JPS5986609A - Methacrylic resin composition and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a methacrylic resin composition containing gadolinium that is optically transparent and has excellent mechanical properties, and a method for producing the same.

Methacrylic resin is used in a variety of fields due to its excellent transparency, weather resistance, and mechanical properties, but it cannot be used for these purposes because it does not have radiation shielding ability. Ta.

Therefore, in recent years, radiation shielding materials containing lead in methacrylic resin have been developed (Japanese Patent Publications No. 3JF-23AO, 99941/1989, JJ-9993, &J-999A, and JP-A-1999-1). !, 3-AJ310, etc.)
.

However, although the lead-containing radiation shielding materials described above effectively shield radiation from electromagnetic waves such as X-rays and R-rays and charged particles such as α-rays and β-rays, they do not shield against neutron radiation. Not enough.

On the other hand, it is also known to add a boron compound to polyethylene or methacrylic resin as a polymeric material for shielding neutron beams (Japanese Patent Application Laid-Open No. 71741597). However, although this method also has a large neutron beam absorption capacity (1) (1),
Since the helium and lithium produced as a result of neutron absorption reactions have very little neutron absorption capacity, their capacity tends to decrease as the amount of neutron absorption increases.
Transparency and mechanical properties have not yet reached a satisfactory level.

In addition to the above-mentioned boron compounds as substances that absorb neutron beams, it is known that gadolinium, which is a rare earth element with an atomic number AII, has an even greater ability to absorb thermal neutron beams than boron. However, since gadolinium is a metallic solid,
Due to its poor compatibility with methacrylic thread polymers, methacrylic resins that are transparent and have excellent mechanical properties have not yet been produced.
Not yet.

As a result of new consideration in view of this situation, the inventor of the present invention found that
A methacrylic resin composition with excellent optical transparency, mechanical strength, and processability can be obtained by incorporating a gadolinium compound into a monomer whose main component is methyl methacrylate of a specific composition and polymerizing it. The present invention was completed after discovering the following. In other words, the gist of the present invention is to provide a methacrylic resin composition containing gadolinium in a methacrylic resin containing methyl methacrylate as a main component, and ta) methyl methacrylate monomer. Resin raw material (b) selected from a monomer mixture containing methyl methacrylate as the main component, or a partial polymer thereof Gadolinium compound (0) The following general formula showing solubility in the components tal and (111) R, -C-OHl/) (In the formula, R1 is a saturated or unsaturated hydrocarbon residue having 7 to 0 carbon atoms.) (In the formula, R2 is hydrogen or a hydrocarbon residue having 1 to 9 carbon atoms. group, R1 is a saturated or unsaturated hydrocarbon residue with carbon number/-!) CH,=C-C-0(-A, 0 to H(,?) (in the formula,
R4 is hydrogen or a methyl group, AI is the number of carbon atoms ~ A O)
an alkyl group, n Get O or an integer of /~/θ] (wherein, R1 is hydrogen or a methyl group, R6 is a carbon number of ~
A is an alkylene group) R, -OH or (in the formula, R? is a saturated or unsaturated hydrocarbon residue having 3 to 0 carbon atoms) (R1 (wherein, RB is a hydroxyl group or a saturated or unsaturated hydrocarbon residue having 1 to 10 carbon atoms, A2 is an alkylene group with an element number of 1 to 10, and m is an integer of a to /θ) A method for producing a methacrylic resin composition, which comprises polymerizing a polymerization mixture comprising at least one solvent and (d) a polymerization initiator in a special mold.

The methacrylic resin composition of the present invention contains gadolinium in a methacrylic resin whose main component is methyl methacrylate. The method for obtaining the methacrylic resin composition of the present invention is not particularly limited, but a preferred method is a cast polymerization method.

The m-fat raw material used to constitute the resin composition of the present invention is a methyl methacrylate monomer, a monomer mixture containing methyl methacrylate as a main component, or a partial polymer thereof.

