JP2015021016A - Method for regenerating spherical aggregate in laminate molding material, regenerated laminate molding material, and method for producing laminate molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in laminate molding using a laminate molding material that a portion of the laminate molding material becomes a laminate molded article but most of the rest becomes a waste material, the problem being specifically that, even though this waste material can be reused as is as the laminate molding material, a laminate molding material which has been used for a selective laser sintering method and the like contains a resin component which is thermally degraded, and therefore, when 100% of this waste material is used as the laminate molding material, a molded article obtained has inferior strength, develops an orange peel surface, and has inferior quality, thus necessitating, when using the waste material, addition of a large amount of a new synthetic resin and spherical aggregate to maintain quality of the molded article, resulting in generation of a large quantity of a waste material every time molding is performed, which is not reused and, thus, makes recycling of all of the waste material practically impossible.SOLUTION: A method for regenerating spherical aggregate in a laminate molding material comprises removing a synthetic resin in the laminate molding material by pyrolysis to obtain regenerated spherical aggregate.

Description

  The present invention relates to a method for regenerating a spherical aggregate in an additive manufacturing material, an additive manufacturing material, and an additive manufacturing method.

  In the production of three-dimensional prototypes and models, models such as stereolithography, selective laser sintering (SLS), hot melt lamination (FDM), and ink jet are used. . This additive manufacturing technique is a useful technique in various fields such as product development, architecture, medical care, and education.

Various synthetic resin materials are used in the additive manufacturing technique. However, when a modeled object is produced using only a synthetic resin, since the elastic modulus is low, the modeled object is easily deformed by various external forces.
Therefore, recently, a technique for obtaining a modeled object with an improved elastic modulus by using a layered modeling material obtained by adding an aggregate to a synthetic resin has been adopted. For example, Patent Literature 1 discloses an additive manufacturing material in which spherical carbon is added to resin powder.

In the additive manufacturing using the additive manufacturing material, there is a problem that a part of the additive manufacturing material becomes an additive manufacturing object, and the other part becomes a waste material.
This waste material can be reused as it is as an additive manufacturing material. However, since it is once subjected to additive manufacturing, it is somewhat affected by heat, light, etc., and the object that uses a large amount of waste material as additive manufacturing material is inferior in strength, It is likely to occur. Yuzu skin is a phenomenon in which the surface of a model has irregularities such as tangerine skin.
For this reason, when reusing a layered modeling material, in order to maintain the quality of the modeled object, it is necessary to limit the ratio of the waste material used in combination with the new layered modeling material, which cannot be reused for each modeling. A large amount of excess waste material was generated.

JP 2009-13395 A

  The present invention has been made in view of the above circumstances, and the spherical aggregate in the additive manufacturing material can be reused without including the deterioration of the quality of the additive manufacturing object. It is intended to provide a reproduction method, a layered modeling material including the regenerated spherical aggregate obtained by the reproduction method, and a method of manufacturing a layered structure using the layered modeling material including the regenerated spherical aggregate. Objective.

In order to achieve the above object, the present invention employs the following configuration.
[1] A method for regenerating a spherical aggregate in an additive manufacturing material, wherein the synthetic resin in the additive manufacturing material containing the spherical aggregate and the synthetic resin is thermally decomposed and removed.
[2] The material for additive manufacturing including the spherical aggregate and the synthetic resin is a discarded material that has not become an additive manufacturing object in the additive manufacturing material provided for additive manufacturing. A method for regenerating a spherical aggregate in an additive manufacturing material.
[3] The method for regenerating a spherical aggregate in the additive manufacturing material according to [1] or [2], wherein the additive manufacturing material is a material of a selective laser sintering method.
[4] The method for regenerating a spherical aggregate in the additive manufacturing material according to any one of [1] to [3], wherein the spherical aggregate is spherical carbon.
[5] The additive manufacturing according to any one of [1] to [4], wherein the synthetic resin is one or more selected from the group consisting of a thermoplastic resin, a thermosetting resin, and a photocurable resin. To regenerate spherical aggregates in construction materials.
[6] The method for regenerating a spherical aggregate in the additive manufacturing material according to [5], wherein the thermoplastic resin is polyamide 11 or polyamide 12.
[7] A regenerated laminate including a regenerated spherical aggregate obtained by the method for regenerating a spherical aggregate in the additive manufacturing material according to any one of [1] to [6], and a synthetic resin. Material for modeling.
[8] Regenerated spherical aggregate obtained by the method for regenerating spherical aggregate in the additive manufacturing material according to any one of [1] to [6], and additive manufacturing for additive manufacturing Recycled additive manufacturing material including a waste material that has not become an additive manufacturing object, a synthetic resin that is not subjected to additive manufacturing, and a spherical aggregate that is not subjected to additive manufacturing.
[9] A method for producing a layered object, wherein the reproduction layered material according to [7] or [8] is layered.

