JP2014131879A - Molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding method for forming a molded article by removing unbound parts from layers having bound parts where granules are bound through a binder while suppressing protruding parts from being deformed.SOLUTION: There is provided a molding method for molding a molded article in which bound parts 22a, 22b, 22c, 22d, 22e are laminated by applying a removing step to a laminate after forming the laminate in which layers containing the bound parts 22a, 22b, 22c, 22d, 22e are laminated by alternately repeating a layer forming step and a binding step. The bound parts 22b, 22d are protruded from above the bound parts 22a, 22c, a slurry layer including the bound parts 22a, 22c is formed by using a first slurry, and a slurry layer containing the bound parts 22b, 22d, 22e is formed by using a second slurry whose solubility in a dissolving liquid is higher than that of the first slurry.

Description

  The present invention relates to a modeling method for forming a modeled article composed of particles bound via a binder.

  Conventionally, an additive manufacturing method is frequently used as a method (rapid prototyping) of a prototype quickly. In the additive manufacturing method, after a model of a three-dimensional CAD model is divided into a number of two-dimensional cross-sectional layers, a layered structure corresponding to each two-dimensional cross-sectional layer is sequentially formed and stacked to form a three-dimensional object. To do.

  Specifically, as described in Patent Document 1, for example, first, a layer is formed by particles including ceramic, metal, or the like. Next, a binding liquid for binding the particles to each other in a part of the layer made of the particles is discharged to the layer made of the particles by, for example, an ink jet type droplet discharge device. Then, a layered structure corresponding to the two-dimensional cross-sectional layer is formed by a binding portion in which the binding liquid that has penetrated into the voids between the particles has bonded the particles together with hardening thereof.

  Thereafter, similarly, the formation of a layer composed of these particles and the discharge of the binding liquid are alternately repeated to form a laminated body in which layers having a layered structure are laminated. Then, for example, the unbound portion is removed by flowing a liquid through the laminated body, and a shaped object that is a laminated body of the bound portion is formed.

Japanese Patent No. 2729110

  By the way, according to the above method, it is also possible to form a shaped article in which the upper binding portion projects from the lower binding portion. In a shaped article having such an overhanging portion, the overhanging portion is surrounded by the unbound portion until the unbound portion is removed. And when an unbound part is removed, such an unbound part is removed at once. Therefore, the force for removing the unbound portion acts on the overhanging portion in a concentrated manner. As a result, the overhanging portion may be deformed by such a force.

  The present invention has been made in view of the above circumstances, and its purpose is to remove a non-bound portion from a layer having a bound portion in which particles are bound to each other via a binder. It is in providing the modeling method which suppresses that an overhang | projection part deform | transforms in the modeling method to form.

  The present invention provides a layer forming step of forming a layer comprising a slurry containing granules, and the binder liquid is cured after infiltrating a part of the layer, and the binder liquid is cured via the binder liquid. A binding step of partitioning the binding portion where the particles are bound to each other, and a removal step of removing unbound portions by supplying a solution to the layer including the binding portion, After the layer formation step and the binding step are alternately repeated to form a laminated body in which the layers including the binding portion are laminated, the binding step is performed by performing the removing step on the laminated body. A modeling method for modeling a model in which portions are stacked, and a binding portion in a (k + 1) -th layer is stretched from a binding portion in a k-th layer (k is an integer of 1 or more). And forming the k-th layer using the first slurry, and That solubility to form the first k + 1 th layer of the layers using a second slurry is higher than the first slurry.

  In this invention, the kth layer is formed by the first slurry, and the k + 1th layer is formed by the second slurry having higher solubility in the solution than the first slurry. The Then, after the stacked body is formed so that the bound portion of the (k + 1) th layer extends from the bound portion of the kth layer, the unbound portion in the stacked body is dissolved. Removed by liquid. According to such a configuration, after the unbound portion of the (k + 1) th layer is removed, the unbound portion of the kth layer is removed. Therefore, while the unbound portion of the (k + 1) th layer is removed by the solution, the overhanging portion is supported by the unbound portion of the kth layer. Therefore, deformation of the projecting portion can be suppressed by the amount of load necessary for removing the unbound portion of the (k + 1) th layer being distributed to the unbound portion of the kth layer.

In this invention, it is preferable that the slurry includes hydrophobic particles, an aqueous solvent, and an amphiphilic polymer dissolved in the aqueous solvent, and the solution is the aqueous solvent.
In the present invention, a slurry is composed of hydrophobic particles, an aqueous solvent, and an amphiphilic polymer having affinity for the hydrophobic particles and the aqueous solvent. Such an amphiphilic solid polymer has affinity for hydrophobic particles at the site and affinity with an aqueous solvent at the site of hydrophilicity. Thus, by passing through the amphiphilic solid polymer, the hydrophobic particles can be uniformly dispersed in the aqueous solvent. Therefore, in the molded object formed using the slurry, the hydrophobic particles as the forming material are uniformly distributed. In addition, since the unbound portion of the layer made of such a slurry is dissolved by the aqueous solution that is the constituent material of the slurry, it becomes easier to remove the unbound portion from the laminate.

  In this invention, the amphiphilic polymer is polyvinyl alcohol, the polymerization degree of the polyvinyl alcohol is 600 or more and 1700 or less, and the polymerization degree of the polyvinyl alcohol contained in the first slurry is the second degree. It is preferable that the degree of polymerization of the polyvinyl alcohol contained in the slurry is higher.

