WO2019088243A1

WO2019088243A1 - Resin composition and method for producing three-dimensional model using same

Info

Publication number: WO2019088243A1
Application number: PCT/JP2018/040797
Authority: WO
Inventors: 啓介溝口; 和也磯部; 永田　員也; 和昭真田
Original assignee: コニカミノルタ株式会社
Priority date: 2017-11-06
Filing date: 2018-11-02
Publication date: 2019-05-09
Also published as: JPWO2019088243A1; JP7099473B2

Abstract

The present invention addresses the problem of providing a resin composition for obtaining a three-dimensional model with high dimensional accuracy, which has high strength and high ductility, while being free from thermal warping and the like. A resin composition that solves the above-described problem is used in a three-dimensional modeling method in which a three-dimensional model is formed by repeating formation of a thin layer that contains the resin composition in the form of particles and selective energy irradiation on the thin layer. The resin composition contains thermoplastic resin particles and plate-like particles that have a thickness of 50-500 nm.

Description

Resin composition and method for producing three-dimensional object using the same

The present invention relates to a resin composition and a method for producing a three-dimensional object using the same.

In recent years, various methods capable of relatively easily producing a three-dimensional object having a complicated shape have been developed, and rapid prototyping and rapid manufacturing using such a method are attracting attention.

Conventionally, these three-dimensional object manufacturing methods have been widely used in the field of modeling, but in recent years there has been an increasing movement to expand these methods directly into manufacturing. In order to use a three-dimensional object for direct production, it is required that the high strength, high ductility, and high forming accuracy.

Among various methods for producing three-dimensional objects, it is known that a method using resin particles such as powder bed fusion bonding method can produce three-dimensional objects with relatively high forming accuracy as compared with other methods. . For example, in a powder bed melt bonding process, resin particles are laid flat to form a thin layer. Then, the thin layer is irradiated with laser light in a pattern (a pattern in which a three-dimensional object is finely divided in the thickness direction). Thereby, the resin particles in the region irradiated with the laser beam are selectively sintered or melt bonded (hereinafter, also simply referred to as “melt bonding”). Then, resin particles are further spread on the obtained shaped object layer, and laser light irradiation is similarly performed. By repeating these procedures, buildup object layers are piled up and a three-dimensional fabrication thing of a desired shape is obtained.

However, when forming the thin layer, even if the resin particles are arranged without gaps, the resin particles are usually spherical. Therefore, the contact area between adjacent resin particles is very small, and heat is not easily transmitted at the interface between resin particles. Therefore, there has been a problem that the molten state when the thin layer is irradiated with the laser light and the temperature are easily varied. Similarly, the contact area between the already formed shaped material layer and the newly formed thin layer (resin particles) is also small. Therefore, it is difficult for heat to be transmitted to each other. Therefore, the degree of thermal contraction is different between the previously formed shaped material layer and the later formed shaped material layer, and the warping (hereinafter, the warping generated in this manner is also referred to as “thermal warping”) Was also a problem that

On the other hand, as a method for producing a three-dimensional object, a method of melt extruding a resin composition in the form of filaments and forming a thin layer finely dividing the three-dimensional object in the thickness direction on a stage to obtain a three-dimensional object Melt lamination method is also known. It has been proposed to impart conductivity to the resulting three-dimensional object, or to increase the elastic modulus of the resulting three-dimensional object, by adding various fillers to such resin compositions (Patent Document 1). .

JP, 2016-28887, A

In recent years, the following methods have also been proposed as another method for producing a three-dimensional object using resin particles. First, resin particles are spread evenly to form a thin layer. Then, a bonding fluid containing an infrared light absorbing agent or the like is applied only to the area to be cured (pattern of the desired three-dimensional object finely divided in the thickness direction) in the thin layer. On the other hand, in the region to which the binding fluid is not applied, a peeling fluid having less energy absorption than the binding fluid is applied. Thereafter, irradiation with infrared light is performed to heat and melt only the powder material in the region to which the bonding fluid is applied. And by repeating these processes, a modeling thing layer is piled up and a desired three-dimensional modeling thing is obtained (Hereinafter, the method is also called "MJF method"). Also in this method, it is difficult to improve the thermal conductivity of adjacent particles, and it is likely that problems occur such as variation in the molten state in the shaped object layer or generation of heat warpage.

Then, it is possible to include a filler like patent document 1 in the inside of the resin particle used for the manufacturing method of the above-mentioned three-dimensional model. However, it is difficult to improve the thermal conductivity between adjacent resin particles only by adding a general filler, and adding the filler is likely to cause a problem that the ductility of the three-dimensional object is lowered. .

The present invention has been made in view of the above problems. That is, the present invention provides a resin composition for obtaining a three-dimensional object with high strength, high ductility, and no thermal warpage and high dimensional accuracy, and a method for producing a three-dimensional object using the same. The purpose is to provide

The present invention provides the following resin composition.
[1] A resin composition used in a three-dimensional shaping method for forming a three-dimensional object by repeating the formation of a thin layer containing a particulate resin composition and the energy irradiation to the thin layer, which is a thermoplastic resin A resin composition comprising: particles comprising: and tabular grains having a thickness of 50 to 500 nm.

[2] The resin composition according to [1], wherein the tabular grains have a width of 1 to 10 μm.
[3] The resin composition according to [1] or [2], wherein the tabular grains adhere around the particles containing the thermoplastic resin.
[4] The resin composition according to any one of [1] to [3], wherein the tabular grains are contained in the inside of the particles containing the thermoplastic resin.

[5] The resin composition according to any one of [1] to [4], wherein the tabular grains are magnesium-containing silicate compounds.
[6] The resin composition according to any one of [1] to [5], wherein the tabular grains are talc.
[7] The resin composition according to any one of [1] to [6], wherein the thermoplastic resin is a crystalline resin.
[8] The resin composition according to any one of [1] to [7], wherein the thermoplastic resin is an olefin resin.

