KR101860671B1 - Ultraviolet resin for 3-D printing - Google Patents

Abstract

Provided is a UV-curable resin for 3D printing, containing a siloxane monomer containing a vinyl group, a polydimethylsiloxane containing a plurality of vinyl groups in a side chain or a mixture thereof, an acrylic monomer, and a photoinitiator. The vinyl group positioned at the side chain on polydimethylsiloxane and 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane and a C=C double bond present in an acrylic monomer are polymerized by UV and the photoinitiator, and rubber toughened plastic is formed, thereby improving mechanical strength.

Description

UV-curable resin for 3-D printing {Ultraviolet resin for 3-D printing}

The present invention relates to a UV-curable resin for 3-D printing, and more particularly to a UV-curable resin for 3-D printing comprising a siloxane monomer containing a vinyl group, a polydimethylsiloxane containing a plurality of vinyl groups in a side chain, The present invention relates to a cured resin.

3-D printing technology is a lamination manufacturing technique, which is a method of manufacturing three-dimensional printed materials through various lamination methods. It was first invented in the company 3-D systems founded by Charles W. Hull of USA in 1984. 3-D printing technology is a next-generation core manufacturing technology that has a ripple effect through fusion with other industries because it is a method of stacking materials based on digital design data. In the major countries such as USA and Japan, we are fostering industry by supporting industrial clustering, industry-academia linkage, and product design technique development. In Korea, we are also expanding application fields of 3-D printing technology and competitiveness of related industries. We are trying to increase. Almost all the materials used for 3-D printing are glass, engineering plastics, and composite materials such as carbon composites. In the technical completion stage, powder, film, and wire are laminated by pressing a laser source or a heated roll It is folding.

For use in nano / microscale structures, biotechnology, and molds, stereolithography apparatus (SLA) systems, which are advantageous for finer geometry, are typical. SLA system The material used for 3-D printing is a UV curable polymer consisting essentially of an oligomer or monomer, a photopolymerization initiator, and various additives. Oligomers form polymer by photopolymerization reaction, which is an important base resin that affects the properties of the output. As oligomers, acrylates such as polyester type, polyether type, urethane type, epoxy type and polyacryl type are mainly used. The monomer serves as a reactive diluent, a crosslinking agent, and forms a film during photopolymerization. The photoinitiator absorbs ultraviolet rays to generate radicals or cations to initiate polymerization. Examples of additives include photo sensitizers, colorants, and thickeners.

As an oligomer used in radical initiated polymerization by photoreaction, an acrylate-based resin has a rapid curing rate and has various advantages in that it can variously control physical properties depending on the type of acryl and the number of reactors. However, the acrylate oligomer prepared through photoreaction has a hard structure which is hard and brittle after curing. Therefore, when continuous stress is applied from the outside, cracks may be generated in the inside of which stress can not be relieved and the property may be lowered. This causes problems with the durability and stability of the structures made with 3-D printers.

SUMMARY OF THE INVENTION The object of the present invention is to provide a 3-D printing method for improving the curing structure of a brittle acrylic monomer by adding a siloxane monomer containing a vinyl group, a polydimethylsiloxane containing a plurality of vinyl groups in a side chain, Ultraviolet ray hardening resin.

In order to accomplish the above object, an aspect of the present invention is to provide a polyimide film comprising a siloxane monomer having a vinyl group, a polydimethylsiloxane having a plurality of vinyl groups in a side chain thereof or a mixture thereof, an acrylic monomer and a photoinitiator, Methylsiloxane is represented by the following formula (1)

[Chemical Formula 1]

the present invention provides an ultraviolet curable resin for 3-D printing wherein n + m is 1 to 20 and m is 1 to 20.

The polydimethylsiloxane containing the vinyl group may have m greater than n.

The polydimethylsiloxane containing the vinyl group may have a molecular weight of 240 g or more and 5000 g or less.

