Radiation shielding material and method for manufacturing radiation shielding material

Abstract

To provide a radiation shielding material that suppresses the generation of hydrogen sulfide during disposal and achieves both electromagnetic wave absorption and strength. [Solution] The radioactive shielding material comprises a main body layer containing cement and a first ferrite layer containing ferrite, which is laminated in the stacking direction relative to the main body layer, wherein the main body layer includes a first polymer layer containing polymer, and at least one of the main body layer and the first ferrite layer contains boron.

Description

Technical Field

[0001] The present invention relates to a radiation shielding material.

Background Art

[0002] As a building material for shielding radiation, a radiation shielding board described in Patent Document 1 is known. This board is manufactured by adding water to a mixture of hydraulic gypsum and barium sulfate, kneading it, and forming it into a plate material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the board described in Patent Document 1 contains gypsum and barium sulfate, hydrogen sulfide may be generated during disposal. In addition, as a radiation shielding building material, it is required to achieve both absorption of electromagnetic waves and ensuring strength.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a radiation shielding material that can suppress the generation of hydrogen sulfide during disposal and achieve both absorption of electromagnetic waves and ensuring strength.

Means for Solving the Problems

[0006] In order to solve the above - described problems and achieve the object, the present invention includes a main body layer containing cement, a first ferrite layer laminated in the lamination direction with respect to the main body layer and containing ferrite, the main body layer includes a first polymer layer containing a polymer, and at least one of the main body layer and the first ferrite layer contains boron.

Effects of the Invention

[0007] The radiation shielding material according to the present invention suppresses the generation of hydrogen sulfide during disposal and can achieve both electromagnetic wave absorption and strength. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view showing a shielding material according to the first embodiment. [Figure 2] Figure 2 is a schematic plan view of the shielding material shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view taken along line III-III in Figure 2. [Figure 4] Figure 4 is a schematic plan view showing the first polymer layer shown in Figure 3. [Figure 5] Figure 5 is a schematic plan view showing the second polymer layer shown in Figure 3. [Figure 6] Figure 6 is a schematic perspective view showing an example of the bonding of the shielding material shown in Figure 1. [Figure 7] Figure 7 is a schematic perspective view showing an example of a connecting member used to join shielding material at a corner. [Figure 8] Figure 8 is a schematic plan view showing an example of the joining of shielding material at a corner. [Figure 9] Figure 9 is a schematic cross-sectional view showing a shielding material according to the second embodiment, and corresponds to Figure 3. [Figure 10] Figure 10 is a schematic cross-sectional view showing a shielding material according to the third embodiment, and corresponds to Figure 3. [Modes for carrying out the invention]

[0009] Examples of the radiation shielding material according to the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited by these examples.

[0010] [First Embodiment] Figure 1 is a schematic perspective view showing a shielding material according to the first embodiment. Figure 2 is a schematic plan view showing the shielding material shown in Figure 1. The shielding material 1 (radiation shielding material) is used, for example, as a building material for a medical facility. The shielding material 1 has the function of shielding against radiation. Radiation includes, for example, X-rays, gamma rays, and neutrons. The shielding material 1 is used to construct a shielding room for the use of radiation equipment. Radiation equipment includes, for example, X-ray machines, CT (Computed Tomography) scanners, barium examination machines, linacs (linear accelerators), proton therapy machines, and heavy ion therapy machines. The type of radiation equipment is not particularly limited.

[0011] As shown in Figures 1 and 2, the shielding material 1 is rectangular in shape overall. In a plan view, the shielding material 1 extends in a longitudinal direction D1 (first direction) and in a transverse direction D2 (second direction) that intersects (e.g., orthogonal to) the longitudinal direction D1. However, the shape of the shielding material 1 is not limited to a rectangle, but may be polygonal or circular, for example, and is not particularly limited. The shielding material 1 has thickness in a thickness direction D3 that intersects (e.g., orthogonal to) both the longitudinal direction D1 and the transverse direction D2.

[0012] The shielding material 1 includes long sides 1a and 1b extending in the longitudinal direction D1, and short sides 1c and 1d extending in the short direction D2. The long sides 1a and 1b are spaced apart from each other in the short direction D2. The short sides 1c and 1d are spaced apart from each other in the longitudinal direction D1.

[0013] The shielding material 1 includes a connecting projection 11 provided on the long side 1a and a connecting recess 12 provided on the long side 1b. The connecting projection 11 protrudes from the side surface of the shielding material 1 that constitutes the long side 1a. The connecting recess 12 is a recess provided on the side surface of the shielding material 1 that constitutes the long side 1b. The shape of the connecting recess 12 corresponds to the shape of the connecting projection 11. Specifically, the shape of the connecting recess 12 is such that the connecting projection 11 can be inserted into it. The connecting projection 11 and the connecting recess 12 extend in the longitudinal direction D1.

[0014] In this embodiment, the coupling convex portion 11 is provided on the long side 1a, and the coupling concave portion 12 is provided on the long side 1b. Further, the coupling convex portion 11 and the coupling concave portion 12 are not provided on the short sides 1c and 1d. However, the coupling convex portion 11 may be provided on one of the short sides 1c and 1d, and the coupling concave portion 12 may be provided on the other. In this case, the coupling convex portion 11 and the coupling concave portion 12 may not be provided on the long sides 1a and 1b.

[0015] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. The shielding material 1 has a structure in which a plurality of layers are laminated. The shielding material 1 includes a main body layer 2 and a ferrite layer 3 (first ferrite layer) laminated on the main body layer 2 in the lamination direction Da. At least one of the main body layer 2 and the ferrite layer 3 contains boron. For example, at least one of the main body layer 2 and the ferrite layer 3 contains boron carbide, boric acid, or borate.

[0016] The form of boron contained in at least one of the main body layer 2 and the ferrite layer 3 is not limited to a specific form. For example, boron may be contained in at least one of the main body layer 2 and the ferrite layer 3 as crystalline boron, or may be contained in at least one of the main body layer 2 and the ferrite layer 3 as boron carbide or borate. In this embodiment, the main body layer 2 contains boron carbide.

[0017] In this embodiment, in addition to the main body layer 2 and the ferrite layer 3, the shielding material 1 includes a ferrite layer 4 (second ferrite layer) different from the ferrite layer 3. The main body layer 2, the ferrite layer 3, and the ferrite layer 4 are laminated on each other in the lamination direction Da. The lamination direction Da coincides with the thickness direction D3 of the shielding material 1. Hereinafter, when explaining the layer structure of the shielding material 1, when explaining the direction in which a plurality of layers are laminated, the term "in the lamination direction Da" may be used.