The present invention provides the following three-dimensional object and a method for producing the three-dimensional object.
[9] A three-dimensional object including a cured product of the resin composition according to any one of the above [1] to [8].
[10] A thin layer forming step of forming a thin layer containing the resin composition according to any one of the above [1] to [8], and the thin layer is selectively irradiated with a laser beam to form a plurality of the above And a laser beam irradiation step of forming a shaped object layer in which the resin composition is melt-bonded, wherein the thin layer forming step and the laser light irradiation step are repeated a plurality of times, and the shaped object layer is laminated. The manufacturing method of the three-dimensional molded item which forms a thing.
[11] A thin layer forming step of forming a thin layer containing the resin composition according to any one of the above [1] to [8], a bonding fluid containing an energy absorbing agent, and energy absorption from the bonding fluid Applying a peeling fluid with a small amount to the adjacent areas of the thin layer, and applying energy to the thin layer after the fluid applying process, the thermoplasticity of the area to which the bonding fluid is applied An energy irradiation step of melting the resin to form a shaped object layer; repeating the thin layer forming step, the fluid application step, and the energy irradiation step a plurality of times to laminate the shaped object layer; The manufacturing method of the three-dimensional molded item which forms a molded article.

According to the resin composition of the present invention, it is possible to manufacture a three-dimensional object with high dimensional accuracy, high strength and high ductility, and no thermal warpage and the like.

1. Resin Composition The resin composition of the present invention is used in a method for producing a three-dimensional object by melt bonding particles containing a resin, such as a powder bed melt bonding method or an MJF method. The resin composition of the present invention includes particles (hereinafter, also simply referred to as “resin particles”) containing a thermoplastic resin, and tabular particles. Here, in the present specification, tabular grains have two main planes facing each other, and the distance (thickness) between these two main planes is also the maximum diameter of the main planes (hereinafter referred to as "width"). And small enough for the smallest diameter.

As described above, in the powder bed fusion bonding method or the MJF method, a thin layer made of resin particles is formed, and the thin layer is irradiated with energy. Thereby, adjacent resin particles are melt-bonded to obtain a shaped object layer in which the three-dimensional shaped object is finely divided in the thickness direction. However, since the resin particles are usually spherical, the contact area between adjacent resin particles is very small, and heat is not easily transmitted. As a result, there has been a problem that the molten state and the temperature of each resin particle are likely to be dispersed in the formed object layer. Furthermore, the thermal conductivity between the formed object layer formed earlier and the formed object layer formed later is also low, and there is also a problem that heat warpage is easily generated due to the difference in the degree of heat contraction of these layers. .

In order to address such problems, the resin composition of the present invention contains tabular particles having a thickness of 50 nm to 500 nm, together with resin particles. Since the tabular grains have a sufficiently small thickness, the temperature is likely to be uniform in the tabular grains. And it becomes possible to equalize the temperature of the resin particle which adjoins by such flat particle. That is, in the resin composition of the present invention, the molten state of each resin particle is likely to be uniform, and the dimensional accuracy and strength of the resulting three-dimensional object are enhanced.

Similarly, according to the resin composition of the present invention, the temperatures of the previously formed shaped material layer and the thin layer containing the resin composition disposed thereon are easily made uniform. As a result, the degree of thermal contraction hardly varies between the formed object layer to be formed first and the formed object layer to be formed later, and the dimensional accuracy is enhanced even if the heat warpage or the like is not easily generated.

Moreover, when the tabular particle of the said thickness is contained in the three-dimensional molded item obtained, the elasticity modulus of a three-dimensional molded item becomes high and the intensity | strength of a three-dimensional molded item becomes high. Furthermore, when a conventional general spherical ceramic particle is included in the three-dimensional object, when a tensile stress or the like is applied to the three-dimensional object, the resin and the ceramic particle are separated due to the difference in elastic modulus between the resin and the ceramic particle. And cracks are likely to occur. And a three-dimensional model becomes easy to fracture because such a crevice and a crack connect. On the other hand, when a tensile stress is applied to a three-dimensional object including tabular grains, the tabular grains have the property of being arranged in parallel with the tensile direction. Therefore, in the case of a three-dimensional object containing flat particles, when tensile stress is applied, it is difficult to form a gap or a crack between the resin and the flat particles, and there is also an advantage that the ductility of the three-dimensional object is increased.

In the resin composition of the present invention, when the thermoplastic resin contained in the resin particles is a crystalline resin, the thermoplastic resin melted during the formation of the shaped object layer is crystal-grown using the plate-like particles as a nucleating agent. It will be easier. As a result, the resin of a uniform crystal structure is likely to be contained in the three-dimensional object, and the strength and ductility of the three-dimensional object are likely to be uniform. In addition, by suppressing irregular crystal growth, dimensional accuracy can be easily enhanced.

Here, in the resin composition of the present invention, the above-mentioned tabular particles may be contained inside the resin particles. Further, the tabular particles may be attached to the periphery of the resin particles. Furthermore, the tabular grains may be contained inside the resin particles and around the resin particles. However, when the tabular particles are attached to the periphery of the resin particles, the tabular particles are likely to be contained between the adjacent resin particles when forming the shaped object layer. As a result, it is preferable from the viewpoint that the temperature and the molten state of the adjacent resin particles are easily uniformed. In addition, when flat particles are also contained in the inside of the resin particle, the strength of the obtained three-dimensional object is likely to be further enhanced.

When the tabular particles are attached to the periphery of the resin particles, it is preferable that the tabular particles are attached to a region of 10 to 80% of the surface area of the resin particles. If the area of the region to which the tabular particles are attached is 80% or less with respect to the surface area of the resin particles, the resin particles are easily melt-bonded to each other during production of the three-dimensional object. On the other hand, when the area of 10% or more of the surface area of the resin particles is covered with the tabular particles, the thermal conductivity by the tabular particles is increased, and the temperature and the molten state of adjacent resin particles are likely to be uniform. . The extent to which the tabular particles are attached around the resin particles depends on the particle diameter of the resin particles, the area of the tabular particles in plan view, the content ratio of the thermoplastic resin to the tabular particles, etc. It can be calculated from In addition, the resin particles in which the tabular particles are attached to the periphery are dissolved with a solvent or the like to determine the content and shape of the tabular particles, and based on these and the shape of the resin particles (particle diameter etc.) The area to which the tabular resin particles are attached may be calculated. Hereinafter, the tabular particles and the thermoplastic resin, and the other components and the like contained in the resin composition will be described in detail.

