JP2020175510A - Molding material with diatom earth and manufacturing method of diatom earth products - Google Patents

Abstract

To provide molding material with diatom earth which, with diatom earth being the main component and being a molding material with diatom earth for 3D printers, can be used for molding freely, and a manufacturing method of diatom earth products.SOLUTION: Its mixing ratio is such that diatom earth, aggregates, resin adhesive, and fluidity improver are contained in descending order of content, and for 31-43 vol% of diatom earth, the aggregates are adjusted at 24-36 vol%, the resin adhesive at 24-32 vol%, and the fluidity improver at 4-9 vol%.SELECTED DRAWING: Figure 2

Description

The present invention relates to a molding material containing diatomaceous earth and a method for producing a diatomaceous earth product using a mixed powder containing diatomaceous earth as a main raw material.

Diatomaceous earth, which is a deposit (sedimentary rock) composed of fossil shells of diatom, which is a type of algae, is used as a raw material for various products by taking advantage of its characteristics of heat resistance, heat insulation, water absorption, and moisture absorption and desorption. There is.
For example, pizza kilns that utilize the heat resistance and heat insulation of stoves and shichirin, bath mats that apply plastering technology, and diatomaceous earth block series that utilize cut-out diatomaceous earth have been developed. However, on the other hand, in the conventional techniques such as cutout molding, press molding, and silicon mold molding, it is generally considered difficult to develop a product having a free and complicated design using diatomaceous earth.

Patent Document 1 provides "(problem) a modeling material in a powder-fixed lamination method capable of pouring a refractory metal having a melting point of more than 1000 ° C., and a functional agent (solution) 70% by weight. A molding material in a powder-fixed lamination method in which the above-mentioned casting sand and cement or a heat-resistant resin, which is a powdery precursor of a binder that binds the casting sand to each other, is mixed is produced. Then, together with this kind of modeling material, a functional agent that transforms the powdery precursor into a binder is used. "

Patent Document 2 describes "(Claim 1) a mixed powder for forming a three-dimensional cast product containing hemihydrate gypsum, an inorganic powder, a water-soluble polymer, and a gypsum hardening accelerator, and the semi-water For casting, the gypsum is 18 to 75% by weight, the inorganic powder is 13 to 70% by weight, the water-soluble polymer is 1 to 10% by weight, and the gypsum hardening accelerator is 5 to 30% by weight. Mixed powder for forming a three-dimensional molded product. (Claim 2) The inorganic powder is a metal oxide containing at least one of silica, alumina, gypsum, gypsum, and magnesia, an inorganic nitride, an inorganic carbide, and phosphorus. A mixed powder for forming a three-dimensional cast product according to claim 1, which comprises at least one of the acid salts. (Claim 3) The gypsum hardening accelerator is dihydrate gypsum or an alkali metal. It is characterized by being composed of one or more selected from gypsum, alkaline earth metal gypsum, alkali metal chloride salt, alkaline earth metal chloride salt, ammonium salt of inorganic acid, and gypsum. The mixed powder for forming the three-dimensional molded product for casting according to claim 1 or 2.

Patent Document 3 states that "(Claim 1) contains a binder containing diatomaceous earth as a main component and mixed therein, and is formed and fired into a predetermined shape to form a large number of fine pores possessed by the diatomaceous earth as a whole. A diatomaceous earth fired product characterized by being provided. (Claim 2) A diatomaceous earth fired product is characterized in that diatomaceous earth clay, anhydrous silicic acid, an appropriate amount of water, or a flow pattern type natural glass powder is added to them as a binder. The diatomaceous earth fired product according to claim 1. (Claim 3) The diatomaceous earth fired product according to claim 1 or 2, wherein the fired product is glazed. (Claim 4) Binder and water on diatomaceous earth. Diatomaceous earth, which is characterized by mixing and kneading, forming this kneaded product into a predetermined shape, laying a cloth for adjusting the shrinkage balance of the modeled product on the bottom, drying it, and then firing it to obtain a product. A method for producing a baked product. ”Is disclosed.