[0018] The main body layer 2 is the main body layer of the shielding material 1. The main body layer 2 contains cement. The main body layer 2 includes a main surface 2a (third surface) and a back surface 2b (fourth surface) opposite to the main surface 2a in the lamination direction Da. In the following description, one of the surfaces formed by each layer may be referred to as the "main surface," and the surface opposite to the main surface in the lamination direction Da may be referred to as the "back surface." The main body layer 2 includes an internal layer 21 and constituent layers 22 and 23.

[0019] The inner layer 21 constitutes the central part of the shielding material 1 in the lamination direction Da. The inner layer 21 includes a main surface 21a and a back surface 21b.

[0020] The inner layer 21 includes a polymer layer 211 (internal polymer layer), a ferrite layer 212 (first internal ferrite layer), and a ferrite layer 213 (second internal ferrite layer).

[0021] The polymer layer 211 contains a polymer. The polymer includes, for example, at least one of polyolefins (e.g., polypropylene, polyethylene) and PET (Polyethylene terephthalate). In this embodiment, the polymer is PET. The type of polymer is not particularly limited. Because polymers have high tensile strength due to their intermolecular forces, the polymer layer 211 improves the tensile strength of the shielding material 1.

[0022] The thickness of the polymer layer 211 is less than the thickness of the ferrite layer 212 or the ferrite layer 213. The thickness of the polymer layer 211 is 0.01% to 0.05% (0.025% in this embodiment) of the thickness of the shielding material 1. Specifically, the thickness of the polymer layer 211 is 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, or 0.05% of the thickness of the shielding material 1, and may be in the range between any two of these values. The thickness of the polymer layer 211 is 0.1 mm to 1.0 mm (0.3 mm in this embodiment).

[0023] The polymer layer 211 includes a main surface 211a (fifth surface) and a back surface 211b (sixth surface).

[0024] The ferrite layer 212 contains ferrite. The ferrite layer 212 is, for example, a soft ferrite sheet. Since ferrite is a magnetic material, the ferrite layer 212 converts the energy of electromagnetic waves into thermal energy through magnetic loss. For this reason, the ferrite layer 212 absorbs electromagnetic waves. In addition, because ferrite has a high electron density, the ferrite layer 212 shields against X-rays and gamma rays. Furthermore, the ferrite layer 212 improves the compressive strength of the shielding material 1.

[0025] The ferrite layer 212 includes an adhesive surface containing an adhesive. The ferrite layer 212 is laminated on the main surface 211a. The ferrite layer 212 is bonded to the polymer layer 211, for example, via the adhesive surface. The side of the ferrite layer 212 opposite to the polymer layer 211 constitutes the main surface 21a of the inner layer 21.

[0026] The thickness of the ferrite layer 212 is 0.1% to 10% (0.1% in this embodiment) of the thickness of the shielding material 1. Specifically, the thickness of the ferrite layer 212 is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2% of the thickness of the shielding material 1. 0.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7.0%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8% The percentages are 7.9%, 8.0%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, 9.0%, 9.19%, 9.2%, 9.3%, 9.4%, 9.5%, 9.6%, 9.7%, 9.8%, 9.9%, and 10.0%, and may be in the range between any two of these values. The thickness of the ferrite layer 212 is 0.5 mm to 2.0 mm (1.0 mm in this embodiment).

[0027] In this embodiment, the structure of the ferrite layer 213 is the same as that of the ferrite layer 212. However, the ferrite layer 213 only needs to contain ferrite, and the structure of the ferrite layer 213 may differ from that of the ferrite layer 212. The ferrite layer 213 is laminated on the back surface 211b. The ferrite layer 213 is bonded to the polymer layer 211, for example, via an adhesive surface. The side of the ferrite layer 213 opposite to the polymer layer 211 constitutes the back surface 21b of the inner layer 21.

[0028] The constituent layer 22 includes boron layers 221 and 222, cement layers 223, 224 and 225, a polymer layer 226 (first polymer layer), and an end cement layer 227.

[0029] The boron layer 221 contains boron. In this embodiment, the boron layer 221 contains boron carbide. The boron layer 221 may also contain boric acid or a borate. Since boron absorbs neutrons, the boron layer 221 shields against neutron radiation. The boron layer 221 may be formed by coating the cement layer 223 or cement layer 224 with boron carbide. The boron layer 221 includes a main surface 221a (first surface) and a back surface 221b (second surface).

[0030] In this embodiment, the configuration of the boron layer 222 is the same as that of the boron layer 221. However, the boron layer 222 only needs to contain boron, and the configuration of the boron layer 222 may differ from that of the boron layer 221. The boron layer 222 is separated from the boron layer 221 in the stacking direction Da. The boron layer 222 includes a main surface 222a and a back surface 222b.

[0031] The cement layer 223 (first cement layer) contains cement. The cement layer 223 may be formed, for example, by mixing cement material (e.g., 1300g) with water (e.g., 250cc to 280cc). The thickness of the cement layer 223 is greater than the thickness of the ferrite layer 212.

[0032] The thickness of the cement layer 223 is 10% to 25% (16.7% in this embodiment) of the thickness of the shielding material 1. Specifically, the thickness of the cement layer 223 is 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25% of the thickness of the shielding material 1, and may be in the range between any two of these values. The thickness of the cement layer 223 is, for example, 1.0 mm to 5.0 mm (2.0 mm in this embodiment). The cement layer 223 is laminated on the main surface 221a.

[0033] In this embodiment, the configurations of cement layer 224 (second cement layer) and cement layer 225 are the same as those of cement layer 223. Cement layers 224 and 225 only need to contain cement, and the configurations of cement layers 224 and 225 may differ from those of cement layer 223. Cement layer 224 is spaced apart from cement layer 223 in the lamination direction Da, and cement layer 225 is spaced apart from cement layer 224 in the lamination direction Da. Cement layer 224 is laminated on the back surface 221b and the main surface 222a. Cement layer 225 is laminated on the back surface 222b.

[0034] In this embodiment, the structure of the polymer layer 226 is the same as that of the polymer layer 211. However, the polymer layer 226 only needs to contain a polymer, and the structure of the polymer layer 226 may differ from that of the polymer layer 211. The polymer layer 226 is provided between the center of the main body layer 2 in the lamination direction Da and the ferrite layer 3. The polymer layer 226 is laminated on the cement layer 223. The polymer layer 226 is laminated on the side of the cement layer 223 opposite to the boron layer 221.

[0035] In this embodiment, the structure of the end cement layer 227 is the same as that of the cement layer 223, except for its thickness. The thickness of the end cement layer 227 is smaller than that of the cement layer 223. The thickness of the end cement layer 227 is 10% to 70% (30% in this embodiment) of the thickness of the cement layer 223. Specifically, the thickness of the end cement layer 227 is 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70% of the thickness of the cement layer 223, and may be in the range of any two of these values. For example, the thickness of the end cement layer 227 is 0.5 mm to 2.5 mm (1.0 mm in this embodiment).

