WO2024106234A1

WO2024106234A1 - Resin powder, three-dimensional molded article, and method for producing three-dimensional molded article

Info

Publication number: WO2024106234A1
Application number: PCT/JP2023/039749
Authority: WO
Inventors: 勇佑依田; 勝彦岡本; 和人杉山
Original assignee: 三井化学株式会社
Priority date: 2022-11-15
Filing date: 2023-11-02
Publication date: 2024-05-23

Abstract

A resin powder which contains a propylene-based polymer powder, and satisfies [1] and [2] when a molded article is formed from the resin powder. [1] The tensile elasticity is 1,500-3,000MPa. [2] The Charpy impact strength when measured at -30℃ is 2.0kJ/m2 or higher.

Description

Resin powder, three-dimensional molded product, and method for producing three-dimensional molded product

This disclosure relates to resin powder, three-dimensional molded objects, and methods for manufacturing three-dimensional molded objects.

Representative examples of 3D printing methods using thermoplastic resins include the Material Extrusion method (MEX) and Powder Bed Fusion (PBF) using powder materials. The PBF method has high modeling accuracy and can produce fine objects, so various methods have been proposed.

Polyamide 12 is used for the particles contained in the above powder material because it is easier to handle with a wider difference between its melting point (Tm) and crystallization temperature (Tc) and because of its laser absorption properties. On the other hand, polypropylene resin is also attracting attention because of its wider difference between its melting point (Tm) and crystallization temperature (Tc) and its wide range of applications.

For example, a resin powder for three-dimensional modeling containing ethylene-propylene copolymer particles, which has good tensile strength and excellent elongation at break, and a method for producing a three-dimensional object by the PBF method using the resin powder for three-dimensional modeling have been proposed (see Patent Document 1).

International Publication No. 2020/213586

The resin powder for three-dimensional modeling in Patent Document 1 does not have sufficient mechanical properties such as bending elasticity, or impact strength at low temperatures, and there is room for improvement before it can be used in applications that require mechanical properties and low-temperature impact resistance, such as automobile parts.

The present disclosure has been made in consideration of the above, and aims to provide a resin powder having excellent mechanical properties and low-temperature impact properties, a three-dimensional molded product molded using the resin powder, and a method for manufacturing a three-dimensional molded product using the resin composition.

Means for solving the above problems include the following embodiments.
<1> A resin powder containing a propylene-based polymer powder, the resin powder satisfying the following [1] and [2] when molded into a molded article:
[1] The tensile modulus is 1500 MPa to 3000 MPa.
[2] The Charpy impact strength measured at -30 ° C is 2.0 kJ / ^m2 or more.
<2> The resin powder according to <1>, which satisfies the following [3]:
[3] The heat distortion temperature (HDT) measured in accordance with JIS K7191 is 105°C or higher.
<3> The resin powder according to <1> or <2>, wherein the resin powder has an average powder particle size (R) of 1 μm to 200 μm.
<4> The resin powder is a mixture containing the propylene-based polymer powder, a thermoplastic elastomer, and a filler,
per 100 parts by mass in total of the propylene-based polymer powder, the thermoplastic elastomer, and the filler,
The content of the propylene-based polymer powder is 30 parts by mass to 90 parts by mass,
The content of the thermoplastic elastomer is 1 part by mass to 40 parts by mass,
The resin powder according to any one of <1> to <3>, wherein the content of the filler is 1 part by mass to 50 parts by mass.
<5> The resin powder according to any one of <1> to <4>, which satisfies the following [4]:
[4] The melting point (Tm) of the resin powder measured by DSC is 150° C. to 170° C.
<6> The resin powder according to any one of <1> to <5>, which satisfies the following [5]:
[5] The melt flow rate (MFR) of the propylene polymer measured in accordance with ASTM D1238 at 230° C. under a load of 2.16 kg is 0.05 g/10 min to 150 g/10 min.
<7> The resin powder according to any one of <1> to <6>, wherein the propylene-based polymer is a propylene-based block copolymer, and satisfies the following [6] to [8]:
[6] The propylene-based block copolymer is composed of 5% by mass to 35% by mass of a 23° C. n-decane soluble portion (D _sol ) and 65% by mass to 95% by mass of a 23° C. n-decane insoluble portion (D _insol ) (wherein the total amount of D _sol and D _insol is 100% by mass).
[7] The intrinsic viscosity [η] of D _sol is 1.0 dl/g to 10.0 dl/g.
[8] D _sol is mainly composed of a copolymer of propylene and one or more olefins selected from ethylene and α-olefins having 4 to 20 carbon atoms, and the content of olefins other than propylene in D _sol is 10 mol % to 60 mol %.
<8> The resin powder according to any one of <1> to <7>, wherein the propylene-based polymer is a propylene-based block copolymer, the propylene-based block copolymer contains structural units derived from one or more olefins selected from ethylene and α-olefins having 4 to 20 carbon atoms, and a total content of the olefins other than propylene is 4.0 mol % to 30 mol %.
<9> The resin powder according to any one of <1> to <8>, wherein the resin powder contains a thermoplastic elastomer, and the thermoplastic elastomer satisfies the following [9] to [11].
[9] The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190° C. under a load of 2.16 kg is 0.05 g/10 min to 100 g/10 min.
[10] The glass transition temperature (Tg) measured by DSC is −30° C. or lower.
[11] The tensile modulus is less than 500 MPa.
<10> The resin powder according to any one of <1> to <9>, which is used for three-dimensional molding.
<11> A three-dimensional molded article obtained by molding the resin powder according to any one of <1> to <9> by a powder bed fusion method.
<12> A method for producing a three-dimensional molded article, comprising the steps of: producing a three-dimensional molded article by a powder bed fusion method using the resin powder according to any one of <1> to <9>.

The present disclosure provides a resin powder having excellent mechanical properties and low-temperature impact properties, a three-dimensional molded product molded using the resin powder, and a method for producing a three-dimensional molded product using the resin composition.

In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in the present disclosure. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.
In the present disclosure, when a resin powder or the like contains a plurality of substances corresponding to each component, the amount of each component means the total amount of the plurality of substances contained in the resin powder or the like, unless otherwise specified.
In the present disclosure, combinations of two or more preferred aspects are more preferred aspects.
In this disclosure, the physical properties described in the description of the embodiment of the invention can be measured by the methods described in the examples section.

<Resin powder>
The resin powder of the present disclosure contains a propylene-based polymer powder, and when the resin powder is molded into a molded article, the following [1] and [2] are satisfied.
[1] The tensile modulus is 1500 MPa to 3000 MPa.
[2] The Charpy impact strength measured at -30 ° C is 2.0 kJ / ^m2 or more.
As a result, the resin powder of the present disclosure and a three-dimensional molded product obtained using the same are excellent in mechanical properties and low-temperature impact resistance. The resin powder of the present disclosure is excellent in mechanical properties and low-temperature impact resistance, and is suitable for use in three-dimensional molding, and is more suitable for use in three-dimensional molding by powder bed fusion bonding.

The resin powder of the present disclosure has a tensile modulus of elasticity of 1500 MPa to 3000 MPa when molded into a product, preferably 1600 MPa to 3000 MPa, and more preferably 1800 MPa to 2800 MPa. Since the resin powder of the present disclosure has a tensile modulus of elasticity of 1500 MPa or more when molded into a product, it can be suitably used for applications requiring mechanical properties such as automobile parts.

The resin powder of the present disclosure, when molded, has a Charpy impact strength at −30° C. of 2.0 kJ/m ² or more, preferably 2.0 kJ/m ² to 10 kJ/m ² , and more preferably 3.0 kJ/m ² to 8 kJ/m ^2. Since the resin powder of the present disclosure has a Charpy impact strength at −30° C. of 2.0 kJ/m ² or more when molded, it can be suitably used for applications requiring low-temperature impact properties, such as automobile parts.