  Since the spherical aggregate obtained by the method for regenerating a spherical aggregate in the additive manufacturing material of the present invention does not deteriorate the quality of the additive manufacturing object even when used in a large amount, it can be reused efficiently. Moreover, even if the reproduction of the spherical aggregate according to the present invention is repeated, the quality of the spherical aggregate is not deteriorated. Furthermore, when a layered modeling material including the recycled aggregate is used, a layered model having excellent strength can be obtained. Furthermore, the workability of additive manufacturing is also improved.

1 shows a model of an additive manufacturing recycling system according to the present invention. The model of the conventional additive manufacturing recycling system is shown.

[Recycling method of spherical aggregate in additive manufacturing material]
The method for regenerating a spherical aggregate in the additive manufacturing material of the present invention is a method of regenerating the spherical aggregate (hereinafter referred to as “regenerated spherical aggregate”) by thermally decomposing and removing the synthetic resin in the additive manufacturing material. The process of obtaining. The additive manufacturing material includes a spherical aggregate and a synthetic resin.

(Layered material)
In the present invention, the material for layered modeling to be recycled is a waste material that has not become a layered model in the layered modeling material subjected to layered modeling, but has not yet been used for layered modeling processing, but is stored for a long time As a result, a layered material in which the synthetic resin has deteriorated over time, a layered product that has become unnecessary, and the like can be cited. Especially, since the said waste material generate | occur | produces in large quantities in additive manufacturing, it is a material suitable for the reproduction | regenerating method of the spherical aggregate in the additive manufacturing material of this invention.
Among waste materials, low-degradation waste materials with high powder flowability and low degree of degradation are easy to reuse as additive manufacturing materials. Therefore, among the waste materials, the method for regenerating the spherical aggregate in the additive manufacturing material of the present invention is applied to a material that is likely to cause lumps during the modeling process and has a relatively high degree of deterioration. It is preferable to do.

  The additive manufacturing material is used as a material for additive manufacturing methods such as stereolithography, selective laser sintering, hot-melt lamination, and inkjet methods. Among these, the method for regenerating a spherical aggregate in the additive manufacturing material of the present invention can be suitably applied to a material of a selective laser sintering method that easily causes thermal deterioration.

The additive manufacturing material of the present invention includes a spherical aggregate and a synthetic resin.
The aggregate is included in the additive manufacturing material so that the additive object is not deformed, for example, by improving the elastic modulus. In the present invention, a spherical aggregate is used in particular.
The degree of the spherical shape of the spherical aggregate can be expressed by sphericity.

The sphericity is an index calculated by “the diameter of a circle equal to the projected area of the particle / the diameter of the smallest circle circumscribing the projected image of the particle”, and the closer to 1.0, the closer to a true sphere. The sphericity of the spherical aggregate of the present invention is preferably 0.7 or more, more preferably 0.95 or more, and most preferably 1.0 (true sphere).
If it is more than the said lower limit, in the case of modeling, the powder of a spherical aggregate can be sprinkled uniformly and it becomes easy to model.