[0036] The end cement layer 227 is laminated on the polymer layer 226. The end cement layer 227 is laminated on the side of the polymer layer 226 opposite to the cement layer 223. The side of the end cement layer 227 opposite to the polymer layer 226 constitutes the main surface 2a of the main layer 2.

[0037] The constituent layer 22 is laminated on the main surface 21a of the inner layer 21. Specifically, the cement layer 225 is laminated on the side of the ferrite layer 212 opposite to the polymer layer 211.

[0038] In this embodiment, the structure of the constituent layer 23 is the same as the structure of the constituent layer 22. The constituent layer 23 includes boron layers 231 and 232, cement layers 233, 234 and 235, a polymer layer 236 (second polymer layer), and an end cement layer 237. The boron layers 231 and 232 correspond to boron layers 221 and 222, respectively. The cement layers 233, 234 and 235 correspond to cement layers 223, 224 and 225, respectively. The polymer layer 236 corresponds to polymer layer 226. The end cement layer 237 corresponds to end cement layer 227.

[0039] The polymer layer 236 is provided between the center of the main layer 2 in the lamination direction Da and the ferrite layer 4. The side of the end cement layer 237 opposite to the polymer layer 236 constitutes the back surface 2b of the main layer 2.

[0040] The constituent layer 23 is laminated on the back surface 21b of the inner layer 21. Specifically, the cement layer 235 is laminated on the side of the ferrite layer 213 opposite to the polymer layer 211.

[0041] In this embodiment, the main body layer 2 includes a boron layer 221 and cement layers 223 and 224. The cement layer 223 is laminated on the main surface 221a of the boron layer 221, and the cement layer 224 is laminated on the back surface 221b of the boron layer 221. Thus, the main body layer 2 is constructed by alternately laminating boron layers and cement layers. For example, when manufacturing the shielding material 1, the main body layer 2 can be formed by repeatedly applying a boron-containing substance (e.g., a boron compound) to the cement layer after forming the cement layer. Therefore, the process of mixing boron into the cement is omitted, improving manufacturing efficiency.

[0042] Ferrite layers 3 and 4 contain ferrite. The composition of ferrite layers 3 and 4 is the same as that of ferrite layer 212. Ferrite layer 3 is laminated on the main surface 2a of the main layer 2. Specifically, ferrite layer 3 is bonded to the main layer 2 via an adhesive surface. Ferrite layer 4 is laminated on the back surface 2b of the main layer 2.

[0043] Figure 4 is a schematic plan view showing the first polymer layer shown in Figure 3. The polymer layer 226 contains a plurality of polymer pieces 5, each containing polymer. In other words, the polymer layer 226 is composed of a plurality of polymer pieces 5. The plurality of polymer pieces 5 are spaced apart from each other when viewed from the stacking direction Da.

[0044] As described above, the polymer layer 226 is laminated between the cement layer 223 and the end cement layer 227. Since the multiple polymer pieces 5 are spaced apart from each other, the cement layer 223 and the end cement layer 227 adhere to each other between adjacent polymer pieces 5. Therefore, the adhesion between the cement layer 223 and the end cement layer 227 can be improved.

[0045] In this embodiment, the polymer layer 226 includes polymer pieces 5 formed by cutting a PET bottle. However, the polymer pieces 5 may also be formed by joining PET pieces obtained by cutting a PET bottle. The method for manufacturing the polymer pieces 5 is not particularly limited.

[0046] By using cut pieces of PET bottles as polymer pieces 5, the environmental impact can be reduced, and the shielding material 1 can be easily recycled when it is disposed of. In addition, discarded PET bottles can be recycled and used in the manufacture of the shielding material 1.

[0047] The multiple polymer pieces 5 include a plurality of first polymer pieces 51 and a plurality of second polymer pieces 52.

[0048] Multiple first polymer pieces 51 extend in the longitudinal direction D1. Multiple first polymer pieces 51 are arranged in the short direction D2. The length of the first polymer piece 51 (length in the longitudinal direction D1) is 10% to 40% (30% in this embodiment) of the length of the shielding material 1. Specifically, the length of the first polymer piece 51 is 10, 15, 20, 25, 30, 35, or 40% of the length of the shielding material 1, and may be in the range between any two of these values. For example, the length of the first polymer piece 51 is 50 mm to 250 mm (150 mm in this embodiment).

[0049] The width of the first polymer piece 51 (length in the short direction D2) is 2% to 20% (4% in this embodiment) of the width of the shielding material 1. The width of the first polymer piece 51 may be 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20% of the width of the shielding material 1, and may be in the range between any two of these values. For example, the width of the first polymer piece 51 is 2 mm to 10 mm (5 mm in this embodiment).

[0050] Multiple second polymer pieces 52 extend in the short direction D2. Multiple second polymer pieces 52 are arranged in the long direction D1. The length of the second polymer piece 52 (length in the short direction D2) is longer than the length of the first polymer piece 51. The length of the second polymer piece 52 is 65% to 95% (90% in this embodiment) of the width of the shielding material 1. The length of the second polymer piece 52 is 65, 70, 75, 80, 85, 90, or 95% of the width of the shielding material 1, and may be in the range between any two of these values. For example, the length of the second polymer piece 52 is 130 mm to 400 mm (220 mm in this embodiment).

[0051] The width of the second polymer piece 52 is equal to the width of the first polymer piece 51. The width of the second polymer piece 52 is 2% to 20% (5% in this embodiment) of the length of the shielding material 1. Specifically, the width of the second polymer piece 52 is 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20% of the length of the shielding material 1, and may be in the range between any two of these values. For example, the width of the second polymer piece 52 is 2 mm to 10 mm (5 mm in this embodiment).

[0052] In this embodiment, the polymer layer 226 includes a first region R1 and a second region R2. The polymer layer 226 includes two first regions R1.

[0053] The first region R1 is a region containing a plurality of first polymer pieces 51 arranged in the short-side direction D2 when viewed from the stacking direction Da. One first region R1 is located on the short side 1c side than the second region R2. Another first region R1, different from the first first region R1, is located on the short side 1d side than the second region R2.

[0054] The second region R2 is a region containing multiple second polymer pieces 52 arranged in the longitudinal direction D1 when viewed from the stacking direction Da. The second region R2 is adjacent to the first region R1 in the longitudinal direction D1. The second region R2 is located between the two first regions R1.

[0055] In this embodiment, the polymer layer 226 includes two first regions R1 and a second region R2. However, the polymer layer 226 may also include one first region R1 and a second region R2. Furthermore, the size and arrangement of the polymer pieces 5 can be changed as appropriate.