The resin powder of the present disclosure preferably has a melting point measured by DSC of 150°C to 170°C, more preferably 155°C to 168°C, and even more preferably 157°C to 165°C. By having a melting point of 150°C or higher, the resin powder of the present disclosure can be suitably used for applications requiring heat resistance, such as automobile parts.

The resin powder disclosed herein preferably has a heat distortion temperature (HDT) measured in accordance with JIS K7191 when molded into a molded product of 105°C or higher, more preferably 110°C to 150°C, and even more preferably 115°C to 140°C.

(Propylene-based polymer powder)
The resin powder includes a propylene-based polymer powder. Examples of the propylene-based polymer powder include a propylene homopolymer, a propylene random copolymer including a structural unit derived from propylene and a structural unit derived from an olefin monomer other than propylene, and a propylene block copolymer. The resin powder may include only one type of propylene-based polymer powder, or may include two or more types of propylene-based polymer powder.

The propylene copolymer may be a block copolymer, a random copolymer, or a graft copolymer. From the viewpoint of the heat resistance, mechanical properties, and low-temperature impact properties of the resin powder, it is preferably a propylene homopolymer or a block copolymer. From the viewpoint of the heat resistance of the resin powder, it is preferable that the melting point (Tm) measured by DSC is 150°C to 170°C, more preferably 155°C to 170°C, and even more preferably 155°C to 169°C. Furthermore, from the viewpoint of the heat resistance, mechanical properties, and low-temperature impact properties of the resin powder, it is preferable that the propylene-based polymer powder is a propylene homopolymer or a propylene-based block copolymer.

The stereoregularity of the propylene-based polymer powder where propylene-derived structural units are repeatedly bonded may be either an isotactic structure or a syndiotactic structure, and from the viewpoint of the rigidity and heat resistance of the resin powder, an isotactic structure is preferable.

Propylene-based block copolymers are composed of a skeleton derived from propylene as the essential skeleton, and skeletons derived from ethylene and one or more olefins selected from α-olefins having 4 to 20 carbon atoms. Examples of α-olefins having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

When the propylene copolymer is a propylene-based block copolymer, the propylene-based block copolymer contains structural units derived from one or more olefins selected from ethylene and α-olefins having 4 to 20 carbon atoms, and the total content of the olefins other than propylene is preferably 0.5 mol% to 30 mol%, more preferably 4.0 mol% to 30 mol%, even more preferably 4.5 mol% to 25 mol%, and particularly preferably 5 mol% to 20 mol%, from the viewpoint of the mechanical properties and low-temperature impact properties of the resin powder.

The average powder particle size (R) of the resin powder is preferably 1 μm to 200 μm, more preferably 5 μm to 200 μm, and even more preferably 10 μm to 180 μm, from the viewpoint of suitable use in three-dimensional molding by powder bed fusion bonding.

The average powder particle size of the resin powder can be adjusted, for example, by subjecting particles whose particle size has been controlled by polymerization or particles containing a prepared propylene-based polymer to a grinding process such as mechanical grinding or wet grinding, a particle spheronization process, classification, etc.

Methods for measuring particle size include the Coulter counter method, laser diffraction method, light scattering method, and ultrasonic spectroscopy.

The melt flow rate of the propylene-based polymer measured at 230° C. under a load of 2.16 kg in accordance with ASTM D-1238 is preferably 0.05 g/10 min to 150 g/10 min, more preferably 5 g/10 min to 150 g/10 min, and further preferably 18 g/10 min to 100 g/10 min, from the viewpoints of the mechanical properties and low-temperature impact resistance of the resin powder.
For example, the melt flow rate may be adjusted by mixing two or more types of resin powders having different propylene polymer compositions, or by adjusting the weight average molecular weight of the propylene polymer.

The weight average molecular weight of the 23° C. n-decane insoluble portion (D _insol ) of the propylene polymer contained in the resin powder is not particularly limited.
The weight average molecular weight can be calculated from the molecular weight distribution in terms of polystyrene (PS) by gel permeation chromatography (GPC).
The molecular weight distribution (weight average molecular weight: Mw/number average molecular weight: Mn) is preferably 1.0-10, more preferably 2.0-10, and even more preferably 3.0-10.

The melting point of the propylene polymer constituting the propylene polymer powder, as measured by DSC, is preferably 150°C to 170°C, and more preferably 155°C to 168°C.

The propylene-based block copolymer constituting the propylene-based polymer powder may have a portion soluble in n-decane at 23°C.
The "23°C n-decane soluble portion" refers to a portion of the propylene-based block copolymer that is dissolved in the n-decane solution when the copolymer is heated and dissolved in n-decane at 145°C for 30 minutes and then cooled to 23°C, as described in the Examples below.

The propylene-based block copolymer may have a portion insoluble in n-decane at 23°C in addition to a portion soluble in n-decane at 23°C. The amount of the portion soluble in n-decane at 23°C is preferably 5% by mass to 35% by mass, more preferably 6% by mass to 25% by mass, and even more preferably 8% by mass to 20% by mass, based on the total amount of the propylene-based block copolymer. In the propylene-based block copolymer, the total amount of the portion soluble in n-decane at 23°C and the amount of the portion insoluble in n-decane at 23°C is 100% by mass.

The intrinsic viscosity [η] of the n-decane soluble portion at 23°C is preferably 1.0 dl/g to 10 dl/g, more preferably 1.5 dl/g to 9.0 dl/g, and even more preferably 2.0 dl/g to 8.0 dl/g.

The 23° C. n-decane soluble portion is preferably mainly composed of a copolymer of propylene and one or more olefins selected from ethylene and α-olefins having 4 to 20 carbon atoms. Furthermore, the content of olefins other than propylene in the 23° C. n-decane soluble portion (the total content of ethylene and one or more olefins selected from α-olefins having 4 to 20 carbon atoms) is preferably 10 mol% to 60 mol%, more preferably 14 mol% to 50 mol%, and even more preferably 20 mol% to 50 mol%.
The content of olefins other than propylene in the 23° C. n-decane soluble portion may be read as the ethylene content in the 23° C. n-decane soluble portion.

The method for producing the propylene-based polymer powder is not particularly limited. For example, the propylene-based polymer powder and the resin powder containing the same can be produced by referring to the catalysts, production methods, etc. described in paragraphs 0022 to 0082 of WO 2012/102050.

The resin powder containing the propylene-based polymer powder of the present disclosure can also be produced by referring to the catalysts and production methods described in, for example, International Publication No. 2009/011231, JP 2011-57789 A, JP 2019-206616 A, and International Publication No. 2012/102050.

The resin powder of the present disclosure may contain a thermoplastic elastomer, a filler, etc., or may be a mixture containing the aforementioned propylene-based polymer powder, a thermoplastic elastomer, and a filler.

When the resin powder contains other components (preferably when it contains a thermoplastic elastomer and a filler), the content of the propylene-based polymer powder is preferably 30 parts by mass to 90 parts by mass, more preferably 35 parts by mass to 85 parts by mass, and even more preferably 35 parts by mass to 80 parts by mass, per 100 parts by mass of the propylene-based polymer powder and other components in total (preferably 100 parts by mass of the propylene-based polymer powder, the thermoplastic elastomer, and the filler in total).

(Thermoplastic elastomer)
The resin powder is preferably a mixture containing a propylene-based polymer powder and a thermoplastic elastomer. When the resin powder contains a thermoplastic elastomer, deformation of a three-dimensional object is effectively suppressed when the resin powder is used for molding the three-dimensional object, and elongation, toughness, and impact resistance at a lower temperature are imparted. The resin powder may contain only one type of thermoplastic elastomer, or may contain two or more types of thermoplastic elastomers.