The monomer mixture containing methyl methacrylate as a main component is a mixture of methyl methacrylate and another vinyl monomer copolymerizable with the methyl methacrylate. Other vinyl monomers copolymerizable with methyl methacrylate are not particularly limited, but include, for example, alkyl acrylates of carbon Xi/-da, carbon ii
2~Tei alkyl methacrylate, styrene, α-methylstyrene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, tetraethylene glycol dimethacrylate,
Examples include tetraethylene glycol acrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate, allyl acrylate, allyl methacrylate, and the like.

The amount used is less than or equal to the weight percent of SO in the monochloride composition. Furthermore, it is desirable that the polymer content in the partial polymer of plum oil raw material used be as low as possible so as not to impair the optical properties of the polymer (9) finally obtained.

Gadolinium used to constitute the composition of the present invention is a gadolinium compound such as gadolinium nitrate, gadolinium methacrylate, gadolinium acrylate, etc. obtained by reacting an oxide of gadolinium with an inorganic or organic acid. Gadolinium complex compounds such as tris(acetylacetonato)gadolinium or tris(benzoylacetonato)gadolinium obtained by reacting gadolinium salts of inorganic or organic acids, or gadolinium oxides with acetylacetone, benzoylacetone, etc. can give. The amount of these gadolinium compounds to be used is such that the weight concentration of gadolinium atoms is 00% to 10% by weight, preferably 7 to 3% by weight, based on the total weight of the resin composition. If the amount is 0.0/wt%, the resulting resin composition has little neutron beam shielding effect, and
: Exceeding 10% reduction will result in a decrease in optical transparency or mechanical strength///)1.

Also, the general formula 1/) l (-2), 1. used to form the composition of the present invention. ? ) t (da)
The solvents indicated by f (-j) and (shun) are cosolvents for uniformly dissolving the gadolinium compound in the resin raw material, and include, for example, unsaturated carboxylic acids such as methacrylic acid and acrylic acid, propionic acid, and octylic acid. , saturated or unsaturated acids such as isobutyric acid, hexanoic acid, octylbenzoic acid, stearic acid, palmitic acid, naphthenic acid, -
Examples include unsaturated alcohols such as 2-human tetraxyethyl acrylate and co-hydroxyethyl methacrylate, saturated aliphatic alcohols such as propyl alcohol and cyclohexyl alcohol, and glycols such as ethylene glycol, diethylene glycol and propylene glycol.

Among these solvents, monomers copolymerizable with methyl methacrylate, such as methacrylic acid, acrylic acid, co-hydroxyethyl methacrylate, and -monohydroxyethyl acrylate, are preferred. These solvents can be used alone or in combination. The amount of the solvent used in the present invention cannot be determined unconditionally depending on the type of gadolinium compound used and the amount of the solvent used, but it may be
The following is preferably io% by weight. If the amount used exceeds the weight percent of DaO, it is not preferable because the mechanical and thermal properties of the resulting resin plate will deteriorate.

Examples of the polymerization initiator used in the present invention include peroxides such as benzoyl peroxide and lauroyl peroxide, λ,-'-azobisisobutyronitrile,
21λ'-azobis-(co.

Known radical initiators can be used, such as azobis threads such as dirdimethylvale p-nitrile), λ1:1'-azobis-(co, dirdimethyl-gmethoxyvale tetranitrile), and the like. These polymerization initiators can be used alone or in combination of one or more, and the amount used is 0.007 NO/part by weight based on ioo parts by weight of the resin raw material.

In the template polymerization of the polymerization mixture in the present invention, the components ta
J r lb) + The polymerization mixture consisting of (o) and (d) is placed in a mold made of, for example, an inorganic glass plate, a stainless steel plate, a nickel chromium plate, or an aluminum plate, and a soft vinyl chloride gasket. and polymerize. The degree of polymerization in template polymerization is lj ~ 9
3C1 polymerization time was 03-1S hours, followed by 100 N
/4t! Polymerization is completed at a polymerization temperature of rC.

In the present invention, ultraviolet absorbers, mold release agents,
Heat stabilizers, colorants, and other neutron shielding compounds, lead compounds, etc. can also be added.