[0056] In this embodiment, the polymer layer 226 includes a plurality of first polymer pieces 51 extending in the longitudinal direction D1 and a plurality of second polymer pieces 52 extending in the short direction D2. Furthermore, the first region R1 and the second region R2 are adjacent to each other in the longitudinal direction D1. Therefore, the tensile strength of the shielding material 1 can be ensured regardless of whether tensile stress is applied in the longitudinal direction D1 or the short direction D2.

[0057] Figure 5 is a schematic plan view showing the second polymer layer shown in Figure 3. The polymer layer 236 contains a plurality of polymer pieces 5. The polymer layer 236 is composed of a plurality of polymer pieces 5. In the polymer layer 236 as well, the plurality of polymer pieces 5 are spaced apart from each other. Therefore, the adhesion between the cement layer 233 and the end cement layer 237 can be improved.

[0058] The multiple polymer pieces 5 include multiple third polymer pieces 53 and multiple fourth polymer pieces 54.

[0059] Multiple third polymer pieces 53 extend in the short direction D2. Multiple third polymer pieces 53 are arranged in the long direction D1. The length of the third polymer piece 53 (length in the short direction D2) is 15% to 40% (30% in this embodiment) of the width of the shielding material 1. Specifically, the length of the third polymer piece 53 is 15, 20, 25, 30, 35, or 40% of the width of the shielding material 1, and may be in the range between any two of these values. For example, the length of the third polymer piece 53 is 22 mm to 150 mm (90 mm in this embodiment).

[0060] The width of the third polymer piece 53 (length in the longitudinal direction D1) is 5% to 20% (11% in this embodiment) of the length of the shielding material 1. The width of the third polymer piece 53 is, for example, 20 mm to 80 mm (50 mm in this embodiment).

[0061] Multiple fourth polymer pieces 54 extend in the longitudinal direction D1. Multiple fourth polymer pieces 54 are arranged in the short direction D2. The length of the fourth polymer piece 54 (length in the longitudinal direction D1) is longer than the length of the third polymer piece 53. The length of the fourth polymer piece 54 is 70% to 99% (95% in this embodiment) of the length of the shielding material 1. Specifically, the length of the fourth polymer piece 54 is 70, 75, 80, 85, 90, 95, or 99%, and may be in the range between any two of these values. The length of the fourth polymer piece 54 is, for example, 300 mm to 500 mm (400 mm in this embodiment).

[0062] The width of the fourth polymer piece 54 (length in the short direction D2) is shorter than the width of the third polymer piece 53. The width of the fourth polymer piece 54 is 2% to 10% (4% in this embodiment) of the width of the shielding material 1. Specifically, the width of the fourth polymer piece 54 is 2, 3, 4, 5, 6, 7, 8, 9, or 10%, and may be in the range between any two of these values. For example, the width of the fourth polymer piece 54 is 1 mm to 10 mm (3 mm in this embodiment).

[0063] In this embodiment, the polymer layer 236 includes a third region R3 and a fourth region R4. The polymer layer 236 includes two third regions R3.

[0064] The third region R3 is a region containing multiple third polymer pieces 53 arranged in the longitudinal direction D1 when viewed from the stacking direction Da. One third region R3 is located on the longer side 1a side than the fourth region R4. Another third region R3, different from the first third region R3, is located on the longer side 1b side than the fourth region R4.

[0065] The fourth region R4 is a region containing multiple fourth polymer pieces 54 arranged in the short direction D2 when viewed from the stacking direction Da. The fourth region R4 is adjacent to the third region R3 in the short direction D2. The fourth region R4 is located between two third regions R3.

[0066] In this embodiment, the polymer layer 236 includes two third regions R3 and a fourth region R4. However, the polymer layer 236 may also include one third region R3 and a fourth region R4. Furthermore, the size and arrangement of the multiple polymer pieces 5 can be changed as appropriate.

[0067] In this embodiment, the polymer layer 236 includes a plurality of third polymer pieces 53 extending in the short direction D2 and a plurality of fourth polymer pieces 54 extending in the longitudinal direction D1. Furthermore, the third region R3 and the fourth region R4 are adjacent to each other in the short direction D2. Therefore, the tensile strength of the shielding material 1 can be ensured regardless of whether tensile stress is applied in the longitudinal direction D1 or the short direction D2. In addition, in the polymer layer 226 provided on the ferrite layer 3 side, the first region R1 and the second region R2 are adjacent to each other in the longitudinal direction D1. As a result, the plurality of polymer pieces 5 are arranged in a balanced manner by both the polymer layer 226 and the polymer layer 236. Therefore, tensile stress can be absorbed in a balanced manner on both the ferrite layer 3 side and the ferrite layer 4 side.

[0068] Figure 6 is a schematic diagram showing an example of the joining of shielding materials shown in Figure 1. Shielding material 1 may be used, for example, by joining it with another shielding material 1. First, the joining projection 11 of one shielding material 1 is inserted into the joining recess 12 of the other shielding material 1. Next, the joining position of the two shielding materials 1 is solidified with cement. In this way, a radiation shielding room can be constructed by joining multiple shielding materials 1. Alternatively, the two shielding materials 1 may be fixed using C-shaped connecting members such as metal clamps.

[0069] The above example shows two shielding materials 1 joined in a straight line, but when constructing a radiation shielding room, it is conceivable to form a corner using two shielding materials 1. Figure 7 is a schematic perspective view showing an example of a connecting member T used to join the shielding materials 1 at a corner. The connecting member T as a whole is a right-angled triangular prism. The cross-sectional shape of the connecting member T is not particularly limited, as long as it includes a right angle as an interior angle. The cross-sectional shape of the connecting member T may be, for example, a square. The connecting member T may be made of metal, wood, or cement.

[0070] Figure 8 is a schematic plan view showing an example of joining shielding materials at a corner. When forming a corner with two shielding materials 1, first, the ends of the two shielding materials 1 are brought into contact with each other to form the corner. Next, the right-angle portion of the connecting member T is placed in the corner formed by the two shielding materials 1. Then, the corner is formed by bonding the connecting member T to each of the two shielding materials 1. The connecting member T may be bonded to the shielding materials 1 using, for example, cement.

[0071] By using the above method when joining two shielding materials 1 together, the possibility of radiation and electromagnetic waves passing through the joint portion of the shielding material 1 can be reduced.