The polydimethylsiloxane containing the vinyl group may have a weight ratio of 0.1 wt% to 3 wt% with respect to the ultraviolet ray hardening resin for 3-D printing.

The siloxane monomer containing the vinyl group may be 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane.

The 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane may have a weight ratio of 1 wt% to 7 wt% with respect to the UV-curable resin for 3-D printing.

The UV curable resin for 3-D printing of the present invention may have a zero shear viscosity of 0.48-1.1 Pa · s.

The acrylic monomer may be a mixture of acrylic monomers having 2 to 6 different numbers of functional groups, and the acrylate may be added to 1, 6-hexanediol diacrylate (HDDA) And 9 parts by weight of dipentaerythritol hexaacrylate (DPHA) may be added.

According to embodiments of the present invention, an ultraviolet curable resin for 3-D printing can be prepared which comprises a polydimethylsiloxane, an acryl monomer, and a photo-curing agent having a plurality of vinyl groups in a side chain. In this case, the C = C double bonds present in the side chain of the polydimethylsiloxane and the C = C double bonds in the acrylic monomer are polymerized by ultraviolet rays and the photoinitiator, and rubber toughened plastic is formed, .

Further, in the ultraviolet curing resin for SLA type 3-D printing, the flow characteristics of the material are very important for applying a slide-and-separate (SAS) technique in which a layer is cured and the material accumulated in the next layer is dispersed Characteristics. According to the embodiments of the present invention, excellent flow characteristics of the acrylic monomer can be maintained while improving the mechanical strength.

Also, by using acrylic monomers having various numbers of functional groups in combination, it is possible to produce a UV-curable resin for 3-D printing having strength, flow characteristics, enthalpy value and curing time suitable for each 3-D printer.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a chemical formula showing a polydimethylsiloxane (V-PDMS) comprising a plurality of vinyl groups in the side chain according to an embodiment of the present invention.
Figures 2 and 3 are formulas representing 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^vi ) and octamethylcyclotetrasiloxane (D ₄ ).
Figure 4 is a chemical formula showing a polydimethylsiloxane (V _100% -PDMS) comprising one vinyl group per all repeat units of the polymer in accordance with one embodiment of the present invention.
5 is 1,3,5,7-vinyl -1,3,5,7- tetramethyl cyclotetrasiloxane (D ₄ ^vi) (a) and octamethylcyclotetrasiloxane (D ₄₎ of ¹ (b) ≪ 1 > H-NMR spectrum.
6 is a graph showing a ¹ H-NMR spectrum of V _100% -PDMS.
FIG. 7 is a graph showing the molecular weight of V _100% -PDMS according to the ratio of V _100% -PDMS prepared according to an embodiment of the present invention and the included endcapping agent, DVDS.
8 is a graph showing the Izod impact strength of 3-D printing UV-curable resin according to the ratio of repeating units containing a vinyl group in the side chain, in V-PDMS having a molecular weight of 1300 according to an embodiment of the present invention .
FIG. 9 is a graph showing the Izod impact strength of 3-D printing UV curable resin prepared according to one embodiment of the present invention, according to the molecular weight of V _100% -PDMS.
10 is a graph showing the zero shear viscosity of the UV-curable resin for 3-D printing according to the weight ratio of V _100% -PDMS of D ₄ , D ₄ ^vi or a molecular weight of 1300.
Figure 11 is a 3-to a thermogravimetric analysis graph of a 3-D printing ultraviolet curable resin including acrylic monomers in Table 1, Figure 11 b includes a V -PDMS _100% of the acrylic monomer, and 3wt% of Table 1 D is a thermogravimetric analysis graph of an ultraviolet curable resin for printing.
12 shows the results of a UV-curable resin for 3-D printing comprising the acrylic monomers of Table 1 and V _100% -PDMS having a weight ratio of 3 wt% according to one embodiment of the present invention and 3- D printing UV-curable resin after heat treatment.
13 is a graph showing the change of the photo-curing enthalpy of 3-D printing UV-curable resin containing the acrylic monomer shown in Table 1 according to the weight ratio of V _100% -PDMS prepared according to an embodiment of the present invention .
14 is a graph showing the photo-curing enthalpy and hardening of 3-D printing UV curable resins comprising 9 parts by weight of DPHA per 1 part by weight of HDDA, based on the weight ratio of V _100% -PDMS, FIG. 5 is a graph showing a change in time. FIG.
FIG. 15 is a graph showing the photo curing enthalpy change of UV-curable resin for 3-D printing prepared according to Production Example 2 using D ₄ , D ₄ ^vi or V _100% -PDMS, PlasGray as an acrylic monomer.
Figure 16 is a graph showing the Izod impact strength of 3-D printing UV curable resins comprising the acrylic monomers listed in Table 1, according to the weight ratio of V _100% -PDMS, prepared according to one embodiment of the present invention, to be.
Figure 17 is a graphical representation of D ₄ , D ₄ ^vi or V _100% -PDMS according to the weight ratio of the HDDA acrylic monomer to the UV curable resin for 3-D printing.
Figure 18 is a graphical representation of D ₄ , D ₄ ^vi or V _100% -PDMS in 1 wt%, and Izod impact strength of 3-D printing UV-cured resin using PlasGray as an acrylic monomer.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Like reference numerals designate like elements throughout the specification.