Japanese Patent No. 4722988 Japanese Unexamined Patent Publication No. 2015-100999 Japanese Patent No. 2927415

In recent years, various shaped objects have been produced by 3D printers, and the types include a powder sintering method and an inkjet powder lamination method, and the latter uses a molding material mainly made of gypsum. There is.
Therefore, if diatomaceous earth can be mixed with powdered modeling material such as gypsum, the development of unprecedented free and complicated shapes can be expected. However, diatomaceous earth has high water absorption and has a problem in stickability in 3D printers of the inkjet powder lamination method. Therefore, even if diatomaceous earth is simply added to a gypsum-based material, the moisture absorption and desorption properties and water absorption of diatomaceous earth can be utilized freely. It is not possible to manufacture diatomaceous earth products with complicated shapes.

Here, Patent Document 3 solidifies diatomaceous earth with a cement material, but the cement material is preferable because it requires the use of a large amount of water and may block porous pores. Absent. According to the research by the inventors of the present application, the cement material requires more water to solidify than the industrial gypsum material. Therefore, when diatomaceous earth having high water absorption is used as the material, the cement material is fixed by the inkjet powder lamination method. It is not preferable because it has a problem in sex.
Patent Documents 1 and 2 are materials for modeling in a powder-fixing laminating method in which a refractory metal having a melting point exceeding 1000 ° C. can be poured, but diatomaceous earth is porous when fired at about 800 to 1000 ° C. It is known that the moisture absorption / desorption property, which is a feature of the above, is lost, which is not preferable.

Therefore, an object of the present invention is to provide a modeling material containing diatomaceous earth as a main component in a modeling material such as a 3D printer and capable of freely modeling, and a method for producing a diatomaceous earth product.

In order to solve the above problems, the modeling material containing diatomaceous earth of the present invention has a mixing ratio of diatomaceous earth, aggregate, resin adhesive, and fluidity improving agent in the order of these, and 31 to 43 vol%. It is characterized in that the ratio of the aggregate, the resin adhesive, and the fluidity improving agent is adjusted with respect to the diatomaceous earth of the above. By setting the blending ratio of diatomaceous earth to 31 to 43 vol%, the blending ratio is the largest among the modeling materials containing diatomaceous earth of the present invention, and the features of porous diatomaceous earth (moisture absorption / desorption, heat insulation, water absorption, etc.) Can be utilized.
According to the present invention, even if diatomaceous earth having high water absorption, which has a problem in stickability in a 3D printer, is used as a main raw material, it has the characteristics of porous diatomaceous earth by adjusting the ratio of a resin adhesive or the like to diatomaceous earth. You will be able to manufacture shaped objects.
Here, it is preferable to adjust the resin adhesive or the like at a ratio of 24 to 32 vol% with respect to 31 to 43 vol% or less of diatomaceous earth. According to the experiments of the inventors of the present application, when the amount of calcined diatomaceous earth is more than 43 vol%, the adhesiveness cannot be sufficiently ensured. However, by adjusting the resin adhesive or the like to 24 vol% or more, it was possible to secure the adhesiveness to the powder, and to produce a diatomaceous earth product having sufficient moisture absorption / desorption and water absorption. When the amount of the resin adhesive is more than 32 vol%, the compounding ratio is larger than that of calcined diatomaceous earth, which affects the characteristics of the porous diatomaceous earth, and the compounding ratio is larger than that of the aggregate, and the viscosity when the ink is applied increases ( It may become sticky) and affect the stackability of the powder.

