KR101774941B1 - Multi-filament composition for 3-dimensional printer and manufacturing method thereof - Google Patents

Abstract

One embodiment of the present invention is a thermoplastic resin composition comprising 100 parts by weight of a thermoplastic resin; And 5 to 80 parts by weight of one carbon fiber selected from the group consisting of a rayon series, a pitch series, a polyacrylonitrile series, and a mixture of two or more thereof, and a process for producing the composite filament composition. to provide.

Description

TECHNICAL FIELD [0001] The present invention relates to a composite filament composition for a 3D printer,

The present invention relates to a composite filament composition for a 3D printer and a method of manufacturing the same.

Recently, environmental regulations have been strengthened in all business areas due to environmental problems that have been continuously raised. In particular, the automobile sector has been designated as a major industry for generating greenhouse effect by emitting carbon dioxide, and the emission standards for carbon dioxide have been set worldwide. As a result, the development direction of automobiles is aimed at improving fuel efficiency. In the United States, the fuel efficiency is improved by 15.1 km / l by 2016, 23 km / ℓ by 2025, and 17 km / ℓ by 2015 in Korea We are aiming.

In the automobile industry, it is proposed to reduce the weight of the vehicle with the aim of improving the fuel efficiency, and there are methods of lightening the material and optimizing the body design. In recent years, non-ferrous metals such as aluminum alloys and magnesium alloys have been used in order to reduce the weight of materials. Recently, polymer composite materials have been widely used. In particular, carbon fiber reinforced plastics reinforced with appropriate strength Plastic, CFRP) are attracting attention as lightweight materials among polymer composite materials. However, due to the difficulty of the molding process, automobile applications such as forming parts of carbon fiber reinforced plastic have been limited.

On the other hand, the body design optimization is a method to lighten the vehicle by minimizing the air resistance of the body, but it takes much time and cost to manufacture and apply the prototype.

In this regard, a method for shortening the time required for product development and production using 3D printer technology has been proposed. 3D printer is a technology for manufacturing products by processing and laminating materials according to design data.

The raw materials used in 3D printers can be in the form of liquids, powders, and solids. In the case of liquid and powder raw materials, equipment and materials are expensive, while filament printing methods using solid raw materials are low cost due to the use of thermoplastic plastics. And is widely used. However, there is a problem that it is difficult to improve the mechanical properties of a product to a certain level or more with only thermoplastic plastics.

Accordingly, it is necessary to develop a composite material composition which can be easily and inexpensively applied to a 3D printer, while improving the mechanical properties of the product.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a composite filament composition for a 3D printer for manufacturing automobile lightweight parts by introducing 3D printer technology.

According to an aspect of the present invention, there is provided a thermoplastic resin composition comprising 100 parts by weight of a thermoplastic resin; And 5 to 80 parts by weight of one carbon fiber selected from the group consisting of rayon series, pitch series, polyacrylonitrile series, and mixtures of two or more thereof.

In one embodiment, the thermoplastic resin is selected from the group consisting of acrylonitrile butadiene styrene, polyethylene, polypropylene, polyvinyl chloride, polyurethane, And mixtures thereof.

In one embodiment, the thermoplastic resin is selected from the group consisting of polycarbonate, polybutylene terephthalate, polyoxymethylene, polyamide 6, polyamide 66, A modified polyphenylene oxide, a polyphtalamide, a liquid crystal polymer, a polyether ether ketone, a polyimide, a polyamide, and a mixture of two or more thereof ≪ / RTI >

In one embodiment, the carbon fiber is rayon-based or pitch-based carbon fiber, and the content of the carbon fiber is 10 to 80 parts by weight based on 100 parts by weight of the thermoplastic resin.

In one embodiment, the carbon fibers are polyacrylonitrile-based carbon fibers, and the content of the carbon fibers is 5 to 70 parts by weight based on 100 parts by weight of the thermoplastic resin.

In one embodiment, the composite filament composition for a 3D printer may further comprise one flame retardant additive selected from the group consisting of magnesium hydroxide, calcium carbonate, silica, aluminum hydroxide, and mixtures of two or more thereof.

In one embodiment, the content of the flame-retardant additive may be 5 to 80 parts by weight based on 100 parts by weight of the thermoplastic resin.