The average particle diameter of the spherical aggregate is not particularly limited as long as it is within the range of the particle diameter of the spherical aggregate usually used for the additive manufacturing material.
In this specification, the average particle diameter means a volume average particle diameter measured by a laser diffraction scattering method.
In this invention, 10-150 micrometers is preferable as an example of the average particle diameter of a spherical aggregate, and 40-60 micrometers is more preferable. If it is at least the lower limit value, it is easy to spread the material at the time of modeling, and if it is not more than the upper limit value, a molded product with a fine shape can be obtained.

The melting point of the spherical aggregate is not particularly limited, but may be higher than the thermal decomposition temperature of the synthetic resin to be blended in order to obtain the effects of the present invention.
For example, when polyamide 11 is used as the synthetic resin, the melting point of the spherical aggregate is preferably 450 ° C. or higher because the thermal decomposition temperature of polyamide 11 is 350 ° C.

Examples of the material of the spherical aggregate include spherical carbon, glass beads, aluminum powder and the like. Among these, spherical carbon is preferable because it is easy to obtain a shaped article that is less prone to static electricity.
The spherical carbon is preferably spherical carbon made from a thermosetting spherical resin. The spherical carbon is obtained by carbonizing a thermosetting spherical resin at a temperature of 400 to 1000 ° C. in a nitrogen atmosphere. Specifically, the GC series made by Gunei Chemical Industry Co., Ltd. can be mentioned.
Moreover, as a raw material of the said thermosetting spherical resin, the spherical hardened | cured material of a phenol resin or a furan resin can be used, for example. A spherical cured product of a phenol resin is obtained by subjecting phenols and aldehydes to a condensation reaction in an aqueous medium under the conditions of high temperature and high pressure in the presence of a condensation reaction catalyst and an emulsifying dispersant. Specifically, a fully curable spherical phenol resin is mentioned, and more specifically, HF series manufactured by Gunei Chemical Industry Co., Ltd. is preferable.
A spherical cured product of furan resin is obtained by reacting a furan compound and an aldehyde in an aqueous medium in the presence of a reaction catalyst and a dispersant.

The kind of synthetic resin will not be specifically limited if it is normally used for the material for layered modeling. For example, a thermoplastic resin, a thermosetting resin, or a photocurable resin can be used, and among them, a thermoplastic resin or a thermosetting resin is preferable from the viewpoint of mechanical strength.
Examples of the thermoplastic resin include polyamide, polystyrene, polyaryletherketone, polybutylene terephthalate, polyacetal, polypropylene, and polyethylene.
Examples of the thermosetting resin include a phenol resin, an epoxy resin, and a melamine resin.
Among these resins, polyamide, polystyrene, and polyaryl ether ketone are preferable, and polyamide 11 and polyamide 12 are more preferable.
Moreover, you may use a synthetic resin in mixture of 2 or more types.

In the additive manufacturing material containing the regenerated spherical aggregate, the blending ratio of the spherical aggregate and the synthetic resin is preferably 10/90 to 80/20 in mass ratio represented by “spherical aggregate / synthetic resin”. 30 / 70-60 / 40 is more preferable, 40 / 60-50 / 50 is further more preferable, and 50/50 is most preferable. If the ratio of the spherical aggregate is equal to or higher than the preferable lower limit, the shrinkage rate of the obtained molded body is reduced, the moldability is further improved, and if it is equal to or lower than the preferable upper limit, The strength represented by the tensile fracture strain is further improved.
In particular, when the spherical aggregate is spherical carbon, the volume resistivity is 10 ⁶ to 10 ¹⁰ Ω when the content of the spherical carbon in the additive manufacturing material including the regenerated spherical aggregate is 35 to 55% by mass.・ It becomes cm, and the effect of preventing static electricity is high. In addition, when the content of spherical carbon in the additive manufacturing material including the regenerated spherical aggregate is 55 to 80% by mass, the volume resistivity is 10 ¹ to 10 ⁶ Ω · cm, which is used for packaging in the electrical and electronic field. It is useful for parts and parts for OA equipment.

