JP3105337B2 - Transparent radiation shielding material and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent radiation shielding material and a method for producing the same.

[0002]

2. Description of the Related Art It is known that a radiation shielding material which is lightweight and has good workability and moldability can be obtained by incorporating a lead compound such as lead oxide, lead halide, or lead acetate into a synthetic resin.
However, a material having a transparent, hard thermoplastic resin containing a lead compound as described above and having a substantially satisfactory radiation shielding ability often loses its transparency and has a bleed phenomenon. It has various practical problems, such as causing it to become fragile.

In order to solve this problem, for example, JP-A-53-9994 discloses that (A) at least one monomer of methyl methacrylate or styrene is contained as an essential component, and a heat distortion temperature of 65 ° C. or higher. 35-87% by weight of a thermoplastic polymer selected from the group consisting of a polymer having a total light transmittance of 70% or more as measured at a thickness of 8 mm, polycarbonate, polyvinyl chloride, and (B)
65 to 13% by weight of organic acid lead represented by the general formula (RCOO) _a Pb (where a is an integer equal to the valence of lead, and R represents a saturated or unsaturated hydrocarbon group having 5 to 20 carbon atoms) % Of a radiation shielding composition is disclosed.

[0004] However, the above radiation shielding composition contains lead which shows an effective shielding ability against electromagnetic waves such as X-rays and γ-rays and charged particles such as α-rays and β-rays. However, it is insufficient for thermal neutrons.

On the other hand, as a neutron beam shielding polymer material,
It is also known to add boron compounds to polyethylene or methacrylic resins. However, although this method is also neutron absorption ability is large, helium produced with the neutron absorption reaction, lithium because neutron absorption ability is little, tend to its ability with increasing neutron absorption amount decreases At the same time, optical and mechanical properties are not satisfactory.

[0006] In addition to the boron compounds described above, samarium, europium and gadolinium, which are rare earth elements having atomic numbers of 62, 63 and 64, are used as neutron absorbing substances.
It is known that the thermal neutron beam absorption capacity is higher than that of boron. Japanese Patent Application Laid-Open No. 60-99150 discloses a composition containing such components, for example, a transparent thermoplastic resin excluding methacrylic resin in the visible region and / or
Alternatively, there is disclosed a resin composition obtained by uniformly dispersing and dissolving a rare earth element compound composed of at least one of gadolinium, samarium and europium in a resin composed of a thermosetting resin.

[0007]

However, Japanese Patent Application Laid-Open No.
A rare earth element compound such as gadolinium is added to the resin composition disclosed in Japanese Patent Publication No. 0-99150 only in the range of 0.001 to 10% by weight based on the total resin content. According to the publication, the reason is that the compounding amount is 10% by weight.
It is said that the mechanical properties and the transparency of the resin composition are impaired when it exceeds. However, even a resin composition to which the above-mentioned upper limit amount of a rare earth element is added and blended cannot be said to have a sufficient neutron absorption ability, and cannot be said to be a transparent radiation shielding material having good performance.

[0008] Accordingly, an object of the present invention is to provide a transparent radiation shielding material having a good radiation shielding performance, in which a larger proportion of a rare earth element, particularly gadolinium, can be added and compounded without impairing the transparency, and a method for producing the same. Is to provide.

Another object of the present invention is that a larger amount of a rare earth element, particularly gadolinium, can be added and compounded without impairing transparency, and lead can be added and compounded at the same time. An object of the present invention is to provide a transparent radiation shielding material having excellent radiation shielding performance and a method for producing the same.

[0010]

According to the present invention, there is provided a transparent radiation shielding material comprising gadolinium acrylate, acetylacetonate.
Gadolinium and gadolinium propionate
17 to 51 % by weight of a gadolinium salt selected from the group consisting of: an amine solvent or an amide solvent for dissolving the gadolinium salt 0.2 to 20% by weight; a resin 40 to 7
0% by weight and 0.01 to 1% by weight of a reaction initiator.