The gadolinium-containing methacrylic resin composition of the present invention having the above-mentioned structure and having excellent optical transparency and mechanical properties can be easily manufactured using the same manufacturing process as general acrylic resins, and can be produced mainly using neutron beams. It can be used as a radiation shielding material. Furthermore, when a lead compound is used in combination with the composition of the present invention, it becomes possible to shield against X-rays, γ-rays, and neutron beams. The methacrylic resin composition of the present invention is particularly useful as a neutron shielding material (13). However, it can also be used in other applications, such as optical filters.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Reference Example 1 Synthesis of gadolinium methacrylate 3 g of hydroquinone monomethyl ether θ as a polymerization inhibitor was uniformly dissolved in a mixture of λgθg methacrylic acid and 10θO of toluene, and after humidifying this to AθC, gadolinium oxide powder/AA9 was added to the solution. was added over 20 minutes and stirring continued for 7 hours.

Next, the reaction solution was allowed to stand for one day, and then filtered to remove the P solution to obtain dolinium methacrylate oxide. The yield was 33 kuku.

Reference Example - Synthesis of Gadolinium Nitrate A slight excess of gadolinium oxide is heated and dissolved in concentrated nitric acid and reacted. After 7 hours, the f solution was cooled to precipitate gadolinium nitrate crystals. The yield was 6 cm)%.

Reference Example 3 Synthesis of tris(acetylacetonato)cadrinium 100cc of acetylacetone and gadolinium oxide TGO
9 was suspended in anhydrous diethyl ether, yooocc, and refluxed for several hours, followed by removing the diethyl ether as an oil to obtain crystals of tris(acetylacetonato)gadolinium. The yield was 41%.

Example 1 3 g of gadolinium nitrate synthesized in Reference Example 2 is dissolved in a mixture of 1-1hydro-4xyethyl methacrylate/79t6 and propylene glycol, and methyl methacrylate 7S is added to this solution and mixed by stirring. This liquid mixture was a transparent liquid.

Next, θot, tg of co,co′-azobis-(,2,!-dimethylvaleronitrile) was added to this mixture as a polymerization catalyst.
And dioctyl sulfosuccinate sodium salt of θoosg as a mold release agent is added and dissolved, then degassed and poured into a conventional inorganic glass mold whose thickness is set in advance to 3 silk. Place this mold in A3C warm water.
The polymerization was completed by dipping for 1 minute and then staying in an air bath at //θC for 120 minutes. The resin plate taken out from the mold was transparent.

Gadolinium nitrate 119 synthesized in Examples and Reference Examples is dissolved in -monohydropoxyethyl methacrylate g3, and this is added to methyl methacrylate qo9 and mixed with stirring. This mixture was clear. Example 1
Cast polymerization was carried out under the same conditions as in Example No. with the addition of the same type and location of polymerization catalyst and mold release agent as used in Example No. 0. The resin plate obtained was transparent.

Example 3 Tris(acetylacetonato)gadolinium 1Sg synthesized in Reference Example 3 is dissolved in methacrylic acid gjg, and this solution is added to methacrylic acid methacrylic acid htiog and stirred to mix.

The same polymerization catalyst and mold release agent as in Example 1 were added to this mixture, and the same cast polymerization as in Example 1 was carried out. After completion of polymerization - the resin plate peeled off from the mold was transparent ◇ Example D Reference example! Gadolinium methacrylate tt9 synthesized in
g and methyl methacrylate 1139 were mixed, and cast polymerization was repeated under the same polymerization conditions as in Example 1. The obtained resin plate was transparent. Example S: 3 gadolinium acrylate, 3 g samarium methacrylate, 3 g pium methacrylate, 317 g n-octylic acid. One liter of propylene glycol was mixed with methyl methacrylate 1199, and cast polymerization was repeated under the same polymerization conditions as in Example 1.

The obtained resin plate was transparent.

Examples are as follows: Gadry methacrylate obtained in Reference Example I: 1 mudak, lead methacrylate: 4'g%, n-octylic acid: 3g, propylene glycol copolymer: 9. ! -Hydroxy and ethyl methacrylate/9 were mixed with methyl methacrylate IAq and subjected to cast polymerization f:tia under the same conditions as in Example 1. The obtained resin plate was transparent.

Table 1 shows the measurement results of the total light transmittance (%), haze value, and bending fracture strength (119/j) of the methacrylic resin t obtained in Example/-4.

