JP7123682B2 - COMPOSITION FOR THREE-DIMENSIONAL PRINTER AND METHOD FOR MANUFACTURING LARGE LAMINATED PRODUCT USING SAME COMPOSITION - Google Patents

Description

The present invention is a composition suitable for use in a three-dimensional (3D) printer, in particular a composition for a 3D printer capable of producing a large laminate model (a model having a laminate thickness of 10 mm or more). And, it relates to a method for producing a large laminate-molded article using the composition.

3D printers that laminate-model three-dimensional objects based on three-dimensional digital data are expected to be put to practical use in various fields. As a method for manufacturing a three-dimensional object with a 3D printer, mainly a stereolithography method, a powder sintering lamination method, a hot fusion lamination method, and an inkjet method are known.

In FDM (Fused Deposition Modeling), filaments made of thermoplastic resin such as PLA (polylactic acid) and ABS (acrylonitrile-butadiene-styrene) are used as raw materials, and molten resin is laminated layer by layer. It is common to obtain a three-dimensional object made of thermoplastic resin by cooling and solidifying.

If you want to manufacture metal or ceramic products with a 3D printer instead of products made of thermoplastic resin, there is a method of directly sintering inorganic powder with a high-power laser, or a method of dispersing inorganic powder in a photocurable resin. commonly adopted. However, these methods have the problem that the equipment is expensive and the lamination speed is slow.

On the other hand, by using a compound made by adding ceramics or metal powder to a thermoplastic resin, a modeled object is manufactured with a three-dimensional printer, and then degreased and sintered to produce a metal or ceramic product. has been proposed (Patent Document 1).
As a three-dimensional printer capable of manufacturing a modeled object using such a compound (pellet), a three-dimensional printer having an extrusion device has been proposed (Patent Document 2).

JP-A-2000-144205 WO2015/129733

According to the method of Patent Document 1, a compound containing inorganic powder is used as a raw material, and after manufacturing a modeled object using a three-dimensional printer of a hot melt lamination method (FDM method), powder injection molding (PIM) ), metal or ceramic products can be obtained by degreasing and sintering (firing) that are generally performed in ), so the problem of expensive equipment and slow lamination speed can be solved. It is possible.

However, in the case of compounds using polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), and polystyrene as binder components, when a large-sized shaped object with a thickness of 10 mm or more is manufactured using an FDM three-dimensional printer, However, there is a problem that deformation due to its own weight occurs during the degreasing process, and blistering and deformation are likely to occur.
On the other hand, polyacetal, which is used as a countermeasure against deformation in metal injection molding (MIM), etc., has a mixture of amorphous and crystalline parts. There was a problem that it was easy to occur.

Also, in the method of manufacturing a three-dimensional model using a three-dimensional printer, then degreasing and sintering to obtain a metal or ceramic product, if a compound similar to conventional PIM is used, stringing occurs. The problem was that it was easy. More specifically, after laminating and modeling a desired three-dimensional structure while discharging molten resin from a nozzle with an FDM three-dimensional printer, when moving the nozzle to the next lamination position, three There is a problem that stringing occurs between the dimensional structure and the tip of the moving nozzle, and whisker-like burrs adhere to the 3-dimensional structure, resulting in a poor appearance. In addition, when trying to improve this stringing, there is a problem that problems tend to occur during degreasing.

Therefore, the present invention uses a composition containing an inorganic powder as a raw material and uses an FDM three-dimensional printer to produce a large laminate model with a laminate thickness of 10 mm or more. To provide a composition for a three-dimensional printer, which has a composition capable of obtaining a modeled article with good ductility and is less likely to be deformed when the organic binder is removed (degreased) from the modeled article.
Another object of the present invention is to provide a method capable of manufacturing a large laminate-molded article made of ceramics, cermet, or metal using the composition for a three-dimensional printer.

As a result of repeated studies in order to solve the above problems, the inventors of the present invention found that by mixing a specific organic binder with an inorganic powder in a specific ratio, it is possible to achieve stringiness even when used in a three-dimensional printer. The inventors succeeded in obtaining a composition that has properties suitable for manufacturing a large-sized laminate-molded product with a low degreasing property (deformation, cracks, etc.) and a lamination thickness of 10 mm or more.