Further, the present invention is a molding material containing diatomaceous earth, which is a mixture of diatomaceous earth, aggregate, resin adhesive, and fluidity improving agent, and the proportion of diatomaceous earth is larger than that of aggregate. It is a diatomaceous earth product characterized by containing 8.5 to 18.5 mass% urethane in the diatomaceous earth product after being produced by an inkjet powder laminating method using a material for molding.
According to the present invention, even if diatomaceous earth is used as a main raw material (even if the proportion of diatomaceous earth is larger than that of aggregate), a model having the characteristics of porous diatomaceous earth (moisture absorption / desorption, heat insulation, water absorption, etc.) is produced. become able to. As a result of conducting a modeling test with a plaster 3D printer, modeling was possible without any problem, and the modeled object could be taken out from the powder after modeling without damage. It also has the effect of preventing powder from adhering to the hands.

The present invention is characterized in that the produced diatomaceous earth product contains 8.5 to 18.5 mass% urethane. Urethane can be brushed and immersed in the modeled object.
According to the present invention, when immersed in urethane, the amount of moisture absorbed and released was maintained at the same level as that of cut-out diatomaceous earth, and the bending strength could be significantly improved to about 3 times. These diatomaceous earth products have excellent moisture absorption and desorption properties, and can be manufactured with practical bending strength. Moreover, even if it was immersed in water, it did not collapse.

In the present invention, the diatomaceous earth is a powder of calcined diatomaceous earth, the aggregate is a powder of a gypsum-based material, the fluidity improving agent is fumed silica (FS), and the resin adhesive is polyvinyl alcohol (). It is characterized by being PVA) or polyvinylpyrrolidone (PVP). The blending ratios obtained in the modeling test with good stackability and stickiness were 38 vol% for calcined diatomaceous earth, 29 vol% for gypsum material, 9 vol% for FS, which is a fluidity improver, and 24 vol% for PVP or PVA. It became.

As the diatomaceous earth, calcined diatomaceous earth produced in Noto was used. Calcined diatomaceous earth is a powder discharged when producing diatomaceous earth brick used as a heat insulating material for various industrial furnaces. In a specific step, diatomaceous earth is extruded, fired at 600 to 800 ° C., and then discharged when it is carved into a standard brick. In general, diatomaceous earth is rarely used as a product as it is, and in most cases, it is used after firing at a predetermined temperature from the viewpoint of hygiene.

As the aggregate, hemihydrate gypsum, dihydrate gypsum, anhydrous gypsum (soluble anhydrous gypsum), and a mixture thereof can be used. Semi-hydrated gypsum is a white powder obtained by heating gypsum and dehydrating it, and has the property of generating heat, expanding and hardening when water is added. Moreover, silica (silicic anhydride) or the like can also be used as an aggregate. The blending ratio of the aggregate is preferably 24-36 vol%. When the aggregate content is more than 36 vol%, the blending ratio is larger than that of calcined diatomaceous earth, which may affect the characteristics of porous diatomaceous earth (moisture absorption / desorption, heat insulation, water absorption, etc.). Further, when the aggregate content is less than 24 vol%, the blending ratio of the resin adhesive increases, and the viscosity when the ink is applied increases (stickiness), which may affect the stackability.

As the resin adhesive, an adhesive made of a water-soluble polymer material such as PVA and PVP was used. The upper limit of the median diameter of these PVA and PVP is preferably 100 ± 10 μm or less. By using PVA and PVP of 100 ± 10 μm or less, it became easy to dissolve in ink and the adhesiveness of diatomaceous earth was improved. Further, the resin adhesive may be pulverized and used. The median diameter after pulverization is preferably 20 ± 10 μm or more. If it is less than that, the hygroscopic effect of the resin adhesive becomes large and it becomes difficult to handle it in the state of dry powder. Therefore, the median diameter of the resin adhesive is preferably 20 ± 10 to 100 ± 10 μm.