  If the degree of saponification in polyvinyl alcohol is the same, the solubility of polyvinyl alcohol in an aqueous solvent varies depending on the degree of polymerization in polyvinyl alcohol. That is, the higher the degree of polymerization of polyvinyl alcohol, the lower the solubility of polyvinyl alcohol in an aqueous solvent. In this regard, according to the above method, the polymerization degree of polyvinyl alcohol is 600 or more and 1700 or less, and the polymerization degree of polyvinyl alcohol in the first slurry is higher than the polymerization degree of polyvinyl alcohol in the second slurry. Therefore, while the unbound portion of the (k + 1) th layer is removed by the solution, the overhanging portion is reliably supported by the unbound portion of the kth layer.

  In this invention, the amphiphilic polymer is polyvinyl alcohol, the saponification degree of the polyvinyl alcohol is 86 or more and 96 or less, and the saponification degree of the polyvinyl alcohol contained in the second slurry is the first saponification. It is preferable that the degree of saponification of the polyvinyl alcohol contained in the slurry is higher.

  When the saponification degree in the polyvinyl alcohol is 86 or more and 96 or less, the higher the saponification degree, the more the crystallization of the polyvinyl alcohol proceeds, and the polyvinyl alcohol becomes less soluble in the aqueous solvent. According to this invention, the saponification degree of polyvinyl alcohol is 86 or more and 96 or less, and the saponification degree of polyvinyl alcohol contained in the first slurry is higher than the saponification degree of polyvinyl alcohol contained in the second slurry. Therefore, while the unbound portion of the (k + 1) th layer is removed by the solution, the overhanging portion is reliably supported by the unbound portion of the kth layer.

According to the present invention, in the binding step, it is preferable that the binding liquid is infiltrated into the layer using a droplet discharge method in which the binding liquid is discharged as droplets.
According to the present invention, it is possible to increase the accuracy of the shape of the binding portion, and consequently improve the accuracy of the shape of the modeled object.

The flowchart which shows the procedure of the modeling method in one embodiment of this invention. (A) (b) (c) is a schematic diagram which shows each process of the modeling method along a procedure. (A) (b) is a schematic diagram which shows each process of the modeling method along a procedure. (A) (b) is a schematic diagram which shows each process of the modeling method along a procedure.

Hereinafter, an embodiment of a modeling method according to the present invention will be described with reference to FIGS. First, the composition of the slurry will be described.
The slurry of the present embodiment is a suspension in which the following three materials are kneaded.

(A) Hydrophobic granule (B) Aqueous solvent (C) Amphiphilic polymer The hydrophobic granule is a main constituent material of a shaped article formed using a slurry. As the hydrophobic particles, hydrophobic resin particles such as acrylic resin powder, silicon resin powder, acrylic silicon resin powder, polyethylene resin powder, and polyethylene acrylic acid copolymer resin powder can be used. In addition, the hydrophobic particle | grains in this Embodiment are the particle | grains which do not melt | dissolve 1g or more with respect to 100g of aqueous solvents.

  With respect to the aqueous solvent, the solubility of the hydrophobic particles constituting the modeled object is low as described above. Therefore, it is difficult for the hydrophobic particles to be modified due to dissolution in the solvent or absorption of the solvent. Therefore, it is preferable as a medium for suppressing scattering of hydrophobic particles. The aqueous solvent includes water and a non-organic solvent such as an aqueous solution of an inorganic salt. Of these, water is preferably used as the aqueous solvent. Further, the aqueous solvent may be one obtained by adding a water-soluble organic solvent to water.

  The amphiphilic polymer is a material that constitutes a shaped object together with the hydrophobic particles. This polymer is amphiphilic. Therefore, the hydrophilic part dissolves in the aqueous solvent due to the affinity with the aqueous solvent, and the hydrophobic part causes the hydrophobic particles to disperse in the solvent by the affinity with the hydrophobic part. To express. As the amphiphilic polymer, a material having a hydrocarbon chain as a main chain and a hydrophilic functional group as a side chain can be used. Among them, it is preferable to use polyvinyl alcohol which has a straight hydrocarbon chain but has higher hydrophilicity than other materials.

  In the slurry in which the above three materials are kneaded, the hydrophobic particles are cross-linked with each other by the hydrophobic portion of the amphiphilic polymer. In other words, even when vibration or the like is given to the slurry during formation of the modeled object, the hydrophobic particles are held in the structure formed by crosslinking between the particles. For this reason, scattering of a granular material comes to be suppressed.

  In addition, the hydrophobic particles are uniformly dispersed in the aqueous solvent through the hydrophilic portion of the amphiphilic polymer that interacts in the hydrophobic portion. Therefore, in the molded object formed using such a slurry, the hydrophobic particles as the forming material are present uniformly. In addition, since such an amphiphilic polymer itself is a forming material for a modeled object, an operation of removing the amphiphilic polymer from the modeled object that is being formed or completed is not required when the modeled object is formed.

Specific examples of (A) hydrophobic particles and (C) amphiphilic polymers are described below.
[(A) Hydrophobic granules]
The powder resin material as the hydrophobic particles preferably contains true spherical particles. Thereby, the controllability concerning the shape of the modeled object, particularly the controllability of the shape at the sides and corners that define the outer shape of the modeled object is improved.

  Moreover, when forming a modeling thing by the well-known lamination modeling method using the slurry containing the said powder resin material, the particle size of a powder resin material is below the thickness per slurry layer formed with a slurry. It is preferable. Furthermore, it is more preferable that it is 1/2 or less of the thickness of a slurry layer. Thereby, the volume filling rate of the granule in a slurry layer can be improved, and the mechanical strength of a molded article can be improved by extension.