The three-dimensional printer composition (compound) of the present invention, which can solve the above problems,
(A) an inorganic powder, (B) an organic binder and (C) a three-dimensional printer composition containing an organic compound,
The organic binder (B) includes (B1) a thermoplastic resin in which an amorphous part and a crystalline part are mixed, (B2) a compatibilizing polymer that is a binary copolymer composed of two types of monomer constitutional units, and (B3) B1 and containing a thermoplastic polymer other than B2;
The organic compound (C) is an organic compound having a molecular weight or weight average molecular weight of 2000 or less, and the weight of the inorganic powder (A) with respect to the total amount of the organic binder (B) and the organic compound (C) The ratio is (A) / [(B1) + (B2) + (B3) + (C)] = 100/5 to 100/30, and the organic binder (B) of the thermoplastic resin (B1) and the mass ratio to the total amount of the organic compound (C) is (B1) / [(B1) + (B2) + (B3) + (C)] = 0.05 to 0.25, and the thermoplastic The mass ratio of the resin (B1) and the compatibilizing polymer (B2) is (B2)/(B1)=0.5 to 15.0, and the organic compound (C) and the organic binder (B) The mass ratio of the organic compound (C) to the total amount is (C)/[(B1)+(B2)+(B3)+(C)]=0.1 to 0.5. .

Further, the present invention provides a three-dimensional printer composition having the above characteristics, wherein the inorganic powder (A) is yttria-stabilized zirconia powder, alumina powder, tungsten powder, tungsten carbide powder, stainless steel powder, iron-nickel It is selected from the group consisting of powder and iron-silicon powder, the thermoplastic resin (B1) is a polyolefin polymer-modified polyacetal, and the compatibilizing polymer (B2) is an ethylene-vinyl acetate copolymer. It is characterized by being selected from the group consisting of polymer resins, maleic anhydride-modified polypropylene resins, ethylene-glycidyl methacrylate copolymer/polystyrene resins, and polypropylene/acrylonitrile styrene resins.

Further, the present invention provides a three-dimensional printer composition having the above characteristics, wherein the thermoplastic polymer (B3) is a polystyrene resin, an acrylic resin, an acrylonitrile-butadiene-styrene resin, a polypropylene resin, a polyethylene resin, a polyamide resin. , polybutylene terephthalate resin, polyethylene terephthalate resin, polycarbonate resin, acrylonitrile styrene resin and amorphous polyolefin, and the organic compound (C) is selected from waxes, lubricants, plasticizers and antioxidants. It is also characterized by being selected from a group of

Further, the present invention is a method for manufacturing a large-sized laminate-molded article made of ceramics, cermet or metal, the method comprising the following steps A to C:
Step A: A step of forming a large laminated structure having a lamination thickness of 10 mm or more by using the composition for a three-dimensional printer and a three-dimensional printer of a hot-melt lamination method;
Step B: a step of degreasing the large-sized laminated structure; and Step C: a step of sintering the degreased large-sized laminated structure obtained in the step B.

The composition for three-dimensional printers of the present invention has low stringiness, and in the process of forming a large-sized laminated structure with an FDM three-dimensional printer, whisker-like burrs are less likely to occur, resulting in a laminated structure with excellent appearance. can be obtained.
In addition, when the composition of the present invention is used, deformation, cracks, blisters, etc. are less likely to occur in the heat degreasing process, so it is possible to use the same degreasing and sintering process as PIM to shape large ceramic products. can be done. Therefore, it is possible to manufacture a product having a complicated shape made of ceramics or the like, which is a difficult-to-work material, based on three-dimensional CAD data or the like.

Examples of the inorganic powder (A) that can be used in the three-dimensional printer composition of the present invention include sinterable powders such as metal powders, ceramics powders and cermet powders.
Specifically, as the metal powder, for example, pure iron, iron-nickel, iron-cobalt, iron-silicon, iron-based alloys such as stainless steel, tungsten, tungsten carbide (WC), cemented carbide (WC-Co-based alloys, etc.), powders of aluminum alloys, copper, copper alloys, and the like. Ceramic powders include oxides such as _{Al2O3 , BeO} and ZrO2, carbides such as TiC, ZrC and _B4C , borides such as CrB and _ZrB2 , and nitrides such as TiN and ZrN. mentioned. Cermet powders include Al ₂ O ₃ --Fe system, TiC--Ni system, TiC--Co system, B ₄ C--Fe system, and the like.
Particularly preferred examples of the inorganic powder (A) used in the present invention include metal oxides such as alumina (Al ₂ O ₃ ) and zirconia (ZrO ₂ ). The zirconia may be yttria partially stabilized zirconia. Particularly preferred is a metal oxide powder having an average particle size (D ₅₀ ) of 0.1 to 1.0 μm, more preferably 0.1 to 0.8 μm.

