KR102427613B1 - Polypropylene resin composition for 3D printer having isotropic shrinkage and high impact properties, manufacturing method of the same, and molded articles manufactured thereby - Google Patents

Abstract

The present invention relates to a polypropylene resin composition for a 3D printer having isodirectional contractibility and high impact properties, a manufacturing method thereof, and a molded product manufactured thereby. More specifically, a polypropylene resin is manufactured by mixing a polypropylene homopolymer with an ethylene-propylene block copolymer, a nucleating agent having beta crystals, a neutralizing agent, and an antioxidant as essential components. Accordingly, mechanical properties, such as isodirectional contractility and high impact, are excellent. Therefore, stackability during 3D printing is improved and excellent shape stability can be obtained after molding. In addition, according to the polypropylene resin composition for a 3D printer of the present invention, since no expensive catalysts or fillers are included, manufacturing costs can be reduced, and also a polypropylene molded product with low specific gravity can be manufactured.

Description

Polypropylene resin composition for 3D printer having isotropic shrinkage and high impact properties, manufacturing method of the same, and molded articles manufactured thereby thereby}

The present invention relates to a polypropylene resin composition for a 3D printer having isodirectional shrinkage and high impact properties, a method for manufacturing the same, and a molded article manufactured by the same.

The use of 3D printers is increasing in various industries. In the meantime, it has been mainly used as a preliminary review of the model before product development, but recently, it is applied to actual products after molding in some fields such as medical, footwear, and architecture, and the field is gradually spreading.

There are various types of 3D printers developed so far depending on the raw material and the lamination method. Among them, the FDM (Fused Deposition Method) method, which manufactures and applies a thermoplastic material in the form of a filament, has advantages in terms of low manufacturing cost and fast printing speed. holds

Currently, commercial materials for FDM-type 3D printers are polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and polycarbonate (PC). This is because less deformation occurs due to low shrinkage before/after manufacturing the product, resulting in good dimensional and shape stability. However, the material cost is high and the specific gravity is large, so there is a limit to mass production or light weight products.

Therefore, research is being conducted on a method of using inexpensive and low specific gravity polypropylene to replace it. However, polypropylene has a high degree of crystallinity and a fast solidification rate, so the lamination performance is poor during 3D printer manufacturing, and deformation occurs even after molding, making it difficult to secure the shape stability of the product.

To solve this problem, the polypropylene-based 3D printer filament developed so far is a method of adding fillers such as talc, calcium carbonate, glass wool, and carbon fiber. Research on reducing the degree of crystallinity by applying a special catalyst to the polymerization of polypropylene and polypropylene is being actively conducted.

However, when the filler is added and commercialized as a 3D printer, it is difficult to realize the low specific gravity (less than 1.0), which is the advantage of polypropylene, and when the filler content is high, it is difficult to manufacture a filament having a uniform diameter, and the nozzle during 3D printing is difficult. There was a clogging problem. In addition, there is a problem in that the manufacturing cost of the final product is increased because the catalyst used during polymerization is mainly applied to the high-priced metallocene-based catalyst for the production of polypropylene capable of 3D printing.

Conventional Korean Patent Registration No. 10-1617099 discloses a filament for a 3D printer using atactic polypropylene, but has a disadvantage in that it lacks physical properties due to the characteristic of atactic polypropylene.

Korean Patent No. 10-1617099

In order to solve the above problems, an object of the present invention is to provide a polypropylene resin composition for a 3D printer.

Another object of the present invention is to provide a molded article prepared from the polypropylene resin composition.

Another object of the present invention is to provide a method for producing a polypropylene resin composition for a 3D printer.

The present invention includes 0.1 to 0.4 parts by weight of a beta nucleating agent in 100 parts by weight of a mixture comprising a polypropylene homopolymer and an ethylene-propylene block copolymer; 0.001 to 0.2 parts by weight of a neutralizing agent; and 0.1 to 0.3 parts by weight of an antioxidant. In the polypropylene resin composition for a 3D printer, the polypropylene resin composition has a linear expansion coefficient of 113 to 119 ° C. ^-1 in the longitudinal direction (Machine direction, MD), Transverse direction, TD) It provides a polypropylene resin composition for a 3D printer that has a coefficient of linear expansion of 111 to 117 °C ^-1 , and a ratio of the coefficient of linear expansion in the longitudinal/transverse direction of 0.95 to 1.05.

The present invention also provides a molded article prepared from the polypropylene resin composition.