Thermoplastic elastomers have rubber-like elasticity. Rubber-like elasticity refers to the property that when a load is applied to a resin, the shape of the resin changes, and when the load applied to the resin is removed, the shape of the resin returns to its original shape. Specifically, a thermoplastic elastomer refers to a thermoplastic resin with a tensile modulus of elasticity of less than 600 MPa at 25°C. In this respect, thermoplastic elastomers are distinguished from thermoplastic resins such as the propylene-based polymers mentioned above.

Thermoplastic elastomers include ethylene-α-olefin random copolymers, ethylene-α-olefin-non-conjugated polyene random copolymers, hydrogenated block copolymers, other elastic polymers, and mixtures of these.

When the thermoplastic elastomer is a copolymer, the thermoplastic elastomer may be a block copolymer, a random copolymer, or a graft copolymer.
From the viewpoint of the heat resistance, mechanical properties, and low-temperature impact properties of the resin powder, the elastic modulus of the thermoplastic elastomer may be less than 500 MPa, and the glass transition temperature of the thermoplastic elastomer measured by DSC may be −30° C. or lower. It is preferable that the elastic modulus is less than 500 MPa and the glass transition temperature is −40° C. or lower.

Olefins include ethylene, propylene, and α-olefins having 4 to 10 carbon atoms. Thermoplastic elastomers may contain one type of olefin-derived structural unit alone or a combination of two or more types.

Specific examples of the α-olefins having 4 to 10 carbon atoms include propylene, 1-butene, 1-hexene, and 1-octene. These α-olefins can be used alone or in combination. Among these, 1-butene and 1-octene are particularly preferred.

The ethylene/α-olefin random copolymer preferably has a molar ratio of ethylene to α-olefin (ethylene/α-olefin) of 95/5 to 70/30, and more preferably 90/10 to 75/25.

The ethylene-α-olefin random copolymer preferably has an MFR of 0.05 g/10 min or more at 190°C under a load of 2.16 kg, and more preferably 0.05 g/10 min to 100 g/10 min.

The ethylene-α-olefin random copolymer can be produced by a conventional method, but various commercially available products can also be used. Preferred commercially available products include the Tafmer A series and H series manufactured by Mitsui Chemicals, the Engage series manufactured by Dow Chemical, and the Exact series manufactured by ExxonMobil.

The ethylene/α-olefin/non-conjugated polyene random copolymer may be a random copolymer rubber of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene.
Specific examples of the α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene. These α-olefins can be used alone or in combination. Among these, propylene, 1-butene, 1-hexene, and 1-octene are particularly preferred. Examples of the non-conjugated polyenes include cyclic non-conjugated dienes such as 5-ethylidene-2-norbornene, 5-propylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, and norbornadiene; and chain non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,7-octadiene, and 7-methyl-1,6 octadiene.

The ethylene/α-olefin/non-conjugated polyene random copolymer preferably has a molar ratio of ethylene, α-olefin, and non-conjugated polyene (ethylene/α-olefin/non-conjugated polyene) of 90/5/5 to 30/45/25, and more preferably 80/10/10 to 40/40/20.

The ethylene-α-olefin-non-conjugated polyene random copolymer preferably has an MFR of 0.05 g/10 min or more at 190°C and a load of 2.16 kg, and more preferably 0.05 g/10 min to 100 g/10 min. Specific examples of ethylene-α-olefin-non-conjugated polyene random copolymers include ethylene-propylene-diene terpolymers (EPDM).

The hydrogenated block copolymer is a hydrogenated product of a block copolymer whose block form is represented by the following formula (a) or (b), and is a hydrogenated block copolymer having a hydrogenation rate of 90 mol % or more, preferably 95 mol % or more.
X(YX) _n ...(a)
(XY) _n ... (b)

Examples of the monovinyl-substituted aromatic hydrocarbons constituting the polymer block represented by X in formula (a) or (b) include styrene, α-methylstyrene, p-methylstyrene, chlorostyrene, lower alkyl-substituted styrene, vinylnaphthalene, and other styrenes or derivatives thereof. These can be used alone or in combination of two or more.

Conjugated dienes constituting the polymer block represented by Y in formula (a) or (b) include butadiene, isoprene, chloroprene, etc. These may be used alone or in combination of two or more. n is an integer of 1 to 5, preferably 1 or 2.

Specific examples of hydrogenated block copolymers include styrene-based block copolymers such as styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and styrene-ethylene-propylene block copolymer (SEP).

The block copolymer before hydrogenation can be produced, for example, by a method of performing block copolymerization in an inert solvent in the presence of a lithium catalyst or a Ziegler-Natta catalyst. Detailed production methods are described, for example, in JP-B-40-23798. Hydrogenation treatment can be carried out in an inert solvent in the presence of a known hydrogenation catalyst. Detailed methods are described, for example, in JP-B-42-8704, JP-B-43-6636, and JP-B-46-20814.

When butadiene is used as the conjugated diene, the proportion of 1,2-bonds in the polybutadiene block is preferably 20% by mass to 80% by mass, and more preferably 30% by mass to 60% by mass.

Commercially available hydrogenated block copolymers can also be used. Specific examples include Kraton G1657 (trademark, manufactured by Kraton Polymers), Septon 2004 (trademark, manufactured by Kuraray Co., Ltd.), and Tuftec H1052 (trademark, manufactured by Asahi Kasei Co., Ltd.).

The melt flow rate of thermoplastic elastomers such as ethylene-α-olefin copolymers and propylene-α-olefin copolymers is preferably 0.05g/10min to 100g/10min, more preferably 0.1g/10min to 100g/10min, at 190°C and under a load of 2.16kg, in accordance with ASTM D-1238.

The weight average molecular weight of the hydrogenated block copolymer is not particularly limited and may be, for example, 100,000 to 500,000.
The weight average molecular weight can be calculated from the molecular weight distribution in terms of polystyrene (PS) by gel permeation chromatography (GPC).
The molecular weight distribution (weight average molecular weight: Mw/number average molecular weight: Mn) is preferably 1.0-10, more preferably 1.5-9, and even more preferably 1.5-8.

When the resin powder contains a thermoplastic elastomer, the content of the thermoplastic elastomer is preferably 1 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 10 to 35 parts by mass, per 100 parts by mass of the propylene-based polymer powder and other components in total (preferably 100 parts by mass of the propylene-based polymer powder, the thermoplastic elastomer, and the filler in total).

When the resin powder of the present disclosure contains a thermoplastic elastomer, the thermoplastic elastomer preferably contains an ethylene-α-olefin random copolymer. The content of the ethylene-α-olefin random copolymer in the thermoplastic elastomer is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 60% by mass to 90% by mass, based on the total amount of the thermoplastic elastomer.

When the thermoplastic elastomer contains a hydrogenated block copolymer, the content of the hydrogenated block copolymer in the thermoplastic elastomer is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 60% by mass to 90% by mass.
When the thermoplastic elastomer contains an ethylene/α-olefin random copolymer and a hydrogenated block copolymer, the content of the ethylene/α-olefin random copolymer in the thermoplastic elastomer is preferably 50% by mass to 99% by mass, more preferably 60% by mass to 95% by mass, and even more preferably 60% by mass to 90% by mass, and the content of the hydrogenated block copolymer in the thermoplastic elastomer is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 40% by mass, and even more preferably 10% by mass to 40% by mass.

(Filler)
The resin powder is preferably a mixture containing a propylene-based polymer powder and a filler. As the filler, one type may be used alone, or two or more types may be used in combination.

The filler may be dry blended with the resin powder or may be contained in the resin. By including a filler, the heat resistance, strength, etc. of the resin powder can be improved, and the warping of the resulting three-dimensional molded body tends to be reduced.