The transparent radiation shielding material is made of acrylic.
Gadolinium acid, gadolinium acetylacetonate and
Selected from the group consisting of gadolinium and propionate
17-51% by weight of gadolinium salt is dissolved in 0.2-20% by weight of an amine-based or amide-based solvent for dissolving the gadolinium salt. Initiator 0.01 ~
It can be manufactured by casting a solution obtained by adding and mixing 1% by weight in a mold having a predetermined shape.

Further, the transparent radiation shielding material according to the present invention comprises:
Gadolinium acrylate, acetylacetonato gadolin
Selected from the group consisting of gallium and gadolinium propionate
17 to 51 % by weight of gadolinium salt selected , acrylic
From the group consisting of lead oxalate, lead octylate and lead linoleate
40 % by weight or less of a selected lead salt, 57 % by weight or less of a total amount of a gadolinium salt and a lead salt, 0.2 to 20% by weight of an amine solvent or an amide solvent for dissolving the gadolinium salt and the lead salt, It is characterized by comprising 40 to 70% by weight of a resin and 0.01 to 1% by weight of a reaction initiator.

The transparent radiation shielding material is made of acrylic.
Gadolinium acid, gadolinium acetylacetonate and
Selected from the group consisting of gadolinium and propionate
Gadolinium salt 17-51% by weight , lead acrylate , octane
Selected from the group consisting of lead citrate and lead linoleate
Lead salt 40 % by weight or less, total amount of gadolinium salt and lead salt
Not more than 57 % by weight of an amine-based or amide-based solvent for dissolving the gadolinium salt and the lead salt,
Was dissolved in 0 wt%, then, the gadolinium and lead-containing solution addition 40 to 70 wt% resin and 0.01 to 1% by weight initiator, were obtained by mixing the solution to a predetermined fixed form shaped mold It can be manufactured by casting.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The transparent radiation shielding material of the present invention comprises a mixture of gadolinium having excellent neutron absorption capability alone or in combination with gadolinium and lead. By dissolving in a system solvent and then mixing with a resin component or a reaction initiator, the amount of gadolinium or gadolinium that could not be added or compounded because of the possibility of impairing transparency or mechanical performance until now was It can contain lead.

The gadolinium salt used in the transparent radiation shielding material of the present invention is not particularly limited as long as it is soluble in an amine-based solvent or amide-based solvent described later. Examples thereof include gadolinium acrylate and gadolinium acetylacetonate. And organic acids such as gadolinium propionate. Addition of gadolinium salt,
The compounding amount is 17 to 51% by weight ( 10 % in terms of gadolinium).
-30% by weight ) .

The lead salt used in the transparent radiation shielding material of the present invention is not particularly limited as long as it is soluble in an amine solvent or an amide solvent described later. For example, lead acrylate, octyl Organic acids such as lead acid and lead linoleate can be mentioned. The addition and blending amount of the lead salt is 40% by weight or less ( 20% by weight or less in terms of lead ) . When the lead salt and the gadolinium salt are used in combination, the total amount of the lead salt and the gadolinium salt must be 57% by weight or less ( 30% by weight or less in terms of lead and gadolinium ) . This is because if the total amount exceeds 57 % by weight, the transparency of the transparent radiation shielding material may be impaired.

The feature of the present invention resides in that the gadolinium salt or the gadolinium salt and the lead salt as described above are once dissolved in an amine solvent or an amide solvent and mixed with a resin component and a reaction initiator. A gadolinium salt or lead salt is dissolved in an amine-based solvent or an amide-based solvent, and then mixed with a resin component and a reaction initiator, so that a higher proportion of gadolinium can be obtained without impairing the transparency of the obtained transparent radiation shielding material. And lead can be blended. Usable amine solvents or amide solvents include N, N-dimethylformamide, N, N-dimethylisobutylamine, N
-Sec-butyl-n-propylamine, cyclohexylamine, diethylamine, N-ethylamine, hexamethylphosphoric triamide, N- (2-hydroxypropyl) ethylenediamine, n-octylamine, n-heptylamine and the like. The addition and blending amount of the amine solvent and the amide solvent are 0.2 to 20% by weight based on the total blending amount.
Preferably 5 to 10% by weight of within range.