The organic binder (B) used in the present invention comprises a thermoplastic resin (B1) in which an amorphous part and a crystalline part are mixed, and a compatibilizing polymer (B2) which is a two-component copolymer composed of two types of monomer constitutional units. , including a thermoplastic polymer (B3) other than the above B1 and B2.
In the present invention, by using the above (B1), (B2), and (B3) in combination, deformation due to its own weight is less likely to occur even when manufacturing a large modeled object, and degreasing can be performed at once during the degreasing process. Since the removal of the organic binder progresses step by step without progressing, deformation during degreasing can be suppressed.

Examples of the thermoplastic resin (B1) in which an amorphous part and a crystalline part are mixed include a polyolefin-based polymer _- modified polyacetal. )n-(CH ₂ CH ₂ O)m-.
The above polyacetal copolymer has both crystallinity and non-crystallinity, and when combined with a compatibilizing polymer (B2) described later, the adhesion between layers is improved. In addition, by maintaining the strength of the modeled object when the binder is removed, deformation that tends to occur in the case of a large modeled object is suppressed, and the shape of the modeled object is maintained.
The weight average molecular weight of the thermoplastic resin (B1) is preferably 10,000 to 500,000, more preferably 20,000 to 200,000. In the present invention, the weight average molecular weight is determined using gel permeation chromatography (GPC). can be done.

The compatibilizing polymer (B2), which is a two-component copolymer composed of the two types of monomer constitutional units, has a polar segment and a non-polar segment in the molecule, and the thermoplastic resin (B1), B1 and B2 It can be a random copolymer, a block copolymer, or a graft copolymer.
Examples of the compatibilizing polymer (B2) include ethylene-vinyl acetate copolymer (EVA) resin, maleic anhydride-modified polypropylene resin, ethylene-glycidyl methacrylate copolymer/polystyrene (EGMA/PS) resin, polypropylene/ Examples include acrylonitrile styrene (PP/AS) resins, and two or more of these compatibilizing polymers may be blended in the composition for three-dimensional printers of the present invention.
As the maleic anhydride-modified polypropylene resin, for example, Yumex (trademark) manufactured by Sanyo Chemical Industries, Ltd. can be used, and as the EGMA / PS resin, for example, MODIPER (registered trademark) A series manufactured by NOF Corporation is available.
In the present invention, the weight average molecular weight of the compatibilizing polymer (B2) is preferably 10,000 to 500,000, more preferably 20,000 to 200,000.

Examples of the thermoplastic polymer (B3) include polystyrene (PS) resin, acrylic (PMMA) resin, acrylonitrile-butadiene-styrene (ABS) resin, polypropylene (PP) resin, polyethylene (PE) resin, polyamide (PA). Resins include polybutylene terephthalate (PBT) resins, polyethylene terephthalate (PET) resins, polycarbonate (PC) resins, acrylonitrile styrene (AS) resins and amorphous polyolefins.
The melting point of the thermoplastic polymer (B3) is preferably 170° C. or less, and examples of more preferable resins include PS, acrylic resins, ABS and PP. From the viewpoint of reducing stringiness, it is preferable to use an acrylic resin.

The thermoplastic polymer (B3) may be of one type or a plurality of types, but it is more preferable to use a plurality of resins with different thermal decomposition behaviors in combination. By using two or more types of thermoplastic resins having different thermal decomposition behaviors in combination, troubles (particularly cracks and blisters) during degreasing can be sufficiently suppressed.

A particularly preferred example when using a plurality of thermoplastic polymers (B3) is an acrylic resin or a combination of an acrylic resin and PS.
The mass ratio of acrylic resin to PS is preferably 50 to 130, more preferably 60 to 110, with respect to 100 of acrylic resin.

As the acrylic resin, a polymer of (meth)acrylic ester, which is an ester of alcohol having 1 to 8 carbon atoms of (meth)acrylic acid, can be used. Specific examples of such (meth)acrylic acid ester monomers include, for example, n-alkyl (meth)acrylates having 1 to 8 carbon atoms in the alkyl group, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate and the like. Among these, n-alkyl (meth)acrylates having 1 to 4 carbon atoms in the alkyl group such as n-butyl (meth)acrylate, isopropyl (meth)acrylate, and isobutyl (meth)acrylate are particularly preferable, and these are preferably used alone. or two or more of them may be used in combination.