  In addition, the powder resin material preferably contains particles having different particle diameters within the above particle diameter range. The particle size distribution in the slurry may be a dispersion close to a Gaussian distribution (normal distribution), or a dispersion having a maximum particle size distribution on the maximum diameter side or the minimum diameter side (single dispersion). ). When the particle size of the particles contained in the powder resin material is a single value, the volume filling rate of the particles when forming a shaped product exceeds 69.8%, which is the theoretical value at the time of closest packing. In fact, the filling rate is about 50 to 60%. As described above, particles having different particle diameters are included in the powder material, in other words, if the particle diameters are distributed with a range, for example, by particles having relatively large particle diameters. The volume filling factor is improved by disposing particles having a relatively small particle diameter in the formed void. Thereby, the mechanical strength of a molded article can be improved.

  For example, when the thickness of the slurry layer is 100 μm, the particle size of the granules contained in the powder resin material is preferably 100 μm or less, and further, the average particle size is 20 μm to 40 μm, and from several μm to It is more preferable to have a dispersion of 100 μm or less.

The powder resins satisfying the above conditions are listed below.
Examples of the silicon resin powder material include Tospearl 1110 (particle diameter 11 μm), Tospearl 120 (particle diameter 2 μm), Tospearl 130 (particle diameter 3 μm), Tospearl 145 (particle diameter 4.5 μm), Tospearl 2000B (particle diameter 6 μm). And Tospearl 3120 (particle size: 12 μm) (manufactured by Momentive Performance Materials) (Tospearl: registered trademark).

Examples of the acrylic silicon resin powder include Charine R-170S (particle size: 30 μm) (manufactured by Nissin Chemical Industry Co., Ltd.) (Charine: registered trademark).
As the acrylic resin, for example, Eposter MA1013 (particle size: 12 to 15 μm), Epostor MA1010 (particle size: 8 to 12 μm), Epostor MA1006 (particle size: 5 to 7 μm) (manufactured by Nippon Shokubai Co., Ltd.) (Eposter: registered trademark) Is mentioned.

  In addition, Matsumoto Microsphere M-100 (particle diameter 5 to 20 μm), Matsumoto Microsphere S-100 (particle diameter 5 to 25 μm), manufactured by Matsumoto Yushi Seiyaku Co., Ltd. (Matsumoto Microsphere: registered trademark) can be mentioned. .

  Examples of the polyethylene resin include flow beads LE-1080 (particle size 6 μm), flow beads LE-2080 (particle size 11 μm), flow beads HE-3040 (particle size 11 μm), flow beads CL-2080 (particle size 11 μm). (Manufactured by Sumitomo Seika Co., Ltd.) (Flow Beads: registered trademark).

Examples of the ethylene acrylic acid copolymer resin include flow beads EA-209 (particle size: 10 μm) (manufactured by Sumitomo Seika Co., Ltd.).
[(C) Amphiphilic solid polymer]
A preferred example of the amphiphilic solid polymer is polyvinyl alcohol. The structure of polyvinyl alcohol is shown below.

ポリビニルアルコールは、主鎖として直鎖状の炭化水素を有するとともに、側鎖として親水性の官能基であるヒドロキシル基を有する。ポリビニルアルコールには、その単位構造当りにおよそ一つのヒドロキシル基が含まれることから、該ポリビニルアルコールは、疎水性の粒体との親和性を主鎖によって維持しつつ、水系溶媒との親和性が高いものとなる。なお、ポリビニルアルコールの単量体であるビニルアルコール（Ｈ_２Ｃ＝ＣＨＯＨ）はケト−エノール互変異性による平衡がケト体であるアセトアルデヒド（ＣＨ_３ＣＨＯ）側に大きく偏っていて不安定であることから、ポリビニルアルコールは一般に以下の手順で生成される。

Polyvinyl alcohol has a linear hydrocarbon as a main chain and a hydroxyl group which is a hydrophilic functional group as a side chain. Since polyvinyl alcohol contains approximately one hydroxyl group per unit structure, the polyvinyl alcohol maintains affinity with hydrophobic particles by the main chain and has affinity with an aqueous solvent. It will be expensive. In addition, vinyl alcohol (H ₂ C═CHOH), which is a monomer of polyvinyl alcohol, is unstable because the equilibrium due to keto-enol tautomerism is largely biased toward the keto acetaldehyde (CH ₃ CHO) side. Thus, polyvinyl alcohol is generally produced by the following procedure.

(A) First, polyvinyl acetate is produced by polymerizing acetic acid (CH ₃ COOH) and vinyl acetate having a structure esterified (CH ₃ COOCH═CH ₂ ).
(B) Hydrolyze (saponify) the ester bond of polyvinyl acetate to replace —C═OCH ₃ with —H.

Therefore, as shown in the chemical formula (1), polyvinyl alcohol has a part of —OC═OCH ₃ group in addition to a hydroxyl group (—OH) as a functional group in the side chain. Substances collectively referred to as polyvinyl alcohol include substances having different ratios of the number of hydroxyl groups to the degree of polymerization of polyvinyl acetate due to the difference in the degree of hydrolysis. The percentage of the ratio of the number of hydroxyl groups to the degree of polymerization is called the degree of saponification and is used as an indicator of the characteristics of polyvinyl alcohol.

Further, as an index indicating the characteristics of polyvinyl alcohol, the unit structure represented by the chemical formula (1), that is, the degree of polymerization which is the number of polymerization of vinyl acetate is also used.
These polymerization degrees and saponification degrees tend to be as follows.

-The higher the degree of polymerization, the lower the solubility of polyvinyl alcohol in an aqueous solvent.
-The smaller the degree of polymerization, the higher the solubility of polyvinyl alcohol in an aqueous solvent.
-The higher the degree of saponification, the higher the hydrophilicity, so that the solubility of polyvinyl alcohol in an aqueous solvent increases.