As the fluidity improving agent, FS having an average particle size of primary particles of 50 nm or less is preferable to magnesium stearate and calcium stearate. Some FSs are hydrophilic or hydrophobic, but either one may be used.
Here, the diatomaceous earth is a powder of calcined diatomaceous earth, the aggregate is a powder of a gypsum-based material, the fluidity improver is fumed silica (FS), and the fluidity index of Carr is the calcined FS. It is characterized by having a fluidity index higher than that of the diatomaceous earth powder and the powder of the gypsum-based material. When the amount of FS added is increased, the fluidity index becomes high and the jettability index becomes high, which makes it easy to scatter. Therefore, 4 to 9 vol% is preferable. As for the fluidity of FS, the fluidity index is higher than that of the powder of calcined diatomaceous earth or the powder of gypsum-based material, so that the amount of FS added is reduced and the fluidity index of diatomaceous earth is set to 3D plaster. It can have a liquidity index similar to that of powder. It is preferable that the fluidity index of the powder of calcined diatomaceous soil and the fluidity index of the powder of the gypsum-based material are about the same, or the fluidity index of the gypsum-based material is higher.

Then, a diatomaceous earth product was manufactured by an inkjet powder lamination method. As diatomaceous earth products, we manufacture perfect circular and elliptical prototypes (A-1 and A-2 in Fig. 2), and those with a pin shape of 5 mm or more and those with a hole diameter of 2 mm or more (Fig. 2). B-1, B-2), manufactured by changing the size of the diameter. Products with a pin shape of 5 mm or more and products with a hole diameter of 2 mm or more are test products of how much the diameter can be reduced by changing the size of the diameter.
According to the present invention, as a result of performing a modeling test with a gypsum 3D printer, all of the above products could be modeled without any problem, and after modeling, the modeled object could be taken out from the powder without damage. These diatomaceous earth products (A-1, A-2, B-1, B-2) have excellent moisture absorption and desorption properties and water absorption, and can be manufactured with practical bending strength. Moreover, even if it was immersed in water, it did not collapse.

According to the modeling material containing diatomaceous earth of the present invention, even if diatomaceous earth is contained in a larger amount than the aggregate such as gypsum-based material, the characteristics of the porous diatomaceous earth are utilized, such as moisture absorption / desorption, heat insulation, and water absorption. It will be possible to manufacture shaped objects with features.
Further, according to the method for producing a diatomaceous earth product of the present invention, when urethane is contained in the diatomaceous earth product produced by the above-mentioned diatomaceous earth-containing molding material, the amount of moisture absorbed and released is maintained at the same level as that of the cut diatomaceous earth. Therefore, the bending strength can be significantly improved to about 3 times.

It is a figure explaining the modeling method of the gypsum 3D printer and the problem in material development. It is a figure which shows the manufacturing process of the diatomaceous earth product which is 1st Embodiment of this invention. It is a graph which measured the median diameter (the particle diameter which the cumulative frequency becomes 50%) of the molding material containing diatomaceous earth of the first embodiment. It is a graph which shows the particle size when the median diameter of the resin material of the 1st Embodiment is changed. It is an electron micrograph before and after the urethane immersion of the sample modeled in Example 1-1. It is an X-ray diffraction pattern of a 3D gypsum powder and a sample formed in Example 1-1.

Specific embodiments to which the present invention is applied will be described in detail below.

(First Embodiment)
In the first embodiment, a modeling material containing diatomaceous earth was developed, which is used in an apparatus for modeling by an inkjet powder lamination method represented by a gypsum 3D printer. As shown in FIG. 1, this method is a method in which powders are laminated by 0.1 mm each and a portion where ink is ejected from an inkjet nozzle is solidified to form a model. Therefore, the problems in the development of the powder material by this method are the stackability of the powder and the adhesiveness between the powder and the ink. The present invention has developed a powder material that can be formed by this 3D printer, and produced a diatomaceous earth product. FIG. 2 is a diagram illustrating a manufacturing process of a diatomaceous earth product according to an embodiment of the present invention.

