JP6701920B2 - Polypropylene resin composition and strand for hot melt laminating method - Google Patents

Description

  The present invention relates to a polypropylene-based resin composition for hot melt lamination modeling, and particularly to provide a polypropylene-based resin composition and a strand thereof in which molding defects such as shrinkage, warpage, and twist during modeling are less likely to occur. Is.

  2. Description of the Related Art Conventionally, there is known a technique of performing three-dimensional modeling by sequentially laminating resin for each cross section obtained by cutting a modeling target object with a plurality of parallel planes and generating a modeling object that becomes a three-dimensional model of the modeling target object. . Such a technique is called three-dimensional modeling, and can be used for parts trial production and product manufacturing.

  The three-dimensional modeling method includes an optical modeling method using a photocurable resin, a powder laminating method using a metal or resin powder, a hot melt laminating method (FDM method) in which a resin is melted and laminated, and a liquid or powder form. An ink jet method for ejecting resin or metal is known.

As an example of the hot-melt laminating method, for example, Patent Document 1 (Japanese Patent Publication No. 2005-531439) discloses a method of depositing a layer of a thermoplastic resin composition containing about 0.5 to 10% by weight of silicone. .. In this technology, as a thermoplastic resin composition, polyether sulfone, polyether imide, polyphenyl sulfone, polyphenylene, polycarbonate, high impact polystyrene, polysulfone, polystyrene, acrylic resin, amorphous polyamide, polyester, nylon, PEEK, PEAK and ABS are illustrated.
In addition to these, polylactic acid is also widely used.

However, many of these thermoplastic resin compositions are amorphous, and are inferior in organic solvent resistance and chemical resistance, so that although they can be used for producing shaped objects, they are only used in extremely limited applications. It could not be used.
In addition, there are some that emit an unpleasant odor during modeling, some may deteriorate in quality due to moisture absorption, and some may foam during modeling, and there is room for improvement from the viewpoint of workability.

  As thermoplastic resins having excellent organic solvent resistance, chemical resistance, and moisture absorption resistance, crystalline and semi-crystalline polyolefins such as polypropylene resins and polyethylene resins are known, and polypropylene resins are particularly heat resistant. It is widely used for various molded products such as food containers, daily necessities, packaging films, sheets, blow bottles, automobile parts, medical containers, etc. because it is excellent in transparency and easily exhibits high transparency and high gloss.

  However, polyolefin resins such as polypropylene-based resins and polyethylene-based resins generally have crystallinity, and therefore, when a three-dimensional structure is manufactured by the hot melt laminating method, shrinkage particularly occurs during molding due to crystallization during cooling and solidification. There is a problem that molding defects such as warp and twist occur, and thus far, no polypropylene-based resin composition applicable to hot melt lamination applications has been known.

Japanese Patent Publication No. 2005-531439

  An object of the present invention is to provide a polypropylene resin composition and a strand thereof in which, in view of the problems of the above-described conventional techniques, shrinkage or warpage during modeling in hot-melt lamination method modeling, and less occurrence of modeling defects such as twisting. is there.

The present invention is
[1] A polypropylene resin composition (Y) for hot-melt lamination molding, which contains a polypropylene resin (X) having the following properties (X-1) to (X-3).
Characteristic (X-1): Melt flow rate (MFR: Method A of JIS K7210:1999, condition M (230° C., 2.16 kg load)) is 1.0 to 100 g/10 minutes.
Characteristic (X-2): Using a differential thermal scanning calorimeter (DSC), the temperature was once raised to 200° C. to erase the thermal history, and then the temperature was lowered to −10° C. at a temperature lowering rate of 10° C./min. The measured crystallization peak temperature (Tc) is 105° C. or lower.
Characteristic (X-3): Using a differential scanning calorimeter (DSC), the temperature is once raised to 200° C. to erase the thermal history, and then the temperature is lowered to −10° C. at a temperature lowering rate of 10° C./min. The heat of fusion (ΔHm) in the range of 10 to 200° C., which is measured when the temperature is raised again to 200° C. at the rate of temperature increase of 10° C./min, is 70 J/g or less.
[2] The polypropylene resin composition (Y) for hot-melt lamination molding according to [1], wherein part or all of the polypropylene resin (X) is a metallocene polymer.
[3] The hot melt laminating method modeling according to [1] or [2], wherein the polypropylene resin (X) is a block copolymer of propylene and ethylene and/or an α-olefin having 4 to 12 carbon atoms. Polypropylene resin composition (Y).
[4] A strand composed of the polypropylene resin composition (Y) for hot-melt lamination molding according to [1] to [3], which has a strand diameter of 1.0 to 5.0 mm.
Is provided.