In addition, the present invention provides (a) an isotactic pentad fraction of 97% or more, a weight average molecular weight of 150,000 to 400,000 g/mol, and a melt index of 30 to 45 g/10min (230 ° C., 2.16 kg) load) of preparing a polypropylene homopolymer; (b) preparing a mixture by mixing an ethylene-propylene block copolymer with the polypropylene homopolymer; and (c) preparing a polypropylene resin composition by polymerization after adding a beta nucleating agent, a neutralizing agent, and an antioxidant to the mixture, wherein the polypropylene resin composition has a machine direction (MD) coefficient of linear expansion 113 to 119 ℃ ^-1 , the transverse direction (Transverse direction, TD) coefficient of linear expansion is 111 to 117 ℃ ^-1 , the longitudinal / transverse coefficient of linear expansion ratio is 0.95 to 1.05 polypropylene resin composition for a printer It provides a manufacturing method of

The polypropylene resin composition for a 3D printer according to the present invention is a polypropylene homopolymer with an ethylene-propylene block copolymer, a nucleating agent having beta crystals, a neutralizing agent, and an antioxidant as essential components, thereby providing isotropic shrinkage and high impact properties. It has excellent mechanical properties, and thus lamination property is improved during 3D printing, and can have excellent shape stability after molding.

In addition, the polypropylene resin composition for a 3D printer of the present invention does not contain expensive catalysts or fillers at all, so it is possible to reduce the manufacturing cost, and it is possible to manufacture a polypropylene molded article having a low specific gravity.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a three-dimensional figure for comparing 3D printing performance using the polypropylene resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention.
2 is a three-dimensional figure for comparing 3D printing performance using the polypropylene resin composition prepared in Example 2 of the present invention and PLA and ABS, which are commercial materials for 3D printers.

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

The present invention relates to a polypropylene resin composition for a 3D printer having isodirectional shrinkage and high impact properties, a method for manufacturing the same, and a molded article manufactured by the same.

The polypropylene resin composition for a 3D printer according to the present invention is a polypropylene homopolymer with an ethylene-propylene block copolymer, a nucleating agent having beta crystals, a neutralizing agent, and an antioxidant as essential components, thereby providing isotropic shrinkage and high impact properties. It has excellent mechanical properties, and thus lamination property is improved during 3D printing, and can have excellent shape stability after molding. In addition, the polypropylene resin composition for a 3D printer of the present invention does not contain expensive catalysts or fillers at all, so it is possible to reduce the manufacturing cost, and it is possible to manufacture a polypropylene molded article having a low specific gravity.

Specifically, the present invention includes 0.1 to 0.4 parts by weight of a beta nucleating agent in 100 parts by weight of a mixture comprising a polypropylene homopolymer and an ethylene-propylene block copolymer; 0.001 to 0.2 parts by weight of a neutralizing agent; and 0.1 to 0.3 parts by weight of an antioxidant. In the polypropylene resin composition for a 3D printer, the polypropylene resin composition has a linear expansion coefficient of 113 to 119 ° C. ^-1 in the longitudinal direction (Machine direction, MD), Transverse direction, TD) It provides a polypropylene resin composition for a 3D printer that has a coefficient of linear expansion of 111 to 117 °C ^-1 , and a ratio of the coefficient of linear expansion in the longitudinal/transverse direction of 0.95 to 1.05.

In order for the polypropylene resin composition to have sufficient mechanical properties, the polypropylene homopolymer may have high crystallinity, and preferably, the isotactic pentad fraction may be 97% or more. In this case, if the isotactic pentad fraction is less than 97%, rigidity may be insufficient and other mechanical properties such as flexural strength may be low, which may be undesirable. In addition, due to the high viscosity of the polymerized polypropylene resin composition, it may stick to the process equipment or cause agglomeration.

The polypropylene homopolymer may have a weight average molecular weight of 150,000 to 400,000 g/mol, preferably 190,000 to 310,000 g/mol, and most preferably 210,000 to 270,000 g/mol. In this case, if the weight average molecular weight range is not satisfied, the ethylene-propylene block copolymer may not be properly polymerized in the polypropylene homopolymer or may not be uniformly dispersed, so that the impact strength may be reduced.

Melt Index of the polypropylene homopolymer can be adjusted by adjusting the ratio of propylene monomer and hydrogen input during polymerization, preferably 30 to 45 g/10min (230 ° C., 2.16 kg load), more Preferably it may be 33 to 41 g/10min, and most preferably 35 to 38 g/10min.

