JP6657645B2 - Water-decomposable resin composition, molding support material, and molding - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a water-decomposable resin composition that can be molded by being melted under heat and decomposed by water.

  2. Description of the Related Art Conventionally, in the fields of medicine, architecture, manufacturing, and the like, three-dimensional modeling technology has been used in order to obtain products and parts having a desired shape. As an example, in the three-dimensional modeling technology of the hot melt lamination method (Fused deposition modeling, FDM), a resin composition called a model material is melted to form a layer of a predetermined shape, and this operation is repeated to laminate the model material By doing so, a desired three-dimensional shaped object is obtained. In this case, by shaping while supporting the model material with another resin composition called a support material, for example, a shape like a cup spread in the lamination direction or a torus-like shaped object like a handle You can also get

  In consideration of the moldability, the function of supporting the model material during molding, and the like, the support material is required to have heat fusibility and heat resistance. Further, in consideration of removing the support material from the molded article after the molding, the support material is also required to be easily removable. As a material having such properties, a water-soluble thermoplastic composition containing poly (2-ethyl-2-oxazoline) and an inert filler has been disclosed (see Patent Document 1). According to this document, the composition can be extruded at a high temperature and has solubility in water, so that it can be easily removed from a model material. However, the solubility of poly (2-ethyl-2-oxazoline) in water is not sufficient, and when used as a support material, the removal operation may require time and labor.

  By the way, a polyvinyl alcohol resin is used as a material for film forming that can be melt-formed and has high solubility in water. Patent Literature 2 discloses that a polyvinyl alcohol resin having a predetermined composition is molded to a thickness of 1 mm, and then immersed in water at 30 ° C., so that the molded product swells or almost dissolves to the extent that the original mold is not retained. It has been disclosed.

  In the case of molding a resin composition, molding into various shapes such as lump, not limited to a film shape, may be required. However, according to the conventional resin composition, for example, there is a problem that the ejection stability from the nozzle is low, and it is difficult to mold the resin into a desired shape, or it is difficult to remove the resin from the object after molding. .

  The water-decomposable resin composition of the invention according to claim 1 contains a polyvinyl alcohol resin and a water-absorbing resin, and the polyvinyl alcohol resin has a difference between a melting point and a temperature at the time of 10% mass reduction by heating. It is characterized by being at least 100 ° C.

  ADVANTAGE OF THE INVENTION According to this invention, in the resin composition containing a polyvinyl alcohol resin, there exists an effect that shaping | molding and the removal from the object after shaping | molding become easy.

FIG. 1 is a diagram illustrating an example of a model formed using a support material.

  Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments described below.

<< Overall configuration >>
First, the overall configuration of the water-decomposable resin composition according to the embodiment will be described.
The water-decomposable resin composition of one embodiment of the present invention contains a polyvinyl alcohol resin and a water-absorbing resin, and the difference between the melting point of the polyvinyl alcohol resin and the temperature at the time of 10% mass reduction by heating is reduced. 100 ° C. or higher.

According to one embodiment of the present invention, the above-mentioned water-decomposable resin composition can be used as a water-decomposable material after being formed into a desired shape, for example, as a molding support material (hereinafter, referred to as a support material). Each drawing in FIG. 1 is a diagram illustrating an example of a modeled object formed using a support material.
Conventional support materials used for three-dimensional modeling require a lot of time to remove the support material after the modeling is completed, and the molded object deforms, discolors, and even removes the support material There were many problems, such as taking time and destroying the molded object. Further, even during the molding, the support material is decomposed or solidified in the process of being discharged from the nozzle, and the nozzle is clogged, or even if it can be discharged, the desired shape cannot be formed, and the molding accuracy is reduced. There were issues such as. ADVANTAGE OF THE INVENTION According to this invention, in a resin composition containing a polyvinyl alcohol resin, ejection failure hardly occurs and modeling can be performed stably. Furthermore, when the molded article is immersed in water, the resin composition is quickly melted or decomposed, and the support material can be quickly and easily removed after the molding.
FIG. 1A is a top view of the model before the support material is removed. FIG. 1B is a schematic cross-sectional view schematically showing an AA cross section of the modeled object in FIG. 1A. FIG. 1C is a schematic cross-sectional view schematically showing an A-A cross section of the molded article immersed in water.

