JP7606171B2 - Method for producing three-dimensional laminated object, support material and article - Google Patents

Description

The present invention relates to a method for producing a three-dimensional additive manufacturing object using a support material that supports the three-dimensional additive manufacturing object below the three-dimensional additive manufacturing object during the manufacturing process of the three-dimensional additive manufacturing object using a material extrusion method, as well as a support material and an article.

3D additive manufacturing (AM) is a technology that creates three-dimensional shapes by additive processing based on 3D CAD data and other data. AM can be broadly divided into seven types, one of which is the material extrusion method, which creates a model by extruding a plastic material from a nozzle and layering it. It is generally known that models are created using a thermoplastic resin that melts when heated as the material. In addition, when using the material extrusion method to create a shape that does not have a member to support the model below it (for example, an overhang shape or a bridge shape), a technology is known in which a support material is used to support the model.

In this case, if the supporting material is made of the same material as the model, the supporting material will fuse to the model after degreasing and firing, making it impossible to remove the supporting material from the model. To address this issue, a method has been disclosed in which the supporting material is made of an interface layer (peeling layer) to prevent the supporting material from fusing with the model, and a supporting material body to absorb shrinkage during the degreasing and firing process of the model, and the supporting material body is fired with the interface layer interposed between it and the supporting material body, making it easier to remove the supporting material from the model after firing (see, for example, Patent Documents 1 and 2).

Special table 2019-522105 publication JP 2020-501022 A

The interface layer is made of a material different from that used for the model so that it can be easily peeled off from the model. Also, since it does not shrink to the same extent as the model, a configuration has been adopted in which the interface layer is made thin and the support material body made of the same material as the model (a material with the same shrinkage rate as the model) is made thick in order to absorb the shrinkage of the model. However, when the model is made of an expensive material such as zirconia ceramics, the support material body is also made of the same expensive material as the model. Therefore, if the interface layer is made thin, the support material body must be made thick accordingly, which creates a problem in that the cost of producing the model increases. Furthermore, the support material is discarded after firing, which generates a large amount of waste material and causes environmental problems.

The present invention aims to provide a method, support material, and article for producing a three-dimensional additive manufacturing object using a material extrusion method, which can adequately support the three-dimensional additive manufacturing object during degreasing and firing, while reducing production costs and allowing the support material to be recovered and reused.

The present invention relates to a method for producing a three-dimensional layered object as described below in (1) to (12).
(1) A method for producing a three-dimensional additive model, comprising forming a support material that supports the three-dimensional additive model below the three-dimensional additive model during a modeling process using a material extrusion method for the three-dimensional additive model, the support material having a shrinkage relief layer that shrinks in response to the shrinkage of the three-dimensional additive model when fired, and a self-disintegrating layer that is made of a filament material that is a mixture containing a high-melting point inorganic filler and a thermoplastic resin and can be peeled off from the three-dimensional additive model after firing, the self-disintegrating layer shrinking in response to the shrinkage of the three-dimensional additive model when fired but having a smaller shrinkage rate when fired than the shrinkage relief layer .
(2) A method for producing a three-dimensional additively manufactured body described in (1) above, in which the three-dimensional additively manufactured body is a ceramic body and is manufactured using a ceramic material containing ceramic powder, and the shrinkage relaxation layer is formed from a filament material that is a mixture containing ceramic powder and a thermoplastic resin.
(3) The method for producing a three-dimensional additive manufacturing object described above in (2), wherein the filament material forming the shrinkage relaxation layer has a ceramic powder content of 30 volume % or more.
( 4 ) A method for producing a three-dimensional additive manufacturing object according to any one of (1) to ( 3 ) above, wherein the filament material forming the self-disintegrating layer has a content of the high melting point inorganic filler of 30 volume % or more.
( 5 ) The method for producing a three-dimensional additive manufacturing object according to (1) or ( 4 ) above, wherein the high melting point inorganic filler has a melting temperature that is 100° C. or more higher than a firing temperature of the three-dimensional additive manufacturing object.
( 6 ) The method for producing a three-dimensional additive manufacturing object according to any one of (1) to ( 5 ) above, wherein the high-melting point inorganic filler has an average particle size of 1 μm or more and 40 μm or less, and the increase rate of the average particle size before and after firing is 150% or less.
( 7 ) A method for producing a three-dimensional additive manufacturing object according to any one of (2) to ( 6 ) above, wherein the filament material forming the shrinkage relaxation layer and/or the self-disintegrating layer has a viscosity of 20 to 500 Pa·s at the modeling temperature.
( 8 ) The method for producing a three-dimensional additive manufacturing object according to any one of (1) to ( 7 ) above, wherein the self-disintegrating layer has a compressive strength of 5 MPa or less after firing.
( 9 ) The support material according to any one of (1) to ( 8 ) above, wherein the self-disintegrating layer has a constituent ratio of 5% or more and 60% or less.
( 10 ) A method for producing a three-dimensional additive manufacturing object according to any one of (1) to (9 ) above, wherein the supporting material has a thermal deformation rate of 10% or less during degreasing, and the difference in shrinkage rate between the supporting material and the three-dimensional additive manufacturing object during firing is 4% or less.
( 11 ) The method for producing a three-dimensional additive manufacturing object according to any one of (1) to ( 10 ) above, wherein the three-dimensional additive manufacturing object is a manufacturing object formed into an overhang shape or a bridge shape.

The present invention also relates to the following support materials ( 12 ) to ( 15 ).
( 12 ) A support material that supports a three-dimensional additive model under a three-dimensional additive model during a modeling process using a material extrusion method for the three-dimensional additive model, the support material having: a shrinkage relief layer that shrinks in response to the shrinkage of the three-dimensional additive model during firing; and a self-disintegrating layer that is formed from a filament material that is a mixture containing a high-melting point inorganic filler and a thermoplastic resin, prevents adhesion between the three-dimensional additive model and the shrinkage relief layer and is peelable from the three-dimensional additive model after firing , wherein the self-disintegrating layer shrinks in response to the shrinkage of the three-dimensional additive model during firing, but has a smaller shrinkage rate during firing than the shrinkage relief layer .
( 13 ) The supporting material according to ( 12 ) above, wherein the three-dimensional additive manufacturing object is an overhang-shaped or bridge-shaped manufacturing object.
( 14 ) The supporting material according to ( 12 ) or ( 13 ) above, wherein the material extrusion method is a method for producing a molded object by extruding a material having plasticity from a nozzle and laminating it in a three-dimensional additive manufacturing (AM) technology.
( 15 ) The support material according to any one of (12) to (14) above, wherein the material of the support material is such that the shrinkage relaxation layer is a mixture containing a ceramic powder and a thermoplastic resin, and the self-disintegrating layer is a mixture containing a high melting point inorganic filler and a thermoplastic resin.