The ethylene-propylene block copolymer may have a molar ratio of ethylene/ethylene-propylene block copolymer of 0.3 to 0.5, preferably 0.35 to 0.43, and most preferably 0.37 to 0.39. At this time, as the molar ratio of the ethylene/ethylene-propylene block copolymer decreases, the interfacial tension between the polypropylene homopolymer and the ethylene-propylene block copolymer is weakened as the propylene content is relatively increased, and the ethylene-propylene block The dispersibility of the copolymer may be improved, and, conversely, as the molar ratio increases, the content of the ethylene-propylene block copolymer may increase to improve impact strength. However, if the molar ratio is less than 0.3, the ethylene-propylene random copolymer is polymerized and an excellent impact strength improvement effect cannot be expected. can represent

The mixture may include 72 to 84% by weight of a polypropylene homopolymer and 16 to 28% by weight of an ethylene-propylene block copolymer. Preferably, the mixture may include 75 to 81 wt% of a polypropylene homopolymer and 19 to 25 wt% of an ethylene-propylene block copolymer. In particular, if the content of the ethylene-propylene block copolymer is less than 16% by weight, it may have a structure similar to that of the polypropylene homopolymer and it may be difficult to secure sufficient impact strength. Since the polypropylene resin composition sticks to the reactor, there is a problem that a smooth reaction is difficult.

The beta nucleating agent is a nucleating agent having beta crystals, and has an advantage of high strength and strong resistance to stress compared to a nucleating agent having alpha crystals. The beta nucleating agent may be an organic or inorganic nucleating agent. Preferably, the organic nucleating agent may be at least one selected from the group consisting of an aluminum salt of carboxylic acid, quinacridone quinone, calcium stearate and sodium benzoate, and the inorganic nucleating agent is talc, dibenzylidene It may be at least one selected from the group consisting of sorbitol and substituted dibenzylidene sorbitol.

More preferably, the beta nucleating agent may be an organic nucleating agent sodium benzoate, quinacridone quinone, or a mixture thereof, and most preferably a mixture of sodium benzoate and quinacridone quinone in a weight ratio of 2.6: 7.4. have. When the mixture is used as the beta nucleating agent, mechanical properties can be improved, and at the same time, there is an advantage of providing excellent morphological stability by controlling the shrinkage ratio along the MD and TD directions to be the same.

The beta nucleating agent may include 0.1 to 0.4 parts by weight, preferably 0.15 to 0.30 parts by weight, based on 100 parts by weight of the mixture. At this time, if the content of the beta nucleating agent is less than 0.1 parts by weight, the impact strength is lowered, the shrinkage deviation along the MD and TD directions is large, there is a problem that the shape stability is deteriorated. Conversely, if it exceeds 0.4 parts by weight, the crystallinity and viscosity of the polypropylene resin composition may be excessively increased, and flowability and moldability may be deteriorated.

The neutralizing agent may be at least one selected from the group consisting of calcium stearate, zinc oxide and hydrotalcite.

The neutralizing agent may include 0.001 to 0.03 parts by weight, preferably 0.005 to 0.015 parts by weight, based on 100 parts by weight of the mixture.

The antioxidant may be at least one selected from the group consisting of phenol-based, phosphorus-based and thiodipropionate-based antioxidants. The phenolic antioxidant may be ethyl phosphite, semi-hindered phenol, or a mixture thereof.

The antioxidant may be included in an amount of 0.05 to 0.30 parts by weight, preferably 0.05 to 0.25 parts by weight, based on 100 parts by weight of the mixture.

The polypropylene resin composition may have a weight average molecular weight of 190,000 to 350,000 g/mol, preferably 210,000 to 330,000 g/mol, and most preferably 230,000 to 300,000 g/mol. In this case, if the weight average molecular weight is less than 190,000 g/mol, it may be difficult to secure sufficient fluidity, and if it exceeds 350,000 g/mol, impact strength and moldability may be reduced.

The polypropylene resin composition may have a molecular weight distribution (Mw/Mn) of 3.0 to 7.0, preferably 3.3 to 5.0, more preferably 3.8 to 4.9, and most preferably 4.6 to 4.8. At this time, if the molecular weight distribution is less than 3.0, it is difficult to secure sufficient rigidity and fluidity, and conversely, if it exceeds 7.0, impact strength may be reduced.