According to another aspect of the present invention, there is provided a method of manufacturing a flame retardant additive, comprising the steps of: (a) melt-kneading 100 parts by weight of a thermoplastic resin and 5 to 80 parts by weight of a carbon fiber, ; (b) extruding the mixture into a single-screw extruder or a twin-screw extruder to produce an extrudate; And (c) cutting the extrudate into pellets. The present invention also provides a method for producing a composite filament composition for a 3D printer.

In one embodiment, the extruder may have a length to diameter ratio of 25 to 50: 1.

In one embodiment, the driving speed of the extruder may be 50 to 500 rpm.

The composite filament composition for a 3D printer according to one aspect of the present invention can improve the mechanical properties and moldability by mixing a predetermined amount of carbon fibers with respect to the thermoplastic resin and can be used for manufacturing lightweight parts for automobiles or electronic products It can save cost and time, and can be optimized for multi-product, multi-structure small-volume production system.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a schematic view illustrating a method of manufacturing a composite filament composition for a 3D printer according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Composite filament composition for 3D printer

One aspect of the present invention relates to a thermoplastic resin composition comprising 100 parts by weight of a thermoplastic resin; And 5 to 80 parts by weight of one carbon fiber selected from the group consisting of rayon series, pitch series, polyacrylonitrile series, and mixtures of two or more thereof.

The composite filament composition for a 3D printer may be a composition prepared by melt-kneading a carbon fiber with a thermoplastic resin as a matrix.

Generally, a thermoplastic resin and a thermosetting resin can be used as a matrix of a composite filament composition for a 3D printer, but thermosetting resins have problems of hardening and impact resistance, and thus there is a difficulty in a subsequent molding process.

On the other hand, since the thermoplastic resin is superior in moldability to the thermosetting resin, it is preferable to use a thermoplastic resin as a matrix.

Wherein the thermoplastic resin is selected from the group consisting of acrylonitrile butadiene styrene, polyethylene, polypropylene, polyvinyl chloride, polyurethane, and mixtures of two or more thereof But it is not limited thereto.

As used herein, the term "Commodity plastics" refers to plastics having general plastic properties.

The thermoplastic resin may be selected from the group consisting of polycarbonate, polybutylene terephthalate, polyoxymethylene, polyamide 6, polyamide 66 and modified polyphenylene oxide. polyphenylene oxide, polyphtalamide, liquid crystal polymer, polyether ether ketone, polyimide, polyamide, and mixtures of two or more thereof. But is not limited to, one engineering plastics or super engineering plastics selected from plastics.

As used herein, the term "engineering plastics" refers to plastics having physical properties that can be applied to engineering materials by complementing thermal and mechanical strength, which are the most disadvantage of general plastics, Super-engineering plastics "refers to high-performance plastics with improved thermal and mechanical properties over engineering plastics.

The universal plastic and the engineering or super engineering plastic may be used independently of one another as a matrix of the composite filament composition for a 3D printer, and may be mixed and used as necessary in consideration of use, physical properties, manufacturing cost, and the like of the final product. For example, it is desirable to realize the inherent physical properties of engineering or super engineering plastics, but in this case, it is possible to mix commercial plastics in a certain ratio since commercial possibilities are low and manufacturing costs may increase.

The carbon fibers may be rayon-based or pitch-based carbon fibers, and the content of the carbon fibers may be 10 to 80 parts by weight based on 100 parts by weight of the thermoplastic resin.

The carbon fibers can be prepared by pyrolyzing an organic precursor material in the form of fibers, that is, a starting material, in an inert atmosphere. It is important to increase the carbonization yield among the properties of the carbon fiber. For this purpose, it is necessary to manufacture a polymer precursor fiber having a controlled internal structure and high purity, a stabilized pretreatment process, and a carbonization process.

The carbon fibers may be classified into rayon, pitch, and polyacrylonitrile based on precursor materials. Among them, a high modulus carbon fiber produced from a pitch system and a high strength carbon fiber produced from a polyacrylonitrile system are widely used. In the present invention, rayon based, pitch based, and polyacrylonitrile based carbon fibers are selectively used, Mixtures of two or more of them may also be used.

The rayon-based carbon fiber can be produced using a special grade viscous rayon having few defects. The carbonization yield is 2 to 20%, and the carbon fibers produced may have a tensile strength of 345 to 690 MPa, a tensile elastic modulus of 20 to 55 GPa, and a density of 1.0 to 1.43 g / cm < ³ >. Such physical properties can be further improved by drawing graphitization at 2800 to 3000 ° C.