In addition, the total light transmittance and haze value are ASTM-D-10.
03-1/, and the bending fracture strength is ASTM-D.
It was measured according to the -490 method.

Table 7 (19) Procedural amendment (spontaneous) September q, 1980, Japanese Patent Application No. 195800 2, Title of invention: methacrylic resin composition and its manufacturing method 3, Relationship with the case of the person making the amendment Patent application Person: Mitsubishi Rayon Co., Ltd. 4, 3-19 Kyobashi 2-chome, Chuo-ku, Tokyo (603), Agent: Akira Kawasaki, Patent attorney, Mitsubishi Rayon Co., Ltd., 3-19 Kyobashi 2-chome, Chuo-ku, Tokyo (6949) Toshio Fukuzawa 5, date of amendment order voluntary amendment full text corrected specification 1, name of invention methacrylic resin composition 8 and method for producing the same 2, claim 1, gadolinium in methacrylic resin containing methyl methacrylate as the main component A methacrylic resin composition according to claim 1, characterized in that the weight concentration of gadolinium atoms is 0.01 to 10% by weight relative to the entire composition. .

3. (a) Resin-forming raw material selected from methyl methacrylate monomers, monomer mixtures containing methyl methacrylate as a main component, or partial polymers thereof, (b) gadolinium compound, and (c) polymerization initiator. A methacrylic resin composition characterized by polymerizing a polymerization mixture as follows? 4 'l'-A''!!!L cedar.

(1) 4. The gadolinium compound is gadolinium oxide.

4. The method for producing a methacrylic resin composition according to claim 3, wherein the methacrylic resin composition is selected from gadolinium carbonate, gadolinium hydroxide, and a complex compound of gadolinium.

5. The following general formula % formula (1) showing solubility in resin forming raw materials and gadolinium compounds (wherein, RI is a saturated or unsaturated hydrocarbon residue having 1 to 20 carbon atoms) ( In the formula, R2 is hydrogen or a saturated or unsaturated hydrocarbon residue having 1 to 9 carbon atoms, and R8 is a saturated or unsaturated hydrocarbon residue having 1 to 4 carbon atoms. or a methyl group, A is an alkyl group having 2 to 6 carbon atoms, n is 0 or an integer of 1 to 10) (wherein, R6 is hydrogen or a methyl group, R6 is a carbon number 2 to 6)
6 alkylene group) R, -OH (5) or (in the formula, R1 is a saturated or unsaturated hydrocarbon residue having 3 to 10 carbon atoms) R8% -A, -0 random H (6 ) (wherein R8 is a hydroxyl group or a saturated or unsaturated hydrocarbon residue having 1 to 10 carbon atoms, A2 is an alkylene group having 2 to 4 carbon atoms, and m is an integer of 2 to 1°) 4. The method for producing a methacrylic resin composition according to claim 3, wherein the polymerization is carried out by adding a small amount of a solvent.

6. The gadolinium compound is gadolinium nitrate.

6. The method for producing a methacrylic resin composition according to claim 5, wherein the methacrylic resin composition is selected from a gadolinium salt of an organic acid or a complex compound of gadolinium.

7. The gadolinium compound is selected from gadolinium methacrylate, gadolinium acrylate or tris(acetylacetonato)gadolinium, and the solvent is octylic acid and propylene glycol and/or 2-hydroxyethyl methacrylate or 2-hydroxyethyl. 6. The method for producing a methacrylic resin composition according to claim 5, wherein the methacrylic resin composition is an acrylate.

3. Detailed Description of the Invention The present invention relates to a methacrylic resin composition containing GadIJnium and having excellent optical and mechanical properties, and a method for producing the same.

Methacrylic resin is used in a variety of fields due to its excellent transparency, weather resistance, and mechanical properties, but it cannot be used for these purposes because it does not have radiation shielding ability. Ta.

Therefore, in recent years, radiation shielding materials containing lead in methacrylic resin have been developed (Special Publication No. 35-2360,
Japanese Patent Publication No. 53-9994.

No. 53-9995, No. 53-9996, and No. 53
-63310 etc.).

However, although the lead-containing radiation shielding materials described above effectively shield radiation from electromagnetic waves such as X-rays and R-rays and charged particles such as α-rays and β-rays, they do not shield against neutron radiation. Not enough.