The polypropylene resin composition has a melt index of 30 to 46 g/10 min (230° C., 2.16 kg load), preferably 34 to 42 g/10 min, more preferably 36 to 41 g/10 min, most preferably It may be 38 to 40 g/10 min.

The polypropylene resin composition has a tensile strength of 17 to 20 MPa according to ASTM D638, a flexural strength of 800 to 900 MPa according to ASTM D790, and an Izod impact strength of 123 to 130 J/m according to ASTM D256. can

Since the polypropylene resin composition does not contain any expensive catalysts and fillers, it can exhibit low specific gravity and low cost, which are the strengths of polypropylene materials. In addition, it has a high impact property compared to a polypropylene resin composition that does not include an ethylene-propylene block copolymer, and has a constant shrinkage in the longitudinal and transverse directions, so it can be used as a filament product for a 3D printer with isodirectional shrinkage.

Preferably, the polypropylene resin composition has a machine direction (MD) coefficient of linear expansion of 113 to 119 °C ^-1 , and a transverse direction (TD) coefficient of linear expansion of 111 to 117 °C ^-1 , and the longitudinal direction / The coefficient of linear expansion in the transverse direction may be 0.95 to 1.05. Most preferably, the coefficient of linear expansion in the longitudinal direction is 115 to 116 °C ^-1 , the coefficient of linear expansion in the transverse direction is 113 to 114 °C ^-1 , and the longitudinal/transverse coefficient of linear expansion ratio may be 0.98 to 1.02. In particular, when the coefficient of linear expansion ratio is less than 0.95, or, conversely, when it exceeds 1.05, the isodirectional shrinkage is deteriorated after lamination in 3D printing, and deformation occurs due to non-uniform shrinkage, and shape stability may be significantly reduced.

In particular, although not explicitly described in the following Examples or Comparative Examples, the polypropylene resin composition according to the present invention is prepared at 5 to 230 ° C. Thermal properties, mechanical properties, formability, and shape stability were evaluated in the temperature range of

As a result, unlike other conditions and other numerical ranges, when all of the following conditions were satisfied, shape stability was very excellent in a temperature range of 5 to 230 ° C. without fillers and catalysts, and thermal properties, mechanical properties, and moldability were equally excellent was confirmed to be visible.

① The polypropylene homopolymer has an isotactic pentad fraction of 97% or more, a weight average molecular weight of 210,000 to 270,000 g/mol, and a melt index of 35 to 38 g/10min (230 ° C., 2.16 kg). load), ② the ethylene-propylene block copolymer has a molar ratio of ethylene/ethylene-propylene block copolymer of 0.37 to 0.39, and ③ the mixture contains 75 to 81 wt% of a polypropylene homopolymer and an ethylene-propylene block copolymer 19 to 25% by weight, ④ the polypropylene resin composition has a weight average molecular weight of 230,000 to 300,000 g/mol, a molecular weight distribution (Mw/Mn) of 4.6 to 4.8, and a melt index of 38 to 40 g/10 min (230 ° C, 2.16 kg load), ⑤ the longitudinal coefficient of linear expansion is 115 to 116 ° C ^-1 , the transverse coefficient of linear expansion is 113 to 114 ° C ^-1 , and the longitudinal/transverse coefficient of linear expansion ratio is 0.98 to 1.02.

However, when any one of the above five conditions was not satisfied, heat resistance and dimensional stability were rapidly reduced at a temperature of 70 ° C. or higher, and deformation occurred in the molded article, and the viscosity of the polypropylene resin increased, resulting in poor moldability.

On the other hand, the present invention provides a molded article prepared from the polypropylene resin composition.

In addition, the present invention provides (a) an isotactic pentad fraction of 97% or more, a weight average molecular weight of 150,000 to 400,000 g/mol, and a melt index of 30 to 45 g/10min (230 ° C., 2.16) kg load) of polypropylene homopolymer; (b) preparing a mixture by mixing an ethylene-propylene block copolymer with the polypropylene homopolymer; and (c) preparing a polypropylene resin composition by polymerization after adding a beta nucleating agent, a neutralizing agent, and an antioxidant to the mixture, wherein the polypropylene resin composition has a machine direction (MD) coefficient of linear expansion 113 to 119 ℃ ^-1 , the transverse direction (Transverse direction, TD) coefficient of linear expansion is 111 to 117 ℃ ^-1 , the longitudinal / transverse coefficient of linear expansion ratio is 0.95 to 1.05 polypropylene resin composition for a printer It provides a manufacturing method of

The step of preparing the polypropylene homopolymer may be prepared without a solvent, but when a solvent is used, it may be prepared using a hydrocarbon solvent. The hydrocarbon solvent may be one or more selected from the group consisting of pentane, heptane, hexane, octane, decane, dodecane, toluene, benzene and cyclohexane.