The pitch of the pitch-based carbon fibers can be produced from petroleum pitch and coal pitch depending on the raw material. The pitch is present in a complex mixture of many heterogeneous organic compounds in which the condensed benzene ring has an alkyl chain or is separated by an alkyl chain. In particular, the precursor fibers produced by liquid crystal spinning of a mesophase pitch melt can maintain or enhance the axial orientation during the carbonization and graphitization processes and can have a tensile modulus of elasticity of about 830 GPa without stretching.

 On the other hand, the content of the rayon-based or pitch-based carbon fibers may be 10 to 80 parts by weight based on 100 parts by weight of the thermoplastic resin. If the content of the rayon-based or pitch-based carbon fibers is less than 10 parts by weight, the mechanical properties may be deteriorated. If the content of the rayon-based or pitch-based carbon fibers is more than 80 parts by weight, the relative content of the thermoplastic resin may be decreased to lower the uniformity of the composite filament composition, Can rise.

In one embodiment, the carbon fibers are polyacrylonitrile-based carbon fibers, and the content of the carbon fibers is 5 to 70 parts by weight based on 100 parts by weight of the thermoplastic resin.

The polyacrylonitrile-based carbon fibers can be produced by preparing polyacrylonitrile precursor fibers and stabilizing, carbonizing, and graphitizing the precursor fibers. Specifically, when a linear polymer, polyacrylonitrile, is used as a starting material and subjected to stabilization at 200 to 300 ° C for 1 to 2 hours in the air, the precursor material is subjected to carbonization by chain cutting, crosslinking, dehydrogenation and cyclization. It is possible to form a thermally stable ladder structure capable of withstanding.

In order to maintain and improve the orientation of the molecules in the stabilization step, stretching may be applied to reduce shrinkage to within 15%. Further, in the stabilization step, complicated multi-step chemical reactions are carried out and water, carbon dioxide, hydrogen cyanide and the like are released to cause weight loss of 5 to 8%, and the carbon content in the precursor fiber is 68 to 62% . ≪ / RTI > Thereafter, when the precursor fibers are carbonized at 1200 to 2500 DEG C under an inert gas atmosphere, carbon fibers of 45 to 55 wt% based on the total weight of the precursor fibers can be obtained.

Since the polyacrylonitrile-based carbon fiber is substantially composed only of carbon, weight reduction can be minimized even in a graphitization process at 2500 ° C or higher, and a structural change in the axial direction of the carbon fiber can be increased, Can be improved.

The tensile elastic modulus of the polyacrylonitrile-based carbon fiber may be 517 GPa or more when heat-treated at 3000 ° C or more, depending on the heat treatment temperature between graphitization processes. In order to lower the process temperature and shorten the process time in the graphitization process, a boron compound catalyst may be used.

The content of the polyacrylonitrile-based carbon fiber may be 5 to 70 parts by weight based on 100 parts by weight of the thermoplastic resin. If the content of the polyacrylonitrile-based carbon fiber is less than 5 parts by weight, the mechanical properties may be deteriorated. If the content is more than 70 parts by weight, the relative content of the thermoplastic resin may be decreased to lower the uniformity of the composite filament composition. Can rise.

In one embodiment, the composite filament composition for a 3D printer may further comprise one flame retardant additive selected from the group consisting of magnesium hydroxide, calcium carbonate, silica, and aluminum hydroxide.

The additive serves to impart flame retardancy to plastics which are poor in thermal properties and resistance to burning, and a halogen flame retardant, an inorganic flame retardant, a phosphorus flame retardant, and a melanin flame retardant may be used depending on the components.

The halogen-based flame retardant may be classified into a bromine-based flame retardant and a chlorine-based flame retardant. The bromine-based flame retardant can be used for ABS, PS, PBT, epoxy resin, etc., and has an advantage that it can realize an excellent flame retardant effect even in a small amount. However, it is impossible to recycle plastic and discharges poisonous environmental pollutants such as dioxin There is a problem.