  The support material 10 is formed of a water-decomposable resin composition containing a polyvinyl alcohol resin having a difference between the melting point and the temperature at the time of 10% mass reduction by heating of 100 ° C. or more, and a water-absorbing resin. The water-absorbent resin has a water-absorbing ability, and when the support material 10 is immersed in the water W together with the modeled object 20, the water-absorbent resin changes into a gel. This change promotes the decomposition of the support material 10, so that even when the support material 10 has a thickness, it is easy to remove the support material 10 from the modeled object 20.

  The above-mentioned water-decomposable resin composition may further contain a foaming agent. The above-mentioned foaming agent is more preferably a foaming agent which generates a gas when in contact with water. When the support material 10 containing a foaming agent that generates a gas upon contact with water is immersed in the water W together with the modeled object 20, a gas is generated in the support material and a void is formed. Thereby, the decomposition of the support material 10 is promoted, so that even when the support material 10 has a thickness, the support material 10 can be easily removed from the modeled object 20.

  The resin composition may contain a filler together with or instead of the above-mentioned foaming agent. The filler is also effective because it promotes the destruction of the support material similarly to the above-mentioned void.

<< constituent materials >>
Then, each constituent material which comprises the said water-decomposable resin composition is demonstrated.

<Polyvinyl alcohol resin>
Since the water-decomposable resin composition of the present invention decomposes or disintegrates when immersed in water, the resin used as a constituent material has water solubility. As the resin, a polyvinyl alcohol resin is used. In the present embodiment, the polyvinyl alcohol resin includes, in addition to polyvinyl alcohol, a polymer containing vinyl alcohol as a structural unit, a saponified product thereof, and the like.

  The difference between the melting point of the polyvinyl alcohol resin in the present invention and the temperature when the mass is reduced by 10% by heating is 100 ° C. or more, and more preferably 140 ° C. or more. The melting point is a temperature at which the polyvinyl alcohol resin melts when heated and becomes liquid, and can be measured by various methods. In the present invention, the melting point can be measured using a differential scanning calorimeter (DSC) or a differential thermal analysis (DTA), but is more preferably measured using a DSC. A DSC is a device that measures a difference in the amount of heat between a reference substance and a sample while applying a constant amount of heat, and measures an endothermic reaction or an exothermic reaction due to a change in the state of the sample. The measurement is performed according to JIS K7121. At this time, the heating rate is 10 ° C./min, and the melting point is the temperature at the top of the melting peak.

  On the other hand, the temperature at which the mass is reduced by 10% by heating is the decomposition temperature of the polyvinyl alcohol resin, that is, the temperature at which the molecular chain is cut by heat and the mass is reduced by 10% due to the reduction in molecular weight, and is measured by various methods. Although it is possible to carry out the measurement, in the present invention, the measurement is preferably performed using thermogravimetric-differential thermal analysis (TG-DTA). TG-DTA is an apparatus for continuously measuring the mass change and the heat generation or heat absorption of a sample when the sample is heated. The measurement is performed according to JIS K0129. The measurement was performed in an atmosphere of an inert gas such as nitrogen. The temperature was raised at a rate of 10 ° C./min, and the temperature at which the mass was reduced by 10% was 10% by mass based on the mass of the polyvinyl alcohol resin at 100 ° C. in the TG curve. The temperature at which the decrease was observed.

  When the difference between the melting point and the temperature at the time of 10% mass reduction by heating is 100 ° C. or more, when forming a filament of the support material, and when producing a three-dimensional molded article using a three-dimensional molding device using the support material Further, it is possible to prevent the occurrence of nozzle clogging caused by the decomposition and solidification of the water-decomposable resin composition contained in the support material. In addition, since the influence of thermal decomposition is small, modeling can be performed at a temperature at which an appropriate melt viscosity can be obtained, so that nozzle clogging due to an increase in viscosity can be prevented. As a result, it is possible to provide a support material with few modeling errors and capable of quickly and easily removing the support material from the obtained modeled object.

