TW201621918A - Sheet-shaped radiation shielding material - Google Patents

Abstract

To provide a sheet-shaped radiation shielding material having high radiation shielding ability. In the present invention, various types of sheets are fabricated in which tungsten, dysprosium (Dy), europium (Eu), and the like having radiation shielding ability are blended at a high concentration in an elastomer, the various sheets are layered, and a sheet-shaped radiation shielding material having high radiation shielding ability is fabricated.

Description

Flaky radiation shielding material

The present invention relates to a sheet-shaped radiation shielding material.

In recent years, with the progress of radiation medicine, and the use of nuclear energy such as nuclear power generation, and the shielding of radiation exposure caused by such radioactive waste, there have been various developments, but the shielding ability of radiation shielding materials. There are still problems with material problems, manufacturing methods, and so on.

The radiation system includes α-rays, β-rays, neutron lines, etc. belonging to particle lines, and γ-rays and X-rays belonging to electromagnetic waves, and the penetration force of α-rays is weak, even if the degree of a sheet of paper can be shielded, β-rays It can also be prevented by using aluminum foil with a thickness of several mm. However, the penetration of gamma rays is strong. If the concrete needs to be 50 cm, even lead must have a thickness of 10 cm. The neutron beam has a stronger penetrating power and can be initially interrupted by using hydrogen atoms contained in the thick walls of water and concrete.

Most of these radiation shielding materials have used high-specific gravity metals such as lead and concrete. However, most of the lead materials are treated as the target substance, which is not preferable for the materials used in the radiation operation, and is treated as waste materials. Time, environment, cost Faces will also increase the problem. Further, in the case of concrete, such as Patent Documents 1, 2, 3, and 4, it is necessary to increase the thickness in order to obtain a high shielding rate, and there is no problem in fixing a building, but it is used as a barrel for storing and transporting radioactive materials. Or the size of the container, the amount of container can be reduced, and the weight of the container becomes heavy, which causes problems during transportation. Most of the concrete will crack with the progress of the hydration reaction, and there is a danger of leakage of contents. Sex.

Further, as in Patent Documents 5, 6, and 7, many examples are substituted for lead, and a high-specific gravity metal is mixed in a resin, and is used after being formed into a sheet, and a Banbury mixer, a kneader, or the like is used. A machine having a strong shearing force mixes a high-specific gravity metal or the like in a thermoplastic resin or the like, and after kneading, it is processed into a sheet to form a product. The exfoliated radiation shielding material can be used after being appropriately cut according to the shape of the place where it is applied.

The shielding rate of the radiation is greatly affected by the density of the masking material. As described in Patent Documents 6 and 7, the shielding sheet is reduced in the filling ratio of the high specific gravity metal or the like to reduce the density of the masking material, thereby making the X-ray shielding rate. It is a very small state of 0.2mmPb, but even such a radiation shielding rate is still difficult to say.

Further, when the sheet is processed into a sheet, if the thickness of the sheet is reduced and the workability is good, the radiation shielding rate is lowered. On the other hand, if the thickness is increased, the thickness is not easily cut, and the shape of the place is not obtained. Moreover, although the radiation shielding rate can be increased by laminating thin sheets, the weight increases as the number of sheets increases, and the shape is difficult to maintain, which is difficult to apply to a wide range.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 10-153690

[Patent Document 2] Japanese Patent Laid-Open No. 2010-8224

[Patent Document 3] Japanese Patent Laid-Open No. 2013-29467

[Patent Document 4] Japanese Patent Laid-Open No. 2004-236196

[Patent Document 5] Japanese Patent Laid-Open No. 2013-18878

[Patent Document 6] Japanese Patent Laid-Open No. 2011-99791

[Patent Document 7] Japanese Patent Laid-Open No. 2007-212304

The purpose of the present invention is to provide an elastomer layer (a layer) in which tungsten powder having a large radiation shielding force is dispersed, an elastomer layer (b layer) containing dysprosium (Dy) dispersed, or an elastic layer containing ruthenium (Eu) dispersed. A sheet-shaped radiation shielding material in which a bulk layer (c layer) is laminated, and exhibits a high radiation shielding rate for all radiation including γ-rays and neutron beams having strong penetrating power, and a film having a thickness of about 50 μm To a sheet-shaped radiation shielding material exceeding 10 cm thick plate.