Examples of the inorganic flame retardant include aluminum hydroxide, antimony oxide, magnesium hydroxide, zinc stannate, molybdate, guanidine, and zirconium. Among them, aluminum hydroxide has advantages of low toxicity, low ductility, excellent electrical insulation and low cost, but it can be applied only to plastic having a decomposition temperature of 180 ~ 220 캜 and a low processing temperature, and should be applied in large quantity in order to impart flame retardancy Therefore, the mechanical properties and processability of the plastic material may be deteriorated.

The phosphorus flame retardant includes, for example, ammonium phosphate, ammonium polyphosphate, and haloalkyl phosphate. The phosphorus flame retardant exhibits an excellent flame retardant effect in the solid phase reaction, and is particularly effective for plastics containing a large amount of oxygen.

Examples of the melanin-based flame retardant include melanin phosphate, melanin cyanurate, and melanin phosphate. The melanin-based flame retardant is free from the generation of toxic gases, and the amount of soot generated during combustion is small, so there is little risk to the environment.

The content of the flame-retardant additive may be 5 to 80 parts by weight based on 100 parts by weight of the thermoplastic resin. If the amount of the flame-retardant additive is less than 5 parts by weight of the thermoplastic resin, a necessary level of flame retardant effect can not be achieved. If the amount is more than 80 parts by weight, the relative content of the thermoplastic resin is decreased, Can rise.

Meanwhile, the composite filament composition for a 3D printer may further include a functional additive such as an ultraviolet absorber, an impact modifier, a pigment, a plasticizer, a binder and the like depending on the use, installation site, have.

Method for producing composite filament composition

1 is a schematic view illustrating a method of manufacturing a composite filament composition according to an embodiment of the present invention.

According to another aspect of the present invention, there is provided a method for producing a flame-retardant additive, comprising the steps of: (a) melt-kneading 100 parts by weight of a thermoplastic resin and 5 to 80 parts by weight of a carbon fiber; (b) extruding the mixture into a single-screw extruder or a twin-screw extruder to produce an extrudate (S200); And (c) cutting the extrudate and pelletizing the extrudate (S300). The present invention also provides a method for producing a composite filament composition for a 3D printer.

In step (a) (S100), the thermoplastic resin may be general-purpose plastic, engineering, or super engineering plastic. The universal plastic and the engineering or super engineering plastic may be used independently of one another as a matrix of the composite filament composition for a 3D printer, and may be mixed and used as necessary in consideration of use, physical properties, manufacturing cost, and the like of the final product.

In addition, in step (a) (S100), the carbon fibers may be administered in the form of pure carbon fibers not mixed with other substances, but in this case, since the dispersibility of the carbon fibers in the mixture may be deteriorated May be administered in the form of a master batch containing carbon fibers and a surfactant and mixed with the thermoplastic resin.

The surfactant may be one selected from the group consisting of a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, and a mixture of two or more thereof.

The nonionic surfactant is selected from the group consisting of methanol, ethanol, isopropanol, butanol, benzyl alcohol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, Propylene glycol, dipropylene glycol, dipropylene glycol, dipropylene glycol, dipropylene glycol, dipropylene glycol, dipropylene glycol, dipropylene glycol, dipropylene glycol, diethylene glycol, Propylene glycol monomethyl ether, propylene glycol phenyl ether, dibutyl diglycol, 3-methyl-3-methoxybutanol, 2- (2-butoxyethoxy) ethanol, polyoxyethylene alkyl ether, Polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty alcohol, and polyoxyethylene alkylphenyl ether It may be an alcohol on, and the like.

The anionic surfactant may be selected from the group consisting of phosphate (sulfate), sulfonate (sulfate), saccharinate (system), glutamate (system), isethionate (system) But it is not limited thereto.

The amphoteric surfactant may be at least one selected from the group consisting of acetate (system), imidazole (system), betaine (system), phosphatide (system) compound and derivatives thereof, It is not.

The definition, properties, and kinds of the above general-purpose plastic, engineering or super engineering plastic, carbon fiber, flame-retardant additive, and other additives are as described above.

Meanwhile, the extruder that can be used in step (b) S200 may be a single-screw extruder or a twin-screw extruder. As used herein, the terms "uniaxial extruder" and "biaxial extruder" refer to a screw extruder having one and two screws, respectively.

The uniaxial extruder is suitable for extrusion molding of most thermoplastic resins, and the biaxial extruder is mainly used for manufacturing a large diameter pipe, for example, a polyvinyl chloride (PVC) pipe. Although the twin-screw extruder has a more complicated structure than the single-screw extruder, the extruded amount is large and stable and stable extrusion is possible even at a slow screw driving speed.