(Tabular grain)
The tabular grains contained in the resin composition of the present invention are not particularly limited as long as they have a thickness of 50 to 500 nm and are tabular grains. The thickness of the tabular grains is more preferably 100 to 400 nm, still more preferably 150 to 300 nm. When the thickness of the tabular grains is 50 nm or more, the strength of the obtained three-dimensional object is likely to be increased. On the other hand, when the thickness of the tabular grains is 500 nm or less, the thermal conductivity tends to be favorable.

The shape of the tabular grains in plan view may be circular, elliptical or polygonal. Among these, an elliptical shape is more preferable. In addition, the width (average maximum diameter) of the tabular particles when viewed in plan is preferably 1 to 10 μm, more preferably 2 to 8 μm, and still more preferably 3 to 6 μm. When the width (average maximum diameter) of the tabular grains is excessively large, the dimensional accuracy of the three-dimensional object is lowered, and the tabular grains are likely to inhibit the melt bonding of the resin particles. On the other hand, when the width (average maximum diameter) of the tabular grains is too small, the tabular grains may not be able to sufficiently transfer heat to the adjacent resin grains.

The average minimum diameter of the tabular grains in plan view is preferably 1 to 6 μm, and more preferably 2 to 5 μm.

The ratio (width / thickness) of the average thickness of the tabular grains to the average maximum diameter (width) is preferably 5 to 15, and more preferably 10 to 12. On the other hand, the ratio (minimum diameter / thickness) of the average thickness of the tabular grains to the average minimum diameter is preferably 5 to 13, and more preferably 6 to 11. When the ratio of the thickness of the tabular grains to the width or the average minimum diameter is in the above range, the thermal conductivity of the tabular grains tends to be favorable.

The thickness, maximum diameter and width of tabular grains are specified, for example, as follows. The thermoplastic resin is removed using a solvent or the like capable of dissolving the thermoplastic resin, and only the tabular particles are taken out. If the resin is difficult to dissolve in the solvent, heating is performed as needed. Then, dry mixing is performed with a propylene resin so that the amount of the tabular grains is 15% by mass. Then, using, for example, a known small kneader and injection molding machine, a dumbbell test piece having a length of 175 mm is produced. However, the shape of the test piece is not particularly limited as long as it can measure 100 or more of the cross section of tabular grains. Then, the test piece is immersed in liquid nitrogen for 10 minutes or more and broken while being frozen in the liquid nitrogen. With respect to tabular grains present on the fractured surface, a thickness of 100 pieces, a maximum diameter (width) of 100 pieces, an average minimum diameter of 100 pieces, and the like are observed with an electron microscope (SEM) to create a histogram. Then, from these data, an average value is calculated for each, and the average value is adopted as the thickness, width, and average minimum diameter of tabular grains.

Examples of tabular grains include various grains commonly referred to as layered clay minerals. Specific examples of tabular grains include kaolin; talc; mica; smectite minerals such as montmorillonite, beidellite, hectorite, saponite, nontronite, and stevensite; vermiculite; bentonite; kanemite; Sodium acid; mica group clay minerals such as Na-type tetrasilastic fluorine mica, Li-type tetrasilisic fluorine mica, Na-type fluorine teniolite, Li-type fluorine teniolite, etc. are included. Such tabular grains may be obtained from natural minerals or may be chemically synthesized. Furthermore, the tabular grains may have their surfaces modified (surface-treated) with an ammonium salt or the like.

Among these, compounds having a thermal conductivity of 0.5 to 5.0 W · m ⁻¹ · K ⁻¹ are preferable. When the tabular grains have the above-described thermal conductivity, the tabular grains easily make the temperature and the like of the adjacent resin grains uniform.

Further, from the viewpoint of particularly good thermal conductivity, it is preferably a silicate compound containing magnesium, and talc and mica are preferred. The component analysis of tabular grains can be performed by, for example, X-ray photoelectron spectroscopy (XPS) or electron spectroscopy for chemical analysis (ESCA). Specific examples include ESCALAB-200R photoelectron spectrometer manufactured by VG Scientific, Inc., and the like.

The tabular grains are preferably contained in an amount of 5 to 40 parts by mass, more preferably 10 to 20 parts by mass, with respect to 100 parts by mass of the total amount of the resin composition. When the amount of tabular particles in the resin composition is too small, the above-mentioned thermal conductivity may not be sufficiently exhibited or the strength of the three-dimensional object may not be sufficiently increased. On the other hand, when the amount of tabular grains is excessive, the amount of the thermoplastic resin relatively decreases, so that the thermoplastic resin can not be sufficiently melt-bonded, and the strength of the three-dimensional object may be reduced.

(Thermoplastic resin)
The kind of thermoplastic resin contained in a resin composition is suitably selected according to the formation method of a three-dimensional model. The thermoplastic resin may be a resin contained in a resin composition for a general powder bed melt bonding method or a resin contained in a resin composition for an MJF method, and the resin particles may be thermoplastic. Only one kind of resin may be contained, or two or more kinds may be contained.

However, if the melting temperature of the thermoplastic resin is too high, it may be necessary to irradiate energy to a high temperature in order to melt the resin particles when producing the three-dimensional object, and it may take time to produce the three-dimensional object, etc. is there. Then, it is preferable that it is 300 degrees C or less, and, as for the melting temperature of a thermoplastic resin, it is more preferable that it is 230 degrees C or less. On the other hand, the melting temperature of the thermoplastic resin is preferably 100 ° C. or more, and more preferably 150 ° C. or more, from the viewpoint of the heat resistance and the like of the three-dimensional object to be obtained. The melting temperature can be adjusted by the type of thermoplastic resin and the like.

Here, the thermoplastic resin may be a crystalline resin or an amorphous resin, but as described above, when the thermoplastic resin is a crystalline resin, the tabular particles are cored As an agent, there is an advantage that it becomes easy to form uniform crystals. Examples of the crystalline resin include polyamide 12, polyolefin resins such as polylactic acid and polypropylene, polyphenylene sulfide (PPS), polybutylene terephthalate and the like. Among them, polyamide 12 or an olefin resin is preferable, and a polypropylene resin is particularly preferable, from the viewpoint that the tabular particles and the crystal structure are close to each other, and it is easily crystallized uniformly using the tabular particles as a nucleating agent.