Furthermore, the present invention relates to the following articles ( 16 ) to ( 19 ).
( 16 ) A ceramic three-dimensional additive manufacturing body, which is shaped by an extrusion method with a shaping material including a sinterable ceramic powder material for forming a final part at a sintering temperature, and which includes one or more resin binders that hold the powder material into a net-shaped object before densifying the powder material into a final part; and a support material for the ceramic three-dimensional additive manufacturing body, which is arranged adjacent to a surface of the ceramic three-dimensional additive manufacturing body and supports the ceramic three-dimensional additive manufacturing body at a lower portion thereof during at least one of degreasing and sintering of the shaping body , and which has both a shrinkage relief layer that shrinks in accordance with the shrinkage of the three-dimensional additive manufacturing body during firing , and a self-disintegrating layer that prevents adhesion between the three-dimensional additive manufacturing body and the shrinkage relief layer and is peelable from the three-dimensional additive manufacturing body after firing, and the self-disintegrating layer shrinks in accordance with the shrinkage of the three-dimensional additive manufacturing body during firing, but has a smaller shrinkage rate during firing than the shrinkage relief layer .
( 17) The article described in (16 ) above, wherein the support material is a material consisting of a mixture containing a ceramic powder of the shrinkage relaxation layer or a high-melting point inorganic filler of the self-disintegrating layer and a thermoplastic resin, and the content of the ceramic powder of the shrinkage relaxation layer or the high-melting point inorganic filler of the self-disintegrating layer is 30 volume % or more, and a filament formed by stranding the mixture is made of a material having a fluidity of a viscosity of 20 to 500 Pa·s at the heating temperature during molding.
( 18 ) The article according to (16) or (17) above, wherein the high-melting-point inorganic filler of the self-disintegrating layer has a melting temperature 100° C. or more higher than the desired sintering temperature of the shaped body, has an average particle size of 1 μm or more and 40 μm or less, the relative density of the ceramic shaped body when the support is removed in the firing process is 50% or more, the compressive strength of the self-disintegrating layer at that time is 5 MPa or less, and the degree of adhesion of the inorganic filler of the self-disintegrating layer is such that the change in the average particle size before firing is 150 % or less , and the article can be recovered and recycled.
( 19 ) The article according to any one of (16) to (18), which is a composite support material for ceramic modeling, in which the composition ratio of the self-disintegrating layer in the composite support material is 5% or more and 60 % or less, the thermal deformation during degreasing of the composite support material is 10% or less, and the difference in shrinkage rate between the ceramic model and the composite support during firing is within 4 %.

The present invention provides a method for producing a three-dimensional additive manufacturing object using a material extrusion method, a support material, and an article that can adequately support the three-dimensional additive manufacturing object during degreasing and sintering, reduce production costs, and enable recovery and reuse of the support material.

1A to 1C are diagrams for explaining a method for producing a ceramic body according to an embodiment of the present invention. 2A to 2C are diagrams for explaining the state of the ceramic body 1 and the supporting material 2 before and after degreasing and firing. FIG. 2 is a schematic diagram showing a configuration of a supporting material according to the present embodiment. 1 is a graph showing the relationship between the average particle size of the silica powder used in the self-collapsing layer and the thermal deformation rate of the self-collapsing layer due to heating. 1 is a graph showing the relationship between the average particle size of silica powder, the firing temperature, and the compressive strength after firing in a self-disintegrating layer.

Below, an embodiment of the present invention will be described with reference to the drawings. Note that, in the following, a ceramic shaped body made of a ceramic material will be described as a preferred example of a three-dimensional additively shaped body according to the present invention, but the shaped body is not limited to a ceramic shaped body as long as it is made of a material that can be used to produce a three-dimensional additively shaped body by a material extrusion method.

Figure 1 is a diagram for explaining the method for producing a ceramic shaped body 1 according to this embodiment, and Figure 2 is a diagram for explaining the state of the ceramic shaped body 1 and the support material 2 before and after degreasing and firing. As shown in Figure 1, the support material 2 is for supporting the ceramic shaped body 1 so that the ceramic shaped body 1 does not deform during degreasing and firing when the ceramic shaped body 1 is shaped into a shape with no support at the bottom of the ceramic shaped body 1 (for example, a bridge shape shown in Figure 1 or an overhang shape not shown). Here, the ceramic shaped body 1 is produced as the final product ceramic shaped body 1 by degreasing and firing after shaping. When the ceramic shaped body 1 is degreased and fired, as shown in Figure 2, the ceramic shaped body 1 shrinks after degreasing and firing compared to before degreasing and firing. For this reason, it is desirable for the support material 2 to be able to continuously support the ceramics shaped body 1 by not melting or collapsing (collapse due to thermal deformation) during degreasing and firing, and by shrinking in accordance with the shrinkage of the ceramics shaped body 1, as shown in Figure 2. Furthermore, since it is necessary to remove the support material 2 from the ceramics shaped body 1 after firing of the ceramics shaped body 1, it is desirable for the support material 2 to be a member that can be easily removed from the ceramics shaped body 1 after firing. In order to have such characteristics, the support material 2 according to this embodiment has the following configuration.

Figure 3 is a schematic diagram showing the configuration of the support material 2 according to this embodiment. As shown in Figure 3, the support material 2 according to this embodiment has a shrinkage relaxation layer 10 and a self-disintegrating layer 20. Also, in this embodiment, as shown in Figure 3, both ends of the support material 2 that contact the ceramic shaped body 1 are configured with the self-disintegrating layer 20, and the shrinkage relaxation layer 10 is configured at a position sandwiched between the self-disintegrating layers 20 that is not in contact with the ceramic shaped body 1.

The shrinkage relaxation layer 10 is preferably formed from a material that shrinks at approximately the same rate as the ceramic shaped body 1 during the degreasing and firing process, and can be formed from the same material as the ceramic shaped body 1. For example, when a mixture containing zirconia ceramic powder and a thermoplastic resin is used as the material for the ceramic shaped body 1, the material for the shrinkage relaxation layer 10 can also be a mixture containing zirconia ceramic powder and a thermoplastic resin. In this way, by forming the shrinkage relaxation layer 10 from the same material as the ceramic shaped body 1, the shrinkage relaxation layer 10 can shrink at approximately the same rate as the ceramic shaped body 1 during firing, and as a result, the difference in the shrinkage rate between the ceramic shaped body 1 and the support material 2 during firing can be reduced.