In this specification, the term " on top of another layer " means that not only these layers are directly in contact but also another layer (s) is located between these layers.

Production Example 1: Polydimethylsiloxane (V-PDMS) containing a plurality of vinyl groups in the side chain

Into a 250 ml three-necked flask equipped with a reflux condenser, a thermometer and a nitrogen inlet were added octamethylcyclotetrasiloxane (hereinafter referred to as D ₄ ), 1,3,5,7-tetravinyl-1,3,5,7-tetramethyl Cyclotetrasiloxane (hereinafter referred to as D ₄ ^vi ) or a mixture thereof was added and 1,3-divinyltetramethyldisiloxane (hereinafter DVDS) was added as a terminal capping agent. Equilibrium polymerization was carried out at 130 ° C for 2 hours using potassium trimethylsiloxanolate as a catalyst. After the reaction was completed, tris (2-chloroethyl) phosphate (tris (2-chloroethyl) phosphate) as a neutralizing agent was added by 0.018 wt% corresponding to 6% of the catalyst content to deactivate the reaction catalyst. The reaction product was added to a vacuum evaporator under reduced pressure and vacuum distillation was conducted to remove the unreacted monomer to obtain a polydimethylsiloxane (hereinafter referred to as V-PDMS) containing a plurality of vinyl groups in a side chain of a copolymer of dimethylsiloxane and methylvinylsiloxane, which are silicon-based polymers .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a chemical formula showing a polydimethylsiloxane (V-PDMS) comprising a plurality of vinyl groups in the side chain according to an embodiment of the present invention. Figures 2 and 3 also illustrate the synthesis of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^vi ) and octamethylcyclotetrasiloxane (D ₄ ) to be.

1, in the V-PDMS, n, which is the number of repeating units having no vinyl group in the side chain, may be 0 to 19, m, which is the number of repeating units having vinyl groups in the side chain, is 1 to 20, and n + m may be from 1 to 20; The ratio of m and n can be controlled by the addition ratio of D ₄ ^vi and D ₄ represented by the formulas shown in FIG. 2 and FIG. 3 in the production method of Preparation Example 1.

Figure 4 is a chemical formula showing a polydimethylsiloxane (V _100% -PDMS) comprising one vinyl group per all repeat units of the polymer in accordance with one embodiment of the present invention.

According to the method of Production Example 1, V _100% -PDMS can be obtained by polymerization using only D ₄ ^{vi as a} monomer.

