KR102234110B1 - A method for manufacturing an article using a 3 dimensional printing - Google Patents

Abstract

One aspect of the present invention, a first step of molding a base structure by 3D printing a thermosetting elastic resin; And a second step of curing the base structure by heat treatment.

Description

Manufacturing method of molded body using 3D printing {A METHOD FOR MANUFACTURING AN ARTICLE USING A 3 DIMENSIONAL PRINTING}

The present invention relates to a method of manufacturing a molded article using 3D printing, and more particularly, to a method of manufacturing a molded article made of a thermosetting elastic resin using 3D printing.

A 3D printer refers to a device that prints (shapes) a three-dimensional shape of a real object as it is based on a three-dimensional drawing (data). That is, after completing a 3D drawing using a CAD or 3D modeling program, the corresponding data is transmitted to the printer through a predetermined data interface, and the 3D printer performs the process of creating the corresponding molded body based on the transmitted drawing data. It is done. Specifically, after creating a virtual cross section based on the corresponding drawing data, the molded body is manufactured by spraying a material such as metal or polymer through a nozzle to create and fuse a continuous layer.

3D printing is applied to various manufacturing fields such as architecture, structure (AEC), industrial design, automobile, aerospace industry, engineering, medical industry, biotechnology, fashion, and footwear.

The 3D printing technology is the SLA (stereolithography) method, which produces a molded body by partially sintering a liquid-based material, the SLS (selective laser sintering) method, which is produced by sintering a powder-based material, and a molded body by discharging a solid-based material. There are various methods such as fused deposition modeling (FDM).

In particular, the FDM type 3D printer, which has been widely distributed due to its low price and small size, is in an urgent need for quality improvement. FDM type 3D printer refers to a 3D printer in which plastic filaments are melted with the heat of a nozzle to make a liquid, and then stacked one by one to create a three-dimensional model. The fact that the strength of the completed three-dimensional model is weak due to the nature of this technology is one of the challenges that the FDM-based 3D printing technology must solve in the future. The basic printing principle of 3D printers is a method of stacking models layer by layer from bottom to top. It can withstand the pressure applied vertically to the finished model, but it is easily damaged by impact or pressure acting horizontally.

In order to increase the strength of the model, it is advantageous to make the thickness of the layer to be laminated as thin as possible. This is because it can increase the density of the model. However, this does not solve the fundamental problem. This is because no matter how high density the model is made, it can be easily damaged even with a small impact depending on the characteristics of the material.

Meanwhile, thanks to the development of 3D printing technology, technologies that apply a 3D printer to shoe manufacturing, such as Korean Patent No. 10-1601688, are currently being developed. In this case, the configuration of a system and device for manufacturing customized shoes is complicated. There are limitations that are limitedly applied to certain members such as, shoe soles, etc.

The present invention is to solve the problems of the prior art described above, and an object of the present invention is that it is possible to easily mold a fine and complex base structure compared to a thermoplastic resin, and to strengthen the bonding force between the layers forming the base structure in a horizontal direction. It is to provide a method of manufacturing a molded article capable of improving durability against an applied impact or pressure.

One aspect of the present invention, a first step of molding a base structure by 3D printing a thermosetting elastic resin; And a second step of curing the base structure by heat treatment.

In one embodiment, the first step may be performed by one selected from the group consisting of fused deposition modeling (FDM), selective laser sintering (SLS), and combinations thereof.

In one embodiment, the heat treatment may be performed at a temperature equal to or higher than the curing temperature of the thermosetting elastic resin.

In one embodiment, the curing temperature may be 90 ~ 250 ℃.

In one embodiment, the first and second steps may be performed in a 3D printer and a heat treatment apparatus connected to a rear end of the 3D printer, respectively.

In one embodiment, the first and second steps may be performed in a single process using fused deposition modeling (FDM) in which the temperature of the nozzle is controlled to be equal to or higher than the curing temperature of the thermosetting elastic resin.

In one embodiment, the tensile strength of the molded body is 50 ~ 200kgf / cm ² , the tear strength is 10 ~ 50kgf / cm, the permanent compression reduction rate may be 50% or less.