In this embodiment, the filament material, which is a mixture of zirconia ceramic powder and thermoplastic resin with the same composition as the ceramic shaped body 1, is inserted into the extrusion head as a filament, and is continuously extruded from a nozzle part of the extrusion head while being heated and melted, and laminated to form the shrinkage relaxation layer 10. In the filament material of the shrinkage relaxation layer 10, the ceramic powder content is preferably 30 volume % or more. If the ceramic powder content is less than 30%, the difference in shrinkage rate with the ceramic shaped body 1 becomes too large (the firing shrinkage becomes too large compared to the ceramic shaped body 1), and there is a possibility that the function as a support will be lost (melted down). In addition, it is preferable to adjust the filament material of the shrinkage relaxation layer 10 so that the viscosity at the shaping temperature is 20 to 500 Pa·s. The viscosity of the filament material can be adjusted by adjusting the type of resin in addition to the ceramic powder content.

The shrinkage buffer layer 10 and the ceramic shaped body 1 may be formed from different materials or with different compositions. If the materials for the shrinkage buffer layer 10 and the ceramic shaped body 1 are different, it is preferable that they have approximately the same shrinkage behavior during firing (for example, the difference in shrinkage rate is within 4%). The shrinkage buffer layer 10 and the ceramic shaped body 1 may also be formed from the same raw materials with different composition ratios of the raw materials.

The self-disintegrating layer 20 is formed by extruding and laminating a filament material made of a mixture containing a high-melting-point inorganic filler and a thermoplastic resin. In particular, the high-melting-point inorganic filler used in the self-disintegrating layer 20 is characterized by having a melting temperature 100°C or more higher than the planned sintering temperature of the ceramic shaped body 1 so that it can be reused even after the ceramic shaped body 1 is fired. For example, when zirconia ceramics is used as the material for the ceramic shaped body 1, the ceramic shaped body 1 is often fired at 1150°C, at which the relative density of the ceramic shaped body 1 is 50% or more, so that the ceramic shaped body 1 does not deform. In this case, silica powder (melting point is 1650°C) having a melting point of 1250°C or more can be used as the high-melting-point inorganic filler of the self-disintegrating layer 20.

The particle diameter of the high-melting-point inorganic filler used in the self-disintegrating layer 20 is not particularly limited, but the average particle diameter is preferably 1 μm or more, and more preferably 2 μm or more. If the average particle diameter of the high-melting-point inorganic filler is less than 1 μm, as described below, the compressive strength of the self-disintegrating layer 20 after firing will be high, and the support material 2 may not be easily removed from the ceramic shaped body 1. In addition, the particle diameter of the high-melting-point inorganic filler is preferably 40 μm or less, and more preferably 30 μm or less. As described below, the higher the average particle diameter of the high-melting-point inorganic filler, the greater the thermal deformation of the self-disintegrating layer 20 during degreasing tends to be, and if the average particle diameter exceeds 40 μm, the support material 2 may melt and the support material 2 may not be able to support the ceramic shaped body 1.

In addition, the support material 2 according to this embodiment is also characterized in that the high melting point inorganic filler contained in the self-disintegrating layer 20 can be recovered and reused. Here, when recovering and reusing the high melting point inorganic filler, if the particle size of the high melting point inorganic filler to be reused varies greatly, it becomes difficult to control the thermal deformation of the self-disintegrating layer 20 in the degreasing process and the contraction of the self-disintegrating layer 20 in the firing process during reuse. Therefore, the ceramic shaped body 1 is manufactured so that the increase rate of the average particle size of the high melting point inorganic filler contained in the self-disintegrating layer 20 before and after firing is 150% or less. Specifically, when the temperature at which the support material 2 is fired is equal to or higher than a predetermined temperature, the average particle size of the high melting point inorganic filler after firing tends to increase. Therefore, for example, in a support material 2 having a self-disintegrating layer 20 using silica powder as a high-melting point inorganic filler, the rate of increase in the average particle size of the silica powder before and after firing can be suppressed to approximately 150% or less by setting the firing temperature of the support material 2 to less than 1400°C.

In this embodiment, the self-disintegrating layer 20 is formed by stacking a filament material made of a mixture of silica powder and thermoplastic resin in a strand shape by a material extrusion method. The filament material of the self-disintegrating layer 20 preferably has a silica powder (high melting point inorganic filler) content of 30% by volume or more. In addition, it is preferable to adjust the filament material of the self-disintegrating layer 20 so that the viscosity at the modeling temperature is 20 to 500 Pa·s so that the filament material of the self-disintegrating layer 20 can be easily stacked to form the self-disintegrating layer 20. Furthermore, in this embodiment, the self-disintegrating layer 20 is configured so that the compressive strength of the self-disintegrating layer 20 after firing is 5 MPa or less so that the support material 2 can be easily peeled off from the ceramic shaped body 1 after firing. As described later, the compressive strength of the self-disintegrating layer 20 after firing can be adjusted by the firing temperature and the average particle size of the high-melting-point inorganic filler of the self-disintegrating layer 20. Therefore, it is preferable to determine the average particle size of the high-melting-point inorganic filler according to the planned firing temperature so that the compressive strength of the self-disintegrating layer 20 is 5 MPa or less.

It is desirable that the support material 2 has little thermal deformation in the degreasing process and shrinks to the same extent as the ceramic model 1 in the firing process so that it can continuously support the ceramic model 1 during degreasing and firing. In addition, it is desirable that the support material 2 can reduce the amount of material waste while reducing the manufacturing cost. Therefore, the support material 2 according to this embodiment is configured such that the thermal deformation rate in the degreasing process is within 10% and the difference in the shrinkage rate between the support material 2 and the ceramic model 1 in the firing process is within 4%. In addition, in the support material 2 according to this embodiment, in order to reduce the manufacturing cost while reducing waste material, the composition ratio of the self-disintegrating layer 20, which can be made from a relatively inexpensive material, is increased, and the high melting point inorganic filler used in the self-disintegrating layer 20 is configured to be reusable. Below, an example of the configuration of the support material 2 according to this embodiment is described.

(1) Amount of thermal deformation in the degreasing process The degreasing process is a process in which organic matter such as the binder resin contained in the ceramics model 1 and the supporting material 2 is thermally decomposed and burned by heating to remove them. In the degreasing process, deformation occurs in the ceramics model 1 and the supporting material 2 due to softening of the binder resin, and those with a large amount of deformation are not suitable as the supporting material 2. For this reason, the supporting material 2 according to this embodiment is configured so that the thermal deformation rate during degreasing is within 10% at the end of degreasing (usually 600° C.). The following shows the results of verifying the configuration of the supporting material 2 that results in an amount of thermal deformation within 10% during degreasing.