  By using the polypropylene resin composition for hot-melt lamination method modeling of the present invention, it is possible to provide a polypropylene-based molded article that causes less molding defects such as shrinkage, warpage, and twisting during modeling. Further, the polypropylene resin for hot melt lamination modeling of the present invention is excellent in organic solvent resistance, chemical resistance, moisture absorption resistance, and heat resistance, so that the molded article can be put to practical use in a wide range of applications. I can.

[Polypropylene resin (X)]
The polypropylene resin (X) used in the present invention exhibits the following properties (X-1) to (X-3).
Characteristic (X-1): Melt flow rate (MFR: Method A of JIS K7210:1999, condition M (230° C., 2.16 kg load)) is 1.0 to 100 g/10 minutes.
Characteristic (X-2): Using a differential thermal scanning calorimeter (DSC), the temperature was once raised to 200° C. to erase the thermal history, and then the temperature was lowered to −10° C. at a temperature lowering rate of 10° C./min. The measured crystallization peak temperature (Tc) is 105° C. or lower.
Characteristic (X-3): Using a differential scanning calorimeter (DSC), the temperature is once raised to 200° C. to erase the thermal history, and then the temperature is lowered to −10° C. at a temperature lowering rate of 10° C./min. The heat of fusion (ΔHm) in the range of 10 to 200° C., which is measured when the temperature is raised again to 200° C. at the rate of temperature increase of 10° C./min, is 70 J/g or less.

  The polypropylene resin (X) may be composed of only one type, or may be a mixture of two or more types. In the case of a mixture of two or more kinds, the above characteristics (X-1) to (X-3) may be shown as a mixture.

  The polypropylene resin (X) has a melt flow rate of 1.0 to 100 g/10 minutes, preferably 5.0 to 50 g/10 minutes, more preferably 10 to 50 g/10 minutes, and particularly preferably 15 to 50 g/10. Minutes. When the melt flow rate is within the above range, it is easy to mold with an appropriate extrusion load and extrusion speed.

  The crystallization peak temperature (Tc) of the polypropylene resin (X) is 105°C or lower, preferably 100°C or lower, more preferably 95°C or lower, and particularly preferably 90°C or lower. When the crystallization peak temperature (Tc) is 105° C. or less, warpage and twist are less likely to occur during modeling.

  The heat of fusion (ΔHm) of the polypropylene resin (X) is 70 J/g or less, preferably 68 J/g or less, more preferably 65 J/g or less. When the amount of heat of fusion (ΔHm) is 70 J/g or less, not only warpage and twist are less likely to occur during modeling, but also shrinkage over time and warpage and twist over time are less likely to occur.

  The method for producing the polypropylene resin (X) is not particularly limited, and those obtained by known methods can be used, but metallocene polymers, that is, those polymerized by a metallocene catalyst are preferable. Those polymerized with a metallocene catalyst have a low heat of fusion (ΔHm) of 70 J/g or less, preferably 68 J/g or less, and more preferably 65 J/g or less, and have a low crystallinity. It has the effect of suppressing the stickiness of the polypropylene resin composition (Y) for lamination type molding.