  If the difference between the melting point of the polyvinyl alcohol resin and the temperature at which the mass is reduced by 10% by heating is less than 100 ° C., a part of the resin is decomposed at the time of molding or molding, and the resulting molded article has supportability. And the accuracy of the formed object may be reduced. In addition, since the margin of the melting temperature becomes low, nozzle clogging may occur, or the adhesiveness to the lower layer may decrease. As a result, modeling is not performed stably, and mistakes may occur frequently, or the accuracy of the obtained molded article or molded article may decrease, and the number of defects may increase.

  The upper limit of the difference between the melting point of the polyvinyl alcohol resin and the temperature at which the mass is reduced by 10% by heating is preferably as large as possible, but is generally about 200 ° C. due to the characteristics of the resin.

  In the present invention, among the above polyvinyl alcohol resins, a polyvinyl alcohol resin having a 1,2-glycol bond in a side chain is preferably used. Specifically, it is a polyvinyl alcohol resin having a 1,2-diol structure having a 1,2-glycol constituent unit represented by the following general formula (1). Examples of these polyvinyl alcohol resins include a G polymer series sold by Nippon Synthetic Chemical Industry Co., Ltd., which can be effectively used in the present invention.

一般式（１）において、Ｒ^１、Ｒ^２、Ｒ^３はそれぞれ独立して水素又はアルキル基である。該アルキル基としては特に限定されないが、例えばメチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｔｅｒｔ−ブチル基等の炭素数１乃至４のアルキル基が好ましい。かかるアルキル基は必要に応じて、ハロゲン基、水酸基、エステル基、カルボン酸基、スルホン酸基等の置換基を有していてもよい。

In the general formula (1), R ¹ , R ² , and R ³ are each independently hydrogen or an alkyl group. The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group and a tert-butyl group. Such an alkyl group may have a substituent such as a halogen group, a hydroxyl group, an ester group, a carboxylic acid group, and a sulfonic acid group, if necessary.

  Further, the polyvinyl alcohol resin may have a structural unit based on another copolymer component in addition to the above structural units. Examples of the structural unit based on the other copolymer component include structural units derived from α-olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene. The content of the α-olefin in the polyvinyl alcohol resin is preferably from 0.1 to 10 mol%, particularly preferably from 2 to 8 mol%.

  Further, the polyvinyl alcohol resin may have a structural unit based on another unsaturated monomer. Examples of such unsaturated monomers include, for example, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, and itaconic acid, and salts or mono- or dialkyl esters thereof, acrylonitrile, methacrylonitrile, and the like. Nitriles, amides such as diacetone acrylamide, acrylamide, methacrylamide, olefinsulfonic acids such as ethylenesulfonic acid, allylsulfonic acid, and methallylsulfonic acid or salts thereof, alkyl vinyl ethers, dimethylallyl vinyl ketone, and N-vinylpyrrolidone , Vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxyalkylene (meth) allyl ether such as polyoxypropylene (meth) allyl ether, polyoxyethylene (meth) Polyoxyalkylene (meth) acrylamide such as polyoxypropylene (meth) acrylamide, polyoxyethylene (meth) acrylamide, polyoxypropylene (meth) acrylamide, polyoxyethylene (1-) (Meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine and the like.

  Other examples of the unsaturated monomer include N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidopropyltrimethylammonium chloride, 2-acryloxyethyltrimethylammonium chloride, and 2-methacryloxyethyl. A cationic group-containing monomer such as trimethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, 3-butenetrimethylammonium chloride, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, etc. Monomer and acetoacetyl group-containing monomer. That.

  Examples of the metal salt used for saponification include alkali metal salts and alkaline earth metal salts. Suitable alkali metal salts from the viewpoint of improving melt moldability include organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, and behenic acid, and sulfuric acid, sulfurous acid, carbonic acid, and phosphoric acid. Potassium salts of inorganic acids, or sodium salts, and the alkaline earth metal salts, organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, behenic acid, sulfuric acid, sulfurous acid, Examples thereof include calcium salts and magnesium salts of inorganic acids such as carbonic acid and phosphoric acid.