The resin used for the transparent radiation shielding material of the present invention is not particularly limited, but examples thereof include transparent resins such as methacrylic resin, styrene resin and hydroxy resin. The addition and blending amount of the resin is in the range of 40 to 70% by weight. If the addition or blending amount is less than 40% by weight, the mechanical strength of the transparent radiation shielding material is inferior. On the other hand, if it exceeds 70% by weight, it is not preferable in relation to the addition and blending amount of other components.

The reaction initiator is a component for curing the resin used, and may be used according to the resin used. Addition of initiator, the amount is usually 0. It is in the range of 01 to 1% by weight, particularly preferably in the range of 0.1 to 0.5% by weight.

The transparent radiation shielding material of the present invention is obtained by dissolving the above-mentioned gadolinium salt or gadolinium salt and a lead salt with an amine-based solvent or an amide-based solvent, and then adding the gadolinium-containing salt.
It can be produced by adding a resin and a reaction initiator to a solution or a solution containing gadolinium and lead and mixing the resulting solution, and then casting the solution in a mold having a predetermined shape.

By adding acrylonitrile to the above composition, the toughness of the product can be increased. Acrylonitrile was added in an amount of 1: 2 to 1:
Addition of 8 increases the toughness of the styrene resin, thereby increasing the toughness and strength of the product.

[0022]

EXAMPLE 1 Gadolinium methacrylate 26.87 wt% Lead methacrylate 10.49 wt% Methyl methacrylate 26.29 wt% Styrene 22.00 wt% Acrylonitrile 9.45 wt% Hexamethylphosphoric triamide 4.72 wt% 1,1-azobis (cyclohexane-1-carbonitrile) 0.18% by weight Hexamethylphosphoric triamide was added to gadolinium methacrylate at the above ratio. On the other hand, methyl methacrylate is added to lead methacrylate and dissolved by heating. After mixing and dissolving both by stirring at 93 ° C. for 10 minutes, styrene was further added and stirred at 100 ° C. for 5 minutes to obtain a transparent liquid. After allowing this liquid to cool to 50 ° C., acrylonitrile and 1,1-azobis (cyclohexane-1-carbonitrile) were added, poured into a glass mold and solidified in hot water at 60 ° C. for 15 hours. C. for 2 hours to complete the polymerization to obtain the transparent radiation shielding material of the present invention. Obtained transparent radiation shielding material (dimensions: 100 × 150 × 3 mm)
Has good transparency and is 12.06% by weight based on the resin
Gadolinium and 7.37% by weight of lead.

Example 2 Gadolinium methacrylate 26.89% by weight Methyl methacrylate 31.10% by weight Styrene 37.19% by weight Hexamethylphosphoric triamide 4.72% by weight 1,1-azobis (cyclohexane-1-carbonitrile) 10% by weight Cast polymerization was carried out at the above ratio under the same conditions as in Example 1. As a result, a resin plate having good transparency was obtained. This resin plate had a gadolinium content of 10.73% by weight with respect to the resin.

Example 3 Gadolinium acrylate 26.87% by weight Lead acrylate 10.49% by weight Methyl methacrylate 26.29% by weight Styrene 31.45% by weight Hexamethylphosphoric triamide 4.72% by weight 1,1-azobis (cyclohexane) -1-carbonitrile) 0.18% by weight Cast polymerization was carried out under the same conditions as in Example 1 at the above ratio. As a result, a resin plate having good transparency was obtained. This resin plate had a gadolinium content of 12.01% by weight and a lead content of 7.38% by weight with respect to the resin.