  The polypropylene resin (X) has a melt flow rate (MFR) of 1.0 to 100 g/10 minutes, a crystallization peak temperature (Tc) of 105° C. or lower, and a heat of fusion (ΔHm) of 70 J/g or lower. However, the melting peak temperature (Tm: measured by the DSC method) is preferably 100 to 166° C., more preferably 110 to 150° C., further preferably 120 to 140, and particularly preferably. When it is 125 to 135, it does not melt even at a temperature of boiling water or higher, so that it can be expected to be widely used for practical use.

  As the polypropylene resin (X), propylene homopolymer, random copolymer of propylene and ethylene and/or α-olefin having 4 to 12 carbon atoms, propylene and ethylene and/or having 4 to 12 carbon atoms. Mention may be made of block copolymers with α-olefins, and combinations thereof.

  The polypropylene-based resin (X) used in the present invention is, for example, a product name: WELNEX manufactured by Nippon Polypro Co., Ltd., a product name: Vistamaxx manufactured by Exxon Mobil Co., a product name: Versify manufactured by Dow Chemical Co., or a product manufactured by Mitsui Chemicals, Inc. Name: Tuffmer PN, Tuffmer XM, Notio SN and the like. In addition, for example, the product name of Japan Polypro Co., Ltd.: polypropylene resin such as WINTEC or Novatec PP and the product name of WELNEX manufactured by Japan Polypro Co., Ltd., the product name of Exxon Mobil Company: Vistamaxx, the product of Dow Chemical Co., Ltd. A mixture of name: Versify and Mitsui Chemicals, Inc. trade name: Tuffmer PN, Tuffmer XM, Notio SN, etc. can be exemplified as the polypropylene resin (X) used in the present invention.

  Further, the method for obtaining the polypropylene resin (X) having a desired MFR includes a method of adjusting the molecular weight at the time of polymerization, a method of degrading the polypropylene resin obtained by the polymerization by heat, a method of melt kneading or a reaction in a solution. A known method such as a method of degrading by oxide treatment may be adopted.

[Polypropylene resin composition (Y) for hot melt laminating method modeling]
The polypropylene resin composition (Y) for hot-melt laminating method modeling of the present invention is obtained by blending the polypropylene resin (X) with an additive which is usually blended with the polypropylene resin, if desired. Examples of the additive include a nucleating agent, an antioxidant, a neutralizing agent, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a metal deactivator, a flame retardant, a flame retardant aid, and heat stability. Examples thereof include agents, slip agents, anti-blocking agents, anti-fog agents, silicones, silicone oils, etc., but they do not necessarily have to be compounded.

  Of these additives, antioxidants are often blended to stabilize the polypropylene resin, and should be blended because they are expected to have the effect of preventing deterioration of the obtained shaped product over time. Is preferred. As the antioxidant, primary antioxidants typified by phenolic antioxidants and secondary antioxidants typified by phosphorus antioxidants are known, but they may be appropriately selected depending on desired performance. Further, the compounding amount is usually about 0.005 to 0.5 part by weight with respect to 100 parts by weight of the polypropylene resin (X), but it may be appropriately adjusted depending on the desired performance.

  Further, it is preferable to add a metal soap widely used as a neutralizing agent from the viewpoints of preventing nozzle clogging of the hot-melt laminating apparatus and preventing eye blemishes. As the metal soap, calcium stearate, zinc stearate, magnesium stearate, magnesium 12-hydroxystearate and the like are known, and may be appropriately selected depending on the desired performance. Further, the compounding amount is usually about 0.005 to 0.5 part by weight with respect to 100 parts by weight of the polypropylene resin (X), but it may be appropriately adjusted depending on the desired performance.

The polypropylene resin composition (Y) for hot-melt lamination method modeling of the present invention comprises a polypropylene resin (X) and, if necessary, other additives, a Henschel mixer (trade name), a V blender, a ribbon blender, It can be obtained by mixing with a tumbler blender or the like. Further, if necessary, it can be obtained by a method of melt-kneading with a kneading machine such as a single-screw extruder, a multi-screw extruder, a kneader or a Banbury mixer after the mixing step.
Further, the respective components may be mixed and/or melt-kneaded at the same time, or a part thereof may be used as a master batch and then mixed and/or melt-kneaded.