(Regeneration process)
The “regenerating method of spherical aggregate in the additive manufacturing material” of the present invention includes a step of obtaining a recycled spherical aggregate by thermally decomposing and removing the synthetic resin in the additive manufacturing material.

In this specification, “pyrolysis” means that the synthetic resin contained in the material is decomposed by heating the additive manufacturing material.
The thermally decomposed synthetic resin is mainly removed from the additive manufacturing material by vaporization. Alternatively, the synthetic resin may be removed from the additive manufacturing material by reacting with oxygen contained in the air mixed in the heating furnace and burning.

In the present specification, “regeneration rate” is used as an index representing the rate at which the spherical aggregate is regenerated by the regeneration process.
The “regeneration rate” is the ratio (%) of the mass of the regenerated spherical aggregate to the mass of the total spherical aggregate contained in the additive manufacturing material subjected to the regeneration process.
Theoretically, when the synthetic resin is completely removed from the additive manufacturing material subjected to the regeneration process and the entire spherical aggregate is regenerated, the regeneration rate is 100%. Further, although the synthetic resin has been completely removed, when the spherical aggregate is thermally decomposed together with the synthetic resin, the regeneration rate becomes a value smaller than 100%.
Actually, since the synthetic resin may become soot and adhere to the regenerated spherical aggregate in a minute amount, even if the synthetic resin is sufficiently removed, the regeneration rate may exceed 100%. When the regeneration rate greatly exceeds 100%, it can be said that the synthetic resin is not sufficiently removed, and therefore, it is not preferable.
The regeneration rate is preferably 90 to 120%, more preferably 94 to 115%, and still more preferably 98 to 110%.

What is necessary is just to set the preset temperature and thermal decomposition time of the heating furnace in the case of thermal decomposition suitably in consideration of the thermal decomposition temperature of a synthetic resin and the heat resistance of a spherical aggregate.
For example, when the synthetic resin is polyamide and the spherical aggregate is spherical carbon, 350 to 800 ° C is preferable, and 400 to 600 ° C is more preferable. If it is more than the said lower limit, a synthetic resin will be easy to be removed, and if it is less than the said upper limit, it will be easy to suppress that a spherical aggregate is thermally decomposed with a synthetic resin.
In addition, the thermal decomposition time is not particularly limited, and is preferably 0.5 to 10 hours because it is sufficient that the removal by the thermal decomposition of the synthetic resin is completed, and varies depending on the type and amount of the material and the thermal decomposition temperature. 1 to 8 hours is more preferable, and 3 to 5 hours is more preferable.

  As an apparatus for thermal decomposition, for example, a heating furnace generally used in industry can be used. Specific examples of the heating furnace include a batch type carbonization furnace “CYT-1700” (manufactured by CFR Kogyo Co., Ltd.).

[Recycled additive manufacturing materials]
The regenerative additive manufacturing material of the present invention includes a regenerated spherical aggregate obtained by the above-described method for regenerating a spherical aggregate in the additive manufacturing material, and a synthetic resin.
The synthetic resin to be included in the recycled additive manufacturing material includes at least a synthetic resin that has not been subjected to additive manufacturing (hereinafter referred to as “new synthetic resin”).
The synthetic resin contains a synthetic resin contained in a waste material that has not become a layered object in the layered object material that has been subjected to the layered object as long as the quality of the layered object is not degraded. Also good.
Moreover, the regenerative additive manufacturing material of the present invention may contain a third component in addition to the synthetic resin and the spherical aggregate.

The spherical aggregate to be included in the recycled additive-molding material may be a recycled spherical aggregate alone, or a spherical aggregate that has not been subjected to additive manufacturing (hereinafter referred to as “new spherical aggregate”) and laminated. Even one or both of the spherical aggregates (hereinafter referred to as “used spherical aggregates”) included in the waste material that has not become a layered product among the additive manufacturing materials provided for modeling. Good.
When adding one or both of a new spherical aggregate and a used spherical aggregate to the recycled spherical aggregate, the new spherical aggregate or the used spherical aggregate may be the same type as the recycled spherical aggregate. , Different types of materials may be used.
In addition, when one or both of a new spherical aggregate and a used spherical aggregate is added to the recycled spherical aggregate, the blending ratio of both spherical aggregates can be determined as appropriate. The regenerative additive manufacturing material of the present invention only needs to contain a regenerated spherical aggregate.