Using silica powders of different particle sizes (2 to 35 μm), the self-disintegrating layer 20 was prepared with a silica powder content of 40 volume %, and the thermal deformation rate (%) of each sample during heating was measured using a thermomechanical analyzer. As a comparative example, the thermal deformation rate (%) of a sample using zirconia (content 40 volume %) used in the ceramic shaped body 1 and the shrinkage relaxation layer 10 was also measured during heating. The evaluation results are shown in FIG. 4. In FIG. 4, (A) shows the evaluation result of a sample using 2.3 μm silica powder, and (B) shows the evaluation result of a sample using 4.0 μm silica powder. In addition, (C) shows the evaluation result of a sample using 8.5 μm silica powder, and (D) shows the evaluation result of a sample using 34.5 μm silica powder. Furthermore, (X) shows the evaluation result of a comparative example using zirconia.

As shown in FIG. 4, when silica powder with an average particle size of 2 to 4 μm is used for the self-disintegrating layer 20, the deviation in thermal deformation rate is smaller than in the comparative example using zirconia, and it is found that it is less likely to deform during degreasing. In particular, when silica powder with an average particle size of 2 to 4 μm is used, the deformation rate during degreasing is within 10%, reducing the risk of the support material 2 melting down due to thermal deformation, and it is found to be suitable as the support material 2. On the other hand, when silica powder with an average particle size of 8 to 35 μm is used, it is found that the thermal deformation rate is larger than in the comparative example using zirconia.

However, even when silica powder with an average particle size of 8 to 35 μm is used for the self-disintegrating layer 20, the influence of thermal deformation of the support material 2 can be reduced by adjusting the composition ratio of the shrinkage relaxation layer 10 using zirconia and the self-disintegrating layer 20 using silica powder. For example, when the average particle size of the silica powder contained in the self-disintegrating layer 20 is 2.3 μm or 4.0 μm, the thermal deformation during degreasing is small, so the composition ratio of the self-disintegrating layer 20 in the support material 2 can be increased to a maximum of 60%. On the other hand, when the average particle size of the silica powder in the self-disintegrating layer 20 is 8.5 μm and 34.5 μm, the thermal deformation during the degreasing process is large, so the composition ratio of the self-disintegrating layer 20 in the support material 2 is set to a maximum of 20%. In this way, in the support material 2 according to this embodiment, the average particle size of the silica powder used in the self-disintegrating layer 20 and the composition ratio of the self-disintegrating layer 20 can be adjusted to within 10% in the degreasing process.

(2) Shrinkage rate of the support material 2 during firing In this embodiment, in order to cause the support material 2 to shrink following the ceramic shaped body 1 during the firing process, it is preferable to use the same material as the ceramic shaped body 1 for the shrinkage relaxation layer 10. Here, when a ceramic material such as zirconia ceramics is used for the ceramic shaped body 1 and the shrinkage relaxation layer 10, it is preferable to make the composition ratio of the shrinkage relaxation layer 10 in the support material 2 as small as possible and the composition ratio of the self-disintegrating layer 20 as large as possible, since ceramic materials such as zirconia ceramics are often very expensive. However, if the composition ratio of the self-disintegrating layer 20 is too large, the support material 2 cannot follow the shrinkage of the ceramic shaped body 1 during firing (cannot absorb the shrinkage of the ceramic shaped body 1), and there is a risk that the ceramic shaped body 1 will be destroyed. Therefore, it is desirable to set the composition ratio of the shrinkage relaxation layer 10 and the self-disintegrating layer 20 of the support material 2 to an appropriate range that can realize cost reduction while preventing destruction of the ceramic shaped body 1.

Therefore, in the support material 2 according to this embodiment, when the support material 2 and the ceramic shaped body 1 are fired, the shrinkage rate of the support material 2 is adjusted to be within 4%, preferably within 3%, of the shrinkage rate of the ceramic shaped body 1. Here, in the firing process of the ceramic shaped body 1, when the relative density of the ceramic shaped body 1 reaches 50% or more, the ceramic shaped body 1 and the support material 2 are removed from the firing furnace, the support material 2 is removed from the ceramic shaped body 1 and recovered, and then the ceramic shaped body 1 alone can be heated again to the desired temperature and sintered. This is because if the support material 2 is removed when the relative density of the ceramic shaped body 1 is less than 50%, the ceramic shaped body 1 may lose support and deform in the subsequent firing process. When the material of the ceramic shaped body 1 is zirconia ceramic, the firing temperature at which the relative density reaches 50% is approximately 1150°C. Therefore, when the material of the ceramic body 1 is zirconia ceramic, it is desirable to keep the difference in shrinkage rate between the ceramic body 1 and the support material 2 within 4%, preferably within 3%, until firing at 1150°C.

In the support material 2, by adjusting the composition ratio of the shrinkage relaxation layer 10 and the self-disintegrating layer 20, it is possible to control the difference in shrinkage rate between the ceramic shaped body 1 and the support material 2 during firing to within 4%. Specifically, the composition ratio of the self-disintegrating layer 20 is preferably 5% or more and 60% or less, and more preferably 10% or more and 50% or less. The reason why the composition ratio of the self-disintegrating layer 20 is set to 5% or more is that if the composition ratio of the self-disintegrating layer 20 is less than 5%, some burning occurs at the interface between the ceramic shaped body 1 and the self-disintegrating layer 20, and when the support material 2 is removed from the ceramic shaped body 1, a part of the self-disintegrating layer 20 is fused to the ceramic shaped body 1, and the amount of the high melting point inorganic filler contained in the self-disintegrating layer 20 is significantly reduced, which may result in a large amount of waste of the support material 2. On the other hand, if the composition ratio of the self-disintegrating layer 20 is greater than 60%, the self-disintegrating layer 20 has a lower shrinkage rate during firing than the shrinkage relaxation layer 10, which increases the difference in shrinkage between the support material 2 and the ceramic shaped body 1, and this may induce defects such as firing cracks.

The composition ratio of the self-disintegrating layer 20 must also be adjusted depending on the particle diameter of the high-melting inorganic filler contained in the self-disintegrating layer 20. For example, when zirconia powder is used for the ceramic shaped body 1 and the shrinkage relaxation layer 10, silica powder is used for the self-disintegrating layer 20, the firing temperature is 1150°C, and the support material 2 is removed after firing, in order to keep the difference in shrinkage rate between the ceramic shaped body 1 and the support material 2 during firing within 3%, when the particle diameter of the silica powder is 2.3 μm, 4.0 μm, or 8.5 μm, the composition ratio of the self-disintegrating layer 20 can be increased to 60%. On the other hand, when the particle diameter of the silica powder is 34.5 μm, the composition ratio of the self-disintegrating layer 20 can be increased to 50%.

In this way, in the support material 2 according to this embodiment, by adjusting the composition of the self-disintegrating layer 20 (for example, the average particle size and content of the high-melting-point inorganic filler used in the self-disintegrating layer 20) and the composition ratio of the shrinkage relaxation layer 10 and the self-disintegrating layer 20, the rate of thermal deformation during degreasing can be controlled to within 10%, and the shrinkage rate of the support material 2 during firing can be controlled to within 4%, and more preferably within 3%, of the shrinkage rate of the ceramic shaped body 1. As a result, the support material 2 does not melt during the degreasing process, and shrinks in accordance with the shrinkage of the ceramic shaped body 1 during the firing process, thereby allowing the ceramic shaped body 1 to be continuously supported.