  In order to obtain a heat-fusible resin composition, the polyvinyl alcohol resin used as a constituent material preferably has heat-fusibility. Examples of the heat-meltable polyvinyl alcohol resin include a thermoplastic polyvinyl alcohol resin and a thermosetting polyvinyl alcohol resin. In order to obtain solubility in water, a thermoplastic polyvinyl alcohol resin is preferably used. The melting start temperature of the polyvinyl alcohol resin can be appropriately selected according to the purpose of use, and for example, is preferably equal to or lower than the melting start temperature of the model material used in combination. The melting start temperature of the polyvinyl alcohol resin is preferably from 180 ° C to 250 ° C, more preferably from 190 ° C to 230 ° C. If the melting start temperature is higher than 250 ° C., the polyvinyl alcohol resin may decompose during molding. If the melting start temperature is lower than 180 ° C., molding failure may occur. The melting start temperature can be measured by a flow measurement and evaluation device.

  The polyvinyl alcohol resin used in the present invention contains the structural unit represented by the general formula (1) in an amount of usually 1 mol% to 15 mol%, preferably 2 mol% to 10 mol%, more preferably 3 mol% or more. Contains up to 9 mol%. If the molar fraction of the structural unit represented by the general formula (1) is excessively high, it tends to be difficult to obtain a polyvinyl alcohol resin having a desired degree of polymerization. On the other hand, if the molar fraction is too low, the melting point will be high and the temperature will be close to the thermal decomposition temperature, so that charring, gel, and fish eyes due to thermal decomposition during melt molding tend to be easily formed.

The average degree of polymerization of the polyvinyl alcohol resin (measured in accordance with JIS K6726) is usually 200 or more and 1800 or less, particularly preferably 300 or more and 1500 or less, and more preferably 300 or more and 1000 or less. If the average degree of polymerization is too high, the melt viscosity tends to be high, and the moldability or moldability tends to decrease. On the other hand, if the average degree of polymerization is too low, the mechanical strength of the shaped article or molded article tends to be insufficient.
The degree of saponification of the polyvinyl alcohol resin (measured in accordance with JIS K 6726) is not particularly limited and is appropriately selected depending on the purpose of use, solubility, moisture resistance, and the like. A partially saponified type of 90 mol% or less is more preferable than a saponified type. In the case of the completely saponified type, the molding stability and the efficiency of removing the support material may be reduced due to poor discharge or reduced water solubility due to nozzle clogging.

<Water absorbent resin>
In the present embodiment, the water-absorbent resin is a polymer material having a function of absorbing and retaining water. In the present embodiment, as the water-absorbing resin, for example, a `` highly water-absorbing resin '' defined in JIS K7223, that is, a hydrophilic substance having a cross-linked structure, absorbs water by contact with water, and once absorbed, the pressure increases. It is possible to suitably use a material having a characteristic that it is difficult to separate water even if it is applied.

  Examples of such water-absorbent resins include synthetic polymers and water-absorbent resins derived from natural products. Examples of the synthetic polymer include compounds having at least one structural unit selected from acrylic acid, sulfonic acid, maleic anhydride, acrylamide, vinyl alcohol, and ethylene oxide. Examples of the water-absorbent resin derived from a natural product include compounds having at least one structural unit selected from aspartic acid, glutamic acid, alginic acid, glucose (starch), and cellulose.

  Examples of the water-absorbent resin having the above structural unit include a polymer containing one of the above structural units as a monomer, a copolymer containing a plurality of the above structural units as a monomer, and the above structural unit and other structural units. A copolymer containing a monomer, a polymer containing a derivative of the above structural unit as a monomer, a neutralized salt thereof, a crosslinked product thereof, and the like are included.

  Among them, polyacrylates are preferable in view of affinity with water. The polyacrylate is not particularly limited, but sodium polyacrylate is preferred.