Preferably, in the step of preparing the polypropylene homopolymer, a solid complex titanium catalyst, an organic aluminum cocatalyst, an external electron donor and hydrogen are added to the propylene monomer and then polymerized to prepare a polypropylene homopolymer.

The solid complex titanium catalyst may use a compound produced by supporting TiCl ₃ or TiCl ₄ on a MgCl ₂ carrier. The organoaluminum co-catalyst may be at least one selected from the group consisting of triethylaluminum, diethylchloroaluminum, tributylaluminum, trisisobutylaluminum and trioctylaluminum, but is not particularly limited in the present invention.

In addition, the external electron donor is an organic silane compound, for example, diphenyldimethoxysilane, phenyltrimethoxysilane, phenylethyldimethoxysilane, phenylmethyldimethoxysilane, methoxytrimethylsilane, isobutyltrimethoxysilane, One selected from the group consisting of diisobutyldimethoxysilane, diisopropyldimethoxysilane, di-t-butyldimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane and dicyclohexyldimethoxysilane may be above, but is not particularly limited in the present invention.

In the step of preparing the polypropylene homopolymer, gas phase polymerization may be performed at a temperature of -10 to 100 °C and a pressure of 0.4 to 5.0 MPa for 0.4 to 1.5 hours. The polymerization temperature may be -10 to 100 °C, preferably 30 to 90 °C, most preferably 60 to 85 °C. In particular, if the polymerization temperature is less than -10 ℃, the activity of the solid complex titanium catalyst may not appear properly, and, conversely, if it exceeds 100 ℃, non-uniform particles are excessively formed, which is not preferable. The polymerization pressure may be 0.4 to 5.0 MPa, preferably 0.6 to 4.0 MPa, and most preferably 2.0 to 3.8 MPa. In particular, if the polymerization pressure exceeds 5.0 MPa, the equipment investment cost is high, which is not preferable.

In the step of preparing the mixture, the ethylene-propylene block copolymer is prepared by polymerizing the polypropylene homopolymer in a series of reactors and then copolymerizing by introducing a mixed gas of ethylene and propylene. can

In the step of preparing the mixture, polymerization may be performed at a temperature of -10 to 90 °C and a pressure of 0.3 to 3.0 MPa for 0.4 to 1.0 hours. The polymerization temperature may be -10 to 90 °C, preferably 30 to 80 °C, most preferably 40 to 50 °C. At this time, if the temperature is less than -10 ℃, the activity of the solid complex titanium catalyst may not appear properly, on the contrary, if it exceeds 90 ℃, non-uniform particles may be excessively formed.

In addition, the polymerization pressure may be 0.3 to 3.0 MPa, preferably 0.4 to 2.0 MPa, and most preferably 0.5 to 1.5 MPa. If the polymerization pressure is less than 0.3 MPa, the polymerization of the ethylene-propylene block copolymer may not be sufficiently performed. Conversely, if the polymerization pressure is greater than 3.0 MPa, equipment investment cost is high.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1

Solid complex titanium catalyst, organic aluminum co-catalyst, external electron donor, propylene monomer and hydrogen were sequentially injected into a polymerization reactor at 10 ° C. or less, and then the temperature was raised to 60-85 ° C., 2.0-3.8 MPa, and gas phase polymerization was carried out for 0.5 hours. A polypropylene homopolymer was prepared, and the melt index was controlled by the amount of hydrogen. After the polymerization of the polypropylene homopolymer was completed, the unreacted material was removed and the pressure was lowered to normal pressure.

Then, in the presence of the polypropylene homopolymer, the temperature was raised again while injecting hydrogen and a mixed gas of ethylene/propylene adjusted in a molar ratio of 0.4:0.6 for 0.5 hours at 40-50 ° C. -A mixture of 22 wt% of a propylene block copolymer was prepared.

Then, in 100 parts by weight of a mixture of 78% by weight of the polypropylene homopolymer and 22% by weight of the ethylene-propylene block copolymer, sodium benzoate (beta nucleating agent) 0.07% by weight, dehydrated hydrotalcite compound (neutralizing agent) 0.01% Parts by weight, 0.10% by weight of phenylphosphite (antioxidant), 0.03% by weight of thiodipropionate (antioxidant), 0.07% by weight of semi-hindered phenol (antioxidant) 0.07% by weight of a twin screw extruder, melt-kneaded to prepare a polypropylene resin composition.