In the first embodiment, the mixing ratio is such that diatomaceous earth, aggregate, resin adhesive, and fluidity improving agent are contained in a large amount in this order, and the ratio of four types of resin adhesive having different median diameters is used. After adjustment, a modeling material (developed material) containing diatomaceous earth was prepared.
The calcined diatomaceous earth produced in Noto was used as the diatomaceous earth, the gypsum-based material manufactured by Sanes Gypsum Co., Ltd. was used as the aggregate, and the FS manufactured by Tokuyama Corporation was used as the fluidity improving agent. As the resin adhesive, water-soluble polymer materials such as PVP1 and PVP2 manufactured by BASF Japan Ltd., PVP3 manufactured by Nippon Shokubai Co., Ltd., and PVA manufactured by Denka Co., Ltd. having different median diameters were used.

Table 1 shows the results of the blending ratio and stickiness of each example.

Each material was weighed so as to have the blending ratio shown in Table 1, and about 20 kg of blended powder was prototyped with a mixer. This compounded powder was put into a gypsum 3D printer (3D Systems, Inc., Project 660Pro) and a modeling test was conducted to confirm the adhesiveness.

The calcined diatomaceous earth and gypsum-based materials used in the first embodiment, and the dry diatomaceous earth and gypsum for 3D printer genuine gypsum powder (3D gypsum powder) median-based (particle size at which the cumulative frequency becomes 50%) are shown. Shown in 3. Since the laminated width of the gypsum 3D printer is 100 μm, the material for modeling with diatomaceous earth used in the present invention preferably has a median diameter of 100 ± 10 μm or less.
The median diameter of the resin adhesive used in the first embodiment is shown in FIG. As shown in Table 1, Examples 1-1 and 1-4 had good adhesiveness, and the modeled object could be taken out from the powder without damage. However, in Examples 1-2 and 1-3, the adhesiveness was poor and the molded product was so brittle that it could not be taken out from the powder. In Example 1-2, the cause is that the amount of PVP was as small as 22 vol%. In Examples 1-3, the amount of PVP was 24 vol%, but the cause was that the median diameter was 100 ± 10 μm or more.
Further, in Example 1-5, even if the median diameter was 82 μm, if the amount of PVA was as small as 20 vol%, the adhesiveness was poor and the modeled object could not be taken out from the powder. Therefore, it is preferable that the resin adhesive has a median diameter of 100 ± 10 μm or less and contains 24 vol% or more (Examples 1-1 and 1-4).

As these resin adhesives, commercially available products are used as they are, but those crushed to a median diameter of about 20 ± 10 μm using a dry crusher may be used. If the median diameter is 20 ± 10 μm or less, the hygroscopic effect of the resin adhesive becomes large and it becomes difficult to handle it in the state of dry powder.

A diatomaceous earth product having a predetermined shape was produced using the modeling materials containing diatomaceous earth of Examples 1-1 and 1-4. Diatomaceous earth products include perfect circular and elliptical prototypes (A-1 and A-2 in Fig. 2), pin-shaped products with a diameter of 1 mm or more, and holes with a hole diameter of 1 mm or more. Manufactured in different sizes (B-1 and B-2 in FIG. 2). As a result, it was clarified that a pin shape having a diameter of 5 mm or more and a hole diameter of 2 mm or more can be manufactured. By immersing it in urethane, it did not collapse even when immersed in water. In addition, diatomaceous earth powder and FS powder no longer adhere to the hands.

(Second Embodiment)
In the second embodiment, calcined diatomaceous earth is used as the diatomaceous earth, FS is used as the fluidity improver, and 3D gypsum powder is used as the aggregate, and the fluidity index and jettability index of the powder material mixed in the blending ratios shown in Table 2 are obtained. It was determined by a powder property evaluation device (Hosokawa Micron Co., Ltd., Powder Tester PT-X). The fluidity index is intended to comprehensively grasp the fluidity (= flowability) of powder, and the jettability index is intended to comprehensively grasp the jettability (= discharge property) of powder. Carr. R. It conforms to the method L studied experimentally.

Table 2 shows the ratio of the fluidity improver to the diatomaceous earth, the fluidity index, and the jettability index in each example.