In one embodiment, the thermosetting elastic resin is natural rubber, polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, butadiene-propylene copolymer, butadiene-ethylene copolymer, butadiene-isoprene copolymer, iso Butylene-isoprene copolymer, brominated isobutylene-isoprene copolymer, ethylene-propylene-diene copolymer, isoprene-isobutylene copolymer, ethylene vinyl acetate (EVA), ethylene-propylene copolymer, chlorinated and chlorosulfonated It may include one selected from the group consisting of polyethylene, silicone elastomer, fluorocarbon elastomer, acrylic rubber, and combinations of two or more of them.

In one embodiment, the molded body may be a shoe member.

In the method of manufacturing a molded article according to an aspect of the present invention, a base structure is formed by 3D printing a thermosetting elastic resin, and then the base structure is heat-treated to cure it, thereby making it possible to easily mold a base structure that is finer and more complex than a thermoplastic resin. In addition, it is possible to improve durability against impact or pressure acting in a horizontal direction by reinforcing the bonding force between the layers constituting the base structure.

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

1 is a schematic diagram of a method of manufacturing a molded article according to an embodiment of the present invention.
2 is a schematic diagram of a method of manufacturing a molded article according to another embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and therefore is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected" with another part, this includes not only "directly connected" but also "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, it means that other components may be further provided, rather than excluding other components unless specifically stated to the contrary.

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

1 is a schematic diagram of a method of manufacturing a molded article according to an embodiment of the present invention.

Referring to FIG. 1, a method of manufacturing a molded article according to an aspect of the present invention includes a first step of forming a base structure by 3D printing a thermosetting elastic resin; And a second step of hardening the base structure by heat treatment.

The 3D printing is a method of forming an object by sequentially forming a plurality of layers in a pattern configured according to the shape and structure of the object to be manufactured, and is also referred to as additive manufacturing.

In the first step, the 3D printing may be performed by one selected from the group consisting of fused deposition modeling (FDM), selective laser sintering (SLS), and combinations thereof, and preferably, it may be performed by FDM. It is not limited.

In the case of the base structure manufactured using the FDM, each layer constituting the base structure may be formed and laminated by dispensing the thermosetting elastic resin through a nozzle preheated to a predetermined temperature.

Typically, in additive processing such as 3D printing, a base structure or molded article made of a curable resin or a composition thereof is manufactured in a single process, and it is difficult to control the chemical and mechanical properties of the base structure or molded article obtained in this process.

A molded article made of a thermosetting elastic resin manufactured through conventional 3D printing may have lower mechanical properties such as lower tensile strength and tear resistance than that manufactured through conventional extrusion molding, and has a high permanent compression reduction rate, resulting in a high elastic recovery rate. There is a slow problem.

On the other hand, the method of manufacturing a molded article according to an aspect of the present invention is to form a base structure by 3D printing a thermosetting elastic resin, and heat-treating the base structure to cure it, thereby forming a fine and complex base structure using a thermosetting elastic resin. It can be molded easily, and it is possible to improve the durability against impact or pressure acting in the horizontal direction by strengthening the bonding force between the layers constituting the base structure, and to significantly improve the elastic recovery rate by reducing the permanent compression reduction rate. .

Specifically, the tensile strength of the molded article manufactured by the method according to one aspect of the present invention is 50 to 200kgf/cm ² , preferably, 100 to 200kgf/cm ² , and the tear strength is 10 to 50kgf/cm, Preferably, 20 to 50 kgf / cm, more preferably, 30 to 50 kgf / cm, and the permanent compression reduction rate may be 50% or less, preferably 40% or less, more preferably 5 to 40%. have.

As used herein, the term "thermosetting elastic resin" can be interpreted as including rubber and elastomer, and in particular, "thermosetting" is included in the elastic resin when the elastic resin is exposed to a predetermined heat source or equivalent heat energy. It can be interpreted as meaning a property in which the elastic resin is solidified by cross-linking, polymerization, and/or vulcanization of the polymers.

At least a part or part of the base structure and the molded body may be made of a thermosetting elastic resin. The thermosetting elastic resin can provide a curable material that exhibits the properties of an elastomer when exposed to thermal energy.