[0072] The shielding material 1 according to the first embodiment comprises ferrite layers 3 and 4. The main body layer 2 includes a polymer layer 226, and the main body layer 2 contains boron. The ferrite layers 3 and 4 have the function of shielding X-rays and gamma rays, and the function of improving the compressive strength of the shielding material 1. The polymer layer 226 has the function of improving the tensile strength of the shielding material 1. Neutron rays are shielded by the boron contained in at least one of the main body layer 2 and the ferrite layer 3. As a result, the shielding material 1 can achieve both electromagnetic wave absorption and strength. Furthermore, unlike conventional shielding materials, the shielding material 1 does not contain gypsum, barium sulfate, etc., so hydrogen sulfide is not generated during disposal. Therefore, the shielding material 1 can suppress the generation of hydrogen sulfide during disposal and achieve both electromagnetic wave absorption and strength.

[0073] Furthermore, if the shielding material contains lead, it is heavy and may release harmful substances when disposed of, resulting in a significant environmental burden. In contrast, shielding material 1 does not contain lead, thus reducing the weight of shielding material 1 while also reducing the environmental burden.

[0074] Furthermore, in shielding material 1, the main layer 2 contains cement. For example, biocement (so-called self-healing cement) can be used as this cement. In this case, even if cracks occur in shielding material 1 due to natural disasters, etc., the shielding material 1 will be repaired by applying microorganisms (e.g., Bacillus bacteria such as Bacillus subtilis) to the cement exposed from the ferrite layers 3 and 4. In addition, medical equipment that emits carbon dioxide may be used inside the radiation shielding room constructed with shielding material 1. Even in this case, the microorganisms applied to shielding material 1 can absorb carbon dioxide, thereby reducing the concentration of carbon dioxide inside the shielding room.

[0075] When constructing a radiation shielding room, instead of building it from scratch on-site (e.g., a hospital), the room can be constructed by assembling pre-manufactured shielding material 1. Therefore, the radiation shielding room can be easily constructed. In short, instead of building it from scratch using cement materials, a formwork for shielding material 1 is manufactured in advance, and the materials are fitted into the manufactured formwork. Then, shielding material 1 is transported to the site and installed during construction, making maintenance and recycling easier.

[0076] In recent years, there has been a surge in the development of radiation-shielding building materials to replace lead, which has a heavy environmental impact, but almost all of them use gypsum. However, when these building materials are landfilled, hydrogen sulfide is generated, and when they are recycled, there are issues that need to be addressed, such as the presence of asbestos, the leaching of fluorine, and the presence of heavy metals and arsenic. Therefore, we have invented a building material that uses cement to facilitate recycling, and also incorporates features to maintain strength, absorb electromagnetic waves, and reduce radiation. Moreover, this building material can be self-repaired using microorganisms, making maintenance easy. Since these microorganisms survive by using carbon dioxide, it is effective in absorbing carbon dioxide used in places such as X-ray rooms and operating rooms in hospitals. In addition, as a cement material, it is innovative in that it is not constructed from scratch at the construction site, but is processed into a composite material by fitting it into a mold at the factory beforehand, and then constructed on-site.

[0077] Furthermore, in the shielding material 1, the main layer 2 includes an inner layer 21. The inner layer 21 includes a polymer layer 211 and ferrite layers 212 and 213. The inner layer 21 can improve the compressive and tensile strength of the shielding material 1, thereby improving its electromagnetic wave absorption performance. In addition, if cracks occur in the shielding material 1 due to natural disasters, etc., the ferrite layers 212 and 213 may rupture. Since the rupture of the ferrite layers 212 and 213 can be detected by a detection device such as a magnetometer, the lifespan of the shielding material 1 can be determined with accuracy.

[0078] [Second Embodiment] Figure 9 is a schematic cross-sectional view showing the shielding material according to the second embodiment, and corresponds to Figure 3. The shielding material 1A according to the second embodiment differs from shielding material 1 in that it includes a constituent layer 22A instead of constituent layer 22, and a constituent layer 23A instead of constituent layer 23. The differences from shielding material 1 will be explained below, with redundant explanations omitted as appropriate.

[0079] The constituent layer 22A includes a mixed layer 61A in place of the boron layers 221, 222 and the cement layers 223, 224, 225. The mixed layer 61A contains cement and boron. The mixed layer 61A may be formed, for example, by mixing water and boron with a cement material. The thickness of the mixed layer 61A may be equal to the thickness of the layer formed by laminating the boron layers 221, 222 and the cement layers 223, 224, 225.

[0080] The constituent layer 22A includes an end mixing layer 62A instead of an end cement layer 227. The material of the end mixing layer 62A is, for example, the same as the material of the mixing layer 61A. The thickness of the end mixing layer 62A is less than the thickness of the mixing layer 61A. The thickness of the end mixing layer 62A is equal to the thickness of the end cement layer 227.

[0081] The composition of structural layer 23A is the same as that of structural layer 22A. Structural layer 23A includes a mixed layer 63A in place of boron layers 231, 232 and cement layers 233, 234, 235. Structural layer 23A includes an end mixed layer 64A in place of the end cement layer 237. The composition of mixed layer 63A is the same as that of mixed layer 61A, and the composition of end mixed layer 64A is the same as that of end mixed layer 62A.

[0082] In the second embodiment, as in the first embodiment, the generation of hydrogen sulfide during disposal is suppressed, and both electromagnetic wave absorption and strength can be ensured. Furthermore, the main body layer 2 includes mixed layers 61A and 63A containing cement and boron. When manufacturing the shielding material 1A, it is not necessary to alternately form the cement layer and the boron layer, so the shielding material 1A can be easily manufactured.

[0083] Furthermore, mixing boron into the cement improves the impact dispersion properties of the shielding material 1A. This is thought to be because boron reacts with water and oxygen in the cement to produce at least one of boric acid and calcium borate. Improved impact dispersion makes it less likely for cracks to form in the shielding material 1A when stress is applied, and even if cracks do occur, the shielding material 1A is less likely to break apart. Therefore, the possibility of defects in the shielding material 1A can be reduced.

[0084] [Third Embodiment] Figure 10 is a schematic cross-sectional view showing the shielding material according to the third embodiment, and corresponds to Figure 3. The shielding material 1B according to the third embodiment includes a constituent layer 22B in place of constituent layer 22, and a constituent layer 23B in place of constituent layer 23. Furthermore, the shielding material 1B includes a ferrite layer 3B in place of ferrite layer 3, and a ferrite layer 4B in place of ferrite layer 4. The differences from shielding material 1 will be explained below, with redundant explanations omitted as appropriate.

[0085] The constituent layer 22B includes a cement layer 61B in place of the boron layers 221, 222 and the cement layers 223, 224, 225. The cement layer 61B contains cement. The composition of the cement layer 61B is the same as that of the cement layer 223. The thickness of the cement layer 61B is greater than the thickness of the cement layer 223. The thickness of the cement layer 61B is equal to the thickness of the mixed layer 61A.

[0086] The composition of structural layer 23B is the same as that of structural layer 22B. Structural layer 23B includes cement layer 62B in place of boron layers 231, 232 and cement layers 233, 234, 235.