-Since the hydrophobicity increases as the degree of saponification decreases, the solubility of polyvinyl alcohol in aqueous solvents decreases.
However, since the polyvinyl alcohol is easily crystallized when the saponification degree is around 100%, the solubility of the polyvinyl alcohol in the aqueous solvent becomes extremely low.

  Next, a modeling method using the slurry will be described with reference to FIGS. 1 shows each process of a modeling method along a procedure, and FIGS. 2-4 has shown typically the process implemented at each said process.

  In the modeling method in the present embodiment, first, in the sacrificial layer forming step (step S11: FIG. 2A), for example, the thickness is set to 200 μm on the substrate 11 such as a glass substrate or a plastic sheet. The second slurry is applied. Thereby, the sacrificial layer 12 which is a layer made of the second slurry and is also the lowermost layer is formed. For applying the slurry, a known method such as a squeegee method, a screen printing method, a doctor blade method, and a spin coating method can form a slurry layer having a substantially uniform thickness on the substrate 11. Can be used. In addition, after apply | coating a 2nd slurry, you may provide a drying process (for example, 60 degreeC, 3 second).

  Next, in the slurry layer forming step (step S12: (b)), a slurry layer that becomes a layer immediately below the layer where the first slurry is applied and the overhanging portion is formed so that the thickness becomes 100 μm. 21a is formed. It should be noted that the above-described known method can be used for forming the slurry layer 21a as well as the formation of the sacrificial layer 12. In addition, like the said sacrificial layer formation process, after apply | coating a 1st slurry, you may provide a drying process (for example, 60 degreeC, 3 second).

  Then, in the ultraviolet curable resin dropping step (step S13: FIG. 2 (c)), a droplet discharge device is formed on the binding portion 22a for forming a part of the shaped article 20 (FIG. 3) in the slurry layer 21a. A UV ink I containing an ultraviolet curable resin as a binding liquid is discharged from 31. Here, in the slurry layer 21a, a hydrophobic particle cross-linked structure is formed by the polyvinyl alcohol, so that the hydrophobic particles are arranged with a predetermined space. Therefore, the UV ink I ejected from above the slurry layer 21a toward the surface of the slurry layer 21a reaches the back surface of the slurry layer 21a through the above-described space. That is, since the UV ink I permeates the entire binding portion 22a, the strength of the binding portion 22a is improved. Incidentally, since the hydrophobic region in the polyvinyl alcohol in the slurry layer 21a has affinity for the UV ink I, the UV ink I is likely to penetrate into the slurry layer 21a.

  Thereafter, in the ultraviolet irradiation step (step S14: FIG. 3A), the entire portion of the slurry layer 21a is irradiated with the ultraviolet light L, whereby the binding portion 22a is cured. Note that the ultraviolet light L does not have to be irradiated to the entire slurry layer 21a, and it is sufficient to irradiate at least the binding portion 22a of the slurry layer 21a. Further, the irradiation of the ultraviolet light L can be performed alternately or simultaneously with the dropping of the UV ink I onto the binding portion 22a by, for example, an ultraviolet irradiation device mounted on the droplet discharge device 31. And it can also carry out for every slurry layer by the ultraviolet irradiation device provided separately from this droplet discharge device 31, or it can carry out to a plurality of slurry layers at once.

  The binding portion 22 a cured by the dropping of the UV ink I and the irradiation of the ultraviolet light L as described above is a binding portion that is a part of the molded article 20. On the other hand, the unbound portion other than the bound portion 22a in the slurry layer 21a is formed in the slurry layer 21b immediately above the slurry layer 21a while being provided with a projecting portion projecting in a direction perpendicular to the stacking direction. Functions as an unattached portion 23a that mechanically supports. Thereby, for example, as shown in FIG. 3B, the modeling object 20 is formed in which the upper binding portions 22 b and 22 d each have an overhanging portion that protrudes from the lower binding portions 22 a and 22 c. However, it is not necessary to separately form an unattached portion that supports the overhang portion. Moreover, since the formation 20 is formed in a state in which the layer made of the first slurry is present in the lower layer of the overhanging portion, it is possible to suppress the overhanging portion from being missing during the formation of the formed object 20. The binding step is composed of the ultraviolet curable resin dropping step and the ultraviolet irradiation step.

  The three steps from the slurry layer forming step (step S12) to the ultraviolet ray irradiating step (step S14) are repeatedly performed until all of the binding portions constituting the shaped article 20 are formed. For example, as shown in FIG. 3B, when the modeled object 20 is composed of five slurry layers 21a, 21b, 21c, 21d, and 21e, the above three steps are repeated five times in order. Thus, since the laminated body comprised from a some layer can be formed by repeating three processes from a slurry layer formation process to an ultraviolet irradiation process in order, of the modeling object 20 formed by the said modeling method The degree of freedom related to the shape can be increased.

  When all of the binding portions 22a, 22b, 22c, 22d, and 22e constituting the modeled article 20 are formed, the support portion removing step (step S15: FIGS. 4A and 4B) includes each slurry layer. Unbound portions 23a, 23b, 23c, 23d, and 23e are removed from the laminate by the solution. The removal of these unbound portions 23a, 23b, 23c, 23d, and 23e is performed by immersing the laminate together with the substrate 11 or by spraying water on the laminate at a predetermined pressure to dissolve the laminate. Can do. Thereby, the molded article which has the overhang | projection part projected in the direction perpendicular | vertical to a lamination direction can be formed.

  By the way, according to the modeling method described above, it is possible to form a modeled object in which the upper binding portion projects from the lower binding portion. In a shaped article having such an overhanging portion, the overhanging portion is surrounded by the unbound portion until the unbound portion is removed. And when an unbound part is removed, such an unbound part will be removed at once. Therefore, the force for removing the unbound portion acts on the overhanging portion in a concentrated manner. As a result, the overhanging portion may be deformed by such a force.