The thermosetting elastic resin may be provided as a composition or mixture containing an elastic polymer, an initiator, a crosslinking agent, a filler, and a pigment. If necessary, the composition or mixture may further include a process oil that facilitates blending and processing, and may further include various additives such as a coupling agent, a titanium or zirconium compound, an antioxidant, an ozone inhibitor, and the like.

The elastic polymer is, for example, polyisoprene and natural rubber (NR) including hevea and guayule rubber, polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer ( NBR or nitrilebutadiene), butadiene-propylene copolymer, butadiene-ethylene copolymer, butadiene-isoprene copolymer, isobutylene-isoprene copolymer (butyl rubber or IIR), brominated isobutylene-isoprene copolymer (bromobutyl Rubber), ethylene-propylene-cyclopentadiene terpolymer, ethylene-propylene-5-ethylidene-norbornene terpolymer, and ethylene-propylene-diene (EPDM) copolymers such as ethylene-propylene-1,4-hexadiene terpolymer. Polymer, isoprene-isobutylene copolymer, ethylene vinyl acetate (EVA), ethylene-propylene copolymer (EPR or EPM), chlorinated and chlorosulfonated polyethylene (CM, CSM), silicone elastomer, fluorocarbon elastomer, acrylic rubber And it may be one selected from the group consisting of a combination of two or more of these, but is not limited thereto.

The initiator is, for example, one selected from the group consisting of dialkyl peroxide, diacyl peroxide, peroxy ester, peroxy ketal, peroxy dicarbonate, peroxy monocarbonate, hydroperoxide, and combinations of two or more thereof. However, it is not limited thereto. Suitable organic peroxides are, for example, di-tert-amyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5- Di(tert-butylperoxy)hexine-3, tert-butyl peroxybenzoate, tert-amyl peroxyacetate, tert-amylperoxy 2-ethylhexyl carbonate, 1,1-(di(t -Butylperoxy)-3,3,5-trimethylcyclohexane), 1,1-di(tert-amylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)cyclohexane, ter T-butyl peroxyisobutyrate, tert-butyl peroxydiethylacetate, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, dibenzoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(ethylhexanoylperoxy)hexane, didecanoyl peroxide, and two or more of them It may be one selected from the group consisting of good bar, but is not limited thereto.

The crosslinking agent may be, for example, a metal salt of an ethylenically unsaturated acid such as zinc diacrylate and magnesium dimethacrylate; Polyacrylates and polymethacrylates such as polybutadiene diacrylate, ethylene glycol dimethacrylate and trimethylolpropane triacrylate; Triallyl cyanuate; Triallyl isocyanurate; And it may be one selected from the group consisting of a combination of two or more of these, but is not limited thereto.

The filler (or filler) is, for example, silica, carbon black, clay, talc, calcium sulfate, calcium silicate, graphite, glass, mica, calcium metasilicate, barium sulfate, zinc sulfide, aluminum hydroxide, diatomaceous earth, carbonate ( Calcium carbonate, magnesium carbonate, etc.), metals (titanium, tungsten, zinc, aluminum, bismuth, nickel, molybdenum, iron, copper, brass, boron, bronze, cobalt, beryllium and alloys thereof, etc.), metal oxides (zinc oxide, Iron oxide, aluminum oxide, titanium oxide, magnesium oxide, zirconium oxide, etc.), particulate synthetic plastics (high molecular weight polyethylene, polypropylene, polystyrene, polyethylene ionomer resin, polyamide, polyester, polyurethane, polyimide, etc.), cotton floc, It may be one selected from the group consisting of cellulose flock, cellulose pulp, leather fiber, and a combination of two or more of them, but is not limited thereto.

The pigments are, for example, carbon black, titanium dioxide, iron oxide pigments such as black iron oxide and red iron oxide, zinc oxide, monoazo and diazo pigments, cobalt blue, ultramarine, bismuth vanadate, azo metal complex, copper phthalocyanine , Anthraquinone, quinacridone, dioxazine, perylene pigment, thioindigo pigment, and may be one selected from the group consisting of a combination of two or more of them, but is not limited thereto.