That is, the present invention is a sheet-shaped radiation shielding material having the following constitution.

[1] A sheet-like radiation shielding material comprising an elastomer layer (a layer) in which tungsten powder is dispersed and an elastomer layer (b layer) in which dysprosium (Dy) is dispersed.

[2] A sheet-like radiation shielding material comprising an elastomer layer (a layer) in which tungsten powder is dispersed and an elastomer layer (c layer) in which europium (Eu) is dispersed.

[3] A sheet-like radiation masking material comprising an elastomer layer in which tungsten powder is dispersed (a The layer), the Dy elastomer layer (b layer) and the Eu (Eu) elastomer layer (c layer) are laminated.

[4] A sheet-like radiation shielding material comprising a Dy elastomer layer (b layer) or an Eu (c layer) from an elastomer layer (a layer) in which tungsten powder is dispersed from both side faces of the layers. Sandwiched and laminated.

[5] The sheet-like radiation shielding material according to any one of the above [1], wherein a lithium compound is mixed in the elastomer layer.

[6] The sheet-like radiation shielding material according to [5], wherein a blending ratio of the tungsten powder to the elastomer precursor is 95:5 to 80:20 (parts by weight) based on the solid content.

The sheet-like radiation shielding material according to any one of the above-mentioned invention, wherein the lithium compound is blended with respect to 100 parts by weight of the mixture of the elastomer precursor and the tungsten powder. 2.0 parts by weight.

The sheet-like radiation shielding material according to any one of claims 1 to 7, wherein the tungsten powder used in the production of the elastomer layer (layer a) in which the tungsten powder is dispersed is coated by a coupling agent. .

The sheet-like radiation shielding material according to any one of the above aspects, wherein the elastomer layer contains (1) boron or a boron compound powder or (2) a fat iron powder.

[10] The sheet-like radiation shielding material according to any one of [1] to [8] wherein the elastomer layer contains (1) boron or a boron compound powder, and (2) a fat iron powder.

[11] The sheet-like radiation shielding material according to any one of the above [1] to [10], wherein the elastomer constituting the elastomer layer (layer a) in which the tungsten powder is dispersed is polyvinyl chloride.

[12] The sheet-like radiation shielding material according to any one of the above [1] to [11], wherein a dysprosium (Dy) elastomer layer (b layer) or europium (Eu) (c layer) is dispersed. The elastomer of the elastomer layer is polypropylene.

It is best to add a lithium compound to increase the radiation shielding rate.

Further, a boron or boron compound powder or a graphite powder having a neutral shielding effect can be added.

Moreover, the radiation shielding rate can be increased by adding the ferrite iron powder.

Further, by adding a sheet of mixed dysprosium (Dy) or/and erbium (Eu), the shielding rate of high-energy radiation such as radioactive cobalt or radioactive cesium can be particularly enhanced.

The present invention has an elastomer layer (a layer) in which a tungsten powder is dispersed with a high radiation shielding rate, and is a dispersion containing high energy radiation energy of a radioactive cobalt or lanthanum, which has a high radiation shielding rate, and contains dysprosium (Dy). The elastomer layer (b layer) or the Eu (Eu) elastomer layer (c layer) provides a sheet-like radiation shielding material capable of absorbing/shading all of the radiation energy.

Furthermore, since the above-mentioned a-layer, b-layer, and c-layer are combined to produce a sheet, various combinations can be provided, for example, (1) c layer: b layer: layered body of c layer; (2) layer a: layer c :b layer: layered body of c layer; (3) layer of a: layer of c: layer of b: layer of c: layer of b: layer of layer of c layer, various kinds of combined sheets, sheets of various thicknesses, which can match the degree of shielding radioactivity The purpose/use of the size, weight, etc. of the radiological energy shielding device can be arbitrarily selected.