(3) Degree of sintering and self-disintegrating strength suitable for recovery and reuse of the support material 2 It is desirable that the support material 2 can be easily removed from the ceramic shaped body 1 after firing. In the firing process, the high melting point inorganic filler contained in the self-disintegrating layer 20 is also sintered, so if the self-disintegrating layer 20 after firing has a high compressive strength, it becomes difficult to remove the self-disintegrating layer 20 from the ceramic shaped body 1. Therefore, in this embodiment, the self-disintegrating layer 20 is configured so that the compressive strength of the self-disintegrating layer 20 after firing is 5 MPa or less, which allows the self-disintegrating layer 20 to be easily disintegrated and recovered.

Figure 5 shows the compressive strength of the self-disintegrating layer 20 made using silica powder (high melting point inorganic filler) of various average particle sizes when fired at each firing temperature. In the self-disintegrating layer 20 (A) fired at 1400 ° C using silica powder with an average particle size of 2.3 μm, the compressive strength of the self-disintegrating layer 20 exceeds 5 MPa, making it difficult to remove the self-disintegrating layer 20 from the ceramic shaped body 1. On the other hand, in the self-disintegrating layers 20 (B) to (D) fired at 1400 ° C using silica powder with an average particle size of 4 μm or more, the compressive strength of the self-disintegrating layer 20 is 5 MPa or less, making it possible to easily remove the self-disintegrating layer 20 from the ceramic shaped body 1. Similarly, when fired at 1300°C, the compressive strength of the self-disintegrating layer 20 (E) using silica powder with an average particle size of 2.3 μm exceeds 5 MPa, making it difficult to remove the self-disintegrating layer 20 from the ceramic shaped body 1, but the compressive strength of the self-disintegrating layer 20 (F) to (H) using silica powder with an average particle size of 4 μm or more is 5 MPa or less, making it possible to easily remove the self-disintegrating layer 20 from the ceramic shaped body 1. Furthermore, as shown in FIG. 4, when the self-disintegrating layer 20 is fired at 1200°C and when fired at 1100°C, the compressive strength of the self-disintegrating layers 20 (I) to (L), (M) to (P) is 5 MPa or less, making it possible to easily remove the self-disintegrating layer 20 from the ceramic shaped body 1 even when silica powder with an average particle size of 2.3 μm is used. Thus, in the self-disintegrating layer 20 according to this embodiment, it is preferable to use silica powder with an average particle size of 4 μm or more in order to make the compressive strength after firing 5 MPa or less. However, even if silica powder with an average particle size of less than 4 μm is used, the compressive strength after firing can be made 5 MPa or less by controlling the firing temperature.

In addition, in the support material 2 according to this embodiment, in order to reduce the amount of waste material, it is preferable that the self-disintegrating layer 20 is made of a material suitable for recovery and reuse. Here, in order to recover and reuse the self-disintegrating layer 20, it is required that there is no significant change in the particle diameter of the high-melting-point inorganic filler before and after firing. If the variation in the particle diameter of the high-melting-point inorganic filler after firing becomes large, it becomes difficult to control the thermal deformation and firing shrinkage, and it becomes unsuitable for reuse. Therefore, in this embodiment, as the high-melting-point inorganic filler of the self-disintegrating layer 20, a filler is used whose average particle diameter (cumulative 50%) increase rate after firing is 150% or less and whose average particle diameter is 40 μm or less.

In this example, 3 mol Y-zirconia powder (average particle size 0.71 μm) was used as the ceramic powder for the ceramic molded body 1 and the shrinkage relaxation layer 10, and silica powder (average particle size 2.3 to 34.5 μm) was used as the high melting point inorganic filler for the self-disintegrating layer 20. In addition, the resin binder used was an acrylic resin, an ethylene vinyl acetate copolymer resin, and a polyethylene resin with appropriate amounts of lubricant and plasticizer added.

Zirconia powder or silica powder was mixed with a resin binder so that the volume percentage was 40%, and the mixture was heated and kneaded at 150°C using a pressure kneader (Toshin, TD0.3-3), and then extruded into rods with a diameter of approximately 3 mm using an extruder (product name "Noztek Pro HT", Noztek) to prepare zirconia filament material and silica filament material.

The ceramic body 1 and support material 2 were created using a fused deposition modeling desktop 3D printer (product name "MF-2200D", manufactured by Muto Industries). This device has two modeling nozzles, and the ceramic body 1 and shrinkage relaxation layer 10 can be created by extruding ceramic filament material from one nozzle 1, and the self-disintegrating layer 20 can be created by extruding silica filament material from the other nozzle 2.

In this example, the support material 2 of Examples 1 to 8 and Comparative Examples 1 to 4 was produced by using the above-mentioned fused deposition model desktop 3D printer to form the shrinkage relaxation layer 10 using the above-mentioned zirconia filament material and the self-disintegrating layer 20 using the above-mentioned silica filament material, and forming the shrinkage relaxation layer 10 and the self-disintegrating layer 20 in the composition ratio shown in Table 1 below. In addition, in the support material 2 of Examples 1 to 8 and Comparative Examples 1 to 4, the self-disintegrating layer 20 is formed using silica powder having the average particle size shown in Table 1 below.

Next, based on Table 1 above, the measurement results of the thermal deformation rate L _D of the support material 2 during degreasing, the difference L _S in the shrinkage rate between the support material 2 and the ceramic body 1 during firing, the compressive strength of the self-disintegrating layer 20 after firing, and the rate of change in particle size of the self-disintegrating layer 20 before and after firing in Examples 1 to 8 and Comparative Examples 1 to 4 will be described.

First, we will explain the thermal deformation rate L _D of the supporting material 2 during degreasing and the difference L _S in the shrinkage rates between the supporting material 2 and the ceramic shaped body 1 during firing. In measuring the thermal deformation rate L _D of the supporting material 2 during degreasing and the difference L _S in the shrinkage rates between the supporting material 2 and the ceramic shaped body 1 during firing, a modeling nozzle with a diameter of 1.0 mm was used to model the supporting materials 2 of Examples 1 to 8 and Comparative Examples 1 to 4 to have dimensions of approximately 3 mm wide x 3 mm long x 3 mm high under conditions of a layer pitch of 150 μm, a modeling nozzle temperature of 120° C., and a modeling table temperature of 75° C.