In the second step, the base structure formed in the first step may be heat-treated to cross-link, polymerize, and/or vulcanize the polymer chains included in the thermosetting elastic resin constituting at least a part of the base structure.

That is, since the thermosetting elastic resin and the base structure in the first step are not exposed to a temperature higher than the curing temperature of the thermosetting elastic resin, they have chemical and mechanical properties similar to those manufactured through conventional 3D printing. Although it can withstand the pressure applied vertically to the base structure, it can be easily damaged by impact or pressure acting horizontally.

In the second step, the base structure is heat-treated to cross-link, polymerize, and/or vulcanize the polymer chains included in the thermosetting elastic resin constituting at least a part of the base structure, so that a fine and complex base using a thermosetting elastic resin The structure can be easily molded, and the durability against impact or pressure acting in the horizontal direction can be improved by strengthening the bonding force between the layers constituting the base structure, and the elastic recovery speed can be significantly improved by reducing the permanent compression reduction rate. I can.

The heat treatment may be performed at a temperature equal to or higher than the curing temperature of the thermosetting elastic resin, and the curing temperature may be 90 to 250°C, preferably 100 to 250°C, more preferably 130 to 250°C. Accordingly, the type of the thermosetting elastic resin is not particularly limited as long as its curing temperature satisfies the above range.

The first and second steps may be performed in a 3D printer and a heat treatment apparatus connected to a rear end of the 3D printer, respectively.

The heat treatment device may be a hot air, an oven, a chamber, or the like, and the type of heat source included in the heat treatment device is not particularly limited as long as it can be controlled to a temperature equal to or higher than the curing temperature of the thermosetting elastic resin.

2 is a schematic diagram of a method of manufacturing a molded article according to another embodiment of the present invention.

Referring to FIG. 2, a method of manufacturing a molded article according to another aspect of the present invention includes a first step of forming a base structure by 3D printing a thermosetting elastic resin; And a second step of heat-treating and curing the base structure; in one embodiment, the first and second steps include fused deposition (FDM) in which the temperature of the nozzle is controlled to be equal to or higher than the curing temperature of the thermosetting elastic resin. modeling) can be used as a single process.

In the case of the base structure manufactured using the FDM, each layer constituting the base structure may be formed and laminated by dispensing the thermosetting elastic resin through a nozzle preheated to a predetermined temperature.

The curing temperature of the thermosetting elastic resin may be 90 to 250°C, preferably, 100 to 250°C, more preferably 130 to 250°C, and the nozzle is preheated above the curing temperature of the thermosetting elastic resin In the case of dispensing the thermosetting elastic resin through the nozzle, the thermosetting elastic resin may be melted and crosslinked while passing through the nozzle. The thermosetting elastic resin dispensed from the nozzle is in a crosslinked state, but may have fluidity or flowability suitable for molding a base structure or a molded article.

According to the single process, the thermosetting elastic resin is dispensed from the nozzle in a melted and crosslinked state and laminated to have a predetermined shape and structure, and additional heat treatment is performed on the laminated base structure or molded body. Since it is not made, it may be difficult to strengthen the bonding force between the layers constituting the base structure or the molded body.

However, even if the bonding force between the layers is excluded, the tensile strength, tear strength, and permanent compression reduction rate of a single layer, base structure or molded article manufactured by the single process are compared to those manufactured using conventional FDM. It can be significantly improved. In addition, since the single process does not require a separate heat treatment device, it may have an advantageous effect in terms of economy and productivity.

Hereinafter, an embodiment of the present invention will be described in detail.

Example 1

Each component was blended according to the composition ratio of Table 1 and then extruded at 100° C. to prepare an elastic filament for 3D printing that is thermally cured at 170° C. A molded article was manufactured by discharging the elastic filament through a nozzle using the FDM method. At this time, the nozzle was preheated to 170° C. to simultaneously stack and cure the molded body.

ingredient content Styrene-butadiene rubber (SBR) 100 Silica 35 Zinc oxide (ZnO) 5 Silane coupling agent (Si-69) 2.5 Sulfur (S) 4 Vulcanization accelerator 1 (dibenzothiazyl disulfide, DM) 3 Vulcanization accelerator 2 (2-mercaptobenzothiazole, M) 1.5 Stearic acid 1.5

(Unit: parts by weight)

Example 2

Each component was blended according to the composition ratio of Table 1 and then extruded at 100° C. to prepare an elastic filament for 3D printing that is thermally cured at 170° C. Using the FDM method, the elastic filament was discharged through a nozzle to prepare a primary molded body. At this time, the nozzle was preheated to 150° C. to be semi-hardened when the primary molded body was laminated.