[Hot-melt lamination method modeling]
The polypropylene resin composition (Y) for hot melt laminating method modeling in the present invention is used for modeling by the hot melt laminating method. The hot melt laminating method refers to a general method of heating and melting a thermoplastic resin, extruding it from the tip of a nozzle, and laminating it to form a three-dimensional object, and is also called a hot melt laminating method or a hot melt deposition method. .. Further, depending on the thermoplastic resin supply structure of the modeling apparatus, there are cases where a particulate (pellet-shaped) raw material is used and cases where the material is once processed into a strand (or sometimes called a filament) and then used for modeling. ..

When it is once processed into a strand shape, the polypropylene resin composition (Y) for hot melt lamination modeling of the present invention is first processed into a strand shape by a known method. As a processing method, a method such as melting and kneading at a cylinder temperature of 170° C. to 260° C., extruding it as a strand into a water tank, and winding it as a strand with a variable speed nip roller, and JP-A-2013-506581 and JP-A-2013 The method described in Japanese Patent Publication No. 506580 can also be used.
Specifically, the propylene resin composition (Y) is supplied to an extruder, melted at a temperature of 170 to 260° C., and then discharged from a spinneret having spinning holes with a hole diameter of 1 to 5 mm, 20 to 60° C. After cooling and solidifying in water, heat to 50 to 100°C with a heating roller if necessary, draw at a draw ratio of 1.0 to 15 times, heat set, dry and wind at a speed of 1 to 200 m/min. Can be obtained by It can also be obtained by using a dedicated machine such as a product name “The Pro ABS And PLA Film Extender For 3D Printers” manufactured by Noztek.
Examples of the strand include a perfect circular shape, a flat shape, and a hollow shape. The shape of the strand is suitable for the hot-melt laminating type molding apparatus used. As an example of a perfect circular strand, its diameter can be adjusted to 1.75 mm, 2.85 mm, and 3.0 mm.

The strand obtained above is subsequently molded into a three-dimensional model by a hot-melt laminating type molding apparatus. As the hot-melt laminating type modeling apparatus, many commercially available apparatuses are distributed in the market, and any one can be used. Examples of commercially available products include Makerbot's trade name "Replicator" series, 3D Systems' trade name "Cube" series, Stratasys' trade name "Idea" series, "Design" series, "Production" series, Hot Proceed company Product name "Blade" series, product name "DaVinci" series manufactured by XYZ Printing Co., Ltd., and as an example of a commercial product using a particulate (pellet) raw material, product name "freeformer" manufactured by ARBURG. Examples include, but are not limited to, series.
Further, in modeling, it is necessary to convert three-dimensional model data (hereinafter referred to as CAD data) into data for hot-melt lamination method modeling (G code conversion). Specifically, CAD data is sliced layer by layer using dedicated software, and the modeling temperature, modeling speed, stacking pitch, and other settings are set as necessary.

(1) Melt flow rate (MFR, unit: g/10 minutes):
The measurement was performed according to JIS K7210:1999 method A, condition M (230° C., 2.16 kg load).
(2) Crystallization peak temperature (Tc, unit: °C):
Using a Q2000 type differential scanning calorimeter (DSC) manufactured by TA Instruments, a 5.0 mg sample was taken, the temperature was once raised to 200° C. and the thermal history was erased, and then 10° C./min. The temperature of the exothermic peak top when the temperature was lowered to −10° C. at the temperature lowering rate and was measured as the crystallization peak temperature (Tc). When a plurality of peaks were observed, the highest peak temperature was taken as Tc.
(3) Heat of fusion (ΔHm, unit: J/g):
Using a Q2000 type differential scanning calorimeter (DSC) manufactured by TA Instruments, a 5.0 mg sample was taken, the temperature was once raised to 200° C. and the thermal history was erased, and then 10° C./min. The heat of fusion (ΔHm) in the range of 10 to 200° C., which is measured when the temperature is decreased to −10° C. at the temperature decreasing rate of 10° C. and is again increased to 200° C. at the temperature increasing rate of 10° C./min. Was measured.
(4) Melting peak temperature (Tm, unit: °C):
Using a Q2000 type differential scanning calorimeter (DSC) manufactured by TA Instruments, a 5.0 mg sample was taken, the temperature was once raised to 200° C. and the thermal history was erased, and then 10° C./min. The endothermic peak top temperature when the temperature was decreased to −10° C. at the temperature decreasing rate of 10° C., and was again increased to 200° C. at the temperature increasing rate of 10° C./minute was defined as the melting peak temperature (Tm). When a plurality of peaks were observed, the highest peak temperature was taken as Tm.