On the other hand, it is also known to add a boron compound to polyethylene or methacrylic resin as a polymeric material for shielding neutron beams (Japanese Patent Laid-Open No. 144597/1983). However, although this method has a large neutron beam absorption capacity, the helium and lithium produced in the neutron absorption reaction have almost no neutron absorption capacity, so their capacity decreases as the amount of neutron absorption increases (tendency). However, the optical and mechanical properties have not yet reached a satisfactory level.

(5) In addition to the above-mentioned boron compounds, gadolinium, which is a rare earth element with an atomic number of 64, is known to have a greater ability to absorb thermal neutron beams than boron. However, since gadolinium is a metallic solid, it has poor compatibility with methacrylic polymers (methacrylic resins with excellent optical and mechanical properties have not yet been produced).

The present inventor has arrived at the present invention as a result of various studies in view of the above circumstances, and the gist of the present invention is as follows:
A methacrylic resin composition containing gadolinium in a methacrylic resin whose main component is methyl methacrylate.

The resin composition of the present invention is achieved by incorporating a gadolinium compound into a methacrylic resin containing methyl methacrylate as a main component.

Therefore, the method for obtaining the composition of the present invention is not particularly limited, and various manufacturing methods can be applied.

For example, a method of blending a gadolinium compound and a methacrylic resin, a method of mixing and polymerizing a gadolinium compound with a monomer or a partial polymer thereof whose main component is methyl methacrylate, or a method of mixing and polymerizing a gadolinium compound with a monomer or a partial polymer thereof whose main component is methyl methacrylate. Examples include a method in which the monomer as a component is mixed with a partial polymer thereof and a solvent and then polymerized.

The resin forming raw material used to constitute the resin composition of the present invention is a methyl methacrylate monomer, a monomer mixture containing methyl methacrylate as a main component, or a partial polymer thereof. The monomer mixture containing methyl methacrylate as a main component consists of methyl methacrylate and another vinyl monomer copolymerizable with methyl methacrylate. Other vinyl monomers copolymerizable with methyl methacrylate are not particularly limited, but include, for example, alkyl acrylates having 1 to 4 carbon atoms.

Alkyl methacrylate having 2 to 4 carbon atoms, styrene, α
- Methylstyrene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate.

Tetraethylene glycol dimethacrylate.

Examples include tetraethylene glycol acrylate, pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate, allyl acrylate, allyl methacrylate, and the like. The amount of these used is 50% by weight or less in the monomer mixture. Further, it is desirable that the polymer content in the partially polymerized resin raw material used be as small as possible so as not to impair the optical properties of the finally obtained polymer.

The gadolinium used to constitute the composition of the present invention can be obtained by reacting a gadolinium compound 9 such as an oxide of gadolinium, gadolinium carbonate, gadolinium hydroxide, or an oxide of gadolinium with an inorganic or organic acid. Tris(acetylacetonato)gadolinium obtained by reacting a gadolinium salt of an inorganic or organic acid such as gadolinium nitrate, gadolinium methacrylate, or gadolinium acrylate, or an oxide of gadolinium with acetylaceto/or benzoylaceto7, etc. , or gadolinium complex compounds such as tris(benzoylacetonato)gadolinium. The amount of these gadolinium compounds used is such that the weight concentration of gadolinium atoms is 0.01 to 10% by weight based on the total weight of the resin composition.
Preferably 1 to 5% by weight is desirable. If the weight ratio is less than 0.01, the resulting resin composition will have little neutron beam shielding effect (.

Moreover, if the weight exceeds 10 weight, the optical properties or mechanical strength will deteriorate.

Although these gadolinium compounds cannot be determined unconditionally depending on the application, methacrylic resin can be produced by blending them with methacrylic resin, mixing them with resin-forming raw materials and polymerizing them, or mixing them with resin-forming raw materials and solvents and polymerizing them. It can be contained inside. Particularly, the method using the latter solvent is suitable for obtaining transparent resin products without scattering.