Here, the thermoplastic resin is preferably contained in an amount of 60 to 95 parts by mass, more preferably 80 to 90 parts by mass, with respect to 100 parts by mass of the total amount of the resin composition. When the amount of the thermoplastic resin in the resin composition is too small, the strength of the three-dimensional object tends to be reduced. On the other hand, when the amount of the resin composition is too large, the amount of tabular grains relatively decreases, and it becomes difficult to exhibit the above-mentioned thermal conductivity.

Further, the shape of the resin particles containing a thermoplastic resin is not particularly limited, but from the viewpoint of enhancing the dimensional accuracy of the three-dimensional object, the shape is preferably spherical. Furthermore, the size (diameter) of the resin particles is preferably 20 to 100 μm, and more preferably 30 to 70 μm. When the size of the resin particles is 100 μm or less, it is possible to produce a three-dimensional object with a fine structure. On the other hand, the size of the resin particles is preferably 20 μm or more from the viewpoint of sufficient fluidity and good manufacturing cost and handling. The average particle size is a volume average particle size measured by a dynamic light scattering method. The volume average particle size can be measured by a laser diffraction type particle size distribution measuring apparatus (manufactured by Microtrack Bell, MT3300EXII) equipped with a wet disperser.

(Other ingredients)
The resin composition may contain components other than the above-mentioned tabular particles and the thermoplastic resin, as long as the objects and effects of the present invention are not impaired. Examples of other components include various additives, fillers and the like.

Examples of various additives include antioxidants, acidic compounds and derivatives thereof, lubricants, UV absorbers, light stabilizers, nucleating agents, flame retardants, impact modifiers, blowing agents, colorants, organic peroxides, Adhesives, adhesives and the like are included. The resin composition may contain only one of these, or two or more of these. Moreover, these may be apply | coated to the surface of the resin particle in the range which does not impair the objective of this invention.

Examples of the filler include inorganic particles that do not correspond to the above-described flat particles, various fibers, and the like. Examples thereof are talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, glass cut fiber, Glass milled fiber, glass flake, glass powder, silicon carbide, silicon nitride, gypsum, gypsum whisker, calcined kaolin, carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, metal powder, ceramic Inorganic fillers such as whiskers, potassium titanate, boron nitride, graphite, and carbon fibers; organic fillers such as polysaccharide nanofibers; various polymers. The resin composition may contain only one of these, or two or more of these. However, these amounts are preferably smaller than the tabular grains described above.

The resin composition used in the powder bed melt bonding method may contain a laser absorber and the like. Examples of laser absorbers include carbon powder, nylon resin powder, pigments, dyes and the like. These laser absorbers may be contained alone in the resin composition, or in two or more kinds.

(Method for producing resin composition)
The method for producing the resin composition is not particularly limited, and it may be appropriately selected depending on whether the tabular particles are attached to the periphery of the resin particles or the tabular particles are contained in the resin particles. It is selected. For example, the resin composition in which the tabular particles adhere around the resin particles can be prepared by preparing resin particles in advance and mixing the resin particles with the tabular particles by a known method. On the other hand, the resin composition in which the tabular particles are contained inside the resin particles can be produced by melt-kneading the tabular particles and the resin, and pulverizing these with a freeze crusher or the like. Also, resin compositions in which tabular grains are present inside and around resin particles can be prepared by combining these methods.

2. Method for Producing Three-Dimensional Shaped Object As described above, the resin composition described above can be used in a method for producing a three-dimensional shaped object by a powder bed bonding melting method or an MJF method. Hereinafter, although the three-dimensional modeling method using the said resin composition is each demonstrated, this invention is not restrict | limited to these methods.

2-1. Method for Producing Three-Dimensional Shaped Object by Powder Bed Bonding and Melting Method In a method for producing a three-dimensional shaped object by powder bed bonding and melting method, the method can be carried out in the same manner as a normal powder bed bonding and melting method except using the resin composition. Specifically, (1) a thin layer forming step of forming a thin layer containing the above-mentioned resin composition, and (2) a thin layer containing the resin composition is selectively irradiated with a laser beam to form the particles. And a laser beam irradiation step of forming a shaped object layer in which the resin compositions are melt-bonded to each other. And a three-dimensional model can be manufactured by repeating a process (1) and a process (2) multiple times, and laminating | stacking a modeling thing layer. In addition, the manufacturing method of the said three-dimensional model may include the other process as needed, for example, may include the process etc. of preheating a resin composition.

.Thin layer forming step (step (1))
In this step, a thin layer containing a resin composition is formed. For example, the resin composition supplied from the powder supply part of a three-dimensional model | molding apparatus is spread on a modeling stage flatly with a recoater. The thin layer may be formed directly on the shaping stage, or may be formed on a powder material that has already been spread or may be in contact with the already formed shaped material layer. The above-mentioned resin composition may be separately mixed with a flow agent or a laser absorbent, if necessary.

The thickness of the thin layer is the same as the thickness of the desired shaped object layer. The thickness of the thin layer can be optionally set according to the accuracy of the three-dimensional object to be produced, but is usually 0.01 mm or more and 0.30 mm or less. By setting the thickness of the thin layer to 0.01 mm or more, it is possible to prevent the resin composition of the lower layer from being melt-bonded by laser light irradiation for forming the next shaped object layer, and further, It is possible to spread the powder uniformly. Further, by setting the thickness of the thin layer to 0.30 mm or less, the energy of the laser beam is conducted to the lower part of the thin layer, and the resin composition constituting the thin layer is sufficiently melt-bonded along the entire thickness direction. It can be done. From the above viewpoint, the thickness of the thin layer is more preferably 0.01 mm or more and 0.10 mm or less. In addition, from the viewpoint of making the resin composition melt and bond more sufficiently throughout the thickness direction of the thin layer and making the formation layer more difficult to crack, the thickness of the thin layer is the beam spot diameter of the laser light described later It is preferable to set so that the difference with it becomes less than 0.10 mm.

Here, examples of the laser absorber that can be mixed with the resin composition include carbon powder, nylon resin powder, pigments, dyes, and the like. The amount of the laser absorber can be appropriately set within the range in which the melt bonding of the resin composition becomes easy. For example, it can be more than 0% by mass and less than 3% by mass with respect to the total mass of the thermoplastic resin. The laser absorbent may be used alone or in combination of two or more.