(5) Polypropylene resin composition (Y)
PP1: Nippon Polypro Co., Ltd. metallocene polymer trade name “WELNEX RMG02” (MFR 20 g/10 min, Tc 92° C., ΔHm 65 J/g, Tm 130° C.) was used.
PP2: Nippon Polypro Co., Ltd. metallocene polymer trade name “WELNEX RFG4VM” (MFR 6 g/10 min, Tc 89° C., ΔHm 65 J/g, Tm 130° C.) was used.
PP3: Japan Polypro Co., Ltd. metallocene polymer trade name “WINTEC WMG03” (MFR 30 g/10 minutes, Tc 110° C., ΔHm 90 J/g, Tm 142° C.) is used as a polypropylene resin composition other than the present invention. I was there.
PP4: As a polypropylene resin composition other than the present invention, a polymer that is not a metallocene-based polymer manufactured by Nippon Polypro Ltd. "Novatech PP FY4" (MFR 5g/10 minutes, Tc 113°C, ΔHm 100J/g, Tm 160°C). ) Was used.
PP5: Nippon Polypro Co., Ltd. metallocene polymer trade name “WINTEC WFX6” (MFR 2 g/10 min, Tc 90° C., ΔHm 75 J/g, Tm 125° C.) is used as a polypropylene resin composition other than the present invention. I was there.

(6) Formation of Strands PP1 to PP5 were introduced into a twin-screw kneading extruder having a screw diameter of 15 mm, and processed into strands.
The twin-screw kneading extruder has a set temperature of 200° C. and a discharge rate of 1.0 kg/hr, and extrudes the resin composition from a die having a diameter of 3 mm having a perfect circular shape, and passes through a water tank of 40° C. for 5 m by a take-up device. /Min. No stretching or heat setting was performed.
The cross section of the obtained strand was substantially circular, the diameter thereof was in the range of 1.70 mm to 1.80 mm, and the average value was 1.75 mm.
(7) Hot Melt Laminating Method Modeling The previously processed strand was supplied to Hot Proceed's trade name "Blade-1" equipped with a 0.4 mm nozzle, nozzle temperature 210°C, molding table temperature 90°C, lamination The pitch was set to 0.2 mm, the molding speed was set to 30 to 60 mm/min, and as a measure against warpage, a double-sided adhesive tape was laid on the molding table, and a three-dimensional model of a frog having a total length of 70 mm, a total width of 80 mm, and a total height of 30 mm was molded. In addition, Slic3r was used for the G code conversion from the frog CAD data, and no support material was used.
What was able to be beautifully molded at the time of modeling is ○, what could be molded but the table and the part of the bottom surface floated due to the influence of warpage △, What was peeled off the table during modeling did.

(Example 1) Using PP1 as a propylene-based resin composition, a strand was obtained by the above-mentioned method, and hot melt lamination molding was performed. The results are shown in Table 1. No remarkable molding defects such as warpage, twisting and shrinkage were observed. Further, the shape of the obtained shaped product was left standing at room temperature for 1 month and then visually checked for shape, but no warp, twist, or the like was found. Further, even if the modeling temperature was lowered to 200° C., modeling could be performed without any problem.