5 is 1,3,5,7-vinyl -1,3,5,7- tetramethyl cyclotetrasiloxane (D ₄ ^vi) (a) and octamethylcyclotetrasiloxane (D ₄₎ of ¹ (b) H-NMR spectrum, and FIG. 6 is a graph showing a ¹ H-NMR spectrum of V _100% -PDMS.

In the case of FIG. The D _4, as identified in the 5 0.1 ppm (chemical shift, CS ) H (from CH 2) that due to this with CH = CH ₂ vinyl peaks for the CH3 H and D ₄ ^vi of the 6 ppm As shown in Fig. In the case of the synthesized V-PDMS, the presence of the vinyl group peak can be confirmed at 6 ppm of the same position in the NMR spectrum of the V-PDMS of FIG. VPDMS with a molecular weight of 1,322 g / mol has 12 repeating units, and the ratio of the number of CH and CH ₂ hydrogen in the methyl group to the number of CH and CH ₂ in the vinyl group is 24: 7: 14, and the ratio of the remaining hydrogen to the vinyl group is 2.21. The area in the vicinity of 6 ppm for a 0.1 ppm around the area due to the CH group to 38.44, CH ₂ of the vinyl group is the 17.24 remaining hydrogen ratio of the vinyl group CH ₂ in the ratio of the peak area of the methyl group of hydrogen and a vinyl group is 2.23, it can be calculated that the synthesis is well done.

7 is a graph showing the molecular weight of V _100% -PDMS according to the ratio of V _100% -PDMS prepared according to Preparation Example 1 and the end-capping agent, DVDS.

Referring to FIG. 7, it can be seen that as the graph shows, the molecular weight increases as the equivalent ratio of the terminal capping agent decreases. Therefore, the equilibrium polymerization of the sugar molecules by the catalyst can be suppressed by increasing the content of the terminal capping agent, so that the molecular weight can be reduced.

Manufacturing example  2 : Vinyl  Included Siloxane  The monomer, V- PDMS  Or 3-D printing UV-curable resin

1 to 5 wt% of a siloxane monomer containing a vinyl group or V-PDMS synthesized according to Preparation Example 1 was added to the acrylic monomer of the polyfunctional group shown in Table 1, and 1-hydroxyethylcyclohexylphenyl 1 wt% of ketone (Irgacure 占 184, Ciba) was added. The mixture was stirred for 20 minutes with a sonicator under ultraviolet ray shielding condition, and then kept in a dark room at 25 ° C in a sealed state to prepare an ultraviolet ray hardening resin for 3-D printing.

The vinyl group-containing siloxane monomer may be 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^vi ), vinyltrimethoxysilane, vinyltriethoxysilane, Vinyltris (2-methoxyethoxy) silane, vinyltrisisopropoxysilane, vinyltris (isopropenyloxy) silane, vinyltris (tert-butylperoxy) silane, vinyltrimethylsilane, vinyltrimethylsilane, vinyl Methyldimethoxysilane, vinylmethyldiethoxysilane, bis (methyldichlorosilyl) ethane, 1,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane, 1,3, Tributyl-1,3,5-trimethylcyclotrisiloxane, 2,4,6-trimethyl-2,4,6-trivinyl-cyclotrisiloxane, 1,1,3,3-tetramethyl- 3-divinyldisiloxane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 1,3-bis (3-methacryloxypropyl) tetrakis (trimethylsiloxy ) 1,3-Bis (3-Methacryloxypropyl) Tetrakis (Trim ethylsiloxy) Disiloxa, 1,3-divinyltetramethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 3-acryloxypropyltris (trimethylsiloxy) silane, 3-methacryloxypropylpentamethyldisiloxane (Trimethylsiloxy) silane, bis (3-methacryloxypropyl) tetramethyldisiloxane, tetraallylososylate allyl silicate, and tris (vinyldimethylsiloxy) methylsilane. It is not.