Fillers are broadly classified into inorganic fillers such as talc, magnesium sulfate fiber, glass fiber, carbon fiber, mica, calcium carbonate, magnesium hydroxide, ammonium phosphates, silicates, carbonates, carbon black, glass beads, fumed silica, hollow glass beads, glass fiber, crushed glass, aluminum oxide, and inorganic oxides, nitrides, borides, and carbides of zirconium, tantalum, titanium, tungsten, boron, aluminum, and beryllium; and organic fillers such as wood flour, cellulose, polyester fiber, nylon fiber, kenaf fiber, bamboo fiber, jute fiber, rice flour, starch, and corn starch.
As the inorganic filler, talc, magnesium sulfate, glass, silica, glass fiber, carbon fiber, wood powder, and cellulose are preferably used.

(talc)
Talc is pulverized magnesium silicate hydrate. The crystal structure of magnesium silicate hydrate is a pyrophyllite-type three-layer structure, and talc is a stack of these structures. Talc is more preferably a plate-like talc in which magnesium silicate hydrate crystals are finely pulverized to the unit layer level.

The average particle size of the talc is preferably 3 μm or less. Here, the average particle size of talc means the 50% equivalent particle size D50 obtained from the integral distribution curve of the sieve size measurement method in which talc is suspended in a dispersion medium of water or alcohol using a centrifugal sedimentation type particle size distribution measurement device. Talc may be used as is, or may be surface-treated with various silane coupling agents, titanium coupling agents, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid salts, or other surfactants in order to improve the interfacial adhesion with the propylene-based block copolymer, dispersibility in resin powder, etc.

(Magnesium sulfate)
The magnesium sulfate is preferably magnesium sulfate fiber. The average fiber length of the magnesium sulfate fiber is preferably 5 μm to 50 μm, and more preferably 10 μm to 30 μm. The average fiber diameter of the magnesium sulfate fiber is preferably 0.3 μm to 2 μm, and more preferably 0.5 μm to 1 μm. An example of a commercially available product is "MOS HIGE" by Ube Industries, Ltd.

(Glass)
The glass may be, for example, selected from the group consisting of solid glass beads, hollow glass beads, porous glass beads, glass fibers, crushed glass, and combinations thereof. In another example, the glass may be selected from the group consisting of soda-lime glass ( _Na2O /CaO/ _SiO2 ), borosilicate glass, phosphate-based glass, quartz glass, and combinations thereof. In yet another example, the glass may be selected from the group consisting of soda-lime glass, borosilicate glass, and combinations thereof. In yet another example, the glass may be any type of amorphous silicate glass.

For example, the surface of the glass may be modified with a functional group selected from the group consisting of acrylate-functional silanes, methacrylate-functional silanes, epoxy-functional silanes, ester-functional silanes, amino-functional silanes, and combinations thereof. Specific examples of glass modified with one or more of the aforementioned functional groups include those from Potters Industries (e.g., epoxy-functional silanes or amino-functional silanes), Gelest (e.g., acrylate-functional silanes or methacrylate-functional silanes), Sigma-Aldrich (e.g., ester-functional silanes), and the like.

For example, the glass is selected from the group consisting of soda lime glass, borosilicate glass, phosphate glass, quartz glass, and combinations thereof; or the surface of the glass is modified with a functional group selected from the group consisting of acrylate-functional silanes, methacrylate-functional silanes, epoxy-functional silanes, ester-functional silanes, amino-functional silanes, and combinations thereof; or combinations thereof.

(silica)
The silica is not particularly limited, and examples thereof include dry process silica (anhydrous silicic acid) and wet process silica (hydrated silicic acid).

Silica may be modified with a surface treatment agent, and the method is not particularly limited, and any conventionally known method can be used. Examples include silane coupling agents such as hexamethyldisilazane (HMDS) and dimethyldichlorosilane (DMDS), silicone oil treatment agents such as dimethyl silicone oil and amino-modified silicone oil, etc.

(Glass fiber)
Examples of the glass fiber include filament-like fibers obtained by melt spinning glass such as E glass (electrical glass), C glass (chemical glass), A glass (alkaline glass), S glass (high strength glass), and alkali-resistant glass. The glass fiber is preferably contained in the resin powder in the form of short fibers of 1 mm or less.

(Carbon fiber)
The carbon fiber preferably has a fiber diameter of more than 2 μm and not more than 15 μm, more preferably 3 μm to 12 μm, and even more preferably 4 μm to 10 μm. When the fiber diameter is 2 μm or less, the rigidity of the fiber is significantly reduced, and when the fiber diameter exceeds 15 μm, the aspect ratio of the fiber (the ratio of length (L) to thickness (D): L/D) is reduced, and therefore sufficient reinforcement efficiency such as rigidity and heat resistance cannot be obtained, which is not preferable. Here, the fiber diameter can be obtained by cutting the fiber perpendicular to the fiber direction, measuring the diameter by observing the cross section under a microscope, and calculating the number average of the diameters of 100 or more fibers.

Furthermore, the carbon fiber preferably has a fiber length of 1 mm to 20 mm, more preferably 2 mm to 15 mm, and even more preferably 3 mm to 10 mm. If the fiber length is less than 1 mm, the aspect ratio is low and sufficient reinforcement efficiency cannot be obtained, and if the fiber length exceeds 20 mm, the workability and appearance are significantly deteriorated, which is not preferable.

Here, the fiber length can be measured using a caliper or the like, and calculated by calculating the number average of the fiber lengths of 100 or more fibers.
The carbon fiber that can be used in the resin powder is not particularly limited, and conventionally known carbon fibers can be used. Examples of carbon fibers include PAN-based carbon fibers made from polyacrylonitrile and pitch-based carbon fibers made from pitch. These carbon fibers can be used as so-called chopped carbon fibers in which the fiber yarn is cut to a desired length, and may also be those that have been subjected to a sizing treatment using various sizing agents as necessary. The sizing agent used for the sizing treatment needs to melt during melt-kneading with the polypropylene resin, so it is preferable that it melts at 200°C or less.

Specific examples of such chopped carbon fibers include PAN-based carbon fibers such as "TORAYCA CHOP" manufactured by Toray Industries, Inc., "PYROFIL (CHOPP)" manufactured by Mitsubishi Rayon Co., Ltd., and "BESFIGHT (CHOPP)" manufactured by Toho Tenax Co., Ltd., and pitch-based carbon fibers such as "DIALEAD" manufactured by Mitsubishi Chemical Industrial Products Co., Ltd., "DONACARBO (CHOPP)" manufactured by Osaka Gas Chemical Co., Ltd., and "KURECA CHOP" manufactured by Kureha Chemical Co., Ltd.

These carbon fiber components are compounded together with the other components that make up the resin powder using a melt-kneading device such as an extruder, but during this melt-kneading, it is preferable to select a compounding method that prevents excessive breakage of the carbon fiber components. For example, when melt-kneading using an extruder, the components other than the carbon fiber components are sufficiently melt-kneaded, and then the carbon fiber components are fed from a position downstream of the position where the resin components are completely melted using a side feed method or the like, thereby dispersing the bundled fibers while preventing fiber breakage.

(Wood flour)
The wood flour may be prepared by breaking wood with a cutter mill or the like, and pulverizing the broken wood with a ball mill, impeller mill, or the like to produce fine powder. The average particle size of the wood flour is preferably 1 μm to 200 μm, more preferably 10 μm to 150 μm. If the average particle size is less than 1 μm, handling is difficult, and if the amount of wood-based filler mixed is large, the mechanical strength of the molded body produced may decrease if the dispersibility in the resin is low. If the average particle size is more than 200 μm, the homogeneity, flatness, mechanical strength, etc. of the molded body may decrease.