When blended with a gadolinium compound or added to a resin forming raw material, preferred examples include those selected from gadolinium(9) oxide, gadolinium carbonate, gadolinium hydroxide compounds, and complex compounds of gadolinium. In addition, when using a gadolinium compound in a mixture with a resin forming raw material and a solvent, gadolinium nitrate, gadolinium methacrylate, or gadolinium acrylate obtained by reacting gadolinium oxide with an inorganic or organic acid. Tris(acetylacetonato)gadolinium or tris(be/diylacetonato)gadolinium obtained by reacting gadolinium salts of inorganic or organic acids such as gadolinium salts and their double salts, or gadolinium oxides with acetylacetone, benzoylacetone, etc. Preferred examples include gadolinium complex compounds such as .

As the solvent used when manufacturing the resin composition of the present invention, the following general formula (10) R, -C-OH (1) (in the formula I R is a saturated or unsaturated hydrocarbon residue having 1 to 20 carbon atoms) (In the formula, I R2 is hydrogen or a saturated or unsaturated hydrocarbon residue having 1 to 9 carbon atoms, and R3 is a carbon number 1 to 4 saturated or unsaturated hydrocarbon residues) (In the formula, R4 is hydrogen or a methyl group, and A is a carbon number of 2 to 4.
6 alkyl group, n is 0 or an integer from 1 to 10) (In the formula, I R is hydrogen or a methyl group, R6 has 2 carbon atoms
-6 alkylene group) R, -0)I (5) or (wherein R7 is a saturated or unsaturated hydrocarbon residue having 3 to 10 carbon atoms) R, (-A, -0 Radiation H (6) (wherein R8 is a hydroxyl group or a saturated or unsaturated hydrocarbon residue having 1 to 10 carbon atoms, A is an alkylev group having 2 to 4 carbon atoms, and m is an integer of 2 to 10 ) is a compound selected from

The general formula (1), (2), (3), (41, (
The solvents shown in 5) and (6) are cosolvents for uniformly dissolving the gadolinium compound in the resin forming raw material, and include unsaturated carboxylic acids such as methacrylic acid and acrylic acid, propionic acid, octylic acid, Inbutyric acid, hexanoic acid, octylbenzoic acid, stearic acid, valmic acid,
Saturated or unsaturated fatty acids such as naphthenic acid, unsaturated alcohols such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, propyl alcohol.

Saturated aliphatic alcohols such as cyclohexyl alcohol,
Examples include glycols such as ethylene glycol, diethylene glycol, and propylene glycol. Among these solvents, monomers copolymerizable with methyl methacrylate, such as methacrylic acid, acrylic acid, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate, are preferred. These solvents can be used alone or in combination of two or more.

The amount of the solvent to be used in the present invention cannot be determined unconditionally depending on the type and amount of the gadolinium compound used, but it is not more than 40 parts by weight, preferably not more than 10 parts by weight.

When the amount used exceeds 40% by weight, the mechanical properties of the resulting resin composition.

This is not preferred because it lowers the thermal properties.

Examples of the polymerization initiator used in the present invention include peroxides such as benzoyl peroxide and lauroyl peroxide, 2,2'-azobisinbutyronitrile, 2,2'-azobis-(2°4-dimethyl Known radical initiators such as azobis-based initiators such as valeronitrile) and 2,2'-azobis-(2@4-dimethyl-4-methoxy-valeronitrile) can be used. These polymerization initiators (13) can be used alone or in combination of two or more, and the amount used is 0.001 to 0.00 parts by weight per 100 parts by weight of the resin raw material.
．． 13i, Okibe.

The polymerization method for obtaining the resin composition of the present invention is as follows:
Although not particularly limited, cast polymerization is a preferred polymerization method. In the case of this cast polymerization, the components (R1,
The polymerization mixture prepared from (hl-# and (cl) is placed in a mold made of, for example, an inorganic glass plate, stainless steel plate, nickel chromium plate, or aluminum plate, etc., and a soft vinyl chloride gasket. Cast polymerization is carried out at 45-95° C. for 0.3-15 hours, and then at 100-145° C. for 10 minutes to 5 hours to complete the polymerization.

In the present invention, an ultraviolet absorber is used as necessary.

A mold release agent, a heat stabilizer, a coloring agent, a light diffusing agent, and other neutron shielding compounds, lead compounds, etc. can also be added.