It is preferable to use PS having a weight average molecular weight of about 100,000 to 300,000, more preferably about 150,000 to 250,000.
As the amorphous polyolefin, those having a weight average molecular weight of about 1,000 to 8,000, preferably about 2,000 to 4,000 can be used.

As the organic compound (C) having a weight-average molecular weight or a molecular weight of 2000 or less, waxes, lubricants, plasticizers and the like are used in terms of imparting good fluidity to the mixture with the inorganic powder and having excellent thermal decomposability. Other additives such as, but not limited to, antioxidants can also be used.
The molecular weight (or weight average molecular weight) of the organic compound (C) is preferably 1,500 or less, particularly preferably 1,000 or less.

Both synthetic and natural waxes can be used, and specific examples include paraffin wax, microcrystalline wax, polyethylene wax, beeswax, carnauba wax, montan wax, and polyalkylene glycol.
Specific examples of lubricants include fatty acids and fatty acid derivatives such as esters, amides and metal salts, preferably higher fatty acids such as stearic acid.
Specific examples of plasticizers include phthalates (dibutyl phthalate, dioctyl phthalate, 4-cyclohexene-1,2-dicarboxylic acid bis(2-ethylhexyl), 1,2-cyclohexanedicarboxylic acid diisononyl ester, etc.). , phosphates, and fatty acid esters (sorbitan monostearate, etc.).

Further, specific examples of antioxidants include, for example, phenolic antioxidants. Specific examples include 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4′-butylidenebis(6-tert-butyl-m-cresol), bis [3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)], bis[3-(3-tert-butyl-4-hydroxy-5-methylphenylpropionate) ionic acid](2,4,8,10-tetraoxaspiro[5,5]undecane-3,9-diyl)bis(2,2-dimethyl-2,1-ethanediyl), pentaerythritol = tetrakis[3- (3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate] and the like.

Examples of organic compounds corresponding to (C) other than waxes, lubricants, plasticizers, and antioxidants include additives such as metal deactivators, ultraviolet absorbers, and nucleating agents.

Moreover, as the organic compound (C), it is preferable to use one having a starting point of weight loss on heating of 150° C. or lower. The starting point of weight loss on heating can be determined by the thermogravimetric method specified in JIS K7120. By blending the organic compound (C), which begins to lose weight on heating at 150° C. or lower, the binder content at 150° C. or lower can be reduced, and the plasticity of the molded body can be reduced to prevent deformation.

In the three-dimensional printer composition of the present invention, the mass ratio of the inorganic powder (A), the organic binder (B) and the organic compound (C) is (A) / [(B1) + (B2) + (B3) + (C)]=100/5 to 100/30. If the mass of (B1)+(B2)+(B3)+(C) is less than 5 with respect to the mass of (A) being 100, the flow value will be low, making modeling difficult. On the other hand, if the mass of (B1) + (B2) + (B3) + (C) exceeds 30 with respect to the mass of (A) 100, the stringiness will increase and problems such as deformation will occur during degreasing. becomes more likely to occur.
When the inorganic powder (A) is ceramic powder (for example, metal oxide powder such as alumina or zirconia), a more preferable mass ratio is (A) / [(B1) + (B2) + (B3) + (C )]=100/10 to 100/30, preferably 100/15 to 100/25.
When the inorganic powder (A) is a metal powder (for example, stainless steel, etc.), a more preferable mass ratio is (A)/[(B1)+(B2)+(B3)+(C)]=100/5 to 100/15, preferably 100/5 to 100/10.

In the three-dimensional printer composition of the present invention, the mass ratio of the thermoplastic resin (B1) to the total amount of the organic binder (B) and the organic compound (C) is (B1)/[(B1)+(B2) +(B3)+(C)]=0.05 to 0.25. If the mass ratio of (B1) to the mass of (B1) + (B2) + (B3) + (C) is less than 0.05, the strength of the modeled product will decrease, the shape retention will decrease, and the product will be removed. Deformation is likely to occur during binder (degreasing). On the other hand, when the mass ratio of (B1) to the mass of (B1) + (B2) + (B3) + (C) exceeds 0.25, the strength of the molded object increases, and deformation and cracks during degreasing occur. can be suppressed, but poor adhesion between the molding layers and cooling shrinkage tend to occur.