On the other hand, the flow agent that can be mixed with the resin composition may be a material having a small coefficient of friction and having self-lubricity. Examples of such flow agents include silicon dioxide and boron nitride. These flow agents may be used alone or in combination of two. The amount of the flow agent can be appropriately set within a range in which the fluidity of the resin particles and the like can be improved and the melt bonding of the resin particles can be sufficiently generated. For example, it can be more than 0% by mass and less than 2% by mass with respect to the mass of the thermoplastic resin.

・ Laser beam irradiation process (process (2))
At this process, a laser beam is selectively irradiated to the position which should form a modeling thing layer among the thin layers containing a resin composition, and the resin composition of the irradiated position is melt-bonded. The melted resin composition melts with the adjacent resin composition (resin particles) to form a melt bonded body, and becomes a shaped object layer. At this time, the resin composition (resin particles) that has received the energy of the laser beam also melt-bonds with the already formed shaped material layer, and adhesion between adjacent layers also occurs.

The wavelength of the laser light may be set within the range of the wavelength absorbed by the resin composition. At this time, it is preferable to reduce the difference between the wavelength of the laser light and the wavelength at which the absorptivity of the resin composition is the highest. Generally, thermoplastic resins absorb light in various wavelength ranges. Therefore, it is preferable to use a laser beam with a wide wavelength band such as a CO ₂ laser. For example, the wavelength of the laser light can be, for example, 0.8 μm or more and 12 μm or less.

The power at the time of output of the laser light may be set within a range where the resin composition (resin particles) is sufficiently melted and bonded at the scanning speed of the laser light described later. Specifically, it can be 5.0 W or more and 60 W or less. From the viewpoint of reducing the energy of the laser beam to reduce the manufacturing cost and simplifying the configuration of the manufacturing apparatus, the power at the output of the laser beam is preferably 30 W or less, and is 20 W or less It is more preferable that

The scanning speed of the laser light may be set within a range that does not increase the manufacturing cost and does not excessively complicate the apparatus configuration. Specifically, it is preferably 1 m / sec to 10 m / sec, more preferably 2 m / sec to 8 m / sec, and still more preferably 3 m / sec to 7 m / sec.
The beam diameter of the laser beam can be appropriately set according to the accuracy of the three-dimensional object to be manufactured.

-About repetition of process (1) and process (2) In the case of manufacture of a three-dimensional molded item, the above-mentioned process (1) and process (2) are repeated arbitrary times. Thereby, a modeling thing layer will be laminated | stacked and a desired three-dimensional modeling thing will be obtained.

Preheating Step As described above, in the method of producing a three-dimensional object by the powder bed bonding melting method, the step of preheating the resin composition may be performed. The preheating of the resin composition may be performed after the thin layer formation (step (1)) or may be performed before the thin layer formation (step (1)). Also, both of them may be performed.

The preheating temperature is set to a temperature lower than the melting temperature of the thermoplastic resin so that the resin compositions do not melt and bond. The preheating temperature is appropriately selected according to the melting temperature of the thermoplastic resin, and can be, for example, 50 ° C. or more and 300 ° C. or less, more preferably 100 ° C. or more and 230 ° C. or less, 150 ° C. or more and 190 ° C. It is more preferable that it is the following.

At this time, the heating time is preferably 1 to 30 seconds, and more preferably 5 to 20 seconds. By performing preheating at the above temperature for the above time, the time until the resin composition (resin particles) melts at the time of laser energy irradiation can be shortened, and a three-dimensional object can be manufactured with a small amount of laser energy. It becomes possible.

Others In addition, from the viewpoint of preventing the strength of the three-dimensional object from being reduced due to oxidation or the like of the resin composition during the melt bonding, it is preferable to carry out at least the step (2) under reduced pressure or in an inert gas atmosphere. . The pressure when decompressing is preferably 10 ⁻² Pa or less, more preferably 10 ⁻³ Pa or less. At this time, examples of inert gas that can be used include nitrogen gas and a noble gas. Among these inert gases, nitrogen (N ₂ ) gas, helium (He) gas or argon (Ar) gas is preferable from the viewpoint of availability. From the viewpoint of simplifying the production process, it is preferable to carry out both step (1) and step (2) under reduced pressure or in an inert gas atmosphere.

2-2. Method for Producing Three-Dimensional Shaped Object by MJF Method The method for producing a three-dimensional shaped object according to the present embodiment includes (1) a thin layer forming step of forming a thin layer containing the above-mentioned resin composition, and (2) an energy absorber A bonding fluid and a fluid applying step of applying a peeling fluid with less energy absorption than the bonding fluid to adjacent regions of the thin layer, and (3) applying energy to the thin layer after the fluid applying step and bonding An energy irradiation step of melting the thermoplastic resin in the application region of the fluid to form a shaped object layer. In addition, the manufacturing method of the said three-dimensional model may include the other process as needed, for example, may include the process etc. of preheating a resin composition.

(1) Thin layer formation process At this process, the thin layer which mainly contains the above-mentioned resin composition is formed. The method of forming the thin layer is not particularly limited as long as a layer having a desired thickness can be formed. For example, this step can be a step of laying the resin composition supplied from the resin composition supply unit of the three-dimensional model forming device flatly on the modeling stage by recoater. The thin layer may be formed directly on the shaping stage, or may be formed on a powder material that has already been spread or may be in contact with the already formed shaped material layer.

The thickness of the thin layer is the same as the thickness of the desired shaped object layer. The thickness of the thin layer can be optionally set according to the accuracy of the three-dimensional object to be produced, but is usually 0.01 mm or more and 0.30 mm or less. By setting the thickness of the thin layer to 0.01 mm or more, it is possible to melt the already-formed shaped object layer by energy irradiation (energy irradiation in the energy irradiating step described later) for forming a new shaped object layer. It can prevent. Moreover, it becomes easy to spread powder material uniformly as the thickness of a thin layer is 0.01 mm or more. In addition, by setting the thickness of the thin layer to 0.30 mm or less, energy (for example, infrared light) can be conducted to the lower portion of the thin layer in the energy irradiation process described later. This makes it possible to melt the thermoplastic resin in the desired area (the area to which the bonding fluid is applied) throughout the thickness direction. From the above viewpoint, the thickness of the thin layer is more preferably 0.01 mm or more and 0.20 mm or less.