[0087] The ferrite layer 3B contains ferrite and boron. The ferrite layer 3B may be formed, for example, by mixing boron with powdered ferrite and forming the mixed material into a sheet. As a method for forming the mixed material into a sheet, a method using a 3D (Three Dimensional) printer or a method using sintering can be used. The thickness of the ferrite layer 3B is equal to or greater than the thickness of the ferrite layer 3. The structure of the ferrite layer 4B is the same as that of the ferrite layer 3B.

[0088] In the third embodiment, as in the first embodiment, the generation of hydrogen sulfide during disposal is suppressed, and both electromagnetic wave absorption and intensity can be ensured. Furthermore, the ferrite layer 3B contains boron. For example, the thickness of the ferrite layer 3B may be smaller than the thickness of the cement layer 61B. In this case, the effort required to mix boron into the ferrite layer 3B is considered to be less than the effort required to mix boron into the cement layer. Therefore, the shielding material 1B can be easily manufactured.

[0089] [Evaluation Test] Evaluation tests were conducted on each layer constituting shielding materials 1, 1A, and 1B. First, strength tests were performed. For the strength tests, shielding materials corresponding to Reference Examples 1 and 2 and Comparative Examples 1 to 3 were manufactured. The composition of each shielding material was as follows. However, these shielding materials were manufactured so that their thicknesses were equal to each other.

[0090] <Reference example 1> Reference Example 1 includes a polymer layer 211 and cement layers 61B and 62B. The polymer layer 211 includes a main surface and a back surface opposite to the main surface in the lamination direction Da. The cement layer 61B is laminated to the main surface of the polymer layer 211, and the cement layer 62B is laminated to the back surface of the polymer layer 211.

[0091] <Reference example 2> Reference Example 2 includes a mixed layer and ferrite layers 3 and 4. The thickness of the mixed layer is twice the thickness of mixed layer 61A. The configuration of the mixed layer is the same as that of mixed layer 61A, except for its thickness. The mixed layer includes a main surface and a back surface opposite to the main surface in the lamination direction Da. Ferrite layer 3 is laminated on the main surface of the mixed layer, and ferrite layer 4 is laminated on the back surface of the mixed layer.

[0092] <Comparative Example 1> Comparative Example 1 has a single-layer structure and consists of one cement layer. This single cement layer is twice the thickness of cement layer 61B. Comparative Example 1 does not include polymer layer 211.

[0093] <Comparative Example 2> Comparative Example 2 differs from Reference Example 1 in that it includes a fiber layer instead of the polymer layer 211. The fiber layer includes multiple nanofibers instead of multiple polymer pieces 5. The nanofibers were manufactured from PET bottles using known methods. The other components of Comparative Example 2 are the same as those of Reference Example 2.

[0094] <Comparative Example 3> Comparative Example 3 differs from Reference Example 2 in that it includes a cement layer instead of a mixed layer. The thickness of the cement layer is the same as the thickness of the mixed layer in Reference Example 2. Regarding other components, the configuration of Comparative Example 3 is the same as that of Reference Example 2.

[0095] An impact test was conducted using the shielding material described above. Specifically, the shielding material was placed on leveled sand. A 1 kg weight was dropped from 30 cm above the shielding material, causing the bell-shaped weight to collide with the shielding material. The condition of the shielding material was then observed.

[0096] The results of the strength test are shown in Table 1. [Table 1]

[0097] Comparing Reference Example 1 with Comparative Example 1, it was confirmed that providing the polymer layer 211 reduces the possibility of cracks occurring when the shielding material is subjected to impact. Furthermore, comparing Reference Example 1 with Comparative Example 2, it was confirmed that providing the polymer layer 211 containing multiple polymer pieces 5 reduces the possibility of cracks occurring more effectively than providing a fiber layer containing nanofibers. In addition, comparing Reference Example 2 with Comparative Example 3, it was confirmed that mixing boron with cement to form a mixed layer reduces the possibility of cracks occurring in the shielding material.

[0098] Next, shielding tests were conducted. These tests included neutron irradiation experiments and X-ray transmission experiments. For the neutron irradiation experiments, shielding materials related to Reference Examples 3 and 4 were manufactured. The composition of each shielding material was as follows:

[0099] <Reference example 3> Reference Example 3 includes an intermediate layer and cement layers 61B and 62B. The configuration of the intermediate layer is the same as that of the internal layer 21, except that it includes a mixed layer instead of the polymer layer 211. The configuration of the mixed layer is the same as that of mixed layer 61A, except for its thickness. The thickness of the mixed layer is the same as that of the polymer layer 211. The intermediate layer includes a main surface and a back surface opposite to the main surface in the lamination direction Da. Cement layer 61B is laminated on the main surface of the intermediate layer, and cement layer 62B is laminated on the back surface of the intermediate layer.

[0100] <Reference example 4> The configuration of Reference Example 4 is identical to that of Reference Example 3, except that it includes a mixed layer instead of an intermediate layer. In other words, Reference Example 4 does not include ferrite layers 212 and 213.

[0101] Neutron irradiation experiments were conducted using the above-mentioned shielding materials. Specifically, neutron beams were irradiated towards each shielding material. Then, the presence or absence of voids in each shielding material after irradiation was checked, and the surface of each shielding material was observed. The neutron beam energy was set to 2.5 MeV, and the irradiation direction of the neutron beam was set to the 4π direction (all directions in three-dimensional space). The neutron emission rate was set to 10 7 n / S was used.

[0102] In the X-ray transmission experiment, in addition to Reference Examples 3 and 4, a shielding material according to Comparative Example 4 was manufactured. The configuration of the shielding material according to Comparative Example 4 was as follows.

[0103] <Comparative Example 4> Comparative Example 4 has a single-layer structure and is composed of one cement layer. This single cement layer is twice the thickness of cement layer 61B.

[0104] X-ray transmission experiments were conducted using the shielding materials described above. Specifically, X-rays were irradiated towards each shielding material, and the amount of X-ray shielding was measured. The tube voltage of the X-ray tube was set to 40kV, and the tube current to 0.4mA. The amount of X-ray shielding by the shielding materials in Reference Examples 3 and 4 was measured, with the amount of X-ray shielding by the shielding material in Comparative Example 4 set to 1.

[0105] The results of the shielding test are shown in Table 2. [Table 2]

[0106] In neutron irradiation experiments, it was confirmed that no voids formed in the shielding material and no damage occurred to the surface of the shielding material when a mixed layer containing boron was used. In X-ray shielding experiments, comparing Reference Example 4 and Comparative Example 4, it was confirmed that a 1.8-fold increase in X-ray shielding effect was obtained by providing a mixed layer between the two cement layers. Furthermore, comparing Reference Example 3 and Comparative Example 4, it was confirmed that approximately twice the X-ray shielding effect was obtained by providing an intermediate layer containing a ferrite layer between the two cement layers.