In Examples 2-2, 2-3, 2-4, and 2-5 shown in Table 2, the fluidity index tends to increase as the amount of the fluidity improving agent added increases. The ratio of the fluidity improver to diatomaceous earth was 8.8% (Example 2-3), and the fluidity index was 40.5, which was about the same as the manufacturer's genuine 3D gypsum powder (Example 2-1) (41.0). )become. In Example 1-1, the ratio of the fluidity improver to the diatomaceous earth was 23.7% and the fluidity index was 52.0, which was higher than that of the 3D gypsum powder and the blending ratio of the fluidity improver was excessive. It is in a state of being. Therefore, with the blending ratio of the gypsum-based material and the resin adhesive of Example 1-1 fixed, the fluidity improving agent can be reduced to 4 vol%, which is 8.8% of the diatomaceous earth. It is possible to increase the amount of diatomaceous earth by that amount (assumed example 1). In this experiment, diatomaceous earth could be increased to 43 vol% (assumed example 1), but a fluidity improver with a high fluidity index was used, or a resin adhesive with a small median diameter was used. By doing so, it can be expected that the amount of diatomaceous earth will be further increased.
Further, in Examples 2-2, 2-3, 2-4, and 2-5, the jetability index also tends to increase as the amount of the fluidity improving agent added increases. In Example 1-1, the jetting property index is 74.0, and the degree of jetting property classified from the jetting property index is classified as "quite strong (60 to 79)". If the amount of the fluidity improving agent is increased more than this, the degree of jetting property is classified as "very strong (80 to 100)" and easily scattered. Therefore, the blending ratio of the fluidity improving agent is preferably 9 vol% or less.

(Third Embodiment)
In the third embodiment, the fluidity of the powder material to which calcium stearate, magnesium stearate, and FS are added as fluidity improving agents by 1 to 5 mass% to a mixed sample of 60 mass% of calcined diatomaceous earth and 40 mass% of 3D gypsum powder. The index was determined by a powder property evaluation device.

Table 3 shows the liquidity index in each example.

As shown in Table 3, the fluidity index does not change even if calcium stearate or magnesium stearate is added in an amount of 1 mass% to the compounded sample of Example 3-1 but becomes higher when FS is added in an amount of 1 mass%. Further, when the amount of FS added is increased, the liquidity index tends to increase. From this result, FS is most effective in improving liquidity.

Table 4 shows an example of assumptions in which the mixing ratio of each diatomaceous earth-containing modeling material is within an appropriate range.

Table 4 shows an assumed example of an appropriate range in which diatomaceous earth, aggregate, resin adhesive, and fluidity improving agent are contained in a large amount in this order. The appropriate range for each material is 31 to 43 vol% for diatomaceous earth, 24 to 36 vol% for aggregate, 24 to 32 vol% for resin adhesive, and 4 to 9 vol% for fluidity improver. The reason why the mixing ratio of diatomaceous earth is the largest is to take advantage of the characteristics of porous diatomaceous earth. The reason why the amount of aggregate is next is that if the proportion of resin adhesive is larger than that of aggregate, the viscosity when ink is applied increases (stickiness occurs), which affects the stackability of powder. is there. The lower limit of the resin adhesive is necessary to obtain good adhesiveness, and the upper and lower limits of the fluidity improver are based on the examples shown in Table 2.