Example 2

A polypropylene resin composition was prepared in the same manner as in Example 1, except that 0.2% by weight of quinacridone quinone was additionally added as a beta nucleating agent.

Example 3

Hydroxybis[2,4,8,10-tetrakis(1,1-dimethylethyl)-6-hydroxy12H-dibenzodioxaphosphosine-6-oxidato]) instead of beta nucleating agent (NA-21) A polypropylene resin composition was prepared in the same manner as in Example 1, except that 0.2% parts by weight was additionally added.

Example 4

In the same manner as in Example 1, except that 0.2% by weight of cis-1,2-cyclohexanedicarboxylate (Calcium cis-1,2-cyclohexanedicarboxylate, HPN-20E) was additionally added instead of the beta nucleating agent, the poly A propylene resin composition was prepared.

Comparative Example 1

A commercial ethylene-propylene block copolymer from Company A was purchased and used in the experiment.

Comparative Example 2

A commercial ethylene-propylene block copolymer from Company B was purchased and used in the experiment.

Comparative Example 3

A commercial ethylene-propylene block copolymer from Company C was purchased and used in the experiment.

Experimental Example 1: Evaluation of mechanical properties in melt index and molecular weight distribution of polypropylene resin composition

For each polypropylene resin composition prepared in Examples 1 to 4 and Comparative Examples 1 to 3, melt index (MI), molecular weight distribution (Mw/Mn, MWD), low-temperature xylene solubility by a conventional method (CXS, Cold Xylene Soluble), C ₂ (ethylene) content was measured. The results are shown in Table 1 below.

According to the results of Table 1, in the case of Examples 1 to 4, the melt index, molecular weight distribution, xylene solubility, and ethylene content were equivalent or similar levels as a result of different types of additives. On the other hand, in Comparative Examples 1 to 3, it was confirmed that there were differences in melt index, molecular weight distribution, xylene solubility, and ethylene content. This serves as a control group to compare physical properties and 3D printing results later.

Experimental Example 2: Evaluation of mechanical properties in polypropylene resin composition

Specimens were prepared using each polypropylene resin composition prepared in Examples 1 to 4 and Comparative Examples 1 to 3, and physical properties were measured. The physical property evaluation method is as follows, and the measurement results are shown in Tables 2 and 3 below.

(1) Density: According to ASTM D 1505, it was measured using a density gradient tube.

(2) Tensile strength: Measured according to ASTM D638.

(3) Flexural strength: Measured according to ASTM D790.

(4) Izod impact strength: Measured according to ASTM D256.

(5) Shrinkage, coefficient of linear expansion: ISO294-4

(6) Vicat softening point: measured according to ASTM D1525.

(7) Melting temperature, crystallization temperature: Measured according to ASTM D3418-12.

According to the results of Table 2, it was confirmed that Examples 1 to 4 and Comparative Examples 1 to 3 had a similar level of density. In Example 2 and Comparative Example 2, the minimum tensile strength of 18 MPa was shown, and similarly, the flexural strength showed low values of 850 and 740 MPa, respectively. In addition, in Comparative Example 3, the maximum tensile strength was 28 MPa, and similarly, the maximum value was 1470 MPa in flexural strength. In addition, in Examples 1, 3, and 4 and Comparative Examples 1 and 4, the tensile strength and the flexural strength were proportional to each other.

On the other hand, Izod impact strength showed the highest values of 125 and 122 J/m in Example 2 and Comparative Example 2, which showed low values in tensile strength and flexural strength, respectively, and showed excellent tensile strength and flexural strength. In the case of Examples 3 and 1, it was confirmed to have low Izod impact strength as 102 and 77 J/m, respectively.

On the other hand, in the case of the shrinkage ratio, except for Example 2, different values were shown according to the MD and TD directions. That is, in the case of Examples 1, 3, 4 and Comparative Examples 1 to 3, since the shrinkage ratio according to the MD and TD directions is different, deformation occurs due to non-uniform shrinkage after lamination using a 3D printer, and it is difficult to secure shape stability. confirmed that there is.

Through this, as in Example 1, the amount of the beta nucleating agent is too small, as in Examples 3 and 4, an additive is mixed instead of the beta nucleating agent, or as in Comparative Examples 1 to 3, ethylene/propylene having different ethylene contents. In the case of using a block copolymer, it was found that even when the same polypropylene resin composition was prepared, the physical properties were significantly changed depending on the content and type of the additive.