(2) Fluid application step In this step, a bonding fluid containing an energy absorbing agent and a peeling fluid with less energy absorption than the bonding fluid are respectively provided in adjacent regions of the thin layer formed in the thin layer forming step. Apply Specifically, the bonding fluid is selectively applied to the position where the shaped object layer is to be formed, and the peeling fluid is applied to the area where the shaped object layer is not formed. By applying the peeling fluid adjacent to the periphery of the region to which the bonding fluid is applied, the resin particles are less likely to melt and bond in the region where the peeling fluid is applied. Either of the bonding fluid and the peeling fluid may be applied first, but it is preferable to apply the bonding fluid first from the viewpoint of the dimensional accuracy of the resulting three-dimensional object.

The method of applying the binding fluid and the release fluid is not particularly limited, and may be, for example, application by a dispenser, application by an inkjet method, spray application, etc. It is preferable to apply at least one of them by the inkjet method from the viewpoint of being able to be applied, and it is more preferable to apply both by the inkjet method.

The application amount of the binding fluid and the release fluid is preferably 0.1 to 50 μL, and more preferably 0.2 to 40 μL, per 1 mm ^{3 of the} thin layer. When the application amount of the bonding fluid and the peeling fluid is in the above range, the powder material in the region forming the shaped object layer and the region not forming the shaped object layer is sufficiently impregnated with the bonding fluid and the peeling fluid, respectively. It is possible to form a three-dimensional object with good dimensional accuracy.

The bonding fluid to be applied in this step may be the same as the bonding fluid used in the conventional MJF method, and may be, for example, a composition including at least an energy absorbing agent and a solvent. The binding fluid may contain known dispersants and the like as required.

The energy absorbing agent is not particularly limited as long as it can absorb the energy irradiated in the energy irradiation step described later and can efficiently increase the temperature of the region to which the binding fluid is applied. Specific examples of energy absorbers include infrared absorbers such as carbon black, ITO (tin indium oxide), ATO (antimony tin oxide), cyanine dyes, phthalocyanine dyes mainly having aluminum or zinc, various naphthalocyanine compounds, planar Infrared absorbing dyes such as nickel dithiolene complexes having a four-coordinate structure, squalium dyes, quinone compounds, diimmonium compounds, and azo compounds are included. Among these, from the viewpoint of versatility and the ability to efficiently increase the temperature of the region to which the binding fluid is applied, infrared absorbers are preferred, and carbon black is more preferred.

The shape of the energy absorbing agent is not particularly limited, but is preferably in the form of particles. The average particle diameter is preferably 0.1 to 1.0 μm, more preferably 0.1 to 0.5 μm. If the average particle size of the energy absorbing agent is too large, the energy absorbing agent is less likely to enter the gaps of the resin particles when the bonding fluid is applied on the thin layer. On the other hand, if the average particle diameter of the energy absorbing agent is 0.1 μm or more, heat can be efficiently transmitted to the thermoplastic resin in the energy irradiation step described later, and the surrounding thermoplastic resin can be melted. Become.

The binding fluid preferably contains 0.1 to 10.0% by mass, more preferably 1.0 to 5.0% by mass, of the energy absorbing agent. It becomes possible to fully raise the temperature of the area | region where the fluid for coupling | bonding was apply | coated in the below-mentioned energy irradiation process as the quantity of an energy absorbing agent is 0.1 mass% or more. On the other hand, if the amount of the energy absorbing agent is 10.0% by mass or less, the energy absorbing agent is less likely to be aggregated in the binding fluid, and the coating stability of the binding fluid is likely to be enhanced.

On the other hand, the solvent is not particularly limited as long as it is a solvent which can disperse the energy absorbing agent and further hardly dissolve the thermoplastic resin and the like in the resin composition, and can be, for example, water.

The binding fluid preferably contains 90.0 to 99.9% by mass, and more preferably 95.0 to 99.0% by mass of the solvent. When the amount of the solvent in the binding fluid is 90.0% by mass or more, the fluidity of the binding fluid is increased, and for example, it becomes easy to apply by an inkjet method or the like.

The viscosity of the binding fluid is preferably 0.5 to 50.0 mPa · s, and more preferably 1.0 to 20.0 mPa · s. When the viscosity of the bonding fluid is 0.5 mPa · s or more, the diffusion when the bonding fluid is applied to the thin layer is easily suppressed. On the other hand, when the viscosity of the bonding fluid is 50.0 mPa · s or less, the coating stability of the bonding fluid tends to be enhanced.

On the other hand, the peeling fluid to be applied in this step may be a fluid relatively less in energy absorption than the coupling fluid, and may be, for example, a fluid containing water as a main component.

The peeling fluid preferably contains 90% by mass or more of water, and more preferably 95% by mass or more. It becomes easy to apply | coat, for example by the inkjet method etc. as the quantity of the water in the fluid for peeling is 90 mass% or more.

(3) Energy Irradiation Step In this step, energy is collectively applied to the thin layer after the fluid application step, that is, the thin layer to which the bonding fluid and the peeling fluid are applied. At this time, in the region where the binding fluid is applied, the energy absorbing agent absorbs energy, and the temperature of the region partially rises. And only the thermoplastic resin of the said area | region fuses, and a modeling thing layer is formed.

The type of energy to be irradiated in this step is appropriately selected according to the type of energy absorbing agent contained in the binding fluid. Specific examples of the energy include infrared light, white light and the like. Among these, it is possible to melt the thermoplastic resin efficiently in the region where the bonding fluid is applied, while it is difficult to increase the temperature of the thin layer in the region where the peeling fluid is applied. The light is preferably infrared light, more preferably light having a wavelength of 780 to 3000 nm, and still more preferably light having a wavelength of 800 to 2500 nm.

The time of energy irradiation in this step is appropriately selected according to the type of the thermoplastic resin contained in the powder material, but in general, it is preferably 5 to 60 seconds, and preferably 10 to 30 seconds. More preferable. By setting the energy irradiation time to 5 seconds or more, it is possible to sufficiently melt the thermoplastic resin and bond them. On the other hand, by setting the time to 60 seconds or less, it is possible to efficiently manufacture a three-dimensional object.