  The water absorption rate of the water-absorbent resin is preferably 40 seconds or less, more preferably 20 seconds or less, and preferably 2 seconds or less, when measured according to the water absorption rate test method for the highly water-absorbent resin described in JIS K7224. It is more preferred that: If the water absorption rate is greater than 40 seconds, the decomposition time of the resin composition may be prolonged when the resin composition is immersed in water.

  The shape of the water-absorbing resin is not particularly limited, but is preferably granular to facilitate dispersion in the polyvinyl alcohol resin. The average particle size of the water-absorbing resin is not particularly limited, but is preferably 25 μm or more and 370 μm or less, and more preferably 70 μm or more and 350 μm or less. When the average particle size is less than 25 μm, there is a case where the increase in water absorption speed is not affected, and when the average particle size exceeds 370 μm, discharge failure may occur during molding. In the present embodiment, the average particle size is obtained by a dynamic light scattering type particle size distribution measuring device.

  The addition amount of the water-absorbing resin is not particularly limited, but is 0.1% by mass or more and 40% by mass or less, preferably 5% by mass or more and 10% by mass or less of the resin composition. If the amount of the water-absorbing resin is less than 0.1% by mass, it may not affect the promotion of the water absorption rate. If the amount exceeds 40% by mass, kneading with the resin may be difficult. .

<Blowing agent>
The foaming agent used in the water-decomposable resin composition of the present invention is not particularly limited, and is a material that foams to generate a gas, and in particular, a foaming agent that foams to generate a gas when in contact with water. . Examples of the foaming agent include a hydrocarbon, an inorganic chemical foaming agent, an organic chemical foaming agent, and expandable microcapsules.

  As the hydrocarbon, one kind of a hydrocarbon such as propane, normal butane, isobutane, cyclobutane, normal pentane, isopentane, cyclopentane, normal hexane, isohexane, cyclohexane, normal heptane, isoheptane, cycloheptane, or two or more kinds may be used. Can be employed in combination, and among them, it is preferable to employ a mixed butane of normal butane and isobutane.

  Examples of the inorganic chemical blowing agent include ammonium carbonate, sodium bicarbonate (baking soda), and anhydrous sodium nitrate. Examples of the organic chemical blowing agent include dinitrosopentamethylenetetramine, N, N′-dimethyl-N, N′-dinitrosoterephthalamide, benzenesulfonylhydrazide, p, p′-oxybis (benzenesulfonylhydrazide), azo Dicarbamide and the like.

  The expandable microcapsules contain a foaming agent (expanding agent) and use a thermoplastic resin as an outer shell component. As the thermoplastic resin constituting the outer shell component of the expandable microcapsule, a homopolymer containing (meth) acrylonitrile, (meth) acrylate, vinyl halide, vinylidene halide, styrene-based monomer, vinyl acetate, or the like as a constituent component or Various thermoplastic resins including copolymers are used. This thermoplastic resin may be cross-linked or cross-linkable with a cross-linking agent such as divinylbenzene or ethylene glycol di (meth) acrylate.

  Among the above foaming agents, sodium bicarbonate (baking soda) is more preferably used because it foams in contact with hot water or an acidic aqueous solution.

  The amount of the foaming agent is not particularly limited, but is 0.1% by mass or more and 40% by mass or less, preferably 5% by mass or more and 10% by mass or less of the resin composition. If the amount of the foaming agent is less than 0.1% by mass, the water absorption rate may not be increased. If the amount exceeds 40% by mass, kneading with the resin may be difficult. .

<Filler>
The filler used in the resin composition is not particularly limited as long as it promotes the decomposition of the support material when the resin composition is used as a support material, and is, for example, compatible with the above resin composition. Fillers that do not.

  Such fillers include dimethylpolysiloxane (PDMS), talc, clay, montmorillonite, calcium carbonate, glass beads, glass fibers, silica, mica, alumina, hydrotalcite, titanium oxide, zirconium oxide, boron nitride, nitrided Examples include inorganic fillers such as aluminum and organic fillers such as melamine-formalin resin. Of these, dimethylpolysiloxane is suitable as a filler for reasons of resin modification. When hot water is not used for decomposing the support material, baking soda described above as a foaming agent can be used as a filler.

