the melting temperature, etc. and mechanical properties such as the hardness, the modulus of elasticity, the tensile elongation, etc. can be manufactured by performing 3D printing at proper conditions using the same.

Description

Technical Field [0001] The present invention relates to a polymer for 3D printing and a 3D printing method using the same,

The present invention relates to a polymer for 3D printing and a 3D printing method using the same. More specifically, the present invention relates to a polymer prepared by blending to suit 3D printing, and a method for producing a polymer having improved thermal and mechanical properties such as strength and elastic modulus by 3D printing under appropriate conditions using the polymer.

3D printing is a technique to freely fabricate a three-dimensional shape by fusing a polymer, and a desired object is repeatedly stacked on a thin layer in the shape of an object based on three-dimensional (3D) data. The development of 3D printers capable of 3D printing was initially limited to plastic materials, but recently the range has expanded to include nylon and metal. Even if only one object is manufactured, the cost is low and the complicated shape can be easily produced, which is very useful in the manufacturing field.

Fiber reinforced composite materials are composite materials using fibers as reinforcing materials. Depending on the type of substrate, fiber reinforced plastics (FRP), fiber reinforced metals (FRM), fiber reinforced ceramics (FR) and fiber reinforced concrete (FRC) have. Fiber materials include metal, glass, carbon, ceramics, and organic materials (artificial and natural). Some of the fibers have been subjected to surface treatment such as electroless plating. Fiber-reinforced composites are used in a wide range of applications such as aircraft and UAV / airframe / parts, lightweight structural materials, manufacturing of electrical and electronic components, automotive structures / components, construction civil engineering materials, liquid / gas filters, high strength plastic materials and components .

Recently, various techniques for fabricating a fiber-reinforced composite material have been developed, such as Korean Patent Laid-Open No. 10-2013-0120113. However, general fiber-reinforced composite material manufacturing techniques are not limited to the prepreg lamination method, It has a limitation that it must go through a complicated process. However, it is expected that the fabrication process of composite materials using 3D printing, which has been developed recently, can be applied to the fabrication of fiber reinforced composite materials by easily forming composite materials with simple devices while maintaining the existing composite material properties do. However, no technology has yet been identified that applies fiber-reinforced composite materials to 3D printing technology.

Accordingly, the present inventors have completed the present invention after completing experiments to develop a polymer applicable to 3D printing and a 3D printing method using the same.

Korean Patent Publication No. 10-2013-0086939 A

Accordingly, it is an object of the present invention to provide a polymer that can be applied to 3D printing by properly blending a polymer.

It is a further object of the present invention to provide a method for manufacturing a 3D-printing composite material by 3D printing using the polymer for 3D printing, omitting a multi-step manufacturing process, precisely and finely forming a complicated shape and improving strength and elasticity, The present invention also provides a 3D printing method for producing a high molecular weight polymer.

In order to achieve the above object, the present invention provides a method of manufacturing a semiconductor device, comprising: a) extruding a polyarylate (PAR); b) mixing the extruded polyarylate of step a) with polyethyleneterephthalate (PET); c) extruding the mixture of step b) at a screw rotation speed of 50-500 rpm using an extruder to produce a monofilament; And d) drying the monofilament. The present invention also provides a method for producing a polymer for 3D printing.

In the present invention, when extruding at the slow screw rotating speed, the extrusion of step c) is not well dispersed due to low shear, and as a result, defects may occur. On the other hand, when extruded at an excessively fast screw rotating speed, it can be dispersed relatively uniformly, but it is very important to maintain an appropriate screw rotating speed because the strength of the polymer may be lowered due to high shear. Therefore, in the present invention, the experiment was repeated to set the screw rotation speed so that the polymer mixture in the step b) could be appropriately dispersed and at the same time, a certain level of strength was exhibited. As a result, extrusion was performed at a screw rotating speed of 50-500 rpm .