Preheating Step In the MJF method, a step of preheating the resin composition may be performed. The preheating of the resin composition may be performed after the thin layer formation (step (1)) or may be performed before the thin layer formation (step (1)). Also, both of them may be performed. By performing preheating, it is possible to reduce the amount of energy irradiated in the (3) energy irradiation step. Furthermore, it becomes possible to form a three-dimensional object layer efficiently in a short time. The preheating temperature is preferably a temperature lower than the melting temperature of the thermoplastic resin and (2) a temperature lower than the boiling point of the solvent contained in the bonding fluid and the peeling fluid applied in the fluid application step. Specifically, the temperature is preferably 50 ° C. to 5 ° C. lower than the melting point of the thermoplastic resin or the boiling point of the solvent contained in the bonding fluid and the peeling fluid, and the temperature is 30 ° C. to 5 ° C. lower More preferable. At this time, the heating time is preferably 1 to 60 seconds, more preferably 3 to 20 seconds. By making heating temperature and heating time into the said range, the energy irradiation amount in (3) energy irradiation process can be reduced.

Hereinafter, specific embodiments of the present invention will be described. The scope of the present invention is not interpreted as being limited by these examples.

Example 1
As a thermoplastic resin, polyamide 12 (PA12, manufactured by Daicel-Evonik Co., Ltd., Diamide L1600 ("Diamide" is a registered trademark of the company) was prepared. Laser diffraction particle size distribution measurement of the thermoplastic resin was equipped with a wet disperser. It ground by the mechanical grinding method until the average particle diameter measured with the apparatus (SYNPATEC company make, HEROS (HELOS)) becomes a value of 50 micrometers.
Next, kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was crushed by a free crusher (M-2, manufactured by Nara Machinery Co., Ltd.) to a thickness of 50 nm and a width of 0.5 μm. Then, the said flat particle was mixed with the said resin particle with the Henschel mixer (made by Nippon Coke Kogyo Co., Ltd.), and the resin composition 1 was produced. The mass ratio of the thermoplastic resin to the tabular particles was 85:15.

Example 2
A resin was prepared in the same manner as in Example 1, except that kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was pulverized by a free crusher (M-2, manufactured by Nara Machine Co., Ltd.) to a thickness of 500 nm and a width of 0.5 μm. Composition 2 was made.

[Example 3]
A resin composition as in Example 1 except that kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was pulverized by a bead mill (UAM015, manufactured by Hiroshima Metal & Machinery Co., Ltd.) and pulverized to a thickness of 50 nm and a width of 1 μm. 3 was produced.

Example 4
A resin composition was prepared in the same manner as Example 1, except that kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was crushed using a bead mill (UAM015, manufactured by Hiroshima Metal & Machinery Co., Ltd.) to a thickness of 300 nm and a width of 5 μm. 4 was produced.

[Example 5]
A resin composition as in Example 1 except that kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was pulverized by a bead mill (UAM015, manufactured by Hiroshima Metal & Machinery Co., Ltd.) to a thickness of 500 nm and a width of 10 μm. 5 was produced.

[Example 6]
The same as Example 1, except that mica (grind by Yamaguchi Mica, A-11) was crushed as tabular particles instead of kaolin (manufactured by Hayashi Kasei Corp., ASPR 400P) and mica having a thickness of 300 nm and a width of 5 μm was used. Resin composition 6 was used.

[Example 7]
Resin composition 7 in the same manner as in Example 1 except that talc (manufactured by Hayashi Kasei Co., Ltd., Micron White # 5000) was used instead of kaolin (manufactured by Hayashi Kasei Corp., ASPR 400P) and talc having a thickness of 300 nm and a width of 5 μm was used. I got

[Example 8]
As the thermoplastic resin, polypropylene resin pellets (PM600A, manufactured by Sun Aroma Co., Ltd.) were used, and the thermoplastic resin was crushed by a freeze crusher until the average particle size became 50 μm. On the other hand, talc (manufactured by Hayashi Kasei Co., Ltd., Micron White # 5000) was pulverized to a thickness of 300 nm and a width of 5 μm in the same manner as in Example 1 and mixed to obtain a resin composition 8. The mass ratio of the thermoplastic resin to the tabular particles was 85:15.

[Example 9]
90 parts by mass of polypropylene resin pellet (manufactured by Sun Aroma Co., Ltd., PM600A) and 10 parts by mass of talc (manufactured by Hayashi Kasei Co., Ltd., micron white # 5000 (thickness 3000 nm, width 10 μm)) in a kneader (Mc 15 manufactured by Xplore) It knead | mixed and produced the talc containing polypropylene resin pellet. Then, the polypropylene resin pellet was crushed by a freeze crusher until the average particle diameter became 50 μm. On the other hand, talc (manufactured by Hayashi Kasei Co., Ltd., Micron White # 5000) was pulverized to a thickness of 300 nm and a width of 5 μm in the same manner as in Example 1 and mixed to obtain a resin composition 9. The mass ratio of the thermoplastic resin to the tabular particles was 85:15.

Comparative Example 1
A resin was prepared in the same manner as in Example 1 except that kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was crushed to a thickness of 10 nm and a width of 0.5 μm using a free crusher (M-2, manufactured by Nara Machinery Co., Ltd.) Composition 10 was made.

Comparative Example 2
A resin was prepared in the same manner as in Example 1 except that kaolin (ASPR 400P, manufactured by Hayashi Kasei Co., Ltd.) was pulverized by a free crusher (M-2, manufactured by Nara Machine Co., Ltd.) to a thickness of 550 nm and a width of 0.5 μm. Composition 11 was made.

[Evaluation]
With respect to the above-mentioned resin compositions 1 to 11, a three-dimensional object was produced by the powder bed fusion bonding method described below, and the rate of improvement in elasticity, elongation at break, and warpage were evaluated.
(1) Preparation of Three-Dimensional Shaped Object The prepared resin composition is spread on a forming stage placed on a hot plate to form a thin layer having a thickness of 0.1 mm, and preheating is performed by adjusting the temperature of the hot plate. Each was heated to a temperature of 150 ° C. The thin layer was irradiated with laser light in the range of 15 mm long × 20 mm wide from a CO ₂ laser mounted with a galvanometer scanner for YAG wavelength under the following conditions to produce a shaped material layer. The above-described steps were repeated until the height reached 55 mm, to manufacture laminated three-dimensional objects.
[Conditions of emitting laser light]
Laser power: 12 W
Laser light wavelength: 10.6 μm
Beam diameter: 170 μm on thin layer surface
[Scanning condition of laser light]
Scanning speed: 2000 mm / sec
Number of lines: 1 line

(2) Measurement of elastic modulus and elongation at break The obtained three-dimensional object is placed in a tensile tester (Tensilon RTC-1250 manufactured by A and D Co.), and the longitudinal direction (the object layer) is obtained at a speed of 1 mm / min. The modulus of elasticity was measured by pulling in the direction perpendicular to the stacking direction. Further, in the same device, the sample was pulled in the longitudinal direction (perpendicular to the laminating direction of the shaped article layer) at a speed of 50 mm / min to measure the breaking elongation. And it evaluated by the following references | standards about an elasticity modulus and breaking elongation, respectively. In addition, a blank is a three-dimensional model manufactured using the resin particle same as an Example or each comparative example except not containing each tabular particle.