Recycled additive manufacturing material of the present invention is a recycled spherical aggregate, a waste material that did not become a laminate modeled material in the additive manufacturing material, a new synthetic resin, and a new spherical aggregate Are preferably included.
As the waste material used as it is for the recycled additive manufacturing material, a low deterioration waste material is preferable. The low-degradation waste material is a waste material having a high powder flowability and a low degree of deterioration. If a highly deteriorated waste material having a high degree of deterioration is used as it is for the recycled additive manufacturing material as it is, the surface of the additive manufacturing object is likely to be crumpled. Therefore, when waste materials are included in the recycled additive manufacturing material as they are, it is preferable to use low-degradation waste materials.

  The regenerative additive manufacturing material can be manufactured by mixing the regenerated spherical aggregate, a new synthetic resin, and, if necessary, other materials. For mixing, a screw-type mixer or the like is used. As a specific procedure, for example, a recycled spherical aggregate, a new synthetic resin, and, if necessary, other materials are put into a screw mixer so as to have a desired blending ratio and mixed for 3 to 10 minutes. To obtain a regenerative additive manufacturing material.

[Manufacturing method of layered object]
The manufacturing method of the layered object of the present invention is characterized by layering the material for reproduction layered modeling of the present invention.

The apparatus used for the additive manufacturing method may be one that is normally used in each additive manufacturing method. For example, as an apparatus used for the selective laser sintering method, a powder additive manufacturing machine “EOSINT P380” (manufactured by EOS) can be mentioned.
The layered object is completed by performing layered modeling by a selective laser sintering method or the like and then taken out from the layered modeling material.

[Multiple modeling recycling system]
According to the present invention, since the spherical aggregate can be regenerated, it is possible to construct an additive manufacturing recycling system that does not waste the spherical aggregate. The additive manufacturing recycling system will be described below by taking as an example the case of using additive manufacturing materials in which polyamide 11 and spherical carbon are blended at 50:50.
FIG. 1 shows a model of an additive manufacturing recycling system using the method for regenerating a spherical aggregate in the additive manufacturing material of the present invention, and FIG. 2 shows a model of a conventional additive manufacturing recycling system.

  As shown in FIG. 2, conventionally, in order not to deteriorate the quality of the layered object, the waste material that can be recycled is only the low-degradation waste material, and the amount thereof is also limited. For example, the model in FIG. 2 is a model that recycles 15 kg of low-degradation waste material in a system that performs additive manufacturing using a total of 30 kg of additive manufacturing materials. In this case, 7.5 kg of polyamide 11 and spherical carbon must be newly added to make a total of 30 kg. When layered modeling processing is performed using this, 2.9 kg of the layered modeling material 30 kg becomes a layered model and the remaining 27.1 kg becomes waste material. In this recycling system, out of the 27.1 kg of the waste material, 15 kg of the low deterioration waste material is recycled again as the additive manufacturing material, but the remaining 12.1 kg is continuously discarded outside the system every time.

  On the other hand, in the model (FIG. 1) of the recycling system according to the present invention, recycled spherical aggregate can be obtained regardless of the degree of degradation of the waste material. Therefore, it is possible to regenerate the spherical carbon by using all the 12.1 kg of waste material discharged every time in FIG. 2 without discharging. In this model, 6.3 kg of regenerated spherical carbon is obtained (when the regeneration rate is 104%), and the amount of newly added spherical carbon may be 1.2 kg. The amount of spherical carbon newly added in FIG. 1 is 16% of 7.5 kg of spherical carbon newly added in FIG.