In other words, a sheet-like radioactive energy shielding material can be produced by combining the above various layers to design a necessary radiation shielding rate, weight, thickness, and the like.

Further, since the sheet-shaped radiation shielding material has elasticity, the impact is also strong, and cracking does not occur even if it is thick. Further, sewing processing or the like can be performed by thinning.

A‧‧‧elastomer layer with tungsten powder dispersed

b‧‧‧Dry layer of elastomer dispersed (Dy)

c‧‧‧Dispersed Eu (Eu) elastomer layer

Fig. 1 (1) to (3) are cross-sectional views of a sheet-shaped radiation shielding material of the present invention.

Hereinafter, the present invention will be described in detail.

The elastomer layer (a layer) in which the tungsten powder is dispersed in the present invention is, for example, a tungsten powder coated with a coupling agent at a high concentration in a polyvinyl chloride and a plasticizer, and heated to form a sheet. .

Further, by adding a lithium compound (for example, lithium carbonate fine powder) or the like, the radioactive energy shielding rate can be further enhanced.

In the present invention, the mixing ratio of the polyvinyl chloride elastomer, the polypropylene elastomer, and the tungsten powder is preferably from 3:97 to 25:75, more preferably from 5:95 to 20:80, by weight.

If the mixing ratio of the elastomer material is less than 3:97, it is difficult to form a sheet, and the strength after hardening is insufficient. On the other hand, when the mixing ratio of the elastomer material is more than 25:75, the density of the masking material (tungsten) is lowered, and high radiation shielding rate cannot be ensured.

In the present invention, a tungsten powder coated with a coupling agent is added to the elastomer.

The coupling agent is particularly preferably a decane coupling agent, and the like may be, for example, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, and a zirconium aluminate coupling agent, and is applied thinly on the surface of the tungsten powder particles. .

Since the tungsten powder particles treated with the coupling agent are not directly in contact with the environment, the tungsten powder particles can be strongly bonded to the elastomer even if the oxidation is not performed even in a high-temperature and high-humidity environment.

Next, the tungsten powder coated with the coupling agent is mixed with the elastomer resin by a stirring and mixing device such as a kneader.

The elastomer resin is preferably a thermoplastic elastomer resin such as polyvinyl chloride or polypropylene. Because it can obtain the suitability, strength and softness to the environment.

After uniformly mixing tungsten and an elastomer resin (including a plasticizer), it can be formed into, for example, calendering, roll rolling, press working, extrusion molding, T-die extrusion, injection molding, and the like. The desired sheet shape.

The elastic system may be, for example, a styrene-based, an olefin-based, a vinyl chloride-based, an amine-ester-based, an ester-based or a guanamine-based thermoplastic elastomer, and the thermosetting elastic system may be a natural rubber or a synthetic rubber such as acrylic acid. Rubber, nitrile rubber, isoprene rubber, amine ester glue, ethylene propylene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, chloroprene rubber, polyoxyethylene rubber, styrene ‧ butadiene rubber, Fluororubber, polyisobutylene rubber.

In addition, when a sheet containing tungsten (layer a) was produced, in particular, when a vinyl chloride-based film was used, it was confirmed that the radioactive energy shielding rate can be further improved.

In the case of containing chlorine, in order to increase the radioactive energy shielding rate, it is preferable to use a plasticizer which is mixed with a polyvinyl chloride elastomer, and a chlorine-containing one is also used.

The average particle diameter of the tungsten powder is preferably 0.5 to 10 μm, more preferably 1 to 5 μm. When the average particle diameter is less than 0.5 μm, it is difficult to carry out high-concentration blending of tungsten, and on the other hand, if the average particle diameter is more than 10 μm, it is difficult to use.

The present invention is a layer (b layer) containing dysprosium (Dy) or a layer (b layer) containing ruthenium (Eu), which absorbs high-energy radiant energy of radioactive cobalt and lanthanum.

