JPH09295828A - Glass for preventing discoloration by exposure to radiation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glass for preventing discoloration by exposure to radiation, excellent in preventing effects on discoloration for a use in radiation sterilization, low in melting at a high temperature, imporved in workability, high in chemical stability, glass density and transprency. SOLUTION: This glass for preventing discoloration by exposure to radiation comprises a glass composition consisting of 65.0-80.0 pts.wt. of SiO2 , 12.0-15.0 pts.wt. of Na2 O, 10.0-12.0 pts.wt. of CaO, 0.5-5.0 pts.wt. of Al2 O3 , 0.1-3.0 pts.wt. of CeO2 , 0.1-2.0 pts.wt. of K2 O, 0.1-2.0 pts.wt. of B2 O3 and 0.1-2.0 pts.wt. of SO3 . Or the glass for preventing discoloration by exposure to radiation comprises 65.0-80.0 pts.wt. of SiO2 , 12.0-15.0 pts.wt. of Na2 O, 10.0-12.0 pts.wt. of CaO, 0.5-5.0 pts.wt. of Al2 O3 , 0.3-3.0 pts.wt. of Fe2 O3 , 0.1-2.0 pts.wt. of K2 O, 0.1-2.0 pts.wt. of of B2 O3 and 0.1-2.0 pts.wt. of SO3 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation irradiation discoloration-preventing glass, and in particular, a small amount of C
eO ₂ , Fe ₂ O _3, or both of them and V ₂ O _5, and a predetermined amount of Na ₂ O, CaO, and the like are added in combination, and the glass composition has the composition and is excellent in radiation irradiation. TECHNICAL FIELD The present invention relates to a radiation irradiation coloring prevention glass having characteristics such as discoloration preventing property.

[0002]

2. Description of the Related Art Conventionally, glass applications such as pharmaceuticals and biochemistry, for example, blood collection tubes, blood collection bottles, petri dishes and beakers for culturing microorganisms, must be sterilized for safety and hygiene. The sterilization method and the autoclave method were generally performed.

However, in such a sterilization method,
Skillful management of gas and high-pressure steam is required, sterilization time is long and sterilization process tends to be inadequate.Furthermore, it is necessary to completely remove sterilized gas or remove water to ensure safety. There were some problems.

Therefore, a radiation irradiation sterilization method has been proposed instead of the gas sterilization method or the high-pressure steam sterilization method. Such a radiation irradiation sterilization method uses an electron beam or γ-ray as a radiation source, and has an advantage that a large amount of complete sterilization can be performed in a short period of time and no post-treatment is required.

However, in such a radiation irradiation sterilization method, since the energy of the radiation used is large, there is a problem that the irradiated glass is discolored or deteriorated.

Therefore, in JP-A-2-279535, a gamma-ray irradiation coloring preventing glass containing 60 to 75% by weight of SiO ₂ , 1 to 8% by weight of CaO and 0.1 to 1% by weight of CeO ₂ is disclosed. Is disclosed.

However, in such a glass composition,
A complicated and costly step of melting the glass composition in a reducing atmosphere is required, while even if the glass composition is melted in a reducing atmosphere, there is variation in the rate of conversion into Ce ³⁺ , and discoloration due to radiation. There is a problem that the prevention effect tends to be insufficient.

Further, the addition of MgO is an essential requirement, and there is a problem that the number of components is large and it is difficult to control in production. Furthermore, when the amount of CaO added exceeds 8% by weight, the glass is Since it is easy to devitrify, a large amount cannot be added, resulting in a low CaO content, high viscosity at high temperature during melting, and poor workability.
There were problems such as low chemical stability and low glass density.

Further, in JP-A-2-21231313, 40 to 60% by weight of SiO ₂ and 25 to 45 of PbO are disclosed.
% By weight, 4.5 to 12% by weight of Na ₂ O, 1.5 to 2.0% by weight of CeO _2, and 2.0 to 9.0% by weight of K ₂ O.
A radiation-shielding glass is disclosed, including such.

However, in such a glass composition, the amount of PbO added is large, the effect of preventing discoloration is insufficient, and further, the high temperature viscosity during melting is high and the workability is poor, the weather resistance and the chemical stability are low. There were some problems, such as low properties and low glass density.