[Operational effects obtained by the present invention]
The layered object obtained by layering the layered material including the layered spherical aggregate obtained by the method of regenerating the spherical aggregate in the layered material of the present invention has sufficient bending strength and density, In addition, the skin is not generated on the surface of the layered object. Conventionally, when the additive manufacturing material is composed only of the waste material, the quality of the additive manufacturing object has been deteriorated because the deterioration of the synthetic resin portion in the waste material is the main cause.
Since the method for regenerating a spherical aggregate in the additive manufacturing material of the present invention removes the synthetic resin by pyrolysis, the additive manufacturing material containing the recycled spherical aggregate causes a deterioration in the quality of the additive manufacturing object. I won't let you.

Moreover, when the reproduction | regeneration layered modeling material of this invention is used, since the layered object is easily taken out from the material after the layered modeling, the work efficiency can be improved.
It is considered that this is because a small amount of soot derived from the synthetic resin attached to the particle surface of the regenerated spherical aggregate fulfills the function of the lubricant, making it easy to take out the layered object.
Moreover, even if the reproduction of the spherical aggregate according to the present invention is repeated, the quality of the spherical aggregate is not deteriorated.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

[Evaluation method]
In each Example and Comparative Example described later, a test piece of 80 mm × 10 mm × 4 mm was obtained as a layered object, and the bending strength and density were measured.
The bending strength was measured by a method based on JIS K 7171. It can be said that the bending strength is sufficient if it is 60 MPa or more.
The density is determined by measuring the volume of each of the obtained five test pieces with a caliper, and further measuring the weight using a precision balance. Each of the “density” = the weight of the test piece (g) / the test piece volume (cm ³ ). The density of the test piece was obtained and the average value was used. If the density is 1.05 g / cm ^3, it can be said that the density is sufficient.
Moreover, the yuzu skin evaluated visually the presence or absence of the yuzu skin in the surface of the laminate-molded article obtained by each below-mentioned Example and comparative example.
Moreover, workability | operativity evaluated in the working time (minutes) which takes out a layered modeling thing from the material for layered modeling in the case of the layered modeling of each below-mentioned Example and comparative example.

(Production of waste materials)
15 kg of spherical carbon “GC-050” (manufactured by Gunei Chemical Industry Co., Ltd.) and 15 kg of polyamide 11 “RILSAN INVENT NATURAL” (manufactured by Arkema Co., Ltd.) are mixed by a screw-type mixer for 5 minutes to perform additive manufacturing. The material was used. From this additive manufacturing material, using a powder additive manufacturing machine “EOSINT P380” (manufactured by EOS), at a modeling temperature (temperature in the process chamber; the same applies hereinafter) at 195 ° C., by selective laser sintering, About 2.9 kg of the layered object was obtained.
At that time, 27.1 kg of the additive manufacturing material that did not become an additive manufacturing object was used as a total waste material. Further, 15 kg of the all waste materials, which were selected with a low degradation portion preferentially, were designated as low degradation waste materials, and the remaining 12.1 kg was designated as residual waste materials.

(Production example)
100 kg of the remaining waste material obtained by repeating the production of the waste material described above was collected, and the polyamide was pyrolyzed and removed at 500 ° C. for 5 hours in a batch type carbonization furnace “CYT-1700” (manufactured by CFR Kogyo Co., Ltd.) Regenerated spherical carbon of 52.1 kg (regeneration rate: 104.2%) was obtained.

Example 1
15 kg of the regenerated spherical carbon of the above production example and 15 kg of polyamide 11 “RILSAN INVENT NATURAL” were mixed with a screw mixer for 5 minutes to obtain an additive manufacturing material.
From the additive manufacturing material, an additive manufacturing object (including a test piece) is formed by a selective laser sintering method at a forming temperature of 195 ° C. using a powder additive manufacturing machine “EOSINT P380”. In the following examples and comparative examples The same was obtained.

(Example 2)
Recycled spherical carbon 6.3 kg of the above production example, 1.2 kg of spherical carbon “GC-050”, polyamide 11 “RILSAN INVENT NATURAL” 7.5 kg, and 15 kg of low-deterioration waste material 5 by a screw mixer. About 2.9 kg of the layered object was obtained in the same manner as in Example 1 except that the material was mixed for minutes to obtain the material for layered object modeling.