(Example 2) The same operation as in Example 1 was performed except that PP2 was used as the propylene resin composition. The results are shown in Table 1. No remarkable molding defects such as warpage, twisting and shrinkage were observed. Further, the shape of the obtained shaped product was left standing at room temperature for 1 month and then visually checked for shape, but no warp, twist, or the like was found. Further, even if the modeling temperature was lowered to 200° C., modeling could be performed without any problem.

(Comparative Example 1) The same operation as in Example 1 was performed except that PP3 was used as the propylene resin composition. The results are shown in Table 1. During molding, the molded product was warped and peeled off from the table, and the desired molded product could not be obtained. In addition, although the ejection was stable even when the modeling temperature was lowered to 200° C., the modeled product was warped during the modeling and peeled off from the table, and the desired modeled product could not be obtained.

(Comparative Example 2) The same operation as in Example 1 was performed except that PP4 was used as the propylene resin composition. The results are shown in Table 1. During molding, the molded product was warped and peeled off from the table, and the desired molded product could not be obtained. Moreover, when the modeling temperature was lowered to 200° C., the ejection from the nozzle became unstable.

(Comparative Example 3) The same operation as in Example 1 was performed except that PP5 was used as the propylene resin composition. The results are shown in Table 1. It was possible to model, but the table and part of the bottom surface floated due to the influence of warpage. Although the ejection was stable even when the modeling temperature was lowered to 200° C., the table and a part of the bottom surface floated due to the influence of warpage.

(effect)
As described above, by using the polypropylene resin composition for hot-melt laminating method modeling of the present invention, it is possible to provide a polypropylene-based molded article that causes less molding defects such as shrinkage, warpage, and twist during modeling. Moreover, since the polypropylene resin is excellent in organic solvent resistance, chemical resistance, moisture absorption resistance, and heat resistance, the shaped article can be put to practical use for a wide range of applications.

Claims (4)

Hot-melt laminating method modeling showing the following characteristics (Y-1) to (Y-4) containing 0.005 to 0.5 parts by weight of an antioxidant based on 100 parts by weight of a polypropylene resin (X). Using a strand obtained from the polypropylene resin composition (Y) for use in a hot melt laminating method.
Characteristic ( Y-1 ): Melt flow rate (MFR: Method A of JIS K7210:1999, condition M (230° C., 2.16 kg load)) is 1.0 to 100 g/10 minutes.
Characteristic ( Y-2 ): Using a differential thermal scanning calorimeter (DSC), the temperature was once raised to 200° C. to erase the thermal history, and then the temperature was lowered to −10° C. at a temperature lowering rate of 10° C./min. The measured crystallization peak temperature (Tc) is 105° C. or lower.
Characteristic ( Y-3 ): Using a differential thermal scanning calorimeter (DSC), the temperature is once raised to 200° C. to erase the thermal history, and then the temperature is lowered to −10° C. at a temperature lowering rate of 10° C./min. The heat of fusion (ΔHm) in the range of 10 to 200° C., which is measured when the temperature is raised again to 200° C. at the rate of temperature increase of 10° C./min, is 70 J/g or less.
Characteristic (Y-4): Using a differential thermal scanning calorimeter (DSC), the temperature is once raised to 200° C. to erase the thermal history, and then the temperature is lowered to −10° C. at a temperature lowering rate of 10° C./min. The melting peak temperature (Tm) measured by raising the temperature to 200° C. again at a temperature rising rate of 10° C./min is 110° C. or higher and 150° C. or lower. The molding method according to claim 1, wherein a part or all of the polypropylene resin (X) is a metallocene polymer. The molding method according to claim 1 or 2, wherein the polypropylene resin (X) is a block copolymer of propylene and ethylene and/or an α-olefin having 4 to 12 carbon atoms. The molding method according to any one of claims 1 to 3, wherein the strand diameter is 1.0 to 5.0 mm.