Example 4 Gadolinium methacrylate 26.88 wt% Lead methacrylate 10.50 wt% Methyl methacrylate 12.26 wt% Hydroxyethyl methacrylate 14.04 wt% Hexamethylphosphoric triamide 4.56 wt% 1,1-azobis (Cyclohexane-1-carbonitrile) 0.18% by weight Styrene 22.02% by weight Acrylonitrile 9.44% by weight Release agent 0.12% by weight Hexamethylphosphoric triamide is mixed with gadolinium methacrylate in the above ratio, while methyl is added. Lead methacrylate was added to a mixture of methacrylate and hydroxyethyl methacrylate and dissolved by heating. 100 ° C
For 10 minutes to obtain a transparent liquid. After allowing this liquid to cool to 50 ° C., acrylonitrile and 1,1-azobis (cyclohexane-1-carbonitrile) were added, poured into a glass mold and solidified in hot water at 60 ° C. for 15 hours.
The polymerization was completed by curing in air at 120 ° C. for 2 hours to obtain a transparent plate. The transparent plate had good transparency and had a gadolinium content of 12.07% by weight and a lead content of 7.38% by weight with respect to the resin.

[0026]

Table 1 Density Transparency Total light transmittance Flexural strength (g / cm ³ ) (%) (kg / cm ² ) Example 1 1.21 Good 92 750 Example 2 1.20 Good 91 720 Example 3 1.21 good 91 700 Example 4 1.21 good 90 750

[0027]

The transparent radiation shielding material of the present invention contains a large amount of gadolinium and lead which cannot be added or compounded conventionally without impairing the transparency, and has a good radiation shielding effect. It has a function.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-99150 (JP, A) JP-A-5-202110 (JP, A) JP-A-5-98067 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08 B29C 39/00

Claims (4)

(57) [Claims] (1) gadolinium acrylate, acetyl ace
Toner gadolinium and gadolinium propionate?
17 to 51 % by weight of a gadolinium salt selected from the group consisting of: 0.2 to 20% by weight of an amine solvent or an amide solvent for dissolving the gadolinium salt;
A transparent radiation shielding material comprising 70% by weight and 0.01 to 1% by weight of a reaction initiator. 2. The method for producing a transparent radiation shielding material according to claim 1 , wherein the gadolinium acrylate and the acetylacetonate are used.
Toner gadolinium and gadolinium propionate?
Gadolinium salt 17-51 weight selected from the group consisting of
% Of the gadolinium salt is dissolved in 0.2 to 20% by weight of an amine solvent or an amide solvent for dissolving the gadolinium salt. adding 1% by weight, method of manufacturing the translucent light radiation shield you characterized by casting the obtained mixed solution at a mold of a predetermined shape. 3. Gadolinium acrylate, acetylacetate
Toner gadolinium and gadolinium propionate?
17 to 51 % by weight of gadolinium salt selected from the group consisting of lead acrylate, lead octylate and lead linoleate
A lead salt selected from the group consisting of 40 % by weight or less, a total amount of a gadolinium salt and a lead salt of 57 % by weight or less, and an amine solvent or an amide solvent for dissolving the gadolinium salt and the lead salt in an amount of 0.2 to 0.2%. A transparent radiation shielding material comprising 20% by weight, 40 to 70% by weight of a resin and 0.01 to 1% by weight of a reaction initiator. 4. Production of the transparent radiation shielding material according to claim 3.
Gadolinium acrylate, acetylacetate
Toner gadolinium and gadolinium propionate?
Gadolinium salt 17-51 weight selected from the group consisting of
% , Lead acrylate, lead octylate and lead linoleate
The lead salt selected from the group consisting of 40 % by weight or less and the total amount of the gadolinium salt and the lead salt of 57 % by weight or less are mixed with an amine solvent or an amide solvent for dissolving the gadolinium salt and the lead salt in an amount of 0.2 to 0.2% was dissolved in 20 wt%, then, the gadolinium and lead-containing solution addition 40 to 70 wt% resin and 0.01 to 1% by weight initiator, were obtained by mixing the solution to a predetermined fixed form shaped mold method of manufacturing a transparency radiation shield characterized by casting Te.