According to the results of Table 3, in the case of Examples 1 to 4, as described above, it was confirmed that the thermal properties also greatly changed depending on the type of additive to be mixed. Example 2 and Comparative Example 2 having excellent Izod impact strength and low tensile strength and flexural strength have a low melting temperature of 153 ° C. Low crystallinity among Examples 1 to 4 and Comparative Examples 1 to 3 was confirmed to have

In addition, Example 1 containing a small amount of beta nucleating agent showed the lowest crystallization temperature and Vicat softening point, whereas Example 2 and Comparative Example 2 showed a relatively high crystallization temperature and Vicat softening point compared to Example 1 confirmed to have

On the other hand, in the case of the coefficient of linear expansion, it was confirmed that the crystallization temperature and the Vicat softening point had an inverse relationship, but it was confirmed that the difference in the MD and TD directions was different for each resin composition. In particular, the smaller the difference according to the MD and TD directions, the smaller the difference in shrinkage in Table 2 was observed, and it was confirmed that the coefficient of linear expansion and the shrinkage were inversely proportional.

Experimental Example 3: Comparison of 3D printing results

Using the polypropylene resin compositions of Examples 1 to 4 and Comparative Examples 1 to 3, 3D printing was performed under the conditions of a nozzle temperature of 220° C. and an output speed of 30 mm/s based on the shape of FIG. 1, and the results were It is shown in Table 4 below.

1 is a three-dimensional figure for comparing 3D printing performance using the polypropylene resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3;

According to the results of Table 4, it was confirmed that the lamination was not performed properly in all except Examples 2 and 4. In addition, in the case of Example 4, although lamination was made, it was confirmed that the amount of shape deformation was excessive, so that actual use was difficult. Through this, it was confirmed that it is very important to secure the linear expansion coefficient and shrinkage with isodirectional uniformity in order to improve the lamination properties and shape stability of three-dimensional figures during 3D printing using the polypropylene resin composition.

Experimental Example 4: Comparison of 3D printing results of commercial materials

In the results of Experimental Example 2, based on Example 2, which has good laminarity and shape stability, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), which are commercial materials for 3D printer filaments, were compared respectively To do this, 3D printing was performed under the conditions of a nozzle temperature of 220 °C and an output speed of 50 mm/s using the shape of FIG. 2 , and the results are shown in Table 5 below.

2 is a three-dimensional shape for comparing 3D printing performance using the polypropylene resin composition prepared in Example 2 and PLA and ABS, which are commercial materials for 3D printers.

According to the results of Table 5, in the case of Example 2, compared to the PLA and ABS, it was confirmed that the lamination was well made according to the shape of FIG. 2, and the shape stability was excellent. Through this, it was found that the polypropylene resin composition of Example 2 had excellent lamination properties and shape stability at a level equal to or higher than PLA and ABS used as commercial materials for 3D printing. In addition, it was found that the polypropylene resin composition of Example 2 can be utilized in various fields because of its low manufacturing cost and good versatility based on heat resistance and chemical resistance compared to PLA and ABS.

Claims (15)

