JPH0761872B2 - Method for producing white bismuth oxide composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to bismuth oxide used as a contrast agent in medical devices such as vascular catheters.

[Prior Art] Recently, medical instruments such as a cardiac catheter used under fluoroscopy have been remarkably developed, and various instruments have been developed.
These instruments were made by kneading Teflon, polyurethane, etc. with barium sulfate as a contrast agent, and molding them, but when using barium sulfate as a contrast agent, in order to obtain a predetermined contrast effect. It is necessary to add a large amount of barium sulfate, such as 40 to 60% by weight, to the resin.
However, if so, the characteristics of the resin are extremely deteriorated, and the resin becomes unusable as a medical device. Therefore, in practice, the contrast effect is sacrificed, and barium sulfate is added within the range that the resin can be used.

[Problems to be Solved by the Invention] In order to solve the above drawbacks, a method has been proposed in which a bismuth compound mainly containing bismuth oxide is substituted for barium sulfate,
Has been adopted. This is because the contrast effect of the bismuth compound is more than twice that of barium sulfate. However, conventional bismuth oxide is yellow, and there is a problem in that the color becomes cloudy when used for coloring such as blue which is preferred as a medical device.
If you try to use bismuth oxychloride, which is a white bismuth compound, bismuth subcarbonate, bismuth subnitrate, etc. in order to avoid this, these bismuth compounds are decomposed by heating at the time of kneading with the resin, and coloring or gas is generated. Not only does it occur, but when the obtained product is used, there is a problem that there is a high possibility of elution of acids and the like that are harmful to the human body.

An object of the present invention is to provide a fine-grained white bismuth oxide composition for contrast agents, which does not have the above problems.

[Means for Solving the Problems] As a result of various studies on the method for producing white bismuth oxide, the present inventor obtained a white bismuth oxide composition usable as a contrast agent by adding a certain amount of sulfate to bismuth oxide. This has led to the present invention.

That is, according to the method of the present invention for solving the above problems, a caustic alkali solution is added to a bismuth nitrate solution to obtain a slurry having a pH of 7 to 9, and the bismuth 1 in the slurry is added to the slurry.
0.16 to 0.50 mol of peroxodisulfate was added to the mol, and while maintaining the liquid temperature at 60 to 90 ° C, preferably 70 to 90 ° C, the mixture was stirred for at least 1 hour, and the produced precipitate was solid-liquid separated. , If necessary, then 400-600 ℃, preferably 45
It is roasted at 0 to 550 ° C. The caustic alkalis that can be used in the present invention are sodium hydroxide, potassium hydroxide, ammonia and aqueous ammonia, which can be used alone or in combination. Peroxodisulfates that can be used are sodium peroxodisulfate, potassium peroxodisulfate, and ammonium peroxodisulfate, and these may be used alone or in combination.

The white bismuth oxide composition thus obtained has a formula (BiOx) ₂ · (3-2x) SO ₄ X of 1.08 ≦ X ≦ 1.36, an average particle size of 0.5 to 10 μm and a whiteness of 93. that's all,
It has a yellowness of 11 or less and a decomposition temperature of 500 ° C or more, and is substantially harmless, and is optimal as a contrast agent for medical devices.
The whiteness is measured according to JIS Z 8720, 8722, 8729, and the yellowness is measured according to JIS K 7103.

[Operation] In the present invention, the pH of the bismuth nitrate solution obtained by dissolving bismuth oxide in nitric acid is set to 7 to 9 because the particle size of the reaction product produced at pH 7 or less exceeds 10 μm, This is because the resin cannot be mixed uniformly with the resin when it is used, and when the pH exceeds 9, it is colored yellow by roasting in the subsequent step.

The amount of alkali peroxodisulfate to be added is 0.16 to 0.50 mol with respect to 1 mol of bismuth in the slurry because the whiteness becomes less than 93 and the yellowness exceeds 11 at less than 0.16 mol and exceeds 0.60 mol. This is because the amount of persulfate that is not directly involved in the reaction increases and the economic efficiency is impaired. The reaction temperature is set to 60 to 90 ° C., if the reaction temperature is lower than 60 ° C., a sufficient reaction does not occur, and the reaction rate does not increase significantly even if heated to 90 ° C. or higher, rather the handling risk increases. This is because it impairs economic efficiency. The reaction time must be at least 1 hour, and if it is less than this, a product having a sufficient whiteness cannot be obtained.

The purpose of roasting the substance obtained in this way is to remove volatile substances and substances that are easily decomposed, and in this way to suppress the generation of decomposition products when mixed with the resin. . Therefore, the roasting temperature must be 400 ° C or higher. However, above 600 ° C., the white bismuth oxide composition decomposes. Therefore, it is necessary to set the roasting temperature to 400 to 600 ° C.