Thereafter, the primary molded body was put into a high-temperature chamber preheated to 170° C. and allowed to stand for 5 minutes to completely crosslink to obtain a final molded body.

Comparative Example 1

A molded article was manufactured in the same manner as in Example 2, except that the primary molded article was not put into the high-temperature chamber.

Comparative Example 2

Each component was blended according to the composition ratio of Table 1 and then extruded at 100° C. to prepare an elastic filament for 3D printing that is thermally cured at 170° C. A molded article was manufactured by discharging the elastic filament through a nozzle using the FDM method. At this time, the nozzle was preheated to 130° C. to be semi-hardened when the molded body was laminated.

Experimental example

Physical properties were measured and evaluated by the following method using the molded articles prepared in Examples and Comparative Examples as test pieces, and the results are shown in Table 2 below.

-Tensile strength (kgf/cm ² ): Tensile strength was measured according to KS M 6518. At this time, the number of test pieces used in the same test was set to five.

-Tear strength (kgf/cm): Tear strength was measured according to KS M 6518. At this time, the number of test pieces used in the same test was set to five.

-Permanent compression set (%): The tear strength was measured according to KS M 6518, and the permanent compression set was measured by compressing the test piece by 25% for 22 hours at 70°C.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Nozzle temperature (℃) 170 150 150 130 High temperature chamber
Heat treatment conditions - 170℃, 5 minutes - - The tensile strength
(kgf/cm ² ) 102 120 12.58 2.32 Tear strength
(kgf/cm) 33 40 7.4 1.4 Permanent compression set
(%) 34 25 60 95 Appearance properties Fully crosslinked rubber molded body Fully crosslinked
Rubber molded body Low degree of crosslinking
Rubber molded body Not crosslinked

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims to be described later, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

Claims (9)

A first step of forming a base structure by 3D printing a thermosetting elastic resin; And
In the method of manufacturing a molded article comprising;
The heat treatment is performed at a temperature equal to or higher than the curing temperature of the thermosetting elastic resin,
The permanent compression reduction rate of the molded article is 50% or less, the method of manufacturing a molded article. The method of claim 1,
The first step is performed by one selected from the group consisting of fused deposition modeling (FDM), selective laser sintering (SLS), and combinations thereof. delete The method of claim 1,
The curing temperature is 90 ~ 250 ℃, the manufacturing method of the molded body. The method of claim 1,
The first and second steps are performed in a 3D printer and a heat treatment apparatus connected to a rear end of the 3D printer, respectively. The method of claim 1,
The first and second steps are performed in a single process using fused deposition modeling (FDM) in which the temperature of the nozzle is controlled to be equal to or higher than the curing temperature of the thermosetting elastic resin. The method of claim 1,
The tensile strength of the molded body is 50 ~ 200kgf / cm ² , the tear strength is 10 ~ 50kgf / cm, the method of manufacturing a molded body. The method of claim 1,
The thermosetting elastic resin is natural rubber, polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, butadiene-propylene copolymer, butadiene-ethylene copolymer, butadiene-isoprene copolymer, isobutylene-isoprene copolymer. , Brominated isobutylene-isoprene copolymer, ethylene-propylene-diene copolymer, isoprene-isobutylene copolymer, ethylene vinyl acetate (EVA), ethylene-propylene copolymer, chlorinated and chlorosulfonated polyethylene, silicone elastomer, fluorine A method for producing a molded article comprising one selected from the group consisting of a low carbon elastomer, an acrylic rubber, and a combination of two or more of them. The method according to any one of claims 1, 2, and 4 to 8,
The molded article is a shoe member, a method of manufacturing a molded article.

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