  Therefore, in the present embodiment, in order to suppress the deformation of the overhanging portion, the slurry for forming the slurry layers 21b and 21d including the overhanging portion and the slurry layers 21a and 21c serving as the foundation of the slurry layer are formed. The slurry is formed of different slurries. More specifically, slurry layers 21a and 21c are formed by the first slurry having relatively low solubility in the solution, and the slurry layer 21b is formed by the second slurry having relatively high solubility in the solution. , 21d are formed.

  In order to obtain different solubility as described above, for example, the polymerization degree of polyvinyl alcohol is 600 or more and 1700 or less, and the polymerization degree of polyvinyl alcohol contained in the first slurry is in the second slurry. What is necessary is just a structure higher than the polymerization degree of the polyvinyl alcohol contained. As described above, if the degree of saponification in polyvinyl alcohol is the same, the solubility of polyvinyl alcohol in an aqueous solvent varies depending on the degree of polymerization in polyvinyl alcohol. That is, the higher the degree of polymerization of polyvinyl alcohol, the lower the solubility of polyvinyl alcohol in an aqueous solvent.

  In order to obtain different solubility as described above, for example, the saponification degree of polyvinyl alcohol is 86 or more and 96 or less, and the saponification degree of polyvinyl alcohol contained in the second slurry is Any structure may be used as long as the degree of saponification of the polyvinyl alcohol contained in the slurry is higher. As described above, when the degree of saponification in polyvinyl alcohol is 86 or more and 96 or less, the higher the degree of saponification, the more the crystallization of polyvinyl alcohol proceeds and the polyvinyl alcohol becomes less soluble in an aqueous solvent.

  And according to said 1st slurry and 2nd slurry, when the water which is an example of a solution is supplied to the said laminated body, as shown to Fig.4 (a), first, the unbound part 23b will be shown. , 23d, 23e are dissolved. Subsequently, as shown in FIG. 4B, the unbound portions 23a and 23c are gradually dissolved. Therefore, while the unbound portions of the slurry layers 21b and 21d are removed, the protruding portions are supported by the unbound portions of the slurry layers 21a and 21c. As a result, the load required to remove the unbound portions of the slurry layers 21b and 21d is dispersed to the unbound portions of the slurry layers 21a and 21c. Therefore, it is possible to suppress deformation of the overhanging portion as compared with the case where the load required for removing the unbound portions of the slurry layers 21b and 21d is concentrated on the overhanging portion.

  Note that the temperature of the solution when dissolving the unbound portions 23b and 23d is preferably a temperature at which the difference between the solubility of the first slurry and the solubility of the second slurry is relatively large. With such a method, the unbound portions 23a and 23c can be more reliably left when the unbound portions 23b and 23d are dissolved in advance.

Examples of combinations of the first slurry and the second slurry that satisfy the above conditions are given below.
Examples of the polyvinyl alcohol constituting the first slurry include Poval JM-17L (polymerization degree 1700, saponification degree 95.0 to 97.0 (96)) (manufactured by Nihon Acetate / Poval). As the polyvinyl alcohol constituting the second slurry, POVAL JP-10 (degree of polymerization 1000, degree of saponification 86.0-90.0 (88)), POVAL JP-15 (degree of polymerization 1500, degree of saponification 86.0) 90.0 (88)) (Nippon Vinegar-Poval Co., Ltd.). And (A) Charine R-170S is used as the hydrophobic particles, (B) water is used as the aqueous solvent, (C) Poval JM-17L or Poval JP-10 is used as the amphiphilic polymer. These materials are preferably blended in the following proportions.
(A) :( B) :( C) = 7: 3.1: 0.22 (unit: g)
In addition, the mechanical strength in this modeling thing is raised, so that the filling rate of the hydrophobic granule becomes high in a modeling thing. Therefore, in order to increase the mechanical strength of the molded article, the aqueous solvent and the amphiphilic polymer are more than the gaps between the closely packed hydrophobic particles so that the hydrophobic particles are packed closest. A blending ratio that reduces the volume occupied is preferable.

  Further, the water in which the unbound portions 23a, 23c, 23d, and 23e are used in the unbound portion removing step includes the hydrophobic particles that constitute the unbound portions. . For this reason, hydrophobic particles that are difficult to dissolve in water as described above can be extracted by providing a hydrophobic particle extraction step that filters the water following the unbound portion removal step. become able to. The hydrophobic particles extracted in this way can be reused as a constituent material of the slurry.

[Example]
Next, more specific configurations of the first slurry and the second slurry will be described with reference to examples.

  (C) As various amphiphilic polymers, eight kinds of polyvinyl alcohols having different degrees of polymerization or saponification were used. These polyvinyl alcohols were evaluated for dissolution time when dissolved in water at a water temperature of 20 ° C. and dissolution time when dissolved in warm water at a water temperature of 60 ° C. The dissolution time was evaluated by immersing a film having a thickness of 100 μm, which was cast at room temperature after casting an aqueous solution of each polyvinyl alcohol, in water having a water temperature of 20 ° C. and warm water having a water temperature of 60 ° C. This was done by measuring. Table 1 shows dissolution times of four kinds of slurries having a polymerization degree of 600 among the above eight kinds of polyvinyl alcohols. Table 2 shows the dissolution times of the remaining four types of slurry having a polymerization degree of 1700.