In one embodiment of the present invention, the extrusion of step a) may be extruded after kneading for 5 to 65 seconds at a screw rotation speed of 400-4000 rpm using an extruder.

In the present invention, the extruder is a kind of a press-forming machine, which is a reciprocating type in which a material is put into a cylinder and extruded, and a continuous type in which a screw is rotated and extruded in a cylinder. It is possible to extrude the rod-shaped or thread-like shape of the monomolecular shape determined according to the above. In the present invention, specifically, a continuous extruder for rotating a screw in a cylinder is used, but an extruder using a screw can continuously obtain a linear or tubular shaped product and can be used for extrusion-spinning of plastics and synthetic fibers. In the present invention, the rotational speed of the screw is appropriately set in order to produce a polymer optimized for 3D printing.

In the present invention, when extruding at a slow rotational speed, extrusion in the step a) is not well dispersed on the microstructure due to low shear, which may cause surface and structural defects. On the other hand, when extruded at an excessively high rotational speed, it is possible to uniformly disperse in a fine structure, but due to high shear, shear stress friction occurs, and molecular cutoff and oxidation are deepened and elasticity brittle may occur. Resulting in deterioration of physical properties. That is, it is important to maintain an appropriate extrusion rate according to the purpose. In the present invention, experiments were repeated to set an appropriate screw rotation speed for 3D printing for use as a fiber-reinforced composite material. As a result, As shown in Fig.

In the present invention, the kneading means an operation of uniformly mixing by applying a mechanical shearing force. In the present invention, an appropriate mixing procedure, a kneading time, and a temperature are set in order to produce a polymer optimized for 3D printing.

In one embodiment of the present invention, the extrusion of step a) may be performed at 250-350 ° C, but preferably at 290-330 ° C. Extrusion is carried out at a high temperature of about 300 캜, so that the liquid crystal polymer can be melted and it is easy to appropriately blend two or more polymers. In the present invention, a nozzle made of a full metal material is used to withstand the high temperature as described above.

In an embodiment of the present invention, the PET of step b) may be replaced with a polymer selected from the group consisting of nylon-6, polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN) Any one selected can be mixed with PAR.

In one embodiment of the present invention, the mixing of the step b) may include mixing the polyarylate and the polyethylene terephthalate in a ratio of 3: 7-7: 3.

In one embodiment of the present invention, the extrusion of step c) may be performed at 250-350 ° C.

In the present invention, the monofilament in step (c) means that the fibers radiated from one nozzle are manufactured as a final product without being twisted with other fibers, and the corresponding concept is a multifilament. According to the present invention, a monofilament in which two or more polymers are mixed can be produced by blending the polymer before extrusion and extruding at a suitable screw rotating speed and an appropriate temperature.

In one embodiment of the present invention, drying in step d) may be performed at 90-110 ° C for 12-16 hours.

In one embodiment of the present invention, the antioxidant may be added in any one of steps a) to c).

In the present invention, the antioxidant refers to a substance added to prevent autooxidation due to the action of oxygen, which is liable to occur in a polymer substance, a petroleum product, a fat, a soap and the like. When an antioxidant is added, It is possible to prevent breakage. Examples of the antioxidant that may be used include hindered phenol-based or sulfur-based antioxidant, but are not limited thereto. In addition, phenyl- beta -naphthalamine is generally used for synthetic rubbers, aromatic amines, hydroquinone and the like are used, and amino acids in latex can be used for natural rubber.

In the present invention, in order to prevent the rapid oxidation of the extruded polymer, it was added. As a result, when the polymer containing the antioxidant was 3D-printed, the polymer prepared by using the polymer containing no antioxidant had better strength, Elastic modulus and tensile elongation (see Example 3).

In the present invention, it is possible to further include a step of performing a surface treatment after the step of extruding the monofilament of the step (c). 3D printing characteristics can cause layers on the surface, which can cause interlayer interfacial breakdown and surface uniformity. Therefore, it is necessary to perform surface treatment after printing in order to minimize defects.