[Example-1] 75 g of bismuth oxide of primary reagent (manufactured by Wako Pure Chemical Industries, Ltd.) was mixed with 1% of 62% nitric acid.
It was dissolved in 44 ml, and then the solution was neutralized to pH 6.22 with 500 ml of pure water and concentrated 1st grade concentrated ammonia water. 30.5 g of reagent grade ammonium peroxodisulfate in the resulting slurry
Was added, and the mixture was stirred at 80 ° C. for 2 hours, filtered and dried to obtain a yellow precipitate, which was dried and roasted in air at 500 ° C. for 2 hours to obtain 80 g of a white bismuth oxide composition. . As a result of compositional analysis, this product shows that x = 1.10 of (BiOx) ₂ · (3-2
x) It was SO ₄ .

The whiteness and yellowness of this composition were calculated with a digital color meter TC-360U manufactured by Tokyo Denshoku Co., Ltd., respectively 97 and 7.
5 and the average particle size obtained from the scanning electron micrograph is 5.
was μm.

[Example-2] 75 g of bismuth oxide of primary reagent (manufactured by Wako Pure Chemical Industries, Ltd.) was mixed with 1% of 62% nitric acid.
Dissolve in 44 ml, then add 500 ml of pure water to the solution,
The pH was adjusted to 7.11. With reagent grade sodium hydroxide. To the resulting slurry, 30.6 g of reagent grade ammonium peroxodisulfate was added, stirred at 80 ° C for 2 hours, filtered and dried to obtain a yellow precipitate, which was dried and dried in air at 500 ° C for 2 hours.
After calcination for an hour, 78 g of a white bismuth oxide composition was obtained. As a result of compositional analysis, this product is x = 1.24 (BiOx) ₂
· (3-2x) it was SO _4.

The whiteness and the yellowness of this composition were determined with a digital color meter TC-360U manufactured by Tokyo Denshoku Co., Ltd., respectively 97 and 8.
7 and the average particle size obtained from the scanning electron micrograph is 5
was μm.

[Example-31] 75 g of reagent grade bismuth oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 62% nitric acid 1
Dissolve in 44 ml, then add 500 ml of pure water to the solution,
The pH was adjusted to 8.25 with concentrated 1st grade concentrated ammonia water. Reagent primary ammonium peroxodisulfate in the resulting slurry
36.4g was added, stirred at 70 ° C for 2 hours, filtered off and dried to give a brown precipitate, which was dried and dried in air at 450 ° C for 2 hours.
After calcination for an hour, 76 g of a white bismuth oxide composition was obtained. As a result of compositional analysis, this product is x = 1.30 (BiOx) ₂
· (3-2x) it was SO _4.

The whiteness and the yellowness of this composition were determined with a digital color meter TC-360U manufactured by Tokyo Denshoku Co., Ltd. to be 94 and 1, respectively.
0.0, the average particle size obtained from the scanning electron micrograph
It was 0.5 μm.

[Comparative example] 75 g of bismuth oxide of the first grade reagent (manufactured by Wako Pure Chemical Industries) was added to 62% nitric acid 1
Dissolve in 44 ml, then add 500 ml of pure water to the solution,
The pH was adjusted to 9.54 with concentrated 1st grade concentrated aqueous ammonia. Reagent primary ammonium peroxodisulfate in the resulting slurry
Add 30.5 g, stir at 80 ° C for 2 hours, filter and dry to obtain a brick colored precipitate, which is dried and 450 ° C in air
After baking for 2 hours, 74 g of a white bismuth oxide composition was obtained. As a result of compositional analysis, this product has x = 1.48 (BiOx)
_{It was 2.} (3-2x) SO ₄ .

The whiteness and yellowness of this composition were determined by a digital color meter TC-360U manufactured by Tokyo Denshoku Co., Ltd., respectively 88 and 1
It was 5.0, and the average particle size obtained from the scanning electron micrograph was 4 μm.

EFFECTS OF THE INVENTION According to the method of the present invention, the formula (BiOx) ₂ · (3−2x) SO ₄ X is easily shown by 1.08 ≦ X ≦ 1.36, the average particle size is 0.5 to 10 μm, and the whiteness is 93 or more,
It is possible to obtain a white bismuth oxide composition having a yellowness of 11 or less and a decomposition temperature of 500 ° C. or more and being substantially harmless, and being most suitable as a contrast agent for medical instruments.

Claims (3)

[Claims] 1. A method for producing a white bismuth oxide composition having a composition of (BiO _x ) ₂ · (3-2x) SO ₄ (where 1.08 ≦ x ≦ 1.36), wherein a bismuth nitrate solution is added with a caustic solution. Was added to obtain a slurry having a pH of 7 to 9, and 0.16 to 0.50 mol of peroxodisulfate was added to 1 mol of bismuth in the slurry, and at least 1 was added while maintaining the liquid temperature at 60 to 90 ° C. A method for producing a white bismuth oxide composition, which comprises agitating for a time, solid-liquid separation of the produced product, and then roasting at 400 to 600 ° C. 2. The average particle size of the white bismuth oxide composition is 0.5.
The manufacturing method according to claim 1, wherein the thickness is from about 10 μm. 3. The method according to claim 1, wherein the white bismuth oxide composition has a whiteness of 93 or more and a yellowness of 11 or less.