表１に示されるように、水温２０℃の水に重合度が６００のポリビニルアルコールを溶解させたときには、その鹸化度が９０から９６に上がっていくと、結晶化の影響により、溶解時間が２５秒から１００秒へと長くなることが認められた。すなわち、鹸化度が結晶化開始前後の範囲にあるときには、鹸化度を低くすることによって水温２０℃の水に対する溶解時間を短縮できることが認められた。しかし、水温６０℃の温水に重合度が６００のポリビニルアルコールを溶解させたときには、その鹸化度が９０から９６に上がっていったとしても、結晶化の影響をほとんど受けないことが認められた。すなわち、各鹸化度に対する溶解時間がいずれも８秒乃至９秒となって鹸化度の高低に依存しなくなるとともに、水温２０℃の水に対する場合よりも溶解時間が大幅に短縮されることが認められた。

As shown in Table 1, when polyvinyl alcohol having a polymerization degree of 600 was dissolved in water at a water temperature of 20 ° C., when the saponification degree increased from 90 to 96, the dissolution time was 25 due to the effect of crystallization. It was observed that the time increased from seconds to 100 seconds. That is, when the degree of saponification is in the range before and after the start of crystallization, it was found that the dissolution time in water at a water temperature of 20 ° C. can be shortened by lowering the degree of saponification. However, it was confirmed that when polyvinyl alcohol having a polymerization degree of 600 was dissolved in hot water at a water temperature of 60 ° C., even if the saponification degree increased from 90 to 96, it was hardly affected by crystallization. That is, it is recognized that the dissolution time for each saponification degree is 8 seconds to 9 seconds and does not depend on the level of saponification degree, and the dissolution time is significantly shortened compared to the case of water at a water temperature of 20 ° C. It was.

  On the other hand, as shown in Table 2, when polyvinyl alcohol having a polymerization degree of 1700 was dissolved in water at a water temperature of 20 ° C., the dissolution time increased from 90 to 96 due to the effect of crystallization. Was found to be significantly longer from 62 seconds to 650 seconds. That is, as in the case of the polymerization degree of 600, when the saponification degree is in the range before and after the start of crystallization, it was confirmed that the dissolution time in water at a water temperature of 20 ° C. can be shortened by lowering the saponification degree. However, when polyvinyl alcohol having a polymerization degree of 1700 is dissolved in hot water having a water temperature of 60 ° C., the effect of crystallization is the same as when the polymerization degree is 600, even if the saponification degree is increased from 90 to 96. It was found that they received almost no. That is, it is recognized that the dissolution time for each degree of saponification is 23 to 25 seconds and does not depend on the degree of saponification, and that the dissolution time is significantly shortened compared to the case of water at a water temperature of 20 ° C. It was. In addition, the dissolution time in water at each water temperature shows the same tendency regardless of the degree of polymerization, but when evaluated for each saponification degree, the lower polymerization degree is shorter regardless of the water temperature, In other words, high solubility was observed.

  As described above, when the degree of saponification is in the range before and after the start of crystallization, polyvinyl alcohol having a low degree of polymerization and saponification is used for the second slurry, and polyvinyl alcohol having a high degree of polymerization and saponification is used for the first slurry. Thus, the difference in solubility in water can be increased. In addition, it is desirable to use water having a relatively high temperature when dissolving the second slurry and to use water having a relatively high temperature when dissolving the first slurry. By so doing, only the highly soluble polyvinyl alcohol can be surely dissolved, and the low solubility polyvinyl alcohol can be reliably left.

  If the degree of saponification is 98 or more, it will be in a completely saponified state in which polyvinyl alcohol is completely crystallized. Further, if the saponification degree is 91.5 or more and 97.5 or less, although crystallization of polyvinyl alcohol has occurred, the intermediate saponification state has not reached the above-mentioned complete saponification, and if the saponification degree is 70 or more and 90 or less. Thus, a partially saponified state in which no crystallization occurs is obtained.

  In the present embodiment, 86 to 96 is exemplified as an example of the degree of saponification of polyvinyl alcohol. That is, as an example of the polyvinyl alcohol used in the second slurry, polyvinyl alcohol products in a partially saponified state (for example, POVAL JP-10 (degree of saponification 86.0-90.0), POVAL JP-15 (degree of saponification)) 86.0-90.0) (Nippon Vinegar-Poval Co., Ltd.) and the like. Moreover, as an example of the polyvinyl alcohol used in the first slurry, a polyvinyl alcohol product in an intermediate saponified state (for example, Poval JM-17L (degree of saponification 95.0 to 97.0 (96)) ( Poval Co., Ltd.)). Within this range of saponification degree, the crystallization of polyvinyl alcohol varies greatly depending on the degree of saponification, that is, the solubility in the solution varies greatly depending on the degree of saponification. Therefore, only the highly soluble polyvinyl alcohol can be reliably dissolved, and the low solubility polyvinyl alcohol can be more reliably left.

As described above, according to the modeling method in the present embodiment, the effects listed below can be obtained.
(1) A slurry was formed from water as an aqueous solvent, resin particles as hydrophobic particles, and polyvinyl alcohol as an amphiphilic polymer. Thereby, the resin granule which forms the molded article 20 exists in the slurry which is a suspension by being mixed with water and polyvinyl alcohol. Moreover, in the said slurry, since the hydrocarbon chain | strand in polyvinyl alcohol has affinity with a resin particle, it exists in the state with which the particle | grains were connected via polyvinyl alcohol. That is, the resin particles are not in an independent state, but are in a state of being cross-linked with each other through the intervention of polyvinyl alcohol. Therefore, also in the formation process of the molded article 20, the resin particles are held in a structure formed by cross-linking between the particles. Therefore, scattering of the particles is suppressed.