0.1 to 0.4 parts by weight of a beta nucleating agent in 100 parts by weight of a mixture comprising a polypropylene homopolymer and an ethylene-propylene block copolymer; 0.001 to 0.2 parts by weight of a neutralizing agent; In the polypropylene resin composition for a 3D printer comprising; and 0.1 to 0.3 parts by weight of an antioxidant,
The polypropylene resin composition has a longitudinal (Machine direction, MD) coefficient of linear expansion of 113 to 119 °C ^-1 , and a transverse direction (TD) coefficient of linear expansion of 111 to 117 °C ^-1 , and the longitudinal/transverse direction A polypropylene resin composition for a 3D printer that has a coefficient of linear expansion ratio of 0.95 to 1.05.
According to claim 1,
The polypropylene homopolymer has an isotactic pentad fraction of 97% or more, a weight average molecular weight of 150,000 to 400,000 g/mol, and a melt index of 30 to 45 g/10min (230 ° C., 2.16 kg load) ) of a polypropylene resin composition for a 3D printer.
According to claim 1,
The ethylene-propylene block copolymer is a polypropylene resin composition for a 3D printer that has a molar ratio of ethylene/ethylene-propylene block copolymer of 0.3 to 0.5.
According to claim 1,
The mixture is a polypropylene resin composition for a 3D printer comprising 72 to 84% by weight of a polypropylene homopolymer and 16 to 28% by weight of an ethylene-propylene block copolymer.
According to claim 1,
The beta nucleating agent is an organic nucleating agent or an inorganic nucleating agent. The polypropylene resin composition for a 3D printer.
6. The method of claim 5,
The organic nucleating agent is at least one selected from the group consisting of an aluminum salt of carboxylic acid, quinacridone quinone, calcium stearate and sodium benzoate, and the inorganic nucleating agent is talc, dibenzylidene sorbitol and substituted di A polypropylene resin composition for a 3D printer that is at least one selected from the group consisting of benzylidene sorbitol.
7. The method of claim 6,
The beta nucleating agent is a polypropylene resin composition for a 3D printer that is a mixture of sodium benzoate and quinacridone quinone in a weight ratio of 2.6: 7.4.
According to claim 1,
The polypropylene resin composition has a weight average molecular weight of 190,000 to 350,000 g/mol, a molecular weight distribution (Mw/Mn) of 3.0 to 7.0, and a melt index of 30 to 46 g/10 min (230 ° C., 2.16 kg load) A polypropylene resin composition for a 3D printer.
According to claim 1,
The polypropylene resin composition has a tensile strength of 17 to 20 MPa according to ASTM D638, a flexural strength of 800 to 900 MPa according to ASTM D790, and an Izod impact strength of 123 to 130 J/m according to ASTM D256 A polypropylene resin composition for a 3D printer.
According to claim 1,
The polypropylene homopolymer has an isotactic pentad fraction of 97% or more, a weight average molecular weight of 210,000 to 270,000 g/mol, and a melt index of 35 to 38 g/10min (230 ° C., 2.16 kg load) )ego,
The ethylene-propylene block copolymer has a molar ratio of ethylene/ethylene-propylene block copolymer of 0.37 to 0.39,
The mixture comprises 75 to 81% by weight of a polypropylene homopolymer and 19 to 25% by weight of an ethylene-propylene block copolymer,
The polypropylene resin composition has a weight average molecular weight of 230,000 to 300,000 g/mol, a molecular weight distribution (Mw/Mn) of 4.6 to 4.8, and a melt index of 38 to 40 g/10 min (230 ° C., 2.16 kg load), and ,
The longitudinal coefficient of linear expansion is 115 to 116 ° C. ^-1 , the transverse coefficient of linear expansion is 113 to 114 ° C. ^-1 , and the longitudinal / transverse coefficient of linear expansion ratio is 0.98 to 1.02 Polypropylene resin for a 3D printer composition.
A molded article made of the polypropylene resin composition of any one of claims 1 to 10.
(a) Poly having an isotactic pentad fraction of 97% or more, a weight average molecular weight of 150,000 to 400,000 g/mol, and a Melt Index of 30 to 45 g/10min (230° C., 2.16 kg load) preparing a propylene homopolymer;
(b) preparing a mixture by mixing an ethylene-propylene block copolymer with the polypropylene homopolymer; and
(c) preparing a polypropylene resin composition by adding a beta nucleating agent, a neutralizing agent and an antioxidant to the mixture and then polymerization;
including,
The polypropylene resin composition has a longitudinal (Machine direction, MD) coefficient of linear expansion of 113 to 119 °C ^-1 , and a transverse direction (TD) coefficient of linear expansion of 111 to 117 °C ^-1 , and the longitudinal/transverse direction A method of producing a polypropylene resin composition for a 3D printer that has a coefficient of linear expansion ratio of 0.95 to 1.05.
13. The method of claim 12,
In the step of preparing the polypropylene homopolymer, a solid complex titanium catalyst, an organic aluminum cocatalyst, an external electron donor and hydrogen are added to the propylene monomer and then polymerized to prepare a polypropylene homopolymer polypropylene resin composition for a 3D printer manufacturing method.
13. The method of claim 12,
The step of preparing the polypropylene homopolymer is a method for producing a polypropylene resin composition for a 3D printer to perform a gas phase polymerization reaction for 0.4 to 1.5 hours at a temperature of -10 to 100 ℃ and a pressure of 0.4 to 5.0 MPa.
13. The method of claim 12,
The step of preparing the mixture is a method for producing a polypropylene resin composition for a 3D printer to perform a polymerization reaction for 0.4 to 1.0 hours at a temperature of -10 to 90 ℃ and a pressure of 0.3 to 3.0 MPa.

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