The gadolinium-containing methacrylic resin composition (14) of the present invention having the above-mentioned structure and having excellent optical and mechanical properties can be easily produced in the same manufacturing process as general acrylic resins, and is mainly neutron ray-containing. It can be used as a radiation shielding material.

Furthermore, when a lead compound is used in combination with the composition of the present invention, X-rays,
It becomes possible to shield from both @ and neutron beams.

The methacrylic resin compositions of the present invention are particularly useful as neutron shielding materials.

Other uses 1 For example, optical filters, optical lenses.

It can also be used for applications such as light conversion materials and lighting materials.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited thereto.

Reference Example 1 Synthesis of gadolinium methacrylate Hydroquinone monomethyl ether 0.3 as a polymerization inhibitor was added to a mixture of methacrylic acid 2807' and toluene 1000I.
After uniformly dissolving J' and heating it to 60°C, gadolinium oxide powder 166! is added to this solution. was added over 20 minutes and stirring continued for 1 hour.

The reaction solution was then allowed to stand for one day, and then filtered.

The F solution is removed to obtain gadolinium methacrylate. The yield was 357F.

Reference Example 2 Synthesis of Gadolinium Nitrate A slight excess of gadolinium oxide is dissolved in concentrated nitric acid by heating and reacted. After 1 hour, the F solution was cooled to precipitate gadolinium nitrate crystals. The yield was 62 inches.

Reference example 3 Synthesis of tris(acetylacetonato)gadolinium Acetylaceto/100cL3 and gadolinium oxide 18
07' was suspended in anhydrous diethyl ether 30006e and refluxed for 2 hours, followed by distillation and removal of diethyl ether to obtain crystals of etris(acetylacetonato)gadolinium. The yield was 65%.

Example 1 Gadolinium 3I synthesized in Reference Example 2 is dissolved in a mixed solution of 2-hydroxyethyl methacrylate) 177' and propylene glycol 21, and methyl methacrylate 78P is added to this solution and mixed by stirring. This liquid mixture was a transparent liquid.

Next, add 0.04 J' of 2.2 to this mixture as a polymerization catalyst.
'-Azobis-(2,4-dimethylvaleronitrile) and 0.00 °C M dioctyl sulfosuccinate sodium salt as a mold release agent were added and dissolved, then degassed and molded to a plate thickness of 3zx in advance. Pour the mold into a conventional inorganic glass mold set to
The polymerization was completed by immersing for 80 minutes and then staying in an air bath at 110°C for 120 minutes. The resin plate taken out from the mold was transparent.

Example 2 Gadolinium nitrate 1.51 synthesized in Reference Example 2 was converted into 2-
Dissolved in hydroxyethyl methacrylate 8.5I,
Further, this was added to 90% of methyl methacrylate and mixed with stirring. This mixture was clear. The same type and amount of polymerization catalyst and mold release agent as used in Example 1 were added to this mixed solution, and cast polymerization was carried out under the same conditions as in Example 1. The obtained resin plate was transparent.

(17) Example 3 1.5 t of tris(acetylacetonato)gadolinium synthesized in Reference Example 3 is dissolved in 8.5 P of methacrylic acid, and this solution is added to methyl methacrylate 907' and mixed by stirring.

The same polymerization catalyst and mold release agent as in Example 1 were added to this mixed solution, and the same cast polymerization as in Example 1 was performed. After completion of polymerization, the resin plate peeled off from the mold was transparent.

Example 4 Gado IJ methacrylate synthesized in Reference Example 1 8t
and n-octylic acid 2P, propylene glycol 1/,
2-hydroxyethyl methacrylate 1l, styrene 5
1 and methyl methacrylate 83J' were mixed, and cast polymerization was repeated under the same polymerization conditions as in Example 1. The obtained resin plate was transparent.

Example 5 Gadolinium acrylate 31. Samarium methacrylate 31. europium methacrylate 1(18)/n-octylic acid 31. Mix propylene glycol 11 with methyl methacrylate 89J'.

Cast polymerization was repeated under the same polymerization conditions as in Example 1.

The obtained resin plate was transparent.