The shaped products of Examples 1-1 and 1-4 having good adhesiveness were taken out from the powder, and then the powder on the surface was removed with air, and a urethane-based curing agent manufactured by WASHIN CHEMICAL INDUSTRIES CO., LTD. It was impregnated with (urethane) for about 3 minutes and dried at room temperature. Further, the modeled product of Example 1-4 was brushed with urethane and dried at room temperature. After that, the following physical property evaluations were performed.
The bending strength of the modeled object is 3 using an autograph (Shimadzu Corporation, AG-5kNXplus) and using a test piece with a width of 8 mm, a thickness of 6 mm, and a length of 70 mm under the condition of a span of 60 mm and a test speed of 0.5 mm / min. A point bending test was performed. The test was carried out at n = 3, and the average value was calculated.
The thermal conductivity of the modeled object is measured by measuring a 50 mm square and 6 mm thick test piece with a steady-state thermal conductivity measuring device (Albac Riko Co., Ltd., GH-1), and the bulk specific gravity is based on the weight and volume of the same test piece. Calculated. The moisture absorption and desorption properties of the modeled object were measured by placing the test piece after the bending test in a container adjusted to a relative humidity of 84.7% and 53.5% and measuring the weight in a 24-hour cycle. The relative humidity was adjusted by putting potassium chloride and magnesium nitrate as a salt saturated solution in the bottom of the container and letting it stand in a constant temperature bath at 23 ° C. The sample was cured at a relative humidity of 53.5% until the weight reached a constant weight.
The water absorption rate of the modeled object was calculated from the weight change after 24 hours after drying the test piece after the bending test at 100 ° C. and immersing it in distilled water.

Impregnation with a curing agent is essential as a post-treatment, but water or alcohol-based curing agents dissolve the modeled object, and urethane was the only one that could cure the modeled object without dissolving it.

Table 5 shows the results of summarizing the physical property evaluations of the modeled products of Examples 1-4, which were brush-coated with urethane and those immersed in urethane.

When urethane is brushed, a minimum of 8.5 mass% urethane can be applied to the modeled object. Further, when immersed in urethane, the modeled object can be impregnated with urethane of a maximum of 18.5 mass%. Urethane brush coating can contain a minimum amount of urethane, and after coating, the surface hardens and powder does not stick to the hands. On the other hand, in the urethane immersion, the urethane is immersed for about 3 minutes until no bubbles are generated, so that the maximum amount of urethane can be contained. As shown in Table 4, when immersed in urethane, the bending strength is improved by about 1.5 times as compared with the one coated with a brush. However, there was no significant difference in the amount of moisture absorption and desorption and thermal conductivity that would affect the moisture absorption and desorption and heat insulation properties that are the characteristics of diatomaceous earth. Therefore, it is possible to contain 8.5 to 18.5 mass% of urethane in the modeled object.

FIG. 5 shows an SEM image before (a) and after (c) the urethane immersion and a COMPO image before (b) and after (d) the urethane immersion of the sample formed in Example 1-1. No difference was confirmed in the microstructure in the SEM images before and after the urethane immersion. On the other hand, in the COMPO image, it can be seen that the dark contrast portion increases after immersion in urethane, and the urethane is impregnated so as to fill the small voids between the particles. However, since voids having a size of about 100 μm were confirmed, even if they were immersed in urethane, not all the voids were filled, so that the moisture absorption and desorption properties were not significantly affected.

Table 6 shows the results of summarizing the physical property evaluations of the cut-out diatomaceous earth and the modeled object after immersion in urethane.

Cut-out diatomaceous earth is made by cutting out diatomaceous earth as a large block mass, and compared to a kneaded product made by kneading diatomaceous earth into a mold, innumerable microvacuums of natural diatomaceous earth remain as they are, and it has heat retention. It has high heat storage, high thermal efficiency, and is durable, and is used for cut-out shichirin (molded in the shape of a shichirin with a chisel and baked in a kiln for a whole day and night).

It was clarified that the molded product after immersion in urethane had about three times higher bending strength than the cut-out diatomaceous earth, and the amount of moisture absorbed and released was about the same. It was confirmed that the thermal conductivity is higher than that of cut diatomaceous earth because it contains a gypsum material, and the heat resistance changes to dark brown at 200 ° C. or higher because it contains PVP. The water absorption rate was about 12% of that of the cut diatomaceous earth, but it was revealed that it had water absorption. The advantages over cut diatomaceous earth are that the surface is hardened by immersing it in urethane, the powder does not reach the hands, and it does not collapse even when immersed in water.
As described above, even if diatomaceous earth is contained in a larger amount than the gypsum-based material which is the aggregate, a model having characteristics such as moisture absorption / desorption, heat insulation, and water absorption can be manufactured by utilizing the characteristics of porous diatomaceous earth. become able to.