A thermomechanical analyzer (product name "TMA402 F1 Hyperion", manufactured by NETZSCH) was used to evaluate the thermal deformation rate L _D during degreasing and the difference in the shrinkage rate L _S between the support material 2 and the ceramic shaped body 1 during firing. Specifically, an alumina push rod was attached to the thermomechanical analyzer, and the lengths of the support material 2 in Examples 1 to 8 and Comparative Examples 1 to 4 were measured under the following conditions: a heating rate of 5°C/min, nitrogen atmosphere, and load of 5 mN in the range of 25°C to 600°C, a heating rate of 5°C/min, air atmosphere, and load of 5 mN in the range of 600°C to 1000°C, and a heating rate of 1°C/min, air atmosphere, and load of 5 mN in the range of 1000°C to 1400°C.

Then, based on the measured lengths of the supporting materials 2 in Examples 1 to 8 and Comparative Examples 1 to 4, the thermal deformation rates L _D of the supporting materials 2 during degreasing in Examples 1 to 8 and Comparative Examples 1 to 4 were calculated by the following formula (1).
Thermal deformation rate of the supporting material 2 during degreasing L _D (%)=(L ₁ −L ₀ )/L ₀ ×100 (1)
In the above formula (1), L ₀ is the sample length (μm) of the supporting material 2 of Examples 1 to 8 and Comparative Examples 1 to 4 at room temperature, and L ₁ is the sample length (μm) of the supporting material 2 of Examples 1 to 8 and Comparative Examples 1 to 4 when the amount of deformation is largest in the range of 25 to 600° C.

Furthermore, the shrinkage rate L _S1 of the ceramic body 1 during firing and the shrinkage rate L _S2 of the supporting material 2 during firing were calculated using the following formulas (2) and (3), and the difference L _S between the shrinkage rates of the supporting material 2 and the ceramic body 1 during firing (L _S = L _{S1 -} L _S2 ) was calculated.
Shrinkage rate of the ceramic shaped body 1 during firing L _S1 (%)=( L ₃₁ − _{L 21} )/ L ₂₁ ×100 (2)
Shrinkage rate of supporting material 2 during firing L _S2 (%) = (L ₃₂ -L ₂₂ ) / L ₂₂ × 100 ... (3)
In the above formula (2), L ₂₁ is the sample length (μm) of the ceramic shaped body 1 at the temperature (1000° C.) when zirconia starts to shrink during firing, and L ₃₁ is the sample length (μm) of the ceramic shaped body 1 at the recovery temperature (1150 to 1400° C.) of the supporting material 2 shown in Table 1. In addition, in the above formula (3), L ₂₂ is the sample length (μm) of the supporting material 2 of Examples 1 to 8 and Comparative Examples 1 to 4 at the temperature (1000° C.) when zirconia starts to shrink during firing, and L ₃₂ is the sample length (μm) of the supporting material 2 of Examples 1 to 8 and Comparative Examples 1 to 4 at the recovery temperature (1150 to 1400° C.) of the supporting material 2 shown in Table 1.

Here, the thermal deformation rate L _D of the supporting material 2 during degreasing is calculated by the above formula (1), but when the supporting material 2 is heated to 600°C or less in the degreasing process, organic substances such as binder resin in the supporting material 2 are thermally decomposed and burned by heating, and the supporting material 2 shrinks, so the thermal deformation rate L _D is expressed as a negative value in Table 1. However, since the "thermal deformation rate of the supporting material 2 during degreasing" in the present invention means the rate at which the supporting material 2 is deformed in the degreasing process, in this embodiment, it is evaluated by comparing it with the absolute value of the thermal deformation rate L _D in Table 1. In that case, as shown in Table 1, it was found that the absolute value of the thermal deformation rate L _D of the supporting material 2 during degreasing was within 10% in all of Examples 1 to 8. Furthermore, as shown in Table 1 above, the difference L _S (L _S1 -L _S2 ) in the shrinkage rate between the supporting material 2 and the ceramics shaped body 1 during firing was within 4% at the recovery temperature (1150 to 1200°C) at which the supporting material 2 was removed. From this, the supporting material 2 in Examples 1 to 8 was able to suppress melting during degreasing, was able to shrink in accordance with the ceramics shaped body 1 during firing, and was able to continuously support the ceramics shaped body 1 during the degreasing and firing processes.

On the other hand, in Comparative Examples 1 to 4, the absolute value of the thermal deformation rate L _D during degreasing of the supporting material 2 exceeded 10%, or the difference L _S (L _S1 -L _S2 ) in the shrinkage rate between the supporting material 2 and the ceramic shaped body 1 during firing exceeded 4% at the recovery temperature at which the supporting material 2 was removed, and there was a risk that the ceramic shaped body 1 could not be continuously supported in the degreasing and firing process. That is, in Comparative Examples 1 to 4, the supporting material 2 was produced in the same manner as in Examples 1 to 8, except for the following points. Specifically, in Comparative Example 1, the composition ratio of the self-disintegrating layer 20 in the supporting material 2 was 80%, which exceeds the upper limit of 60%, and in Comparative Examples 2 and 3, the recovery temperature of the supporting material 2 was 1300 ° C. and 1400 ° C., which are higher than 1200 ° C., respectively, and in Comparative Example 4, the supporting material 2 was produced only with the self-disintegrating layer 20.

As shown in Table 1 above, in Comparative Examples 1 and 4, the absolute value of the thermal deformation amount L _D of the supporting material 2 during degreasing was greater than 10%, which caused the risk of the supporting material 2 melting down. In addition, in Comparative Examples 2 to 4, the difference in shrinkage rate L _S (L _S1 -L _S2 ) between the ceramic shaped body 1 and the supporting material 2 during firing was greater than 4%, which caused the risk of the ceramic shaped body 1 being destroyed during firing. Thus, in Comparative Examples 1 to 4, the absolute value of the thermal deformation rate L _D of the supporting material 2 during degreasing exceeded 10%, or the difference in shrinkage rate L _S (L _S1 -L _S2 ) between the supporting material 2 and the ceramic shaped body 1 during firing exceeded 4% at the recovery temperature at which the supporting material 2 was removed, which caused the risk of the ceramic shaped body 1 not being able to be continuously supported during the degreasing and firing process.

Next, the compressive strength of the self-disintegrating layer 20 (Examples 1 to 8 and Comparative Examples 1 to 4) after firing, which constitutes the support material 2, and the rate of change in particle size of the self-disintegrating layer 20 before and after firing will be described. In the evaluation of the compressive strength and rate of change in particle size of the self-disintegrating layer 20 after firing, a modeling nozzle with a diameter of 1.0 mm was used to model the self-disintegrating layer 20 to approximately 3 mm wide x 3 mm long x 3 mm high under conditions of a layer pitch of 200 μm, a modeling nozzle temperature of 120°C, and a modeling table temperature of 75°C. Then, the self-disintegrating layer 20 was fired for 1 hour at a predetermined temperature with a heating rate of 1°C/min in an air atmosphere, to obtain the self-disintegrating layer 20 (Examples 1 to 8 and Comparative Examples 1 to 4) to be used in the support material 2 after firing.