The acrylic monomer of the polyfunctional group may be selected from the group consisting of methyl acrylate, ethyl acrylate, 2-hydroxyethylacrylate, butyl acrylate and 2-ethylhexyl acrylate Substituted or unsubstituted alicyclic C1-12 alkyl acrylates such as 2-ethylhexyl acrylate and the like, substituted or unsubstituted alicyclic C1-12 alkyl acrylates such as cyclohexyl acrylate, phenyl acrylate, And substituted or unsubstituted aromatic C 6-12 aryl acrylates such as benzyl methacrylate and the like, but are not limited thereto. The acrylic monomer of the polyfunctional group may be at least one selected from the group consisting of 1,6-hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), Plasgray, a product commercialized by ASIGA, or a mixture thereof.

Description Number of functional groups Molecular Weight Tg
(° C) Viscosity
(CPS @ 25 C) 1,6-hexanediol diacrylate
(HDDA) 2 226 43 5 to 15 Trimethylolpropane triacrylate
(TMPTA) 3 296 62 80-120 Pentaerythritol tetraacrylate
(PETA) 4 352 65 120 ~ 200 Dipentaerythritol hexaacrylate
(DPHA) 6 578 54 4000 ~ 7000

The above table shows the number of functional groups, molecular weight, glass transition temperature (Tg) and viscosity of each acrylic monomer.

SLA-type 3-D printers stack liquid-type photocurable polymer materials in a water tank through an inverted ultraviolet light source. Therefore, there is a need for a slicing technique to disperse the material to be stacked next layer after hardening one layer. In order to apply such a slicing technique, it is required that the viscosity of the ultraviolet ray hardening resin for 3-D printing be 0.48 to 1.1 Pa.s. It can be seen that the viscosity of the acrylic monomers shown in Table 1 is greatly increased as the number of functional groups is increased. Particularly, DPHA and PETA having more than 4 functional groups show a viscosity of not less than 1.1 Pa.s, which is not suitable for slicing, and it is necessary to control the viscosity in order to apply it to UV curable resin for 3-D printing.

In Production Example 2, 9 parts by weight of mixed acrylic monomers of DPHA per 1 part by weight of HDDA having similar viscosity to commercial 3-D printing materials were used as individual polyfunctional acrylic monomers and representative mixed acrylic monomers shown in Table 1.

The photoinitiator is not particularly limited as long as the photoinitiator is capable of initiating a polymerization reaction through ultraviolet irradiation or the like. Examples of the photoinitiator include an? -Hydroxyketone compound, a phenylglyoxylate compound, a benzyldimethylketal (Iodonium salt), and a mixture of at least one of the above compounds, at least one compound selected from the group consisting of an? -Aminoketone compound, a monoacylphosphine compound (MAPO), a bisacylphosphine compound, a phosphine oxide compound, a metallocene compound, . In the present invention, one or more of the above can be used, but the present invention is not limited thereto

Experimental Example  One : On the side chain Vinyl  Izod impact strength of UV-curable resin for 3-D printing according to the proportion of repeating units included

8 is a graph showing Izod impact strength of 3-D printing UV-curable resin according to the proportion of repeating units containing a vinyl group in the side chain in a V-PDMS having a molecular weight of 1,300.

The V-PDMS was synthesized according to Preparation Example 1 such that the number of repeating units containing vinyl groups in the side chain was 0%, 25%, 50%, 75% and 100% with respect to n + m. 9% by weight of DPHA per 1 part by weight of HDDA, 1% by weight of synthesized V-PDMS and 1% by weight of photoinitiator to 3% by weight of UV-curable resin for 3-D printing, To prepare a cured resin.

It was confirmed that the Izod impact strength of the UV-curable resin for 3-D printing was increased as the proportion of the vinyl-containing repeating unit in the side chain of the V-PDMS was increased. Therefore, it was confirmed that the polydimethylsiloxane (hereinafter referred to as V _100% -PDMS) having one vinyl group per repeating unit of the polymer had the largest Izod impact strength.