(cellulose)
As the cellulose, cellulose fiber and crystalline cellulose are preferably used.
The cellulose fibers are preferably those having a high purity, for example, those having an α-cellulose content of 80% by mass or more. Organic fibers such as cellulose fibers include fibers having an average fiber diameter of 0.1 μm to 1000 μm and an average fiber length of 0.001 mm to 5 mm.

Crystalline cellulose is made by partially depolymerizing α-cellulose, obtained as pulp from fibrous plants, with mineral acids and refining it. Examples of products include "Ceolas" manufactured by Asahi Kasei Corporation.

　Fillers that have been surface-treated may be used. This can improve the adhesion between the filler and the resin powder. Examples of surface treatment agents used for the surface treatment include silane coupling agents such as aminosilane, epoxysilane, and acrylicsilane. These surface treatment agents may be fixed on the surface of the filler by a coupling reaction, or may cover the surface of the filler. When recycling powders used in three-dimensional molding, those that have been fixed by a coupling reaction are preferred because they are less likely to be modified by heat, etc.

When the resin powder contains a filler, the content of the filler may be 1 to 50 parts by mass, preferably 5 to 45 parts by mass, and more preferably 10 to 45 parts by mass, per 100 parts by mass of the propylene-based polymer powder and other components in total (preferably 100 parts by mass of the propylene-based polymer powder, thermoplastic elastomer, and filler in total).

When the resin powder contains a filler and a thermoplastic elastomer, the mass ratio of the filler to the thermoplastic elastomer, filler/thermoplastic elastomer, is preferably 0.25 to 5, more preferably 0.33 to 4, and even more preferably 0.5 to 3, from the viewpoint of the balance between mechanical properties and low-temperature impact resistance.

The volume average particle diameter of the filler (preferably the volume average particle diameter of the inorganic filler) may be 1 μm to 20 μm, 2 μm to 15 μm, or 3 μm to 10 μm.
The volume average particle size of the filler refers to the value of the particle size when the volume of each particle measured in a state where the filler is dispersed in water using a particle size distribution measuring device such as a laser diffraction/scattering type particle size distribution measuring device, and the volume of each particle is integrated from the small particle size side, and the integrated volume is 50% of the total volume.

(Other ingredients)
The resin powder of the present disclosure may be a powder containing other components in addition to the propylene-based polymer and the thermoplastic elastomer, as long as the effects of the present invention are not impaired. Examples of other components include resin components such as thermoplastic resins other than the propylene-based polymer, thermosetting resins, additive components, etc.
The resin powder may be mixed with a biomass-derived raw material.

Additive components include heat stabilizers, antistatic agents, weather stabilizers, light stabilizers, UV absorbers, antioxidants, antioxidants, neutralizers, fatty acid metal salts, softeners, dispersants, colorants, lubricants, pigments, dyes, brighteners, electrostatic agents, solvents, wetting agents, antimicrobial agents, chelating agents, flow aids, reinforcing materials, energy absorption promoters, energy absorption inhibitors, laser absorbers, fusion agents, and finish improvers. The above-mentioned other components may be used independently, either alone or in combination of two or more. When preparing the resin powder by mixing the other components, the mixing order is arbitrary, and the components may be mixed simultaneously, or a multi-stage mixing method may be used in which some components are mixed and then the other components are mixed.

The resin powder of the present disclosure may contain a flow aid. It is preferable that the flow aid is dry blended with the resin powder. In the present disclosure, the flow aid refers to a substance that suppresses the aggregation of resin powder due to the adhesive force between the resin powders. By including a flow aid, the fluidity of the resin powder can be improved, and there is no unevenness in the filling of the resin powder when it is made into a three-dimensional molded body. As a result, the warping of the obtained three-dimensional molded body is likely to be small.

Examples of flow aids include silica (silicon dioxide) such as fused silica, crystalline silica, and amorphous silica; alumina (aluminum oxide), alumina colloid (alumina sol), and alumina white; calcium carbonate such as light calcium carbonate, heavy calcium carbonate, finely powdered calcium carbonate, and special calcium carbonate-based fillers; nepheline syenite fine powder, calcined clay such as montmorillonite and bentonite; clay (aluminum silicate powder) such as silane-modified clay; silicic acid-containing compounds such as talc, diatomaceous earth, and silica sand; crushed natural minerals such as pumice powder, pumice balloon, slate powder, and mica powder; sulfur; Examples of suitable fillers include minerals such as barium sulfate, lithopone, calcium sulfate, molybdenum disulfide, and graphite, glass-based fillers such as glass fibers, glass beads, glass flakes, and foamed glass beads, fly ash spheres, volcanic glass hollow bodies, synthetic inorganic hollow bodies, single crystal potassium titanate, carbon fibers, carbon nanotubes, carbon hollow spheres, fullerenes, anthracite powder, artificial cryolite, titanium oxide, magnesium oxide, basic magnesium carbonate, dolomite, potassium titanate, calcium sulfite, mica, asbestos, calcium silicate, molybdenum sulfide, boron fibers, and silicon carbide fibers. Among these, silica, alumina, calcium carbonate, glass-based fillers, and titanium oxide are preferred, and silica is more preferred.
Commercially available silica products include the fumed silica "AEROSIL" (registered trademark) series manufactured by Nippon Aerosil Co., Ltd., the dry silica "Reolosil" (registered trademark) series manufactured by Tokuyama Corporation, and the sol-gel silica powder X-24 series manufactured by Shin-Etsu Chemical Co., Ltd.

The resin powder of the present disclosure may include an energy absorption enhancer. The energy absorption enhancer is a material that absorbs electromagnetic radiation.
The energy absorption promoter may also serve as a filler.

Examples of energy absorption promoters include pigments, carbon black, carbon fibers, copper hydroxyphosphate, near infrared absorbing dyes, near infrared absorbing pigments, metal nanoparticles, polythiophenes, poly(p-phenylene sulfide), polyaniline, poly(pyrrole), polyacetylene, poly(p-phenylene vinylene), polyparaphenylene, poly(styrene sulfonate), poly(3,4-ethylenedioxythiophene)-poly(styrene phosphonate) p-diethylaminobenzaldehyde diphenylhydrazone, anti-9-isopropylcarbazole-3-, and conjugated polymers consisting of combinations thereof.

The resin powder of the present disclosure may contain an energy absorption inhibitor, which is a material that does not easily absorb electromagnetic radiation.
The energy absorption inhibitor may also function as a filler.

Energy absorption inhibitors include, for example, substances that reflect particulate electromagnetic radiation, such as titanium, insulating powders, such as mica powder and ceramic powder, and water.

Either the energy absorption promoter or the energy absorption inhibitor may be used, or the energy absorption promoter and the energy absorption inhibitor may be used in combination to adjust the degree of absorption of electromagnetic radiation.

The resin powder of the present disclosure may include a coalescent. The coalescent may be, for example, a dispersion containing a radiation absorbing agent (e.g., an active material). The active material may be any infrared light absorbing colorant. The solvent for the coalescent may be water or a non-aqueous solvent (e.g., ethanol, acetone, n-methylpyrrolidone, aliphatic hydrocarbons, etc.). For example, the coalescent may be a mixture of an active material and a solvent (preferably without other components).
The fusing agent may include, for example, at least one co-solvent; at least one surfactant; at least one anti-kogation agent; at least one chelating agent; at least one buffer; at least one biocide; and water.

The resin powder of the present disclosure may include a finishing improver. The finishing improver may include a surfactant, a co-solvent, and the balance of water. The finishing improver may be a mixture of a surfactant, a co-solvent, and the balance of water, with no other ingredients. The finishing improver may include a colorant, or may be a mixture of a colorant, a surfactant, a co-solvent, and the balance of water, with no other ingredients. The finishing improver may include one or more ingredients such as an anti-kogation agent, an antimicrobial agent, a chelating agent, etc.