Example 6 4t of gadolinium methacrylate obtained in Reference Example 1, 4t of lead methacrylate, 31 of octylic acid, 2J' of propylene glycol, 11 of 2-hydroxy and ethylmethacrylate), and 867' of methyl methacrylate were mixed. Then, the casting polymerization was repeated under the same conditions as in Example 1. The obtained resin plate was transparent.

Example 7 Partial polymer of methyl methacrylate (polymerization rate 18%) 10
α, α′-Azobis-(2
, 4-dimethylvaleronitrile) 0.04 parts by weight, and 0.005 parts by weight of dioctyl sulfosuccinate natritam salt as a mold release agent.

After adding and mixing 2.0 parts by weight of gadolinium oxide with an average particle size of 2μ and degassing, the plate thickness is 311mm! It is poured into a mold made of tempered glass and a soft vinyl chloride gasket.

The resin plate was immersed in warm water at 70°C for 60 minutes and then placed in an air bath at 130°C for 80 minutes to complete polymerization.

Example 8 Methacrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., trade name: Acryvet VH) Average particle size of 0.00% based on loo parts by weight.
Add 2.0 parts by weight of gadolinium hydroxide having a particle size of 5μ and 1.0 part by weight of gadolinium carbonate having an average particle size of 2μ, mix thoroughly with a mixer/blurr to make it homogeneous, and then extrude it from an extruder using a conventional method to obtain a plate thickness. Got 3 seats.

Total light transmittance (%), haze value (%) 1 bending fracture strength ('#/crrL) of the methacrylic resin plates obtained in Examples 1 to 7
) and neutron shielding ability (thermal neutron absorption cross section) results are shown in Table 1.

In addition, the total light transmittance R and haze value are ASTM-I)-10
03-61, bending fracture strength was measured according to ASTM-D-790. The thermal neutron absorption cross section was determined using the numerical values described in Experimental Chemistry Course (12) Radiochemistry (Maruzen) and the following formula.

However, S: Thermal neutron absorption cross section per composition 1007'(cm") Ml: Atomic weight of type 1 element Wi; Abundance of type 1 element 81; Thermal neutron absorption cross section of type i element (barns) N: Avogadro Number (amount = 1...n) (21] (22)

Claims (1)

[Scope of Claims] l A methacrylic resin composition in which gadolinium is contained in a methacrylic resin containing methyl methacrylate as a main component.The weight concentration of gadolinium atoms is 0 relative to the entire composition.
．． 2. The methacrylic resin composition according to claim 1, wherein the amount is 07 to 10% by weight. 3. (a) Resin raw material selected from methyl methacrylate monomer, a monomer mixture containing methyl methacrylate as a main component, or a partial polymer thereof (b) Gadolinium compound (0) The above component (IL) and tb The following general formula (1) showing solubility in , Gt hydrogen or a hydrocarbon residue having 1 to 9 carbon atoms, R5 is a saturated or unsaturated hydrocarbon residue having carbon number/-Q) (wherein, R4 is hydrogen or a methyl group, and AI is a carbon number 2～
A's alkyl group, n is O or an integer of 1-10) (wherein, R5 is hydrogen or a methyl group, R6 is the number of carbon atoms -
R, -OH (,!t) or (in the formula, R1 is a saturated or unsaturated hydrocarbon residue having 3 to 10 carbon atoms) R, (-A, -0+rnl- 1 (Al (in the formula, R1 is a hydroxyl group or a saturated or unsaturated hydrocarbon residue with a carbon number of 1N10, A is a carbon number of a to darylkylene group, mG
A method for producing a methacrylic resin composition, characterized by polymerizing in a mold a polymerization mixture* consisting of at least seven types of solvents far from (dl is an integer between mako and io) and (dl) a polymerization initiator.・Patent characterized by being far from physical objects (mG) Scope described in item 3 σ] Manufacturing method of methacrylic resin composition 0 p The gadolinium compound is gadolinium methacrylate,
selected from gadolinium acrylate or tris(acetylacetonato)gadolinium, and the solvent is octylic acid and propylene glycol and/or co-hydroxyethyl methacrylate or co-hydro-tetraxyethyl acrylate. A method for producing a methacrylic resin composition according to Section 3.