  The amount of the filler added is not particularly limited, but is 0.1% by mass or more and 40% by mass or less, preferably 5% by mass or more and 10% by mass or less of the resin composition. If the amount of the filler is less than 0.1% by mass, the water absorption rate may not be increased. If the amount exceeds 40% by mass, kneading with the resin may be difficult. .

<Other constituent materials>
The resin composition may contain other constituent materials according to the purpose. Other constituent materials include, for example, a group consisting of calcium carbonate, wollastonite, mica, feldspar, and glass.

<< Resin composition >>
The resin composition is obtained by melting and mixing each of the above constituent materials. As a method of melt-mixing each constituent material, a known method is used and is not particularly limited, but a twin-screw extruder, a single-screw extruder, a method of continuously melting and mixing each constituent material with a melt molding machine, or , A kneader, a mixer, or the like, and a method of melt-mixing each batch.

The physical properties of the resin composition can be adjusted according to the types and amounts of the respective constituent materials described above. The melting start temperature of the resin composition may be lower than an assumed molding temperature. For example, when an ABS (Acrylonitrile Butadiene Styrene) resin is used as a model material, it can be appropriately selected according to the amount of addition, but is preferably used. The temperature is from 180 ° C to 230 ° C, more preferably from 190 ° C to 220 ° C. Even when the melting start temperature is lower than 180 ° C. or higher than 230 ° C., it may be difficult to form a support material using the resin composition.
The melt viscosity of the resin composition is preferably 400 Pa · s or more and 2300 Pa · s or less at an assumed molding temperature, for example, 190 to 210 ° C. Even when the melt viscosity is less than 400 Pa · s or exceeds 2300 Pa · s, it may be difficult to mold a support material using the resin composition.
The melt viscosity and the melting start temperature of the support material are greatly affected by the highest viscosity polyvinyl alcohol resin among the constituent materials of the support material. On the other hand, the influence of the water-absorbing resin, the foaming agent, the filler, or other constituent materials on the melt viscosity and the melting start temperature of the support material is small.

  The thermal decomposition temperature of the resin composition is not particularly limited, but is preferably 250 ° C. or higher, more preferably 300 ° C. or higher. If the thermal decomposition temperature is lower than 250 ° C., the resin may be decomposed during molding and colored.

  The use of the above resin composition is not particularly limited, but it can be molded by being melted by heat, has sufficient rigidity, and can be decomposed or dissolved by water. Support materials for modeling are exemplified.

<< Support materials and objects >>
The method of forming a support material for three-dimensional printing using the resin composition is not particularly limited, and examples thereof include a method using a known hot-melt lamination (FDM) type three-dimensional printing machine. In this case, for example, by using a 3D printer as a three-dimensional printing machine, the resin composition is melted and discharged while scanning, thereby forming a layer of the resin composition having a predetermined shape, and repeating this operation to form a layer. Method.

Further, a modeling material (hereinafter, referred to as a model material) made of another resin composition is discharged by a three-dimensional molding machine onto a support material formed of the resin composition, and the model material having a predetermined shape is discharged. By forming this layer and repeating this operation to laminate, a modeled object can be obtained. That is, the modeled object formed by the model material has a shape corresponding to at least a part of the shape of the support material (see FIG. 1B).
By immersing the modeled object together with the support material in water, the support material is melted or decomposed and easily removed from the modeled product, so that a modeled product with less damage and less residual support material can be obtained.

  Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

The raw materials described in Table 1 were melt-mixed by a polymer extrusion molding apparatus, and further molded into strands to obtain strand-like resin compositions of Examples 1 to 46 and Comparative Examples 1 to 21.
Polymer extrusion molding equipment: HAAKE Mini Lab II manufactured by Thermo SCIENTIFIC
Screw rotation speed: 70n / min
Mixing temperature: 195 ° C
Mixing time: 3 minutes

Details of each material described in Table 1 are shown below.
・ PVA
8150P: N-Synthetic Chemical Company G-polymer OKS-8150P, water-soluble and heat-meltable vinyl alcohol-based copolymer 8095P: Nippon Synthetic Chemical Company G-polymer OKS-8095P, water-soluble and heat-meltable vinyl alcohol -Based copolymer 8164P: G-Polymer OKS-8164P manufactured by Nippon Synthetic Chemical Co., Ltd., vinyl alcohol-based copolymer 8163P having water-soluble and heat-meltable properties: G-polymer OKS-8163P manufactured by Nippon Synthetic Chemical Company, water-soluble and heat-meltable Vinyl alcohol-based copolymer 8153P having a polymer: G-polymer OKS-8153P manufactured by Nippon Synthetic Chemical Co., Ltd., vinyl alcohol-based copolymer having water-solubility and heat-melting property 8049: G-polymer OKS-8049 manufactured by Nippon Synthetic Chemical Co., water-soluble And a vinyl alcohol-based copolymer having heat melting property 8089: G-Polymer OKS-8089 manufactured by Gosei Kagaku Co., Ltd., a vinyl alcohol copolymer 1210 having water solubility and heat melting property: CP-1210 manufactured by Kuraray Co., Ltd .; polyvinyl alcohol resin 1220 having water solubility and heat melting property: 1220 manufactured by Kuraray Co., Ltd. CP-1220, a polyvinyl alcohol resin having water solubility and heat melting property JR05: JR-05, manufactured by Nippon Vinegar Co., Ltd., unmodified polyvinyl alcohol resin, partially saponified JL05: JL-05E, manufactured by Nippon Vinegar Bipovar, unmodified polyvinyl alcohol Resin, partially saponified JP05: JP-05S manufactured by Japan Vinegar Co., Ltd., unmodified polyvinyl alcohol resin, partially saponified JF05: JF-05S manufactured by Japan Vinegar Bipovar, non-modified polyvinyl alcohol resin, completely saponified 205: manufactured by Kuraray Co., Ltd. PVA205, unmodified polyvinyl alcohol Resin, partially saponified 105: PVA 105 manufactured by Kuraray Co., Ltd., unmodified polyvinyl alcohol resin, fully saponified GL05: GL-05S manufactured by Nippon Synthetic Chemical Company, unmodified polyvinyl alcohol resin, partially saponified Z100: Gosenex Z100 manufactured by Nippon Synthetic Chemical Company , Unmodified polyvinyl alcohol resin, completely saponified and water-absorbent resin PF: water-absorbent resin manufactured by Sumitomo Seika Co., Ltd., product name: 10SH-NF, median particle size: 25 μm
NF: Sumitomo Seika Co., Ltd. water absorbent resin, product name 10SH-PF, median particle size 160 μm
SA60S: Water-absorbent resin manufactured by Sumitomo Seika Co., Ltd., product name SA60S, median particle size 350 μm
-Foaming agent AD101: foaming agent manufactured by Sekisui Chemical Co., Ltd., product name Advancel EML101, expansion start temperature 120 to 130 ° C
AD501: Sekisui Chemical company foaming agent, product name Advancel EM501, expansion start temperature 210-230 ° C
-Filler PDMS: Nippon Soda's polysilane baking soda: Sodium bicarbonate

<Formation of support material>
The strand-shaped resin composition of each of the above Examples and Comparative Examples was ejected while being scanned by a three-dimensional molding machine to form a diameter of 1.75 mm, which was used for Examples 1 to 31 and Comparative Examples 1 to 16. Obtained support material. The molding conditions are as follows.
3D modeling machine: Replicator 2X manufactured by MakerBot Industries
Molding temperature: 190-210 ° C

<Degradation evaluation for water>
Each of the formed support materials was immersed in water at room temperature (23 ° C.). After each lapse of the time shown in Table 1 after the immersion, the degree of progress of decomposition of each support material was determined based on comparison with a standard sample. In addition, among the results in the table, E indicates that there is no decomposition, and A indicates that there is complete decomposition. B and C were not completely dissolved but were soft and could be disintegrated by touching, but D and E did not disintegrate even if touched by hand. Note that B has a higher degradability than C, and D has a higher degradability than E. Further, "-" in Table 1 indicates that evaluation was not performed.