However, when a tungsten-containing layer is produced, it is difficult to uniformly mix the tungsten powder if the rare earth group is added, and in any case, a partial unevenness occurs, so that a homogeneous sheet-shaped radiation shielding material cannot be produced.

Therefore, the layer (b layer) containing ruthenium (Dy) and the layer containing ruthenium (Eu) (layer b) in the present invention, After separately manufacturing separately from the elastomer layer (layer a) in which the tungsten powder is dispersed, lamination is carried out.

Therefore, by the free combination of the layers, it is possible to respond to the purpose, manner, etc. of the radioactive energy.

The present invention preferably adds lithium as described above, and the lithium compound may be, for example, lithium carbonate, lithium chloride, lithium fluoride, lithium bromide, lithium iodide, lithium hydroxide, lithium hexafluorophosphate, lithium niobate, n-butyllithium, lithium acetate, Lithium citrate, lithium fluorophosphate.

In addition to the above constituent components, boron or boron compound powder, molybdenum powder, silver powder, and other compounds having radiation shielding ability may be added. Further, the shape is not limited to a spherical shape, and may be a scaly shape, a needle shape, a fiber shape, or the like.

As shown in the cross-sectional view of Fig. 1, the laminate of each sheet of the present invention can be freely laminated as follows: as shown in (1), an elastomer layer (a layer) in which tungsten powder is dispersed, and a dispersion containing dysprosium (Dy). a laminated body of an elastomer layer (b layer) (ie, a layer of a layer: a layer of b); as shown in (2), an elastomer layer (a layer) in which tungsten powder is dispersed, and a dispersion containing dysprosium (Dy) a laminated layer of an elastomer layer (b layer) and an elastomer layer (a layer) in which tungsten powder is dispersed (ie, a layer: b layer: a layered layer of a layer); as shown in (3), the dispersion contains bismuth ( An elastomer layer (b layer) of Dy), an elastomer layer (a layer) in which tungsten powder is dispersed, an elastomer layer (b layer) containing dysprosium (Dy), an elastomer layer (a layer) in which tungsten powder is dispersed, and ruthenium (Eu) a laminated body of an elastomer layer (c layer) (that is, a b layer: a layer: b layer: a layer: a layered layer of a c layer).

By the combination of these, it is possible to produce a sheet of various thicknesses and a laminate sheet having various radiological energy shielding rates, and it is possible to provide a sheet-like radiation which can be used for the purpose/use of masking the level of radioactivity, shielding the size/weight of the radiation energy appliance, and the like. Covering material.

Further, the formation and lamination of each layer can be carried out by a known rolling method, a T-die extrusion method, a roll pressing method, a pasting method, or the like.

By using the sheet-shaped radiation shielding material of the present invention, it is possible to produce a radiation shielding material having various shapes and thicknesses, and it is possible to use, for example, a radiation shielding chamber for ensuring a working space in a radiation environment, and a waste containing radioactive material. Storage containers for objects, protective clothing for radiation exposure, medical equipment, curtains, wallpapers, etc.

[Examples]

Hereinafter, specific embodiments of the present invention are exemplified.

Example 1: (1) Use the following polyvinyl chloride compounds:

(a) Vinyl chloride polymer: "TH-3800" average polymerization degree: 3500~4100 (TAIYO VINYL (share) system)

Plasticizer: "W-4010" (adipic acid polyester) (DIC system)

Stabilizer: "AC-255" Ba/Zn liquid one-component stabilizer (manufactured by ADEKA)

Gelling agent (processing aid ‧ strengthening agent): "METABLEN P-531A" (Mitsubishi Rayon)

Acrylic processing aid

(b) blending amount

Vinyl chloride polymer: plasticizer = 1:1

Stabilizer: 4% by weight relative to PVC (compared to the above 1:1 blend)

Gelling agent (processing aid ‧ strengthening agent): 5% by weight relative to PVC (compared to the above 1:1 blending)

(2) Processing method

The mixture of the above polyvinyl chloride, a plasticizer, a stabilizer, a gelling agent and an acrylic processing aid is placed in a Hanschel mixer, mixed at 120 ° C or lower, and stirred and dispersed for about 10 to 20 minutes.