  (2) Moreover, since the hydroxyl group which polyvinyl alcohol has has affinity with water, a resin particle will be in the state disperse | distributed in water through polyvinyl alcohol. For this reason, the resin particles can be uniformly dispersed in water through the polyvinyl alcohol. Therefore, in the molded article 20 formed using such a slurry, the resin particles that are the forming material are uniformly present.

  (3) The k + 1-th layer is formed by the second slurry having a k-th layer (k is an integer of 1 or more) formed by the first slurry and having higher solubility in the solution than the first slurry. An eye layer is formed. Then, after the stacked body is formed so that the binding portions 22b and 22d of the (k + 1) th layer extend from the binding portions 22a and 22c of the kth layer, The unbound portions 23b and 23d are first removed by the solution. According to such a configuration, after the unbound portion of the (k + 1) th layer is removed, the unbound portion of the kth layer is removed. For this reason, while the unbound portions 23b and 23d of the (k + 1) th layer are removed by the solution, the overhanging portions are supported by the unbound portions 23a and 23c of the kth layer. Therefore, the overhanging portion is deformed by the amount of load necessary for removing the unbound portions 23b and 23d of the (k + 1) th layer being distributed to the unbound portions 23a and 23c of the kth layer. Can be suppressed.

  (4) Since water is used as a solvent for suppressing the scattering of the particles, the particles are dissolved in the solvent, or the particles are swollen by absorbing the solvent. Can be prevented from being denatured.

(5) In addition, since polyvinyl alcohol is a constituent material of the modeled object, it is not necessary to separately remove polyvinyl alcohol from the slurry when the modeled object 20 is formed.
(6) Polyvinyl alcohol is used as the amphiphilic solid polymer, and the degree of polymerization is 600 or more and 1700 or less, and the degree of polymerization of polyvinyl alcohol contained in the first slurry is the polymerization of polyvinyl alcohol contained in the second slurry. To be higher than the degree. This ensures that the solubility of the first slurry in the aqueous solvent is lower than the solubility of the second slurry in the aqueous solvent. Therefore, the unbound portion made of the second slurry can be surely dissolved before the unbound portion made of the first slurry.

  (7) Polyvinyl alcohol is used as the amphiphilic polymer, the saponification degree is 86 to 96, and the saponification degree of the polyvinyl alcohol contained in the first slurry is the saponification degree of the polyvinyl alcohol contained in the second slurry. To be higher. As a result, the lower limit of the saponification degree was set to 86 before crystallization of polyvinyl alcohol, so that the solubility of the slurry in an aqueous solvent was increased, and the upper limit value of the saponification degree was set to 96 because the crystallization was progressing. Solubility can also be lowered. Further, the solubility of the first slurry in the aqueous solvent can be suppressed to be lower than the solubility of the second slurry in the aqueous solvent. Therefore, it is possible to intentionally make a difference in the solubility of the non-constituting portion of the shaped article in the layer made of the second slurry and the layer made of the first slurry.

  (8) The binding liquid was infiltrated into the layer formed of the slurry by using a droplet discharge method in which the binding liquid for bonding the particles to each other was discharged as droplets. Thereby, the precision of the shape of a binding part can be raised and by extension, the precision of the shape of the said molded object can also be raised further.

It should be noted that the above embodiment can be implemented with appropriate modifications as follows.
The binding liquid is not limited to the UV ink I containing an ultraviolet curable resin, but can be embodied in a liquid material containing a thermosetting resin. Even if it does in this way, the effect similar to said (1)-(9) can be acquired.

  The binder liquid is supplied to the layer formed by the slurry using the droplet discharge method, but this may be changed and the binder liquid may be supplied using the screen printing method. Even if it is such a method, the effect similar to said (1)-(8) can be acquired.

  In the region where the saponification degree is lower than the saponification degree at which crystallization of polyvinyl alcohol occurs, the saponification degree of the first slurry may be lowered and the saponification degree of the second slurry may be raised. Even if it does in this way, the high and low solubility which can dissolve polyvinyl alcohol in the water of the same temperature can be selected intentionally. Therefore, the same effects as the above (1) to (7) can be obtained.

-The polymerization degree of polyvinyl alcohol may be 300 or more and 1000 or less.
As the degree of polymerization of polyvinyl alcohol increases, the mechanical strength of the structure containing the polyvinyl alcohol increases, while the solubility in aqueous solvents decreases. In view of the mechanical strength of the single layer made of the slurry, it is preferable to increase the degree of polymerization of the polyvinyl alcohol contained in the slurry. However, if a model is formed by laminating a single layer, the solubility of polyvinyl alcohol decreases due to an increase in the degree of polymerization. Therefore, the adhesiveness in the joint surface of an adjacent single layer will fall, and the mechanical strength between layers will fall.

  In this respect, when the water-based solvent contained in the slurry is water, if the degree of polymerization of polyvinyl alcohol is 300 or more and 1000 or less, it is possible to achieve both the mechanical strength in the slurry layer and the adhesion between the layers. is there. Even if it does in this way, the effect similar to said (1)-(6) can be acquired.

  -After forming each slurry layer 21a, 21b, 21c, 21d, 21e, you may make it provide the drying process which dries this slurry layer 21a, 21b, 21c, 21d, 21e. In drying, the water contained in the slurry layers 21a, 21b, 21c, 21d, and 21e may be completely dried, and the water content of the slurry layers 21a, 21b, 21c, 21d, and 21e is in the air. The state may not be changed. That is, the slurry layers 21a, 21b, 21c, 21d, 21e and the atmosphere may be in an equilibrium state. Even when the slurry layers 21a, 21b, 21c, 21d, and 21e are completely dried, the adhesion between the layers is maintained by dissolving the polyvinyl alcohol in the lower slurry layer in the water in the upper slurry layer. The mechanical strength between the layers is ensured.