The resin powder of the present disclosure and the propylene-based polymer powder contained in the resin powder may be coated with any surface-active coating. Examples of surface-active coatings include coatings containing surfactants, acidic polymers, salts of acidic polymers, inorganic particles, etc., and the coating may be one type of these, or two or more types of these.

Surfactants used in surface-active coatings include, for example, anionic surfactants, nonionic surfactants, cationic surfactants, etc. Examples of anionic surfactants include sodium lauryl sulfate, linear or branched alkylbenzene sulfonates, etc.

The surface active coating may be an inorganic particulate coating using inorganic particles, for example, an inorganic particulate coating using fumed metal oxide nanoparticles. Inorganic particles used in the inorganic particulate coating include, for example, silicon dioxide, such as AEROSIL® 200, aluminum oxide, such as AEROXIDE® AluC, and aqueous dispersions thereof, such as AERODISP® W1824, AERODISP® W440, etc.

The surface active coating is applied using any suitable method, such as spray coating, pan coating, air or gas suspension coating, liquid phase coating, liquid dispersion coating, immersion, etc. Additionally, a reaction such as polymerization may be carried out after coating.

The resin powder of the present disclosure is used for molding three-dimensional objects. When used for molding three-dimensional objects, the resin powder of the present disclosure may be used alone or in combination with other components.

Three-dimensional molded products that can be molded using the resin powder of the present disclosure include, but are not limited to, automobile molded products (e.g., console parts, switch parts, door trim parts, instrument panel parts, clips, covers, engine peripheral parts, grip parts, bumpers, back doors, radiator parts, battery parts, etc.), electrical appliance molded products (electrical appliance parts, housings, etc.), furniture parts, building materials, construction materials, aircraft parts, toys, shoes, sporting goods, decorations, cases, etc.

<Three-dimensional molded object>
The three-dimensional molded product of the present disclosure is molded using a resin powder. Examples of the three-dimensional molded product include the above-mentioned molded products for automobiles and other molded products. The three-dimensional molded product of the present disclosure may be a sintered body or a molten body of the above-mentioned resin powder.

The three-dimensional molded product of this disclosure can be manufactured by three-dimensional molding using the powder bed fusion bonding method using the resin powder described above.

<Method of manufacturing three-dimensional molded product>
The method for producing a three-dimensional molded product of the present disclosure is a method for producing a three-dimensional molded product by powder bed fusion using the resin powder of the present disclosure. A three-dimensional molded product can be produced by the same method as the conventional powder bed fusion method, except that the resin powder of the present disclosure is used.

For example, the method for producing a three-dimensional molded product of the present disclosure may include step 1 of forming a thin layer of resin powder, step 2 of selectively irradiating the preheated thin layer with laser light to form a modeled layer in which the propylene-based polymer contained in the resin powder is melt-bonded, and step 3 of laminating the modeled layers by repeating steps 1 and 2 in this order.

One model layer constituting the three-dimensional molded product is formed through steps 1 and 2, and the model layers are sequentially stacked by repeating steps 1 and 2 to produce the three-dimensional molded product. From the viewpoint of achieving high-precision modeling, the manufacturing method for three-dimensional molded products disclosed herein preferably includes step 4 of preheating a thin layer of resin powder before irradiating the laser in step 2.

Each of the above-mentioned steps may be carried out with reference to, for example, the method for producing a three-dimensional molded body described in International Publication No. 2020/213586, HP Multi Jet Fusion technology, and three-dimensional printing using the modeling material described in Patent No. 7071532, etc.

Hereinafter, the embodiment of the present invention will be described in more detail based on examples. However, the present invention is not limited to these examples, which are one embodiment of the present invention.
The physical properties in the examples were measured by the following methods. The results are shown in Tables 1 to 3.
In Tables 1 to 3, blank spaces indicate that the corresponding component is not contained.

(1) Average powder particle size The average powder particle size of the powder particles was measured by a particle size distribution measuring device (Microtrac MT3300EXII, manufactured by Microtrac Bell Co., Ltd.) using the particle refractive index of each powder by a dry (air) method without using a solvent. The particle refractive index was set to 1.5. A sample was used in which 0.1 g of powder particles was added to 0.2 g of a surfactant (EMAL E-27C, manufactured by Kao Corporation) and 30 mL of water, and ultrasonic dispersion was performed for 10 minutes.

(2) Tensile modulus A molded body was produced using the powder particles as follows. First, the prepared powder particles were spread on the modeling stage at a predetermined recoating speed (160 mm/s) using a three-dimensional modeling device (3D SYSTEMS (SINTERSTATION 2500 plus)), forming a thin layer with a thickness of 0.2 mm. This thin layer was irradiated with laser light from a _CO2 laser equipped with a galvanometer scanner for _CO2 laser wavelengths in a range of 360 mm long x 310 mm wide under the following conditions to produce a modeled layer. Thereafter, the powder particles were further spread on the modeled layer, and the modeled layer was laminated by irradiating it with laser light. These steps were repeated to produce a molded body (a laminate of modeled layers).
Laser light emission conditions Laser output: 40W
Laser light wavelength: 10.6 μm
Beam diameter: 500 μm at the surface of the thin layer
The molded article thus produced was used to produce the following test pieces, whose tensile modulus was measured under the following conditions in accordance with JIS K7161.
<Measurement conditions>
Test piece: JIS K7161-2 1BA
Tensile speed: 0.5 mm/min
Gauge distance: 25 mm

(3) Charpy impact strength at -30°C Notched Charpy impact strength (kJ/m2) was measured under the following conditions using test pieces prepared from molded bodies in the same manner as in the above-mentioned measurement of tensile modulus in accordance with JIS K ^7111. The notch was formed by machining.
<Measurement conditions>
Temperature: -30°C
Test piece: 10 mm (width) x 80 mm (length) x 4 mm (thickness)

(4) Heat distortion temperature (HDT)
In accordance with JIS K7191, a test piece was prepared from a molded body molded in the same manner as in the measurement of the tensile modulus described above. An HDT test was carried out using a Toyo Seiki Seisakusho HDT tester Model 6A-2 under conditions of a heating rate of 2°C/min and a tensile stress of 0.45 MPa, and the heat distortion temperature (°C) of the test piece was measured.

(5) MFR
The melt flow rate (MFR) of the propylene polymer was measured under conditions of 230° C. and a load of 2.16 kg in accordance with ASTM D-1238.

(6) Melting point According to the measurement method of ISO 3146 (Measuring method of plastic transition temperature, JIS K7121), a differential scanning calorimeter (Diamond DSC, manufactured by PerkinElmer) was used to heat a propylene-based polymer powder or a resin powder to 230°C at 10°C/min, and the endothermic peak temperature on the high temperature side was taken as the melting point of the propylene-based polymer or the melting point of the resin powder. Then, the powder was cooled at 10°C/min, and the endothermic peak temperature was taken as the crystallization temperature.

(7) Glass Transition Temperature The glass transition temperature (Tg) of a thermoplastic elastomer was measured using a differential scanning calorimeter (DSC7000X type, manufactured by Hitachi High-Tech Science Corporation) as a measuring device.
Approximately 5 mg of sample is sealed in a measuring aluminum pan and heated from room temperature at 10° C./min to 200° C. To completely melt the thermoplastic elastomer, it is held at 200° C. for 5 minutes and then cooled to −200° C. at 10° C./min.
After leaving the sample at -200°C for 5 minutes, the sample was heated a second time to 200°C at 10°C/min to obtain a DSC curve. In the obtained DSC curve, the temperature on the lower side of the point where a line equidistant in the vertical direction from the extended straight line of each baseline intersects with the curve of the stepwise change in the glass transition was determined as the glass transition temperature (Tg).