Experimental Example 2: V _100% Izod impact strength of ultraviolet curing resin for 3-D printing according to molecular weight of PDMS

9 is a graph showing the Izod impact strength of UV-curable resin for 3-D printing prepared according to Production Example 2 according to the molecular weight of V _100% -PDMS.

V _100% -PDMS was synthesized so as to have different molecular weights by equilibration polymerization with addition of DVDS having a different weight ratio to D ₄ ^vi according to Production Example 1. UV-curable resin for 3-D printing was prepared according to Preparation Example 2 using synthesized V _100% -PDMS and HDDA as an acrylic monomer. HDDA was selected because it can accurately measure the mechanical properties according to molecular weight as it maintains a homogeneous phase due to no phase separation with V _100% -PDMS.

Referring to FIG. 9, when the V _100% -PDMS having a molecular weight of 1,300 Mw was added, the impact strength was increased. As the molecular weight was increased, the impact strength was decreased. V _100% -PDMS, which has a high molecular weight, is believed to not only reduce the acrylic monomer and photo-curing but also interfere with the photo-curing between the acrylic monomers and thus reduce the mechanical properties.

Experimental Example  3: D ₄ , D ₄ ^vi  or V _100% - PDMS  For 3-D printing by weight ratio Of ultraviolet curing resin  Zero shear viscosity

10 is a graph showing the zero shear viscosity of the UV-curable resin for 3-D printing according to the weight ratio of V _100% -PDMS of D ₄ , D ₄ ^vi or a molecular weight of 1300.

The UV curable resin for 3-D printing was prepared according to Preparation Example 2 using 9 parts by weight of DPHA as an acrylic monomer and 1 part by weight of HDDA as a mixed acrylic monomer. The UV curing resin for 3-D printing was measured by TA Instruments' AR 2000ex rotational rheometer (shear rate 1 to 50 rad / s). As the weight ratio of V _100% -PDMS added was increased, the viscosity of the UV-curable resin for 3-D printing also increased. It is considered that the viscosity is increased because the molecular weight (1300) of V _100% -PDMS is larger than the molecular weight (DPHA: 578, HDDA: 226 g / mol) of the acrylic monomers used for mixing. On the other hand, it was confirmed that when D ₄ (297 g / mol) and D ₄ ^vi (345 g / mol) having lower molecular weights were added, the viscosity decreased. As described above, the rheological properties of UV-curable resins for 3-D printing are important factors affecting slicing. And can be used as a UV-curable resin for 3-D printing when the zero shear viscosity is 0.48 to 1.1 Pa.s based on commercially available commercial 3-D printers. The present invention can produce a UV-curable resin for 3-D printing having a high viscosity with a suitable viscosity by mixing a siloxane monomer containing a vinyl group having a small molecular weight and V _100% -PDMS having a large molecular weight.

Experimental Example 4: 3 wt% V _100% - PDMS  UV light for 3-D printing Cured resin Thermogravimetry (Thermogravimetric Analyze)

Figure 11 is a 3-to a thermogravimetric analysis graph of a 3-D printing ultraviolet curable resin including acrylic monomers in Table 1, Figure 11 b includes a V -PDMS _100% of the acrylic monomer, and 3wt% of Table 1 D is a thermogravimetric analysis graph of an ultraviolet curable resin for printing.

According to Production Example 2, thermogravimetric analysis of 3-D printing UV-curable resin containing 3 wt% of V _100% -PDMS and acrylic monomer of Table 1 was carried out. A thermogravimetric analyzer (TGA Q50 (trade name), manufactured by TA Corporation) was used to analyze the thermal stability of 3-D printing UV curable resin containing ASIGA PlasGray, polyfunctional acrylic monomer and 3 wt% V _100% ), 4-5 mg of sample was placed and the temperature was measured at a rate of 10 ° C / min from room temperature to 800 ° C under a nitrogen atmosphere.