  -Modeled object 20 illustrated what was formed by five layers of slurry layers 21a, 21b, 21c, 21d, and 21e. Not only this but the number of the layers which comprise the molded article 20 can be made into two or more arbitrary numbers. Moreover, the shape of the structure formed in each slurry layer is also arbitrary.

-If the shape control of the molded article 20 is possible, the resin granule may have a shape other than a true sphere, for example, an ellipsoidal shape.
-Hydrophobic particles that are not the same as the ultraviolet curable resin or in which the same material is not introduced to the surface may be used.

-You may make a slurry contain fiber materials, such as an acetate fiber, for example. Thereby, the mechanical strength of the molded article formed using the slurry can be improved.
-The amphiphilic polymer is not limited to polyvinyl alcohol, and may be any amphiphilic polymer that intervenes between the hydrophobic particles and connects them, and can uniformly disperse the hydrophobic particles in the aqueous solvent. .

The hydrophobic particles are not limited to particles made of resin, but may be other hydrophobic particles, for example, particles such as silicon oxide having hydrophobicity on the surface.
-As the hydrophobic particles, those having a hydrophilic group on the surface thereof may be used.

The aqueous solvent is not limited to water, and may be other non-organic aqueous solvents such as an aqueous solution of an inorganic salt.
The aqueous solvent may be a solvent obtained by adding a water-soluble organic solvent to water.

  -The aqueous solvent is not limited to a non-organic solvent, and if the shape of the shaped article 20 can be controlled, alcohols such as ethanol and n-propanol, polyhydric alcohols such as diethylene glycol and glycerin, pyrrolidone solvents, etc. You may make it use the solvent which has an organic solvent as a main component. In this case, as the hydrophobic particles constituting the shaped article 20, it is preferable to use those having low solubility in an organic solvent such as silicon oxide.

  DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 12 ... Sacrificial layer, 20 ... Modeling thing, 21a, 21b, 21c, 21d, 21e ... Slurry layer, 22a, 22b, 22c, 22d, 22e ... Binding part, 23a, 23b, 23c, 23d, 23e ... unattached part, 31 ... droplet discharge device, I ... UV ink, L ... ultraviolet light.

The present invention provides a layer forming step of forming a layer comprising a slurry containing granules, and the binder liquid is cured after infiltrating a part of the layer, and the binder liquid is cured via the binder liquid. Forming a binding portion in which the particles are bound to each other in the layer, and the layer including the binding portion by alternately repeating the layer forming step and the binding step. After forming a laminated body, a modeling method for modeling a shaped object in which the binding part is stacked by removing an unbound part of the layer using a solution , the kth layer (k is an integer of 1 or more) in a layer of, if the binder part in the (k + 1) th layer of the layers include non-binding moiety to be laminated, said k layer using a first slurry forming the non-binding part of the eye of the layers, the second slide solubility is higher than the first slurry for the solution Forming the binder portion of the first (k + 1) th layer of the layers using chromatography.

In the present invention, when the k-th layer includes an unbound portion in which the bound portions of the (k + 1) -th layer are stacked, the k-th layer is formed by the first slurry. The unbound portion is formed, and the bound portion of the (k + 1) -th layer is formed by the second slurry having higher solubility in the dissolving solution than the first slurry. According to such a configuration, after the unbound portion of the (k + 1) th layer is removed, the unbound portion of the kth layer is removed. Therefore, the unbound portion of the (k + 1) th layer is supported by the unbound portion of the kth layer while the unbound portion of the (k + 1) th layer is removed by the solution. . Therefore, the load necessary to remove the unbound portion of the (k + 1) th layer is distributed to the unbound portion of the kth layer, and the bound portion of the (k + 1) th layer is deformed. Can be suppressed.

Claims (5)

A layer forming step of forming a layer comprising a slurry containing granules;
A binding step in which the binding liquid is cured after infiltrating a part of the layer, and the binding part in which the particles are bound to each other through the binding liquid is divided into the layers. When,
Removing the unbound portion by supplying a solution to the layer including the bound portion,
The layer forming step and the binding step are alternately repeated to form a stacked body in which the layers including the binding portion are stacked, and then the removal step is performed on the stacked body to perform the binding. It is a modeling method for modeling a modeled object in which the wearing part is laminated,
The binding portion in the (k + 1) -th layer is projected from the binding portion in the k-th layer (k is an integer of 1 or more), and
Forming the k-th layer using a first slurry;
The modeling method, wherein the k + 1-th layer is formed using a second slurry having higher solubility in the solution than the first slurry. The slurry is
A hydrophobic particle, an aqueous solvent, and an amphiphilic polymer dissolved in the aqueous solvent,
The solution is
The modeling method according to claim 1, wherein the modeling method is the aqueous solvent. The amphiphilic polymer is polyvinyl alcohol;
The degree of polymerization of the polyvinyl alcohol is 600 or more and 1700 or less,
The modeling method according to claim 2, wherein a polymerization degree of polyvinyl alcohol contained in the first slurry is higher than a polymerization degree of polyvinyl alcohol contained in the second slurry. The amphiphilic polymer is polyvinyl alcohol;
The saponification degree of the polyvinyl alcohol is 86 or more and 96 or less,
The modeling method according to claim 2 or 3, wherein a saponification degree of polyvinyl alcohol contained in the first slurry is higher than a saponification degree of polyvinyl alcohol contained in the second slurry. The shaping | molding as described in any one of Claims 1-4 in which the said binding liquid is osmose | permeated in the said layer using the droplet discharge method which discharges the said binding liquid as a droplet at the said binding process. Method.

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