The compressive strength (MPa) of the self-disintegrating layer 20 used in the support material 2 after firing was measured by applying pressure to Examples 1 to 8 and Comparative Examples 1 to 4 at a crosshead speed of 0.5 mm/min using a universal material testing machine (product name "5566", manufactured by Instron Corporation) and measuring the maximum load until the test piece was compressed and broken (n=7). The compressive strength of the support material 2 after firing was calculated from the following formula (4).
Compressive strength of supporting material 2 after firing (MPa)=breaking load (N)/cross-sectional area of test piece (mm ² ) (4)

Furthermore, the self-disintegrating layers 20 of Examples 1 to 8 and Comparative Examples 1 to 4 used in the compressive strength measurement were collected, and the particle diameter of the high-melting-point inorganic filler in the self-disintegrating layers 20 was measured. The particle size change rate of the collected high-melting-point inorganic filler was measured using a particle size distribution measuring device (product name "Microtrac HRA9320", manufactured by Microtrac Bell Co., Ltd.) with water as the dispersion medium and a refractive index of 1.54. The particle size change rate (%) of the high-melting-point inorganic filler before and after firing was calculated by the following formula (5).
Particle size change rate (%) of high melting point inorganic filler before and after firing = x / x ₀ × 100 ... (5)
In the above formula (5), x ₀ is the average particle size (μm) of the high melting point inorganic filler raw material powder, and x is the average particle size (μm) of the high melting point inorganic filler after recovery.

As shown in Table 1 above, in Examples 1 to 8, the compressive strength of the self-disintegrating layer 20 after firing was 5 MPa or less. In addition, in Examples 1 to 8, the particle size change rate of the recovered high-melting-point inorganic filler was 150% or less. As described above, it was found that in the support material 2 of Examples 1 to 8, the self-disintegrating layer 20 can be easily removed from the ceramic shaped body 1, and the self-disintegrating layer 20 can also be appropriately recovered and reused. On the other hand, as shown in Table 1 above, in Comparative Example 2, the compressive strength was greater than 5 MPa, and there was a risk that the self-disintegrating layer 20 could not be easily removed from the ceramic shaped body 1. In addition, in Comparative Example 3, the particle size change of the high-melting-point inorganic filler exceeded 150%, and the support material 2 was no longer suitable for reuse.

Next, Example 9 and Comparative Example 5 will be described. Table 2 below shows the composition ratio and each physical property value of the support material 2 of Example 9 and Comparative Example 5. In Example 9 and Comparative Example 5, a rectangular parallelepiped ceramic shaped body 1 having dimensions of 14 mm wide x 20 mm long x 12 mm high and a cavity of 10 mm wide x 20 mm long x 10 mm high inside was shaped while applying the support material 2 to the cavity part so that the width was 6 mm wide x 20 mm long x 10 mm high and the filling rate was 50%. The shaping conditions were as follows: a shaping nozzle with a diameter of 1.0 mm was used, the layer pitch was 200 μm, the shaping nozzle temperature was 120 ° C., and the shaping table temperature was 75 ° C. Then, under conditions of an air atmosphere and a temperature rise rate of 1 ° C./min, the ceramic shaped body 1 was heated to a predetermined temperature, cooled, and evaluated whether the support material 2 was properly recovered, and the deformation of the ceramic shaped body 1 during firing after the support material was recovered.

In Example 9, the absolute value of the thermal deformation rate L _D of the supporting material 2 during degreasing was within 10%, and the difference L _S (L _S1 -L _S2 ) in the shrinkage rate between the supporting material 2 and the ceramic shaped body 1 during firing was also within 4%. Furthermore, the compressive strength of the supporting material 2 after firing was 5 MPa or less, and the particle size change rate of the recovered high melting point inorganic filler was 150% or less. In Example 9, the supporting material 2 was easily recovered by heating to the recovery temperature (1150°C) of the supporting material 2 and then cooling to room temperature. Furthermore, after recovering the supporting material 2, the ceramic shaped body 1 was heated to 1400°C and fired under the condition of holding for 1 hour, and no deformation was observed in the ceramic shaped body 1.

In contrast, in Comparative Example 5, the ceramic shaped body 1 and the supporting material 2 were heated to the recovery temperature (1150°C) and then cooled to room temperature, and the supporting material 2 was recovered. In Comparative Example 5, the absolute value of the thermal deformation rate L _D of the supporting material 2 during degreasing was within 10%, and the difference L _S (L _S1 -L _S2 ) in the shrinkage rate between the supporting material 2 and the ceramic shaped body 1 during firing was also within 4%. In addition, the compressive strength of the supporting material 2 after firing was also 5 MPa or less, and the particle size change rate of the recovered high melting point inorganic filler was also 150% or less. However, in Comparative Example 5, since the composition ratio of the self-disintegrating layer 20 was less than 5%, the supporting material 2 was burned and caught on the ceramic shaped body 1, resulting in the supporting material 2 not being able to be removed cleanly.

As described above, in this embodiment, the ceramic shaped body 1 is produced using a support material 2 having a shrinkage relaxation layer 10 that shrinks following the shrinkage of the ceramic shaped body 1 during firing, and a self-disintegrating layer 20 that is made of a filament material that is a mixture of a high-melting-point inorganic filler and a thermoplastic resin and can be peeled off from the ceramic shaped body 1 after firing. In particular, the support material 2 according to this embodiment has a thermal deformation rate of the support material 2 during degreasing that is within 10%, and the difference L _S (L _S1 -L _S2 ) in the shrinkage rate between the ceramic shaped body 1 and the support material 2 during firing is within 4% at each temperature at which the support material 2 is removed. Therefore, it is possible to suppress melting of the support material 2 during degreasing, and it is possible to shrink following the ceramic shaped body 1 during firing, and it is possible to continuously support the ceramic shaped body 1 during the degreasing and firing process. As a result, it is possible to appropriately produce a ceramic shaped body 1 having an overhang shape, a bridge shape, or the like.

In addition, in the support material 2 according to this embodiment, the compressive strength after firing is set to 5 MPa or less, and the particle size change rate of the recovered high-melting-point inorganic filler is set to 150% or less. This allows the support material 2 to be easily removed from the ceramic shaped body 1 after firing, and also allows the self-disintegrating layer 20 to be efficiently recovered and the high-melting-point inorganic filler used in the self-disintegrating layer 20 to be reused. As a result, the material can be recycled, and production costs can be reduced while being environmentally friendly.