<Evaluation of dischargeability from nozzle>
The formed support material was set again on the three-dimensional printing machine, and discharged from the nozzle while scanning, to produce a three-dimensional printing object. At this time, it was evaluated whether the support material could be stably discharged from the nozzle. The molding conditions are as follows.
3D modeling machine: Replicator 2X manufactured by MakerBot Industries
Molding temperature: 210 ° C
The evaluation criteria were as follows.
：: No ejection failure was observed, and ejection was stable.
：: Partial ejection failure occurred.
Δ: ejection failure occurred frequently.
×: No ejection was possible.

<DSC>
The melting point of the polyvinyl alcohol resin was measured using DSC under the following conditions. The melting point was determined from the peak of the endothermic peak. Table 2 shows the results.
Apparatus: DSC-60A manufactured by Shimadzu Corporation
Heating rate: 10 ° C / min
Measurement temperature range: 40 ° C to 400 ° C

<TG-DTA>
For the above polyvinyl alcohol resin, a 10% mass reduction temperature was measured using TG-DTA under the following conditions. As the 10% mass loss temperature, the temperature at which 10% mass loss was observed with respect to the mass at 100 ° C. of the obtained TG curve was determined. Table 2 shows the results.
Apparatus: DTG-60 manufactured by Shimadzu Corporation
Heating rate: 10 ° C / min
Measurement temperature range: 40 ° C to 500 ° C

(Example 2-1 and Comparative example 2-1)
A support material was produced in the same manner as in Example 1, except that the constituent materials were changed to those shown in Table 3. Degradability to water was evaluated in the same manner as in Example 1 except that each of the produced support materials was immersed in a citric acid aqueous solution (concentration: 10%) at room temperature (23 ° C.). Table 3 shows the evaluation results. In addition, since baking soda foams in contact with an acidic aqueous solution, it is described as a foaming agent in Table 3.

(Example 3-1 and Comparative example 3-1)
A support material was produced in the same manner as in Example 1, except that the constituent materials were changed to those shown in Table 4. Degradability to water was evaluated in the same manner as in Example 1 except that each of the produced support materials was immersed in hot water (temperature: 100 ° C.). Table 4 shows the evaluation results. In addition, since baking soda foams in contact with hot water, it is described as a blowing agent in Table 4.

(Comparative Examples 4-1 and 4-2)
A support material was produced in the same manner as in Example 1, except that the constituent materials were changed to those shown in Table 5. Each of the produced support materials was evaluated for water decomposability in the same manner as in Example 1. Table 5 shows the evaluation results. The PLA in Table 5 is manufactured by Nature Works (4032D).

10 Support material 20 Modeling object W Water

JP 2002-516346 A JP 2004-75866 A

Claims (8)

A water-decomposable resin containing a polyvinyl alcohol resin and a water-absorbent resin defined by JIS K7223 , wherein the difference between the melting point and the temperature at the time of 10% mass reduction by heating is 100 ° C. or more. A modeling support material formed of the composition.   The molding support material according to claim 1, wherein the difference between the melting point of the polyvinyl alcohol resin and the temperature when the mass is reduced by 10% by heating is 140 ° C or more. The molding support material according to claim 1, wherein the polyvinyl alcohol resin has a 1,2-diol structure represented by the following general formula (1). 4.

In the general formula (1), R ¹ , R ² , and R ³ are each independently hydrogen or an alkyl group. The molding support material according to any one of claims 1 to 3, wherein the water-absorbent resin has an average particle size of 25 µm or more and 370 µm or less. The molding support material according to any one of claims 1 to 4, further comprising a foaming agent. The molding support material according to claim 5, wherein the foaming agent is a foaming agent that generates a gas when in contact with water. The molding support material according to any one of claims 1 to 6, further comprising a filler. It is a manufacturing method of a model using the modeling support material according to any one of claims 1 to 7,
A method for manufacturing a molded article, wherein the molded article is formed using a modeling model material so as to have a shape corresponding to the shape of the modeling support material.

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