When the inorganic powder (A) is a ceramic powder (for example, a metal oxide powder such as alumina or zirconia), the mass of the thermoplastic resin (B1) with respect to the total amount of the more preferable organic binder (B) and organic compound (C) The ratio is (B1)/[(B1)+(B2)+(B3)+(C)]=0.05 to 0.25, preferably 0.05 to 0.20.
When the inorganic powder (A) is a metal powder (for example, stainless steel, etc.), the more preferred mass ratio of the thermoplastic resin (B1) to the total amount of the organic binder (B) and the organic compound (C) is (B1) /[(B1)+(B2)+(B3)+(C)]=0.05 to 0.25, preferably 0.10 to 0.20.

In the three-dimensional printer composition of the present invention, the mass ratio of the thermoplastic resin (B1) and the compatibilizing polymer (B2) is preferably (B2)/(B1) = 0.5 to 15.0. be. If the value of (B2)/(B1) is less than 0.5, the compatibility between the thermoplastic resin (B1) and the thermoplastic polymer (B3) is reduced, resulting in reduced adhesion between the molding layers. If the value of (B2)/(B1) exceeds 15.0, the stringiness is deteriorated.

In the three-dimensional printer composition of the present invention, the mass ratio of the organic compound (C) to the total amount of the organic binder (B) and the organic compound (C) is (C)/[(B1) + (B2) + ( B3)+(C)]=0.1 to 0.5 is suitable. If the value of (C)/[(B1)+(B2)+(B3)+(C)] is less than 0.1, the fluidity of the composition is reduced, resulting in poor moldability. If the value of (C)/[(B1) + (B2) + (B3) + (C)] exceeds 0.5, the adhesion between the molding layers will decrease, deformation will easily occur during degreasing, and cracks will occur. cannot be sufficiently suppressed.

The three-dimensional printer composition of the present invention is prepared by melt-kneading (A) an inorganic powder, (B) an organic binder, and (C) an organic compound. The type of kneader used for this melt-kneading is not particularly limited, but a preferred example is a pressure kneader. Various kneaders such as a batch type kneader such as a twin-arm kneader type kneader and a Banbury type kneader, and a continuous type kneader such as a single-screw or twin-screw kneading extruder can be used.

The shape of the composition for three-dimensional printers of the present invention is not particularly limited, but a preferred example is a pellet-like shape used in PIM. Although not particularly limited, an example of a preferred form is pelletized by a hot-cut pelletizer that cuts the extruded melt after kneading into pellets in the air with a rotary cutter.

Further, according to the present invention, a large laminated structure is formed by an FDM three-dimensional printer using the three-dimensional printer composition (a composition highly filled with inorganic powder), degreased and sintered, Provided is a method for manufacturing a large additive manufacturing article made of ceramics, cermets or metals, the manufacturing method comprising the following steps A to C:
Step A: A step of forming a large laminated structure having a lamination thickness of 10 mm or more by using the composition for a three-dimensional printer and a three-dimensional printer of a hot-melt lamination method;
Step B: a step of degreasing the large laminated structure, and
Step C: including a step of sintering the degreased large-sized laminated structure obtained in Step B;
In the manufacturing method of the present invention including the above steps A to C, a large laminated structure can be formed using a three-dimensional printer composition having a polymer composition resistant to thermal deformation, and the environmental temperature of the formed body is kept constant (for example, the work environment temperature is 25 to 80° C.), it is possible to maintain the adhesion between the molding layers and suppress warpage due to cooling shrinkage.

In the step A of the present invention, as a feature of the 3D printer, the filling rate of the composition can be easily controlled even when forming a large modeled object, and the effective surface area ( porosity) can be ensured.
In the present invention, a "large-sized laminate-molded article" refers to an article having a lamination thickness of 10 mm or more (for example, 30 mm or more, 50 mm or more, 80 mm or more, or 100 mm or more).
In the present invention, the degreasing time can be shortened by controlling the filling rate of the composition, and the effect of suppressing deformation can also be obtained. In addition, when the filling rate of the composition is less than 20%, sufficient strength of the shaped body cannot be obtained, and deformation is likely to occur during degreasing, which is not preferable.

As the FDM three-dimensional printer used in the process A, for example, an extrusion device having a cylinder, a screw, a gear pump, and a nozzle as disclosed in Patent Document 2 (WO2015/129733) , a table device positioned opposite to the nozzle of the extrusion device, and an X-axis of the extrusion device and/or the table device with respect to a reference plane, which controls the discharge of resin from the nozzle in the extrusion device, A three dimensional printer can be used with controllers to control movement in the Y and Z directions.