Generally gypsum powder used in gypsum 3D printer is hemihydrate gypsum _{(CaSO 4 · 0.5H 2 O)} , changes to the gypsum reacts with shaping after ink. However, as shown in FIG. 6, the sample formed in Example 1-1 has a lower peak intensity of 2θ = 20.7 °, which indicates the strongest line of dihydrate gypsum, than the sample formed with 3D gypsum powder, and most of them have a lower peak intensity. It remains semi-hydrated plaster. Therefore, since it is considered that the gypsum-based material hardly contributes to the fixability after modeling, silica or the like can be used as the aggregate in addition to the gypsum-based material.

In the present embodiment, the modeling material mainly used in the 3D printer has been described as an example, but the present invention is widely applicable to the modeling material using the gypsum-based material.

A-1, A-2 diatomaceous earth products,
B-1, B-2 diatomaceous earth products

Claims (10)

The mixing ratio is such that diatomaceous earth, aggregate, resin adhesive, and fluidity improver are contained in a large amount in this order, and aggregate, resin adhesive, and fluidity improvement are made with respect to 31 to 43 vol% of diatomaceous earth. A molding material containing diatomaceous earth, which is characterized by adjusting the proportion of the agent. Claim 1 is characterized in that the aggregate is adjusted at a ratio of 24 to 36 vol%, the resin adhesive is adjusted at 24 to 32 vol%, and the fluidity improving agent is adjusted at a ratio of 4 to 9 vol% with respect to 31 to 43 vol% of diatomaceous earth. The described material for modeling with diatomaceous earth. The diatomaceous earth is a powder of calcined diatomaceous earth, the aggregate is a powder of a gypsum-based material, the fluidity improver is fumed silica (FS), and the fluidity index of Carr is the powder of the calcined diatomaceous earth. The diatomaceous earth-containing molding material according to claim 1, which is higher than the fluidity index of the powder of the gypsum-based material. The modeling material containing diatomaceous earth according to claim 1, wherein the median diameter of the resin adhesive is 20 ± 10 to 100 ± 10 μm. The diatomaceous earth is a powder of calcined diatomaceous earth, the aggregate is a powder of a gypsum-based material, the fluidity improving agent is fumed silica (FS), and the resin adhesive is polyvinyl alcohol (PVA) or , The diatomaceous earth-containing molding material according to any one of claims 1 to 4, which is polyvinylpyrrolidone (PVP). A diatomaceous earth product is manufactured by a powder-fixing laminating method using a diatomaceous earth-containing molding material having a mixing ratio of diatomaceous earth, aggregate, resin adhesive, and a fluidity improving agent in a large amount in this order. A diatomaceous earth product characterized by containing 8.5 to 18.5 mass% urethane in the diatomaceous earth product. The diatomaceous earth product according to claim 6, wherein the ratio of the aggregate, the resin adhesive, and the fluidity improving agent is adjusted with respect to 31 to 43 vol% or less of the diatomaceous earth. The diatomaceous earth is a powder of calcined diatomaceous earth, the aggregate is a powder of a gypsum-based material, the fluidity improver is fumed silica (FS), and the fluidity index of Carr is the powder of the calcined diatomaceous earth. The diatomaceous earth product according to any one of claims 6 to 7, wherein the diatomaceous earth product is characterized by having a fluidity index higher than that of the powder of the gypsum-based material. A diatomaceous earth product is manufactured by a powder-fixing laminating method using a diatomaceous earth-containing molding material having a mixing ratio of diatomaceous earth, aggregate, resin adhesive, and a fluidity improving agent in a large amount in this order. A method for producing a diatomaceous earth product, which comprises adding urethane to the diatomaceous earth product. The method for producing a diatomaceous earth product according to claim 9, wherein urethane is applied to the diatomaceous earth product by brushing or is immersed in urethane until no bubbles are generated.