Example 3
20. 40 kg of the waste material obtained by the modeling process of Example 1 was pyrolyzed and removed from the polyamide at 500 ° C. for 5 hours in a batch carbonization furnace “CYT-1700” (manufactured by CFR Kogyo Co., Ltd.). 4 kg (regeneration rate 101.5%) of regenerated spherical carbon was obtained.
15 kg of the regenerated spherical carbon and 15 kg of polyamide 11 “RILSAN INVENT NATURAL” were mixed with a screw mixer for 5 minutes to obtain an additive manufacturing material.
About 2.9 kg of a layered object was obtained from the layered material in the same manner as in Example 1 above.

(Comparative Example 1)
About 30 kg of the layered product was obtained from 30 kg of the low deterioration waste material by a selective laser sintering method at a modeling temperature of 195 ° C. using a powder additive manufacturing machine “EOSINT P380”.

(Comparative Example 2)
Without using recycled spherical carbon, 7.5 kg of spherical carbon “GC-050”, 7.5 kg of polyamide 11 “RILSAN INVENT NATURAL”, and 15 kg of low-degradation waste material are mixed for 5 minutes with a screw-type mixer and laminated. About 2.9 kg of a layered product was obtained in the same manner as in Example 1 except that the material for modeling was used.

(Reference Example 1)
Except for using regenerated spherical carbon, 15 kg of spherical carbon “GC-050” and polyamide 11 “RILSAN INVENT NATURAL” 15 kg were mixed with a screw mixer for 5 minutes to obtain the material for additive manufacturing. About 2.9 kg of a layered product was obtained in the same manner as in 1.

(Evaluation results)
“Bending strength”, “density”, and “presence / absence of crushed skin” of the layered objects obtained in Examples 1 to 3, Comparative Examples 1 and 2 and Reference Example 1 were evaluated. These evaluation results are shown in Table 1 below.
Table 2 shows the evaluation results of workability.
In Tables 1 and 2, “recycled” is a recycled spherical carbon, “new” is a newly added spherical carbon, and “reuse” is a spherical contained in a low degradation waste material that is reused as a layered material. Each means carbon.
In Table 1, the number of times the reproduction method of the present invention was repeated is shown in parentheses.

From Table 1, the layered object of Examples 1 to 3 obtained using the regenerated spherical carbon obtained by the regenerating method of the present invention is a comparative example 2 in which a low degradation waste material and a new spherical carbon are used in combination as the spherical carbon. It can also be seen that the bending strength and density are equivalent to those of Reference Example 1 using only new spherical carbon.
On the other hand, it was confirmed that the laminate structure of Comparative Example 1 obtained by using only the low-degradation waste material as spherical carbon has reduced bending strength and density.
Further, as shown in Table 1, in Examples 1 to 3, Comparative Example 2 and Reference Example 1, there was no crushed skin on the surface of the layered object, whereas in Comparative Example 1 crushed skin was produced. .

From the results of Table 1 above, when a layered object is obtained using only a low-degradation waste material, the quality of the layered object decreases, whereas if the recycled spherical aggregate obtained according to the present invention is used, it is spherical. It was found that even if the total amount of aggregate was recycled spherical aggregate, the quality of the layered product obtained using the new spherical aggregate could be maintained.
In Examples 1 and 3, new spherical carbon is not used. In Example 2, 1.2 kg of new spherical carbon is only added.
On the other hand, in Comparative Example 2 or Reference Example 1, 7.5 kg or 15 kg of new spherical carbon is added to the additive manufacturing material.
Therefore, according to the method for regenerating spherical aggregates of Examples 1 to 3 of the present invention, compared with the conventional additive manufacturing methods of Comparative Example 2 and Reference Example 1, the amount of spherical carbon that must be newly added is greatly reduced. Can reduce costs.
Further, as particularly shown in Example 3, it is important in the present invention that even if the regeneration method of the present invention is repeated, the quality of the spherical carbon is not reduced.