(8) 23°C n-decane soluble part 200 mL of n-decane was added to 5 g of a propylene-based polymer powder sample, and the mixture was heated and dissolved at 145°C for 30 minutes. The mixture was cooled to 20°C over about 3 hours and allowed to stand for 30 minutes. Thereafter, the precipitate (α) was filtered off. The filtrate was poured into about three times the amount of acetone to precipitate the components dissolved in n-decane. The precipitate (β) (hereinafter, n-decane soluble part: D _sol ), n-decane, and acetone were filtered off, and the precipitate was dried. Note that no residue was observed even when the filtrate was concentrated to dryness.
The precipitate (α) was added again to 200 mL of n-decane and heated at 145° C. for 30 minutes, and the solution was filtered to remove the filler, etc. The filtrate was cooled to 20° C. over about 3 hours and allowed to stand for 30 minutes, after which the precipitate (γ) (hereinafter, the n-decane insoluble portion of the propylene polymer: D _insol ) was filtered off.
In n-decane fractionation of a propylene-based polymer, the precipitate (γ) corresponds to the n-decane insoluble portion (D _insol ), so the amount of the n-decane soluble portion was calculated as follows.
Amount of n-decane solubles (mass%)=[amount of precipitate (β)/(amount of precipitate (γ)+precipitate (β)]×100

(9) Intrinsic viscosity [η] of n-decane soluble part at 23 ° C.
The measurements were carried out at 135° C. using the above-mentioned D _sol and decalin solvents.
About 20 mg of the D _sol sample was dissolved in 15 mL of decalin, and the specific viscosity η _sp was measured in an oil bath at 135 ° C. The decalin solution was diluted with 5 mL of decalin solvent, and the specific viscosity η _sp was measured in the same manner. This dilution operation was repeated two more times, and the value of η _sp / C when the concentration (C) was extrapolated to 0 was determined as the limiting viscosity.
[η] = lim (η _sp / C) (C → 0)

(10) Ethylene content of 23°C n-decane soluble part D _insol , in order to measure the concentration of ethylene-derived skeleton in D _sol , 20 mg to 30 mg of sample was dissolved in 0.6 mL of 1,2,4-trichlorobenzene/heavy benzene (2:1) solution, and then carbon nuclear magnetic resonance analysis ( ¹³ C-NMR) was performed. The propylene, ethylene, and α-olefin were quantitatively determined from the dyad chain distribution.
For example, in the case of a propylene-ethylene copolymer, PP=Sαα, EP=Sαγ+Sαβ, and EE=1/2(Sβδ+Sδδ)+1/4Sγδ were used, and the values were calculated using the following calculation formulas (Eq-1) and (Eq-2).
Propylene (mol%)=(PP+1/2EP)×100/[(PP+1/2EP)+(1/2EP+EE)...(Eq-1)
Ethylene (mol%)=(1/2EP+EE)×100/[(PP+1/2EP)+(1/2EP+EE)...(Eq-2)

[Preparation of Propylene Polymer 1]
A propylene homopolymer, propylene-based polymer 1 (PP1), was prepared. The physical properties of PP1 are as follows:
-Physical properties of PP1-
MFR (230 ° C, under 2.16 kg load): 30 g / 10 min
Melting point: 165°C

[Preparation of Propylene Polymer 2]
A prepolymerization catalyst was produced as follows, and a propylene polymer 2 was prepared using the prepolymerization catalyst.

(1) Preparation of solid titanium catalyst component 952 g of anhydrous magnesium chloride, 4420 mL of decane, and 3906 g of 2-ethylhexyl alcohol were heated at 130° C. for 2 hours to obtain a homogeneous solution. 213 g of phthalic anhydride was added to this solution, and the mixture was stirred and mixed at 130° C. for another hour to dissolve the phthalic anhydride.
The homogeneous solution thus obtained was cooled to 23°C, and then 750 mL of this homogeneous solution was dropped into 2000 mL of titanium tetrachloride kept at -20°C over 1 hour. After dropping, the temperature of the resulting mixed solution was raised to 110°C over 4 hours, and when it reached 110°C, 52.2 g of diisobutyl phthalate (DIBP) was added, and the mixture was kept at the same temperature for 2 hours while stirring. Next, a solid portion was collected by hot filtration, and this solid portion was resuspended in 2750 mL of titanium tetrachloride, and then heated again at 110°C for 2 hours. After the heating was completed, the solid portion was collected again by hot filtration, and washed with decane and hexane at 110°C until no titanium compounds were detected in the washing solution. The solid titanium catalyst component prepared as above was stored as a hexane slurry, and a part of it was dried to examine the catalyst composition. The solid titanium catalyst component contained titanium in an amount of 2 mass%, chlorine in an amount of 57 mass%, magnesium in an amount of 21 mass%, and DIBP in an amount of 20 mass%.

(2) Production of prepolymerization catalyst 87.5 g of solid titanium catalyst component, 99.8 mL of triethylaluminum, 28.4 mL of diethylaminotriethoxysilane, and 12.5 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 875 g of propylene was charged while maintaining the internal temperature at 15°C to 20°C, and the reaction was carried out for 100 minutes while stirring. After the polymerization was completed, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerization catalyst was resuspended in purified heptane, and the concentration of the solid titanium catalyst component was adjusted to 0.7 g/L with heptane.

(Preparation of Propylene-Based Polymer)
To a jacketed circulation type tubular polymerization reactor having an internal volume of 58 L, 40 kg/h of propylene, 123 NL/h of hydrogen, 0.30 g/h of a prepolymerization catalyst, 2.1 mL/h of triethylaluminum, and 0.88 mL/h of diethylaminotriethoxysilane were continuously fed, and polymerization was carried out in a liquid-filled state in which no gas phase was present. The temperature of the tubular polymerization reactor was 70° C., and the pressure was 3.3 MPa/G.
The obtained slurry was sent to a vessel polymerization reactor equipped with a stirrer having an internal volume of 100 L, and further polymerization was carried out. Propylene was supplied to the polymerization reactor at 15 kg/hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 3.3 mol%. Polymerization was carried out at a polymerization temperature of 70° C. and a pressure of 3.1 MPa/G.
The obtained slurry was transferred to a 2.4 L liquid transfer tube, where it was gasified and subjected to gas-solid separation. After that, the polypropylene homopolymer powder was sent to a 480 L gas phase polymerization reactor, where ethylene-propylene copolymerization was carried out.
Here, propylene, ethylene, and hydrogen were continuously supplied so that the gas composition in the gas phase polymerization reactor was ethylene/(ethylene+propylene)=0.18 (molar ratio of ethylene content), and hydrogen/ethylene=0.15 (molar ratio). After polymerization was performed at a polymerization temperature of 70° C. and a pressure of 1.9 MPa/G, vacuum drying was performed at 80° C. to obtain a propylene-based polymer (propylene-based polymer 2, PP2) composed of a propylene-ethylene block copolymer.

The physical properties of the obtained PP2 are as follows:
-Physical properties of PP2-
MFR (230°C, under 2.16 kg load): 24g/10min
Melting point: 161°C
Crystallization temperature: 120°C
Ethylene content of propylene-ethylene block copolymer: 7 mol%
Amount of n-decane solubles at 23°C: 12% by mass
Intrinsic viscosity [η] of n-decane soluble part at 23°C: 3.0 dl/g
Ethylene content of n-decane soluble part at 23° C.: 35 mol%

[Preparation of Propylene Polymer 3]
Propylene-based polymer particles (propylene-based polymer 3, PP3) composed of a propylene-ethylene block copolymer were obtained in the same manner as in the preparation of propylene-based polymer 2, except that hydrogen was supplied so that the hydrogen concentration in the vessel polymerization reactor became 5.3 mol % and that propylene, ethylene and hydrogen were continuously supplied so that the gas composition in the gas-phase polymerization reactor having an internal volume of 480 L became ethylene/(ethylene+propylene)=0.03 (ethylene-containing molar ratio) and hydrogen/ethylene=0.08 (molar ratio).