Referring to FIG. 11A, it can be seen that the pyrolysis curve is different according to the functional groups. The acrylic monomers of 2,3,4-functional groups are pyrolyzed in two stages. The first decomposition occurs at around 150-200 ° C and the second decomposition occurs at the latter stage of 300 ° C because the acrylic monomer is cured by heat after the first decomposition. On the other hand, DPHA having 6 functional groups, which only occurred at the first stage pyrolysis (393 ° C), is more thermally stable because of its more complicated molecular structure and higher molecular weight than the acrylic monomers of 2,3,4-functional groups. Likewise, PlasGray of the commercial product has a stable pyrolysis temperature (314.0 ° C) compared with other acrylic monomers, but it is confirmed that it has a stable structure through no decrease in thermogravimetry at around 150-200 ° C.

Referring to FIG. 11B, it was confirmed that the thermal decomposition temperature of the UV-curable resin for 3-D printing containing an acrylic monomer having four or more functional groups was increased. This shows that the higher the number of functional groups when V _100% -PDMS is added, the more the thermal stability is increased.

12 shows the results of a UV-curable resin for 3-D printing comprising the acrylic monomers of Table 1 and V _100% -PDMS having a weight ratio of 3 wt% according to one embodiment of the present invention and 3- D printing UV-curable resin after heat treatment.

Referring to FIG. 12, residue after pyrolysis from the TGA thermal analysis curve to 800 ° C. is shown. The residual content of PlasGray (0.31 wt%) is lower than that of other acrylic monomers. Comparing the residues of acrylic monomers with the number of functional groups, the residues are increased as the number of functional groups is increased, and then decreased again by DPHA which is a 6-functional group, which can be explained by the curing reaction. That is, among the 2,3,4-functional groups which were pyrolyzed in two stages, it was confirmed that the residual content remained much as the functional groups having a large amount of curing. The relatively simple structure determined the residual content depending on the thermosetting I could confirm. In the case of V _100% -PDMS having a weight ratio of 3 wt% according to Production Example 2 and the ultraviolet curing resin for 3-D printing containing the acrylic monomer shown in Table 1, it was confirmed that the residual content increased as the number of functional groups increased there was. This is presumably because the V _100% -PDMS is mixed with the acrylic monomer and is affected by the functional group when it reaches the thermosetting.

Experimental Example  5: V _100% - PDMS  For 3-D printing by weight ratio Of ultraviolet curing resin  Light curing Enthalpy  Change measurement

According to Production Example 2, 3-D printing ultraviolet rays containing 3 _{% by} weight of V _100% -PDMS having a molecular weight of 1,300 and having a different weight ratio and containing 9% by weight of DPHA, acrylic acid monomer or PlasGray per 1 part by weight of HDDA To prepare a cured resin. The prepared samples were examined for changes in enthalpy according to UV irradiation using a differential scanning calorimeter (DSC Q2000, UV curing accessary; Photo-DSC) manufactured by TA Corporation. At this time, the UV wavelength range has a wide range of wavelengths from 300 to 500 nm.

13 is a graph showing the change of the photo-curing enthalpy of 3-D printing UV-curable resin containing the acrylic monomer shown in Table 1 according to the weight ratio of V _100% -PDMS prepared according to an embodiment of the present invention .

The enthalpy of HDDA, which is a functional group of two acrylic monomers, increases as the content of added V _{100% -} PDMS increases. However, TMPTA with three functional groups has a behavior that interferes with photo curing. PETA and DPHA, which are relatively large amounts of acrylic monomers, show high enthalpy at low content and tend to decrease again as content increases. This phenomenon is thought to be caused by activation of vinyl radicals formed from an initiator by a UV irradiation in a vinyl group contained in V _100% -PDMS to cause a photo-curing reaction together with an activated double bond of an acrylic monomer. However, when the content of V _100% -PDMS is increased, the addition of V _100% -PDMS may interfere with the photo-curing reaction between acrylic monomers. . In addition, as the content of V _100% -PDMS is increased, the possibility of phase separation with acrylic monomers can not be excluded.