Table 2 shows a layered product (comparative example) produced using only a low-degradation waste material, in which the operation time for taking out the layered product (Examples 1 and 2) using the regenerated spherical carbon obtained by the regeneration method of the present invention is shown. It is 30-40% shorter than 2).
From this, it was found that the use of the regenerated spherical aggregate obtained in the present invention improves the working efficiency of the layered modeling.

[Effect of temperature when pyrolyzing and removing synthetic resin]
Next, the influence of temperature when the synthetic resin was pyrolyzed and removed was examined.

(Experimental example 4)
Of the total waste material, 0.2 g of polyamide 11 was pyrolyzed and removed at 500 ° C. for 1 hour in a muffle furnace “KM-280” (manufactured by Advantech Toyo Co., Ltd.) to regenerate spherical carbon.
As a result, 0.1052 g of regenerated spherical carbon was obtained. The reproduction rate is 105.2%.

(Experimental example 5)
The same procedure as in Example 4 was performed except that the temperature at the time of thermal decomposition and removal was set to 400 ° C. and the time taken was 2 hours.
As a result, 0.1084 g of spherical carbon was obtained. The reproduction rate is 108.4%.

(Experimental example 6)
The same procedure as in Example 4 was performed, except that the temperature during pyrolysis and removal was set to 700 ° C.
As a result, 0.0942 g of spherical carbon was obtained. The regeneration rate is 94.2%.

(Experimental example 7)
The same procedure as in Example 4 was performed except that the temperature during the thermal decomposition and removal was set to 300 ° C. and the time taken was 2 hours.
As a result, the polyamide 11 hardly disappeared.

  From the above results, when the temperature during pyrolysis and removal is performed in the range of 400 to 700 ° C., the regeneration rate is in the range of 90 to 110%, and the spherical aggregate can be sufficiently regenerated. I understand that. On the other hand, when it performed at 300 degreeC, it turns out that a synthetic resin was not removed but a spherical aggregate was not able to be reproduced | regenerated.

Claims (9)

  A method for regenerating a spherical aggregate in an additive manufacturing material, comprising thermally decomposing and removing the synthetic resin in the additive manufacturing material including the spherical aggregate and the synthetic resin.   The additive manufacturing material according to claim 1, wherein the additive manufacturing material including the spherical aggregate and the synthetic resin is a waste material that has not become an additive manufacturing object in the additive manufacturing material provided for additive manufacturing. Regeneration method of spherical aggregate inside.   The method for regenerating a spherical aggregate in the additive manufacturing material according to claim 1 or 2, wherein the additive manufacturing material is a material of a selective laser sintering method.   The method for regenerating a spherical aggregate in the additive manufacturing material according to any one of claims 1 to 3, wherein the spherical aggregate is spherical carbon.   The spherical shape in the additive manufacturing material according to any one of claims 1 to 4, wherein the synthetic resin is one or more selected from the group consisting of a thermoplastic resin, a thermosetting resin, and a photocurable resin. Aggregate regeneration method.   The method for regenerating a spherical aggregate in the additive manufacturing material according to claim 5, wherein the thermoplastic resin is polyamide 11 or polyamide 12.   The reproduction | regeneration additive manufacturing material containing the reproduction | regeneration spherical aggregate obtained by the reproduction | regeneration method of the spherical aggregate in the additive manufacturing material as described in any one of Claims 1-6, and a synthetic resin.   The regenerated spherical aggregate obtained by the method for regenerating the spherical aggregate in the additive manufacturing material according to any one of claims 1 to 6, and the additive manufacturing layered material provided for additive manufacturing A material for regenerative additive manufacturing including a waste material that has not been formed, a synthetic resin that is not subjected to additive manufacturing, and a spherical aggregate that is not subjected to additive manufacturing.   A method for manufacturing a layered object, wherein the reproduction layered material according to claim 7 or 8 is layered.

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