Therefore, further, Japanese Patent Laid-Open No. 6-127973.
In the publication, SiO ₂ is essentially free from lead.
40-60% by weight, Na ₂ O 1-12% by weight, Ca
0 to 10 wt% O, 0.1 to 3 wt% CeO ₂ , S
A radiation shielding glass containing 3 to 23 wt% of rO is disclosed.

However, even in such a glass composition, a large amount of expensive SrO is contained as an essential component, and there is a problem that the cost of the glass becomes high and the use application is limited, and the discoloration preventing effect is insufficient. And
Further, there were also problems such as high viscosity at high temperature during melting and poor workability, weather resistance, chemical stability, and low glass density.

In the glass composition, CaO
Is not an essential component from the content, but is only described in the examples, and also in the examples, CaO
Only the content of 0 to 8 parts by weight is disclosed, and a certain amount of SiO ₂ , Na ₂ O is disclosed.
It is not intended to be provided as a glass composition which is combined with, and CeO ₂ .

On the other hand, Japanese Patent Application Laid-Open No. 53-119907 and Japanese Patent Application Laid-Open No. 63-112438 disclose radiation irradiation coloring prevention glass containing a predetermined amount of Fe ₂ O ₃ or the like.

However, the amount of Fe ₂ O ₃ added is small, or there is no suggestion of the idea of providing a glass component in combination with CaO or the like, and the effect of preventing discoloration on glass is insufficient, or the melting There were problems such as high viscosity at high temperature and poor workability, weather resistance, chemical stability, and low glass density.

[0016]

The present invention has been made in consideration of the above circumstances, and (1) has an excellent effect of preventing discoloration in applications such as radiation sterilization, and (2) melts. High temperature viscosity at low temperature, good workability, (3) high chemical stability, (4) high glass density, (5) high transparency and radiation irradiation discoloration prevention glass It is intended to be provided.

Further, the present invention is particularly effective for radiation, such as electron beams and γ, which have a high energy level and an excellent sterilization effect.
It is an object of the present invention to provide a radiation irradiation discoloration preventive glass suitable for use with lines.

[0018]

That is, according to the present invention, S
iO ₂ , Na ₂ O, CaO, Al ₂ O ₃ , CeO ₂ , K
₂ O, B ₂ O ₃ , SO _3, etc. or SiO ₂ , Na ₂ O,
CaO, Al ₂ O ₃ , K ₂ O, B ₂ O ₃ , SO ₃ , Fe
_{By including 2} O ₃ etc. in a predetermined ratio in a well-balanced manner,
Radiation irradiation discoloration prevention glass that solves the above problems,
Specifically, in terms of parts by weight, SiO ₂ : 65.0 to 8
0.0, Na ₂ O: 12.0 to 15.0, CaO: 1
_{0.0~12.0 Al 2 O 3: 0.5~5.0,} CeO 2: 0.1~3.
_{0, K 2 O: 0.1~2.0,} B 2 O 3: 0.1~2.
_0, SO 3: _0.1~2.0, are those composed of glass composition comprising a.

As another aspect of the radiation irradiation discoloration preventing glass, SiO ₂ : 65.0 to 8 in terms of parts by weight.
0.0, Na ₂ O: 12.0 to 15.0, CaO: 1
_{0.0~12.0 Al 2 O 3: 0.5~5.0,} Fe 2 O 3: 0.3~
_{3.0, K 2 O: 0.1~2.0,} B 2 O 3: 0.1~
It is composed of a glass composition containing 2.0 and SO ₃ : 0.1 to 2.0. Hereinafter, in detail, in the radiation irradiation discoloration preventing glass of the present invention, the purpose of each component,
The addition amount, the type of radiation, the irradiation method, etc. will be described.

(SiO ₂ ) SiO ₂ is one of the essential components of the glass composition, and the addition amount is appropriately in the range of 65 to 80 parts by weight. This is because if the added amount of SiO ₂ is less than 65 parts by weight, the expansion coefficient becomes high and the chemical durability deteriorates. On the other hand, if the added amount exceeds 80 parts by weight, the expansion coefficient becomes too low and the softening temperature becomes high. This is because it becomes difficult to form a ring. Therefore, from the viewpoint that such a balance is more preferable, the addition amount is more preferably in the range of 70 to 75 parts by weight.