The conditions for degreasing and sintering in steps B and C may be the same as those for degreasing and sintering PIM, and can be appropriately set according to the type of inorganic powder contained in the composition. For example, when the inorganic powder is zirconia (yttria-stabilized zirconia, etc.) or alumina, the temperature is raised to about 450-550° C. at a temperature elevation rate of 10-20° C./h for degreasing, followed by a temperature elevation rate of 40-60. Sintering can be performed by raising the temperature up to 1300 to 1600°C at a rate of °C/h. When the inorganic powder is metal, the temperature is raised to about 450 to 550°C at a temperature elevation rate of 10 to 20°C/h in an inert gas atmosphere for degreasing, and then the temperature is raised to 1300 to 1300°C at a temperature elevation rate of 40 to 60°C/h. Sintering can be performed by heating up to 1400°C.
EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples.

[material]
The following materials were used as (A) inorganic powder, (B1) thermoplastic resin, (B2) compatibilizing polymer, (B3) thermoplastic polymer other than B1 and B2, and (C) organic compound.
The flow value was measured by using a flow tester "CFD-500D" manufactured by Shimadzu Corporation, setting a die with a diameter of 1 mm and a length of 1 mm, applying a load of 0.98 MPa, and measuring the flow per unit time at 180 ° C. It was obtained by measuring the volume (ml/sec). At this time, in the case where the fluidity was too high at 180°C and an accurate value could not be measured, the set temperature was changed to 140°C to obtain the flow value.

(A) Inorganic powder : yttria partially stabilized zirconia powder containing 3 mol % of Y ₂ O ₃ (BET specific surface area: 15 m ² /g; average particle diameter D ₅₀ : 0.15 µm)
Yttria partially stabilized colored zirconia powder containing 3 mol % of Y ₂ O ₃ : black (BET specific surface area: 8 m ² /g; average particle diameter D ₅₀ : 0.3 μm)
Alumina powder (BET specific surface area: 6 m ² /g; average particle diameter D ₅₀ : 0.52 μm)
・Stainless steel powder (SUS316L) (average particle diameter D ₅₀ is 7.05 μm, tap density 4.6 g/cm ³ )
・WC-Co powder (average particle size _D50 is 1.4 μm)

(B1) Thermoplastic resin /POM copolymer (flow value 0.051 ml/sec at 180°C, melting point 163°C)
(B2) compatibilizing polymer
・EVA (weight average molecular weight 190,000, flow value 0.064 ml/sec at 180°C, deflection temperature under load 70°C)
・Maleic anhydride modified PP (weight average molecular weight 50,000, melting point 123°C)
・Ethylene-glycidyl methacrylate copolymer/polystyrene (graft copolymer with EGMA as main chain and PS as side chain, composition ratio (% by weight) 70/30, weight average molecular weight 100,000)
(B3) Thermoplastic polymers other than B1 and B2
・PS (weight average molecular weight 190,000, flow value 0.064 ml/sec at 180°C, deflection temperature under load 70°C)
・Acrylic resin (copolymer of n-butyl methacrylate and methyl methacrylate, weight average molecular weight 50,000, flow value 0.110 ml/sec at 180°C)
・PP (weight average molecular weight 240,000, 180°C flow rate 0.051ml/sec, melting point 163°C)
・Amorphous polyolefin (weight average molecular weight 3000, flow rate 0.32 ml/sec at 140°C, softening point 145°C)

(C) Organic compound /paraffin wax (molecular weight 472, melting point 70°C)
・Microcrystalline wax (molecular weight 500-800, melting point 52°C)
・Stearic acid (molecular weight 284)
- Dioctyl phthalate (DOP) (molecular weight 391)
・Sorbitan monostearate (molecular weight 430, melting point 55°C)
・Bis(2-ethylhexyl) 4-cyclohexene-1,2-dicarboxylate (molecular weight 394)
・1,2-cyclohexanedicarboxylic acid diisononyl ester (molecular weight 428)
・Phenolic antioxidant (1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane) (molecular weight 545, melting point 183-185°C)

[Production of composition for three-dimensional printer]
The above (A), (B1), (B2), (B3) and (C) were blended in the proportions shown in the table, and using a pressure kneader manufactured by Nihon Spindle Mfg. Co., Ltd. (former Moriyama Seisakusho Co., Ltd.) Melt-kneading was performed at 170°C. Using a pelletizer-type plunger extruder manufactured by Toshin Co., Ltd., the resulting melt was pelletized into pellets having a diameter of 3 mm and a length of 3 mm.