In addition, the present invention provides a polymer produced by the above-mentioned production method.

In addition, the present invention provides a method for 3D printing using a polymer produced according to the above-described method.

In one embodiment of the present invention, the 3D printing may be performed at a printing speed of 1-200 mm / sec at 230-350 ° C.

In the present invention, the printing speed is used for high crystallinity and fibril phase expression as a result of 3D printing. Due to the nature of the polyarylate used, it does not show high crystallinity when printed at a slow rate and the fibril phase is difficult to be expressed. On the other hand, printing at too high a speed can make formation of the fibril phase difficult and can lead to interface failure between the stiffener and the substrate, resulting in surface or structural defects. Accordingly, in the present invention, experiments were performed to set a printing speed that exhibited high crystallinity and formed a fibril phase and at the same time a defect did not occur. As a result, it is preferable to perform printing at a speed of 1-200 mm / sec as described above Respectively.

The printed polymer according to the present invention can be used in the manufacture of aircraft or UAVs / components, lightweight structural materials, electrical and electronic components, automotive structures / components, architectural civil engineering materials, liquid / gas filters, And can be utilized as a fiber reinforced composite material which can be applied to various fields such as high strength plastic materials and parts.

According to the present invention, it is possible to produce a blend-type polymer applicable to 3D printing, and it is possible to produce a polymer by 3D printing under appropriate conditions by using the same, thereby obtaining a toner having mechanical properties such as glass transition temperature and thermal property such as melting point, strength, elastic modulus and tensile elongation It was confirmed that this excellent polymer can be produced.

FIG. 1 is a diagram illustrating the shape of a polymer prepared by 3D printing according to the present invention.

Hereinafter, the present invention will be described in detail with reference to examples. However, these examples are intended to further illustrate the present invention, and the scope of the present invention is not limited to these examples.

≪ Example 1 > Production of polymer for 3D printing

1.1 Preparation of PAR / PET Polymer

Polyarylate (PAR) was made by Vera of Kuraray Co. in Japan and polyethylene terephthalate (PET) was made of PET Chip Fiber Grade of Kolon. PAR was adjusted to 290 to 330 ° C using a high shear extruder at a screw rotating speed of 500 rpm to 4000 rpm at an extruder, and the kneading time was varied from 10 to 60 seconds to make the flow of PAR favorable. PAR and PET were high-shear extruded as described above and mixed with various contents such as 50:50, 70:30 and 30:70 ratio of PAR and PET using a Benbury mixer. Next, the mixed polymer was extruded at 290 to 330 ° C so that the screw rotation speed of the extruder was 50 to 500 rpm, and was produced in the form of monofilaments having a diameter of 100 to 3000 μm through the die. The prepared PAR / PET monofilaments were dried in an oven at 100 DEG C for 14 hours. Antioxidants were added to prevent the rapid oxidation of the polymer at all stages of the process.

1.2 PAR / Nylon6  Manufacture of Polymers

The same manufacturing process was performed using Nylon 6 instead of PET in Example 1.1. At this time, Hyosung's 1011 BRT was used for Nylon6 chip. An antioxidant was added to prevent the rapid oxidation of the polymer during the production process.

1.3 Preparation of PAR / PBT Polymer

In Example 1.1, the same manufacturing process was performed using polybutylene terephthalate (PBT) instead of PET. The PBT chip was Celanese CELANEX. An antioxidant was added to prevent the rapid oxidation of the polymer during the production process.

1.4 Preparation of PAR / PEN Polymer

In Example 1.1, the same manufacturing process was performed using polyethylene naphthalate (PEN) instead of PET. At this time, the PEN chip was Hyosung's PEN Chip Fiber Grade. An antioxidant was added to prevent the rapid oxidation of the polymer during the production process.

1.5 Preparation of PAR / PFN Polymer

The PAR / PFN polymer was prepared in the same manner as in Example 1.1, but no antioxidant was added.