Next, the mixture was kneaded by a hot roll mixer (kneading machine) in a horizontal row and a double roll, and when the resin was wound around the roll to some extent, the tungsten powder was introduced into the machine to obtain a sheet-shaped tungsten radioactive shielding material.

The processing temperature is set to 140 to 160 ° C, and the resin temperature is set to about 160 ° C.

Example 2:

In the elastic system, the following was used, and yttrium (Dy) was mixed therein to 70%, and molding was carried out in the same manner as in Example 1 to obtain an elastomer layer (b layer) sheet in which Dy was dispersed.

(1) The following soft polypropylene resin compounds are used:

(a) Soft olefin: "NOTIO SN" Mitsui Chemical Co., Ltd.

Processing aid: "METABLEN A-3000" (polytetrafluoroethylene (PTFE) acrylic modified resin made by Mitsubishi Rayon)

(b) blending amount

Add "METABLEN A-3000" 3~5% to "NOTIO SN".

(2) Processing method

The composite is kneaded using a test mini-roller, and kneaded at a processing temperature of 190 to 200 ° C. When the resin is wound around the roller to some extent, the machine is loaded with 镝 (Dy) to obtain a sheet-like 镝 radiation occlusion. material.

Example 3:

In the elastic system, the material of Example 2 was used, and 70% of Eu (Eu) was mixed therein, and molding was carried out in the same manner as in Example 2 to obtain an elastic layer (c layer) sheet in which Eu was dispersed.

A‧‧‧elastomer layer with tungsten powder dispersed

b‧‧‧Dry layer of elastomer dispersed (Dy)

c‧‧‧Dispersed Eu (Eu) elastomer layer

Claims (12)

A sheet-like radiation shielding material is formed by laminating an elastomer layer (a layer) in which tungsten powder is dispersed and an elastomer layer (b layer) containing dysprosium (Dy) dispersed therein. A sheet-like radiation shielding material is formed by laminating an elastomer layer (a layer) in which tungsten powder is dispersed and an elastomer layer (c layer) containing europium (Eu) dispersed therein. A sheet-shaped radiation shielding material is obtained by laminating an elastomer layer (a layer), a Dy (E) elastomer layer (b layer), and an Eu (Eu) elastomer layer (c layer) in which tungsten powder is dispersed. A sheet-shaped radiation shielding material is obtained by sandwiching a Dy elastomer layer (b layer) or an Eu (c layer) from an elastic layer (a layer) in which tungsten powder is dispersed from both side faces of the layers. Laminated. The sheet-like radiation shielding material according to any one of claims 1 to 4, wherein a lithium compound is mixed in the elastomer layer. The sheet-like radiation shielding material according to claim 5, wherein the blending ratio of the tungsten powder to the elastomer is 95:5 to 80:20 (parts by weight) based on the solid content. The sheet-like radiation shielding material according to claim 5 or 6, wherein the lithium compound is blended in an amount of 0.1 to 2.0 parts by weight based on 100 parts by weight of the mixture of the elastomer precursor and the tungsten powder. The sheet-like radiation shielding material according to any one of claims 1 to 7, wherein the tungsten powder used in the production of the elastomer layer (layer a) in which the tungsten powder is dispersed is coated with a coupling agent. The sheet-like radiation shielding material according to any one of claims 1 to 8, wherein the elastomer layer contains (1) boron or a boron compound powder, or (2) a fat iron powder. The sheet-like radiation shielding material according to any one of claims 1 to 8, wherein the elastomer layer contains (1) boron or a boron compound powder, and (2) a fat iron powder. The sheet-like radiation shielding material according to any one of claims 1 to 10, wherein the elastomer constituting the elastomer layer (layer a) in which the tungsten powder is dispersed is polyvinyl chloride. The sheet-like radiation shielding material according to any one of claims 1 to 11, wherein the elastomer constituting the elastomer layer in which the Dy elastic layer (b layer) or the Eu (c layer) is dispersed is condensed. Propylene.