(Al ₂ O ₃ ) Al ₂ O ₃ is added as an essential component of the glass composition in order to improve chemical durability and the like, but the addition amount is 0.5 to 5.0. A range of parts by weight is suitable. The amount of Al ₂ O ₃ added is 0.5
This is because if the amount is less than 5 parts by weight, the chemical durability is deteriorated, while if the amount added is more than 5 parts by weight, the glass becomes inhomogeneous and is likely to be broken. Therefore, from the viewpoint that such a balance is more preferable, the addition amount is more preferably in the range of 1 to 3 parts by weight.

(Na ₂ O) In the present invention, Na ₂ O
Is an alkali metal oxide and is added as an essential component in order to prevent dielectric breakdown caused by irradiation with radiation and to improve the effect of lowering electrical insulation and chemical durability and high temperature viscosity. Here, the addition amount of Na ₂ O is appropriately in the range of 12.0 to 15.0 parts by weight. When the addition amount of Na ₂ O is less than 12 parts by weight,
This is because dielectric breakdown occurs, the softening temperature becomes high, the ring-forming form becomes difficult, and the expansion coefficient becomes too low.
On the other hand, if the addition amount exceeds 15% by weight, the expansion coefficient becomes too large, and the chemical durability decreases. Therefore, from the viewpoint that such a balance is more preferable, 12.
The range of 1 to 14 parts by weight is more preferable.

(CaO) In the present invention, CaO is an alkaline earth metal oxide, which prevents dielectric breakdown caused by irradiation with radiation, and improves the effect of lowering electrical insulation, chemical durability and high temperature viscosity. And let
It is added as an essential component in order to more effectively exhibit the effect of preventing discoloration by radiation. Here, the addition amount of CaO is appropriately in the range of 10.0 to 12.0 parts by weight. If the amount of CaO added is less than 10 parts by weight, dielectric breakdown may occur, electrical insulation and chemical durability may be reduced, and the effect of preventing discoloration by radiation may be poor. If the added amount exceeds 12 parts by weight, the glass tends to be devitrified, which is not preferable. Therefore, from the viewpoint of better balance, the addition amount of CaO is 10.5 to
The range of 12.0 parts by weight is more preferable.

(B ₂ O ₃ ) In the present invention, B ₂ O ₃ is added as an essential component of the glass composition in order to improve the meltability and the chemical durability. Here, the amount of B ₂ O ₃ added is preferably in the range of 0.1 to 2.0 parts by weight. This is because if the addition amount is less than 0.1 parts by weight, the effect of reduction fining cannot be obtained, while if the addition amount exceeds 2 parts by weight, the discoloration preventive property against radiation is lowered and the glass melting temperature is lowered. Higher, or
This is because problems such as severe damage to the furnace material are likely to occur. In addition, from the viewpoint of better balance,
The addition amount is more preferably in the range of 0.5 to 1.0 part by weight.

(CeO ₂ ) In the present invention, CeO ₂ is added as an essential component of the glass composition in order to prevent discoloration due to irradiation with radiation, but it also has the function of improving the light transmittance of the glass. . Where CeO ₂
The amount of addition of 0.1 is suitably in the range of 0.1 to 3 parts by weight. If the addition amount is less than 0.1 parts by weight, the effect of preventing discoloration becomes poor, while if the addition amount exceeds 3 parts by weight, the degree of yellowing due to Ce ⁴⁺ itself becomes strong, or glass products This is because it is not preferable because it increases the cost. Therefore, the range of 0.5 to 2.0 parts by weight is more preferable from the viewpoint of better balance.

(Fe ₂ O ₃ ) In the present invention, Fe ₂ O
₃ is added as a component of the glass composition in order to prevent coloration by irradiation of radiation, but it is also preferable to add ₃ alone or in combination with CeO ₂ . When used alone as a discoloration preventing agent without combining with CeO ₂ ,
It is preferable in that the cost can be reduced and the radiation irradiation discoloration preventing glass of the present invention can be provided. On the other hand, when it is added in combination with CeO ₂ , it is preferable in that a more excellent radiation irradiation discoloration preventing effect can be obtained. is there. Where Fe ₂ O
_The suitable amount of addition of ₃ is in the range of 0.3 to 3 parts by weight. If the addition amount is less than 0.3 parts by weight, the effect of preventing discoloration becomes poor. On the other hand, if the addition amount exceeds 3 parts by weight, the degree of green coloring by Fe ³⁺ itself becomes strong, which is not preferable. From the viewpoint that such a balance is more preferable, the addition amount of Fe ₂ O ₃ is 1.0 to
A range of 2.0 parts by weight is more preferable.