[Evaluation of stringiness]
Before manufacturing a large-sized laminated structure, the composition was evaluated for stringiness by the following method.
Using the pellets produced above as raw materials, an FDM three-dimensional printer (CERA_P3 manufactured by S.Lab Co., Ltd., molding range X150mm x Y150mm x Z150mm, screw diameter φ20mm) equipped with an extrusion device with a pellet inlet was used. , five cylindrical laminated structures (modeled objects) each having a diameter of 30 mm and a height of 100 mm were manufactured such that the distance between each modeled object was 50 mm. At this time, the molding temperature was 140 to 180° C., the nozzle diameter was 1.0 mm, and the filling rate was 99 to 99.5%.
In the evaluation of stringing property, after modeling one modeled object, if stringing is observed when moving the nozzle to the next modeling position, measure the length from the edge of the modeled object to the tip of the thread. , was taken as the stringing length.
When the stringing length was less than 3 mm, it was evaluated as ◯; when it was 3 mm or more and less than 10 mm, it was evaluated as Δ;

[Determination of formability]
Regarding the formability, the presence or absence of stringing when the nozzle moves between the molded objects, the presence or absence of gaps between the layers of the obtained molded object, and the tilt of the molded object ), and the continuity of modeling due to adhesion to the nozzle during modeling.

[Determination of degreasing and sinterability]
The laminate structure obtained above was used as a test piece. The obtained test piece was placed on an alumina setter, and zirconia and alumina were degreased to 500° C. at a heating rate of 10° C./h in the atmosphere, and the degree of deformation (deformation, cracks, blisters) was confirmed.
Out of 5 test pieces each, if deformation or cracks/blisters were confirmed after degreasing, 1 or less was evaluated as ◯, 2 to 3 as △, and 4 or more as x. did.
After degreasing, zirconia was heated up to 1450° C. and alumina was heated up to 1600° C. in air at a heating rate of 50° C./h, and sintered to obtain a sintered body.
The stainless steel was degreased by raising the temperature to around 500° C. at a rate of temperature rise of 10° C./h in a nitrogen gas atmosphere, and deformation, cracks, and blisters were confirmed in the same manner as described above. After that, the temperature was raised to 1350° C. at a heating rate of 50° C./h to obtain a sintered body.
As with stainless steel, WC--Co was also degreased by raising the temperature to around 500° C. at a heating rate of 10° C./h in a nitrogen gas atmosphere, and deformation, cracks, and blisters were confirmed in the same manner as above. After that, the temperature was raised to 1390° C. at a heating rate of 50° C./h to obtain a sintered body.
The relative density of the sintered body was measured by the Archimedes method.

The composition and test results of the three-dimensional printer composition (pellets) are summarized in Tables 1 to 4 below. The numerical value of each component in Tables 1 to 4 indicates % by mass.

As shown in Tables 1 and 2, the mass ratio of the inorganic powder (A) to the total amount of the organic binder (B) and the organic compound (C) is (A) / [(B1) + (B2) + (B3) + (C)] = 100/5 to 100/30, and the mass ratio of the thermoplastic resin (B1) to the total amount of the organic binder (B) and the organic compound (C) is (B1)/[ (B1) + (B2) + (B3) + (C)] = 0.05 to 0.25, and the mass ratio of the thermoplastic resin (B1) and the compatibilizing polymer (B2) is (B2)/(B1 ) = 0.5 to 15.0, and the mass ratio of the organic compound (C) to the total amount of the organic binder (B) and the organic compound (C) is (C)/[(B1) + (B2) + (B3) + (C)] = Examples 1 to 7 in the range of 0.1 to 0.5 (zirconia powder used as inorganic powder), Example 8 (alumina powder used as inorganic powder), Example 9 ( When using the pellets of Example 10 (using stainless steel powder as the inorganic powder) and Example 10 (using WC-Co powder as the inorganic powder), it is possible to produce a large laminated structure with less stringiness and excellent moldability. In addition, when the shaped body was degreased by heating, almost no deformation, cracks, or blisters were observed, and a sintered body with a high relative density (97% or more) could be obtained.