[0107] [Differentiation] Although the first to third embodiments have been described above, the shielding material 1 may be constructed by appropriately combining these embodiments. For example, the shielding material 1 may include a mixed layer 61A instead of each of the cement layers 223, 224, and 225. Also, the shielding material 1 may include a ferrite layer 3B instead of the ferrite layer 3.

[0108] In the above embodiment, the shielding materials 1, 1A, and 1B included an inner layer 21. However, the shielding materials 1, 1A, and 1B do not necessarily have to include an inner layer 21. In this case, the shielding materials 1, 1A, and 1B may include a boron layer instead of the inner layer 21.

[0109] In the above embodiment, the shielding materials 1, 1A, and 1B contained a plurality of polymer pieces 5. However, the shielding materials 1, 1A, and 1B may contain only one polymer piece 5. Also, in the above embodiment, the plurality of polymer pieces 5 were spaced apart from each other when viewed from the stacking direction Da. However, the plurality of polymer pieces 5 may be in contact with each other when viewed from the stacking direction Da.

[0110] In the above embodiment, an example of how to arrange the multiple polymer pieces 5 has been described. However, the arrangement of the multiple polymer pieces 5 can be changed as appropriate. For example, the multiple polymer pieces 5 included in the polymer layer 226 may include only a plurality of first polymer pieces 51 extending in the longitudinal direction D1, and may not include second polymer pieces 52. Similarly, the multiple polymer pieces 5 included in the polymer layer 226 may include only a plurality of second polymer pieces 52, and may not include first polymer pieces 51. Furthermore, the multiple polymer pieces 5 included in the polymer layer 236 may include only a plurality of third polymer pieces 53, and may not include fourth polymer pieces 54. Similarly, the multiple polymer pieces 5 included in the polymer layer 236 may include only a plurality of fourth polymer pieces 54, and may not include third polymer pieces 53.

[0111] In the first embodiment, the shielding material 1 included ferrite layers 3 and 4. However, the shielding materials 1, 1A, and 1B only need to include ferrite layer 3 and do not need to include ferrite layer 4. Similar modifications are possible in the second and third embodiments.

[0112] In the first embodiment, the polymer layer 226 was provided between the center of the main body layer 2 in the stacking direction Da and the ferrite layer 3, and the polymer layer 236 was provided between the center of the main body layer 2 in the stacking direction Da and the ferrite layer 4. However, the positions in which the polymer layers 226 and 236 are provided can be changed as appropriate. For example, the polymer layer 226 may be provided on the main surface 2a of the main body layer 2, and the polymer layer 236 may be provided on the back surface 2b of the main body layer 2. In this case, the ferrite layer 3 may be provided between the center of the main body layer 2 in the stacking direction Da and the polymer layer 226, and the ferrite layer 4 may be provided between the center of the main body layer 2 in the stacking direction Da and the polymer layer 236. Similar modifications are possible in the second and third embodiments.

[0113] In the first embodiment, at least one of the main body layer 2 and the ferrite layer 3 contained boron carbide, boric acid, or a borate. However, at least one of the main body layer 2 and the ferrite layer 3 only needs to contain boron, and may also contain boron compounds other than these boron compounds. Similar modifications are possible in the second and third embodiments.

[0114] In the embodiments described above, the thickness of the ferrite layer was exemplified. However, the thickness of the ferrite layer can be appropriately changed depending on the layer configuration of the shielding material 1. For example, when two ferrite layers are arranged on the front and back surfaces of the shielding material 1, and two other ferrite layers are arranged on the front and back surfaces of the internal layer 21 (sandwiched on the surface and in the middle), the thickness of the ferrite layer can range from 1.5 mm to 6.0 mm.

[0115] In the above embodiment, an example of using the shielding material 1 as a building material for a medical facility was described. However, the use of the shielding material 1 is not particularly limited. The shielding material 1 may also be used as a building material other than in the reactor within a nuclear power plant.

[0116] The thickness of each layer constituting shielding materials 1, 1A, and 1B can be changed as appropriate.

[0117] [Note] The outline of this invention is as follows: (1) The main layer containing cement, The main body layer is laminated in the lamination direction and comprises a first ferrite layer containing ferrite, The main body layer includes a first polymer layer containing a polymer, At least one of the main body layer and the first ferrite layer is a radiation shielding material containing boron. (2) (1) The radiation shielding material described above, The main body layer is, The boron layer containing the aforementioned boron, A first cement layer containing the aforementioned cement, The present invention includes a second cement layer that is different from the first cement layer, The boron layer includes a first surface and a second surface opposite to the first surface in the stacking direction, The first cement layer is laminated on the first surface, The second cement layer is a radiation shielding material laminated on the second surface. (3) (1) The radiation shielding material described above, The main body layer is a radiation shielding material comprising a mixed layer containing the cement and the boron. (4) A radiation shielding material described in any one of (1) to (3), The first ferrite layer is a radiation shielding material containing the boron. (5) A radiation shielding material described in any one of (1) to (4), The first polymer layer comprises a plurality of polymer pieces containing the polymer, The plurality of polymer pieces are spaced apart from each other when viewed from the stacking direction, forming a radiation shielding material. (6) A radiation shielding material described in any one of (1) to (5), The aforementioned radiation shielding material is, A first direction intersecting the stacking direction, It extends in a second direction that intersects both the stacking direction and the first direction, The first polymer layer comprises a plurality of polymer pieces containing the polymer, The plurality of polymer pieces are A plurality of first polymer pieces extending in the first direction, The present invention comprises a plurality of second polymer pieces extending in the second direction, The first polymer layer is A first region comprising the plurality of first polymer pieces arranged in the second direction when viewed from the stacking direction, A radiation shielding material comprising a plurality of second polymer pieces arranged in the first direction when viewed from the stacking direction, and a first region and a second region adjacent to the first direction. (7) (6) The radiation shielding material described above, The main body layer includes a second polymer layer that is different from the first polymer layer. The aforementioned second polymer layer is A plurality of third polymer pieces extending in the second direction, The material comprises a plurality of fourth polymer pieces extending in the first direction, The aforementioned second polymer layer is A third region comprising the plurality of third polymer pieces arranged in the first direction when viewed from the stacking direction, A radiation shielding material comprising a plurality of fourth polymer pieces arranged in the second direction when viewed from the stacking direction, and a third region and a fourth region adjacent in the second direction. (8) A radiation shielding material described in any one of (1) to (7), The present invention further comprises a second ferrite layer different from the first ferrite layer, The main body layer includes a third surface and a fourth surface opposite to the third surface in the stacking direction, The first ferrite layer is laminated on the third surface, The second ferrite layer is a radiation shielding material laminated on the fourth surface. (9) (8) The radiation shielding material described above, The main body layer includes a second polymer layer that is different from the first polymer layer. The first polymer layer is provided between the center of the main body layer in the stacking direction and the first ferrite layer, The second polymer layer is a radiation shielding material provided between the center of the main body layer in the lamination direction and the second ferrite layer. (10) A radiation shielding material described in any one of (1) to (9), The main body layer is, The first internal ferrite layer containing the aforementioned ferrite, A second internal ferrite layer different from the first internal ferrite layer, The internal polymer layer includes the aforementioned polymer, The internal polymer layer includes a fifth surface and a sixth surface opposite to the fifth surface in the lamination direction, The first internal ferrite layer is laminated on the fifth surface, The second internal ferrite layer is a radiation shielding material laminated on the sixth surface. (11) A radiation shielding material described in any one of (1) to (10), A radiation shielding material comprising at least one of the main body layer and the first ferrite layer, containing boron carbide, boric acid, or a borate. (12) A radiation shielding material described in any one of (1) to (11), The aforementioned polymer is PET, a radiation shielding material. (13) (12) A radiation shielding material as described above, The first polymer layer is a radiation shielding material comprising polymer pieces formed by cutting a plastic bottle. [Explanation of symbols]