Although not shown in the drawing, when the thermoplastic resin and the carbon fiber are injected into the material introduction portion, the thermoplastic resin and the carbon fiber into which the screw is injected are melted and kneaded, and a flame retardant additive is further added thereto to prepare a mixture. The extruder can be designed to cut the extrudate after it has been extruded into filaments.

When the extruder extrudes and sprays the mixture, the screw temperature of the extruder can be adjusted to a range of 170 to 250 ° C, preferably 180 to 220 ° C. The screw temperature of the extruder can be controlled differently depending on the type of the thermoplastic resin in consideration of the possibility of the mixture being broken due to the pressure and temperature applied to the mixture in the extrusion process.

Generally, the filament can be extruded to have a predetermined diameter, but use may be restricted if the average diameter of the extruded filament is different from the diameter of the 3D printer nozzle. Therefore, in step (c) S300, The extrudate may be cut and pelletized so as to enable subsequent or additional extrusion or use of the filament, thereby facilitating the subsequent process.

Meanwhile, the extruder may have a length to diameter ratio of 25 to 50: 1. The "length: diameter ratio" of the extruder means a ratio of the length (length, L) and the diameter (diameter, D) of the screw, and this is one of the factors determining the extrusion performance of the extruder. Generally, the larger the "length: diameter ratio" value of the screw, the better the kneading effect and the quality of the product and the less the deviation of the extrusion amount. However, the ratio of the length to the diameter depends on the kind and nature of the material to be fed into the extruder Can be adjusted differently.

If the ratio of the length to the diameter of the extruder is less than 25: 1, a required level of kneading effect can not be realized. If the ratio is more than 50: 1, the size of the extruder and the capacity of the driving motor may be influenced.

The driving speed of the extruder may be 50 to 500 rpm. If the driving speed of the extruder is less than 50 rpm, a necessary level of kneading effect can not be realized. If the driving speed of the extruder is more than 500 rpm, the rotation speed of the motor Due to the large number, the motor and the decelerating device may be subjected to excessive load and be damaged.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (10)

100 parts by weight of a thermoplastic resin;
5 to 80 parts by weight of one carbon fiber selected from the group consisting of pitch, polyacrylonitrile, and mixtures thereof; And
5 to 80 parts by weight of a melanin-based flame retardant,
Wherein the carbon fiber has a tensile elastic modulus of 517 GPa to 830 GPa.
The method according to claim 1,
Wherein the thermoplastic resin is selected from the group consisting of acrylonitrile butadiene styrene, polyethylene, polypropylene, polyvinyl chloride, polyurethane, and mixtures of two or more thereof A composite filament composition for a 3D printer, which is selected.
The method according to claim 1,
Wherein the thermoplastic resin is selected from the group consisting of polycarbonate, polybutylene terephthalate, polyoxymethylene, polyamide 6, polyamide 66, modified polyphenylene oxide ), Polyphtalamides, liquid crystal polymers, polyether ether ketones, polyimides, polyamides, and mixtures of two or more thereof. Wherein the composite filament composition for a 3D printer is one.
The method according to claim 1,
Wherein the carbon fibers are pitch-based carbon fibers, and the content of the carbon fibers is 10 to 80 parts by weight based on 100 parts by weight of the thermoplastic resin.
The method according to claim 1,
Wherein the carbon fibers are polyacrylonitrile-based carbon fibers, and the content of the carbon fibers is 5 to 70 parts by weight based on 100 parts by weight of the thermoplastic resin.
delete delete (a) melt-kneading 100 parts by weight of a thermoplastic resin and 5 to 80 parts by weight of a carbon fiber, and adding 5 to 80 parts by weight of a melanin-based flame retardant to prepare a mixture;
(b) extruding the mixture into a single-screw extruder or a twin-screw extruder to produce an extrudate; And
(c) cutting and pelletizing the extrudate,
Wherein the carbon fiber has a tensile elastic modulus of 517 GPa to 830 GPa.
9. The method of claim 8,
Wherein the extruder has a length: diameter ratio of 25 to 50: 1.
9. The method of claim 8,
Wherein the driving speed of the extruder is 50 to 500 rpm.

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