The above describes preferred embodiments of the present invention, but the technical scope of the present invention is not limited to the above description of the embodiments. Various modifications and improvements can be made to the above embodiments, and such modifications or improvements are also included in the technical scope of the present invention.

1... Ceramic shaped body 2... Support material 10... Shrinkage relaxation layer 20... Self-disintegrating layer

Claims (19)

A method for producing a three-dimensional additive manufacturing object, comprising forming a support material that supports the three-dimensional additive manufacturing object below the three-dimensional additive manufacturing object during a manufacturing process of the three-dimensional additive manufacturing object by a material extrusion method, the method comprising the steps of:
The method for producing a three-dimensional additive model includes forming a support material having a shrinkage relaxation layer that shrinks in response to the shrinkage of the three-dimensional additive model during firing, and a self-disintegrating layer that is made of a filament material that is a mixture containing a high-melting point inorganic filler and a thermoplastic resin and can be peeled off from the three-dimensional additive model after firing, wherein the self-disintegrating layer shrinks in response to the shrinkage of the three-dimensional additive model during firing, but has a smaller shrinkage rate during firing than the shrinkage relaxation layer . The three-dimensional additively manufactured object is a ceramics manufactured object, and is manufactured using a ceramics material containing ceramic powder;
The method for producing a three-dimensional additive manufacturing object according to claim 1 , wherein the shrinkage relaxation layer is formed from a filament material that is a mixture containing a ceramic powder and a thermoplastic resin. The method for producing a three-dimensional additive manufacturing object according to claim 2, wherein the filament material forming the shrinkage relaxation layer contains 30% or more by volume of the ceramic powder. The method for producing a three-dimensional additive manufacturing object according to claim 1 , wherein the filament material forming the self-disintegrating layer has a content of the high melting point inorganic filler of 30 volume % or more. The method for producing a three-dimensional additive manufacturing object according to claim 1 , wherein the high melting point inorganic filler has a melting temperature that is 100° C. or more higher than a firing temperature of the three-dimensional additive manufacturing object. 6. The method according to claim 1 , wherein the high melting point inorganic filler has an average particle size of 1 μm or more and 40 μm or less, and an increase in the average particle size before and after firing is 150% or less. The method for producing a three-dimensional additive manufacturing object according to any one of claims 2 to 6 , wherein the filament material forming the shrinkage relaxation layer and/or the self-disintegrating layer has a viscosity of 20 to 500 Pa·s at the modeling temperature. The method for producing a three-dimensional additive manufacturing object according to claim 1 , wherein the self-disintegrating layer has a compressive strength of 5 MPa or less after firing. The method for producing a three-dimensional additive manufacturing object according to claim 1 , wherein the supporting material has a composition ratio of the self-disintegrating layer of 5% or more and 60% or less. The support material is
The rate of thermal deformation during degreasing is within 10%.
The method according to claim 1 , wherein a difference in shrinkage rate between the supporting material and the three-dimensional additive manufacturing object during firing is within 4%. The method according to claim 1 , wherein the three-dimensional additive manufacturing object is a manufacturing object that is manufactured into an overhang shape or a bridge shape. A support material that supports a three-dimensional additive manufacturing object under a lower portion of the three-dimensional additive manufacturing object during a manufacturing process of the three-dimensional additive manufacturing object by a material extrusion method,
a shrinkage relaxation layer that shrinks in response to shrinkage of the three-dimensional additive manufacturing body during firing;
a self-disintegrating layer that is formed from a filament material that is a mixture containing a high melting point inorganic filler and a thermoplastic resin, prevents adhesion between the three-dimensional additive manufacturing object and the shrinkage relaxation layer, and is peelable from the three-dimensional additive manufacturing object after firing ;
The self-disintegrating layer shrinks in response to shrinkage of the three-dimensional additive manufacturing body during firing, but has a smaller shrinkage rate during firing than the shrinkage relaxation layer . The supporting material according to claim 12 , wherein the three-dimensional additive manufacturing object is an overhang-shaped or bridge-shaped manufactured object. 14. The supporting material according to claim 12 or 13 , wherein the material extrusion method is a method for producing a molded object by extruding a plastic material from a nozzle and laminating it in a three-dimensional additive manufacturing (AM) technology. The support material according to any one of claims 12 to 14 , wherein the material of the support material is a mixture containing a ceramic powder and a thermoplastic resin for the shrinkage relaxation layer, and a mixture containing a high melting point inorganic filler and a thermoplastic resin for the self-disintegrating layer. an article comprising: a ceramic three-dimensional additive manufactured body shaped by an extrusion method with a modeling material including a sinterable ceramic powder material for forming a final part at a sintering temperature, the ceramic three-dimensional additive manufactured body including one or more resin binders that hold the powder material into a net-shape object before densifying the powder material into a final part; and a support material for the ceramic three-dimensional additive manufactured body arranged adjacent to a surface of the ceramic three-dimensional additive manufactured body and supporting the ceramic three-dimensional additive manufactured body underside during at least one of degreasing and sintering of the manufactured body , the support material having both a shrinkage relief layer that shrinks in accordance with the shrinkage of the three-dimensional additive manufactured body during firing , and a self-disintegrating layer that prevents adhesion between the three-dimensional additive manufactured body and the shrinkage relief layer and is peelable from the three-dimensional additive manufactured body after firing, the self-disintegrating layer shrinking in accordance with the shrinkage of the three-dimensional additive manufactured body during firing, but having a smaller shrinkage rate during firing than the shrinkage relief layer . The support material is a material made of a mixture containing a ceramic powder of the shrinkage relaxation layer or a high-melting point inorganic filler of the self-disintegrating layer and a thermoplastic resin, and the ceramic powder of the shrinkage relaxation layer or the high-melting point inorganic filler of the self-disintegrating layer is a mixture having a content of 30 volume % or more, and a filament made of this mixture in a strand shape is made of a material having a fluidity of a viscosity of 20 to 500 Pa s at the heating temperature during molding. The article according to claim 16 . The article according to claim 16 or 17, wherein the high-melting point inorganic filler of the self-disintegrating layer has a melting temperature 100° C. or more higher than the desired sintering temperature of the shaped body, has an average particle diameter of 1 μm or more and 40 μm or less, the relative density of the ceramic shaped body when the support is removed in the firing process is 50% or more, the compressive strength of the self-disintegrating layer at that time is 5 MPa or less, and the degree of adhesion of the inorganic filler that is the self-disintegrating layer is such that the change in the average particle diameter before firing is 150 % or less , and the article can be recovered and recycled. 19. An article according to any one of claims 16 to 18, which is a composite support material for ceramic modeling, in which the composition ratio of the self-disintegrating layer in the composite support material is 5% or more and 60% or less, the thermal deformation of the composite support material during degreasing is 10 % or less, and the difference in shrinkage rate between the ceramic modeled body and the composite support during firing is within 4 %.