≪ Example 2 > 3D printing of a polymer

The monofilament type polymer prepared according to Examples 1.1 to 1.5 was placed in a spool of a 3D printer and was printed at 240 to 320 ° C. At this time, the printing speed was in the range of 1 mm / sec to 200 mm / sec, and the printed polymer was printed so as to have a width of 40 mm, a length of 100 mm and a thickness of 0.9 mm. Thereafter, a surface treatment process of applying a solution to the surface was performed in order to remove the surface layer which may occur due to the 3D printing characteristic.

The printed polymer rapidly solidifies to form a solid phase, which is either retained as a fibrous solid or solidified after being slightly melted and present as a fibrous reinforcement to form a self-reinforcing composite material. On the other hand, PET, Nylon 6, PBT and PEN are melted and printed, then solidified and fused to form a matrix of the finally produced polymer.

The physical properties and thermal properties of the polymer prepared through the above process were evaluated according to Example 3 below.

Example 3 Measurement of Physical Properties of Polymers

The physical properties of the polymer prepared according to Example 1 and 3D-printed according to Example 2 were measured by the following methods, and the results are shown in Table 1 below.

3.1 Measurement of tensile strength, elongation and elastic modulus

The tensile strength, elongation and elastic modulus were measured according to ASTM D638 standard. A clamp of 30 kN load cell and 20 mm / min cross-head speed with constant speed tensile test method using Instron 4467 The other clamps were stationary and moved at a constant speed throughout the test and were measured in the vertical direction without deflection. Tensile strength, elongation and modulus of elasticity of the specimens were measured by pulling under the specified conditions until the specimens were broken.

3.2 Glass transition temperature and melting point measurement

The glass transition temperature (Tg) and melting point (Tm) were measured using a differential scanning calorimeter (DSC) at a rate of 10 ° C / min in a nitrogen atmosphere, The glass transition temperature and melting point of the endothermic behavior were measured by measuring the difference in heat flux generated. The measurement results are shown in Table 1 below.

 As shown in Table 1, the PAR-containing polymer prepared by adding the antioxidant had higher strength, elastic modulus, and elongation than the polymer without addition of the antioxidant. Also, as the content of PAR in polymer increased, strength and modulus of elasticity increased. The glass transition temperature was different according to matrix, PET, Nylon6, PBT and PEN. Melting point was measured by melting point of PAR and showed similar tendency regardless of substrate.

That is, according to the present invention, a polymer having excellent strength, elastic modulus, and tensile elongation applicable to 3D printing can be prepared by preparing a polymer mixed with PAR and a matrix under appropriate conditions, and the polymer prepared according to the present invention can be produced under appropriate conditions It is confirmed that 3D printing can obtain 3D printed articles having excellent physical characteristics.

The present invention has been described with reference to the preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (11)

A process for producing a polymer for 3D printing having a tensile strength of 280-335 (MPa), a tensile elastic modulus of 15-17 (Gpa) and a tensile elongation of 3-9 (%),
a) extruding polyarylate (PAR) at 250-350 占 폚 at a screw rotation speed of 1000-4000 rpm using a high shear extruder;
b) mixing the extruded polyarylate of step a) with polyethyleneterephthalate (PET) in an amount of 3: 7-7: 3;
c) extruding the mixture of step b) at 250-350 ° C at a screw rotation speed of 50-500 rpm to produce a monofilament; And
d) drying the monofilament at 90-110 < 0 > C for 12-16 hours. delete delete [6] The method of claim 1, wherein the PET of step b) is one selected from the group consisting of nylon-6, polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) Is mixed with PAR. delete delete delete The method according to claim 1, wherein the antioxidant is added in any one of steps a) to c). 9. A polymer produced by the production method according to any one of claims 1, 4 and 8. A method for 3D printing using the polymer according to claim 9. The method of claim 10, wherein the 3D printing is performed at a printing speed of 1-200 mm / sec at 230-350 캜.

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