[0118] 1,1A,1B Shielding material (radiation shielding material) 1a, 1b Longer side 1c, 1d Short side 2. Main Layer 2a Main surface (3rd surface) 21a,222a Main surface 211a Main surface (5th surface) 221a Main surface (first surface) 2b Back side (4th side) 21b,222b Back side 211b Back side (6th side) 221b Back side (2nd side) 3,3B Ferrite layer (first ferrite layer) 4,4B (Second ferrite layer) 212 Ferrite layer (first inner ferrite layer) 213 Ferrite layer (second inner ferrite layer) 5 polymer pieces 11 Connecting protrusion 12 Joint recess 21 Inner layer 22,22A,22B,23,23A,23B configuration layer 51. First polymer piece 52 Second Polymer Piece 53 Third Polymer Piece 54. Fourth polymer piece 61A,63A mixed layer 61B, 62B Cement layer 62A,64A End mixed layer 223,233 Cement layer (First cement layer) 224,234 Cement layer (Second cement layer) 225,235 cement layer 211 Polymer layer (internal polymer layer) 226 Polymer layer (first polymer layer) 236 Polymer layer (second polymer layer) 221,231 Boron layer (First boron layer) 222,232 Boron layer (Second Boron layer) 227,237 End cement layer D1 Longitudinal direction (first direction) D2 Width direction (second direction) D3 Thickness direction Da stacking direction R1 1st area R2 2nd area R3 3rd area R4, 4th Domain T-joint material

Claims

1. A radiation shielding material that does not contain gypsum and barium sulfate, The main layer containing cement, A first ferrite layer containing ferrite is laminated in the stacking direction relative to the main body layer, The main body layer includes a first polymer layer containing a polymer, At least one of the main body layer and the first ferrite layer contains boron, The first polymer layer comprises a plurality of polymer pieces containing the polymer, The plurality of polymer pieces are spaced apart from each other when viewed from the stacking direction, forming a radiation shielding material.

2. A radiation shielding material according to claim 1, The main body layer is, The boron layer containing the aforementioned boron, A first cement layer containing the aforementioned cement, The present invention includes a second cement layer that is different from the first cement layer, The boron layer includes a first surface and a second surface opposite to the first surface in the stacking direction, The first cement layer is laminated on the first surface, The second cement layer is a radiation shielding material laminated on the second surface.

3. A radiation shielding material according to claim 1, The main body layer is a radiation shielding material comprising a mixed layer containing the cement and the boron.

4. A radiation shielding material according to any one of claims 1 to 3, The first ferrite layer is a radiation shielding material containing the boron.

5. A radiation shielding material according to any one of claims 1 to 3, The aforementioned radiation shielding material is A first direction intersecting the stacking direction, It extends in a second direction that intersects both the stacking direction and the first direction, The first polymer layer comprises a plurality of polymer pieces containing the polymer, The plurality of polymer pieces are A plurality of first polymer pieces extending in the first direction, The present invention comprises a plurality of second polymer pieces extending in the second direction, The first polymer layer is A first region comprising the plurality of first polymer pieces arranged in the second direction when viewed from the stacking direction, A radiation shielding material comprising a plurality of second polymer pieces arranged in the first direction when viewed from the stacking direction, and a first region and a second region adjacent to the first direction.

6. A radiation shielding material according to claim 5, The main body layer includes a second polymer layer that is different from the first polymer layer. The aforementioned second polymer layer is A plurality of third polymer pieces extending in the second direction, The material comprises a plurality of fourth polymer pieces extending in the first direction, The aforementioned second polymer layer is A third region comprising the plurality of third polymer pieces arranged in the first direction when viewed from the stacking direction, A radiation shielding material comprising a plurality of fourth polymer pieces arranged in the second direction when viewed from the stacking direction, and a third region and a fourth region adjacent in the second direction.

7. A radiation shielding material according to any one of claims 1 to 3, The present invention further comprises a second ferrite layer different from the first ferrite layer, The main body layer includes a third surface and a fourth surface opposite to the third surface in the stacking direction, The first ferrite layer is laminated on the third surface, The second ferrite layer is a radiation shielding material laminated on the fourth surface.

8. A radiation shielding material according to claim 7, The main body layer includes a second polymer layer that is different from the first polymer layer. The first polymer layer is provided between the center of the main body layer in the stacking direction and the first ferrite layer, The second polymer layer is a radiation shielding material provided between the center of the main body layer in the lamination direction and the second ferrite layer.

9. A radiation shielding material according to any one of claims 1 to 3, The main body layer is, The first internal ferrite layer containing the ferrite, A second internal ferrite layer different from the first internal ferrite layer, The internal polymer layer includes the aforementioned polymer, The internal polymer layer includes a fifth surface and a sixth surface opposite to the fifth surface in the lamination direction, The first internal ferrite layer is laminated on the fifth surface, The second internal ferrite layer is a radiation shielding material laminated on the sixth surface.

10. A radiation shielding material according to any one of claims 1 to 3, A radiation shielding material comprising at least one of the main body layer and the first ferrite layer, containing boron carbide, boric acid, or a borate.

11. A radiation shielding material according to any one of claims 1 to 3, The aforementioned polymer is PET, a radiation shielding material.

12. A method for manufacturing a radiation shielding material according to claim 11, A method for manufacturing a radiation shielding material, comprising forming the polymer pieces of the first polymer layer by cutting a plastic bottle.

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