On the other hand, as shown in Tables 3 and 4, the total mass of the organic binder (B) and the organic compound (C)] is less than 5 when the mass of the inorganic powder (A) is 100. In the case of (Comparative Example 1), flowability was poor and molding could not be performed, and in the case of exceeding 30 (Comparative Example 2), the stringing property was not good, and defects such as deformation and cracks occurred during degreasing. .
Further, if the thermoplastic resin (B1) is not contained, that is, the total amount of the organic binder (B) and the organic compound (C) that are the sum of (B1), (B2), and (B3), the thermoplastic resin (B1) When the mass ratio of is less than 0.05 (Comparative Example 3), deformation is likely to occur during degreasing, and cracks and blisters are slightly observed. When the value of (B3)+(C)] exceeded 0.25 (Comparative Example 4), poor adhesion between the molding layers and cooling shrinkage tended to occur.
Furthermore, when the mass ratio ((B2)/(B1)) of the compatibilizing polymer (B2) to the thermoplastic resin (B1) was less than 0.5 (Comparative Example 5), no problem occurred during degreasing. However, when the value of (B2)/(B1) exceeded 15 (Comparative Example 6), the stringiness was poor.
Further, when the organic compound (C) is not contained, that is, when the value of (C)/[(B1) + (B2) + (B3) + (C)] is less than 0.1 (Comparative Example 7) When the above value exceeds 0.5 (Comparative Example 8), sufficient adhesion between the molding layers is obtained. deformation occurred during degreasing, and cracks were likely to occur.

According to the composition and method of the present invention, it is possible to manufacture a large-sized layered product using an FDM three-dimensional printer, and effectively eliminate deformation due to its own weight during modeling and deformation and defects that occur during heat degreasing. can be suppressed.

Claims (4)

(A) an inorganic powder, (B) an organic binder and (C) a three-dimensional printer composition containing an organic compound,
The inorganic powder (A) is a sinterable powder selected from the group consisting of metal powder, ceramic powder, and cermet powder,
The organic binder (B) includes (B1) polyolefin polymer-modified polyacetal , (B2) ethylene-vinyl acetate copolymer resin, maleic anhydride-modified polypropylene resin, ethylene-glycidyl methacrylate copolymer/polystyrene resin, and containing at least one compatibilizing polymer selected from the group consisting of polypropylene/acrylonitrile styrene resins , and (B3) a thermoplastic polymer other than B1 and B2 containing an acrylic resin ;
The organic compound (C) is an organic compound having a molecular weight or weight-average molecular weight of 2000 or less , and waxes, lubricants, plasticizers, antioxidants, metal deactivators, ultraviolet absorbers, and nucleating agents. and the mass ratio of the inorganic powder (A) to the total amount of the organic binder (B) and the organic compound (C) is (A)/[(B1 ) + (B2) + (B3) + (C)] = 100/5 to 100/30, and the organic binder (B) and the organic compound (C) of the polyolefin polymer-modified polyacetal (B1) is (B1) / [(B1) + (B2) + (B3) + (C)] = 0.05 to 0.25, and the polyolefin polymer-modified polyacetal (B1) and the compatibilizing polymer (B2) have a mass ratio of (B2)/(B1)=0.5 to 15.0, and the organic compound (C) contains the organic binder (B) and the organic compound ( For a three-dimensional printer, wherein the mass ratio to the total amount of C) is (C) / [(B1) + (B2) + (B3) + (C)] = 0.1 to 0.5 Composition. The inorganic powder (A) is selected from the group consisting of yttria-stabilized zirconia powder, alumina powder, tungsten powder, tungsten carbide powder, stainless steel powder, iron-nickel powder, and iron-silicon powder. The composition for a three-dimensional printer according to claim 1. The thermoplastic polymer (B3) further includes a group consisting of polystyrene resin , acrylonitrile-butadiene-styrene resin, polypropylene resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polycarbonate resin, acrylonitrile styrene resin and amorphous polyolefin. Claim 1 or 2 , wherein the organic compound (C) is selected from the group consisting of waxes, lubricants, plasticizers and antioxidants. Composition for three-dimensional printers as described. A method for manufacturing a large-sized laminate-molded article made of ceramics, cermets or metals, the method comprising the following steps A to C:
Step A: A step of using the composition for a three-dimensional printer according to any one of claims 1 to 3 and forming a large-sized laminated structure having a lamination thickness of 10 mm or more by a three-dimensional printer of a hot-melt lamination method. ,
Step B: Debinding the large laminated structure; and Step C: sintering the degreased large laminated structure obtained in Step B. Method.