14 is a graph showing the photo-curing enthalpy and hardening of 3-D printing UV curable resins comprising 9 parts by weight of DPHA per 1 part by weight of HDDA, based on the weight ratio of V _100% -PDMS, A graph showing the change of time

Referring to FIG. 14, it can be confirmed that the addition of V _100% -PDMS having a high molecular weight lowers enthalpy. It was also confirmed that as the enthalpy decreases, the photo-curing time increases.

FIG. 15 is a graph showing the photo curing enthalpy change of UV-curable resin for 3-D printing prepared according to Production Example 2 using D ₄ , D ₄ ^vi or V _100% -PDMS, PlasGray as an acrylic monomer.

Referring to Figure 15, D ₄ ^vi or V _100% -PDMS the 3-D printing ultraviolet curable resin that contains, on the other hand has relatively high enthalpy, UV for 3-D printing, comprising a D ₄ no vinyl group The cured resin showed a low enthalpy value. It has been confirmed that the UV-curable resin for 3-D printing according to the present invention can be applied not only to general acrylic monomers but also to commercial 3-D printing materials such as PlasGray.

Experimental Example 6: Izod impact strength change of UV-curable resin for 3-D printing according to the weight ratio of V _100% -PDMS

According to Production Example 2, 3-D printing ultraviolet rays containing 3 _{% by} weight of V _100% -PDMS having a molecular weight of 1,300 and having a different weight ratio and containing 9% by weight of DPHA, acrylic acid monomer or PlasGray per 1 part by weight of HDDA To prepare a cured resin.

Figure 16 is a graph showing the Izod impact strength of 3-D printing UV curable resins comprising the acrylic monomers listed in Table 1, according to the weight ratio of V _100% -PDMS, prepared according to one embodiment of the present invention, to be.

Referring to FIG. 16, when 1 wt% of V _100% -PDMS was added to four acrylic monomers in common, the impact strength was increased. However, the impact strength was decreased as the weight ratio was increased. V _100% -PDMS showed the greatest increase in physical properties with DPHA, which is a 6-functional group, and it was confirmed that the impact strength was decreased by V _100% -PDMS in TMPTA and PETA as in the above-described photocuring behavior.

FIG. 17 is a ^{graph showing the results of} D ₄ , D ₄ ^vi or V _100% -PDMS according to the weight ratio of the HDDA acrylic monomer to the UV curable resin for 3-D printing.

Referring to FIG. 17, it can be seen that D ₄ without a vinyl group does not show photocuring reaction between an acrylic monomer and D ₄ , so that the impact strength is rather reduced. On the other hand, D ₄ ^{vi with} vinyl group had a maximum impact strength of 2.92 kJ / ㎡ at 5 wt%. This is because the V _100% -PDMS is higher than the maximum value at 1 wt% because the photocuring reaction of the vinyl group and the acrylic monomer occurs well in D ₄ ^vi having a molecular weight smaller than V _100% -PDMS having a large molecular weight.

Figure 18 is a graphical representation of D ₄ , D ₄ ^vi or V _100% -PDMS in 1 wt%, and Izod impact strength of 3-D printing UV-cured resin using PlasGray as an acrylic monomer.

For precise testing, specimens were prepared according to ASTM 0256-05 using SLA 3-D printing technology and the Notched IZOD impact strength was measured. As a result, it was found that the addition of siloxane, which had a positive effect on the mechanical properties of acrylic monomers, had the same effect on commercial products.

Claims (9)

A mixture of 9 parts by weight of dipentaerythritol hexaacrylate (DPHA) with respect to 1 part by weight of 1,6-hexanediol diacrylate (HDDA), a siloxane monomer containing a vinyl group 3 to 7% by weight of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane and a photoinitiator. delete delete delete delete delete The method according to claim 1,
A UV curable resin for 3-D printing having a zero shear viscosity of 0.48 to 1.1 Pa.s. delete delete

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