(Elastic modulus)
◎: The elastic modulus was improved by 30% or more compared to the elastic modulus of the blank.
○: The elastic modulus was improved by 10% or more compared to the elastic modulus of the blank.
X: The elastic modulus did not improve relative to the elastic modulus of the blank.

(Breaking elongation)
:: The breaking elongation was 50% or more ○: The breaking elongation was 10% or more and less than 50% x: The breaking elongation was less than 10%

(3) Evaluation of molding characteristics (heat warpage)
The dimensions of the three-dimensional object obtained were measured with a digital caliper (Supercaliper CD67-S PS / PM, manufactured by Mitutoyo Co., Ltd., "Supercaliper" is a registered trademark of the company) for longitudinal and lateral dimensions. The difference between the measured dimensions (length 15 mm x width 20 mm x height 55 mm) and the measured vertical and horizontal dimensions are averaged to evaluate the dimensional accuracy (with or without thermal warpage) of the three-dimensional object based on the following criteria did.
◎: Average of difference in dimension was less than 0.1 mm ○: Average of difference in dimension was 0.1 mm or more and less than 0.5 mm ×: Average of difference in dimension was 0.5 mm or more

As shown in Table 1, even if tabular particles were attached around the resin particles, when the thickness was thin, it was not possible to improve the elastic modulus of the three-dimensional object obtained ((1) Comparative example 1). If the tabular grains are too thin, it is considered that their addition effect is not sufficiently exhibited. On the other hand, when the thickness of the tabular grains was large and approached to a spherical shape, the elongation at break was low and thermal warpage was likely to occur (Comparative Example 2).

On the other hand, according to the resin composition containing flat particles having a thickness of 50 nm or more and 500 nm or less on the outside of the resin particle, any evaluation of elastic modulus, elongation at break, and warpage was also good (Example 1) ~ 9). It is thought that the strength of the three-dimensional object obtained is enhanced by the inclusion of tabular grains of the above thickness. In addition, since the particles are flat, when the three-dimensional object has tensile strength, the flat particles are easily arranged in the direction of elongation of the resin in the three-dimensional object, and between the resin and the flat particles. It is surmised that it was difficult to create a gap. Furthermore, since tabular particles are attached around the resin particles, the thermal conductivity of the resin particles, and between the resin particles and the (previously formed) object layer during the production of a three-dimensional object. It is surmised that the thermal conductivity in the case of (1) is good and thermal warpage is less likely to occur.

Furthermore, in Examples 8 and 9 using polypropylene and talc (tabular particles) whose crystal structures are similar to each other, the breaking elongation was good, and furthermore, the thermal warpage did not easily occur. In the said resin composition, when resin particles fuse | melt in the case of manufacture of a three-dimensional molded item, a tabular particle becomes a nucleating agent and recrystallizes. As a result, a large number of crystals having a uniform structure are contained in the three-dimensional object, so that heat is uniformly transmitted or a load is easily applied uniformly, and these results are considered to be good.

This application claims the priority based on Japanese Patent Application No. 2017-213710 filed on Nov. 6, 2017. The contents described in the application specification are all incorporated herein by reference.

According to the resin composition of the present invention, it is possible to form a three-dimensional object with high accuracy by any of the powder bed melt bonding method and the MJF method. Therefore, the present invention is considered to contribute to the further spread of the three-dimensional modeling method.

Claims

A resin composition used in a three-dimensional shaping method for forming a three-dimensional object by forming a thin layer containing a particulate resin composition and repeating the energy irradiation to the thin layer,
Particles comprising a thermoplastic resin, and tabular particles having a thickness of 50 to 500 nm,
Resin composition.
The tabular grains have a width of 1 to 10 μm.
The resin composition according to claim 1.
The tabular grains are attached around the grains containing the thermoplastic resin,
The resin composition according to claim 1 or 2.
The tabular grains are contained inside the grains comprising the thermoplastic resin,
The resin composition according to any one of claims 1 to 3.
The tabular grains are magnesium-containing silicate compounds,
The resin composition according to any one of claims 1 to 4.
The tabular grains are talc,
The resin composition according to any one of claims 1 to 5.
The thermoplastic resin is a crystalline resin,
The resin composition according to any one of claims 1 to 6.
The thermoplastic resin is an olefin resin,
The resin composition according to any one of claims 1 to 7.
A cured product of the resin composition according to any one of claims 1 to 8,
Three-dimensional object.
A thin layer forming step of forming a thin layer containing the resin composition according to any one of claims 1 to 8;
A laser beam irradiation step of selectively irradiating the thin layer with a laser beam to form a three-dimensional object layer in which a plurality of the resin compositions are melt-bonded;
Including
The three-dimensional object is formed by repeating the thin layer formation step and the laser light irradiation step a plurality of times to laminate the three-dimensional object layer.
A method of manufacturing a three-dimensional object.
A thin layer forming step of forming a thin layer containing the resin composition according to any one of claims 1 to 8;
Applying a bonding fluid comprising an energy absorbing agent, and a peeling fluid with less energy absorption than the bonding fluid, to adjacent areas of the thin layer;
An energy irradiation step of irradiating the thin layer after the fluid application step with energy, melting the thermoplastic resin in the region to which the bonding fluid is applied, and forming a shaped object layer;
Including
The three-dimensional object is formed by repeating the thin layer formation step, the fluid application step, and the energy irradiation step a plurality of times to laminate the three-dimensional object layer.
A method of manufacturing a three-dimensional object.