The physical properties of the obtained PP3 are as follows:
-Physical properties of PP3-
MFR (230 ° C, under 2.16 kg load): 50 g / 10 min
Melting point: 160°C
Crystallization temperature: 115°C
Ethylene content of propylene-ethylene block copolymer: 3 mol%
Amount of n-decane solubles at 23°C: 9% by mass
Intrinsic viscosity [η] of n-decane soluble part at 23°C: 6.0 dl/g
Ethylene content of n-decane soluble part at 23° C.: 25 mol%

[Preparation of Propylene Polymer 4]
Propylene-based polymer particles (PP4) made of a propylene-ethylene random copolymer manufactured by Prime Polymer Co., Ltd. and having the following physical properties were prepared.
-Physical properties of PP4-
MFR (230°C, under 2.16 kg load): 7g/10min
Melting point: 140°C
Crystallization temperature: 105°C
Ethylene content of propylene-ethylene random copolymer: 2 mol%

[Preparation of thermoplastic elastomer and filler]
Thermoplastic elastomers (Elastomers 1 to 3) and a filler (Filler 1) having the following components and physical properties were prepared.
-Components and properties of elastomer 1-
Ethylene-1-octene copolymer elastomer (Dow ethylene-1-octene copolymer elastomer, brand name: EG8100)
MFR (ASTM D-1238, 190°C, under 2.16 kg load): 1g/10min
1-Octene content: 15 mol%
Density: 0.870 g/ ^cm3
Glass transition temperature: -58°C
-Components and properties of elastomer 2-
Hydrogenated styrene-based thermoplastic elastomer (SEBS) (hydrogenated styrene-ethylene-butadiene-styrene block copolymer)
MFR (ISO1133; 230°C, 2.16 kg load) No Flow
Styrene content: 30% by mass
Weight average molecular weight: 230,000 Hydrogenation rate: 95% or more Glass transition temperature: -71°C
-Components and properties of elastomer 3-
Ethylene-1-butene copolymer elastomer (ethylene-1-butene copolymer elastomer manufactured by Mitsui Chemicals, Inc., brand name: A-1050S)
MFR: 1 g/10 min (190° C., load 2.16 kg)
1-Butene content: 20 mol%
Density: 0.860 g/ ^cm3
Glass transition temperature: -66°C
-Components and properties of filler 1-
Talc (Asada Flour Milling Co., Ltd., brand name: JM-209)
Average particle size: 4.2 μm

[Example 1]
The components were dry-blended for 10 minutes in a tumbler (SKD-10, manufactured by Platec Co., Ltd.) in the proportions shown in Table 1, and melt-mixed in a twin-screw kneader (Tex-30α, manufactured by Japan Steel Works) at a set temperature of 200°C, a screw rotation speed of 1100 rpm, and a discharge rate of 100 kg/hr. The mixture was then granulated in a pelletizer (H73023, manufactured by Isuzu Chemical Engineering Co., Ltd.) at a winding output of 60% to obtain pellets containing each component (resin powder that is a mixture of each component). These pellets were used to mold predetermined test pieces, and the physical properties shown in Table 1 were determined.

(Mechanical crushing process)
The pellets obtained above were cooled to about −150° C. with liquid nitrogen and pulverized in a pulverizer (Rinrex Mill) until the average powder particle size became 150 μm.

(Particle Spheroidization Treatment)
After the pulverization, the particles were subjected to a spheroidizing treatment. Specifically, the pulverized material was subjected to a mechanical impact force by hybridization to spheroidize the particles, thereby obtaining a resin powder that was a mixture of the respective components.

[Examples 2 to 13, Comparative Examples 1 to 6]
Each component was treated in the same manner as in Example 1 in the blending ratio shown in Tables 1 to 3 to obtain pellets containing each component (resin powder which is a mixture of each component).

[Examples 14 to 16]
The same procedures as in Examples 1, 7, and 12 were repeated except that in the mechanical crushing treatment of Examples 1, 7, and 12, the powder was crushed using a crusher (Rinrex Mill) until the average powder particle size became 50 μm, thereby obtaining pellets containing each component (resin powder which is a mixture of each component).

The physical properties of the resin powders of Examples 1 to 16 and Comparative Examples 1 to 6 are shown in Tables 1 to 3.

As shown in Tables 1 to 3, resin powders obtained in Examples 1 to 16 had superior mechanical properties and low-temperature impact resistance compared to Comparative Examples 1 to 6. The resin powders of Examples 1 to 16 can be suitably used as powders for three-dimensional modeling using methods such as powder bed fusion bonding.

The disclosure of Japanese Patent Application No. 2022-182774, filed on November 15, 2022, is incorporated herein by reference in its entirety.
All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims

A resin powder containing a propylene-based polymer powder, the resin powder satisfying the following [1] and [2] when molded into a molded article:
[1] The tensile modulus is 1500 MPa to 3000 MPa.
[2] The Charpy impact strength measured at -30 ° C is 2.0 kJ / m2 or more.
The resin powder according to claim 1, which satisfies the following [3]:
[3] The heat distortion temperature (HDT) measured in accordance with JIS K7191 is 105°C or higher.
The resin powder according to claim 1, wherein the average powder particle size (R) of the resin powder is 1 μm to 200 μm.
the resin powder is a mixture containing the propylene-based polymer powder, a thermoplastic elastomer, and a filler,
per 100 parts by mass in total of the propylene-based polymer powder, the thermoplastic elastomer, and the filler,
The content of the propylene-based polymer powder is 30 parts by mass to 90 parts by mass,
The content of the thermoplastic elastomer is 1 part by mass to 40 parts by mass,
The resin powder according to claim 3, wherein the content of the filler is 1 part by mass to 50 parts by mass.
The resin powder according to claim 3, which satisfies the following [4]:
[4] The melting point (Tm) of the resin powder measured by DSC is 150° C. to 170° C.
The resin powder according to claim 3, which satisfies the following [5].
[5] The melt flow rate (MFR) of the propylene polymer measured in accordance with ASTM D1238 at 230° C. under a load of 2.16 kg is 0.05 g/10 min to 150 g/10 min.
The resin powder according to claim 3, wherein the propylene-based polymer is a propylene-based block copolymer and satisfies the following [6] to [8]:
[6] The propylene-based block copolymer is composed of 5% by mass to 35% by mass of a 23° C. n-decane soluble portion (D sol ) and 65% by mass to 95% by mass of a 23° C. n-decane insoluble portion (D insol ) (wherein the total amount of D sol and D insol is 100% by mass).
[7] The intrinsic viscosity [η] of D sol is 1.0 dl/g to 10.0 dl/g.
[8] D sol is mainly composed of a copolymer of propylene and one or more olefins selected from ethylene and α-olefins having 4 to 20 carbon atoms, and the content of olefins other than propylene in D sol is 10 mol % to 60 mol %.
The resin powder according to claim 7, wherein the propylene-based block copolymer contains structural units derived from one or more olefins selected from ethylene and α-olefins having 4 to 20 carbon atoms, and the total content of the olefins other than propylene is 4.0 mol% to 30 mol%.
The resin powder according to claim 8, wherein the thermoplastic elastomer satisfies the following [9] to [11].
[9] The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190° C. under a load of 2.16 kg is 0.05 g/10 min to 100 g/10 min.
[10] The glass transition temperature (Tg) measured by DSC is −30° C. or lower.
[11] The tensile modulus is less than 500 MPa.
　The resin powder according to any one of claims 1 to 9, which is used for three-dimensional molding.
A three-dimensional molded body formed by powder bed fusion bonding using the resin powder according to any one of claims 1 to 9.
A method for producing a three-dimensional molded body by powder bed fusion bonding using the resin powder according to any one of claims 1 to 9.