(V ₂ O ₅ ) In the present invention, V ₂ O ₅ is added in an amount of 0.5 to 3% with respect to 100 parts by weight of another glass composition.
It is preferable to further contain 0 part by weight. V ₂ O ₅ alone has a poor discoloration preventing effect, but CeO ₂ and Fe ₂ O ₃
This is because a more excellent discoloration preventing effect against irradiation of radiation can be effectively obtained by using it together with. Here, the amount of V ₂ O ₅ added is preferably in the range of 0.5 to 3.0 parts by weight when the amount added is less than 0.5 parts by weight, the effect of addition is poor, while the amount added is This is because if the amount exceeds 3.0 parts by weight, discoloration may occur, or the cost may increase.

(Other glass components) In the present invention, it is preferable to add other glass components to the above-mentioned glass composition components depending on the intended use. For example,
It is possible to add P ₂ O ₅ , Li ₂ O, MgO and the like within a range that does not deviate from the effects and purposes of the present invention. Further, the addition amount of the other glass component is preferably in the range of 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the other glass composition. This is because if the addition amount is less than 0.1 parts by weight, the effect of addition is poor, while if the addition amount exceeds 2.0 parts by weight, discoloration may occur, and it may be difficult to adjust the production conditions. . Further, Nb ₂ O ₅ , PbO and the like are also preferably added depending on the application, but since they are strongly discolored by radiation, the addition amount should be minimized when added. Specifically, it is suitable to be less than 0.1 parts by weight with respect to 100 parts by weight of the other glass composition.

(Radiation) The type of radiation and irradiation conditions for the radiation irradiation discoloration preventing glass of the present invention will be described. The radiation which is the object of the present invention includes a wide range of x-rays, γ-rays having the properties of electromagnetic waves, or electron beams, α-rays, β-rays, various ions, neutrons, etc. It is an electron beam that has a high object transparency. However, when irradiating the glass of the present invention for the purpose of sterilization, among such radiation, the energy level is extremely high, and electron beams and γ-rays that can obtain a sterilization effect in a short time are used in the irradiation of the glass. Optimal. Further, in the present invention, the irradiation dose of the radiation is not particularly limited, from the viewpoint that an excellent sterilization effect can be obtained and the influence on the glass is relatively small.
For example, the range of 15 to 25 kGy for electron beams and the range of 20 to 30 kGy for γ rays are suitable.

(Light Transmittance) The glass of the present invention is required to have a constant light transmittance even after irradiation with a certain amount of radiation. Specifically, the visible light region, for example, 60
A change in the light transmittance before and after irradiation with radiation at a wavelength of 0 nm is preferably less than 80%. This is because such a change in light transmittance has little discoloration property, and the content can be sufficiently confirmed even when a glass molded body is prepared using the radiation irradiation discoloration preventing glass of the present invention. Further, in the case of a use requiring more transparency, the change in light transmittance after irradiation with radiation is more preferably 50% or less, and most preferably 20% or less.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to examples.

Example 1 A glass plate (length 2.5) having the glass composition shown in Table 1 (unit: parts by weight, hereinafter the same).
cm, width 1.0 cm, thickness 4.0 mm), melting temperature 1
It was prepared and prepared under the manufacturing conditions of 470 ° C. and a melting time of 1 hour. And then, with a spectrophotometer, a wavelength of 200-9
The light transmittance in the range of 00 nm was measured, recorded on a chart, and visually inspected. Next, using an electron beam irradiation device manufactured by Sumitomo Heavy Industries, Ltd., 20 kG
The electron beam was irradiated so that the irradiation amount was ry.

Then, in the same manner as before irradiation, the light transmittance was measured and the appearance was visually inspected. The results of the measured light transmittance at a wavelength of 600 nm are shown in Table 1 and FIGS.

Further, such a glass composition has advantages such as low viscosity at high temperature during melting, good workability, high chemical stability and high glass density.

Further, the results were obtained that the transparency was higher and the initial light transmittance was higher than that of the composition in which CeO ₂ or Fe ₂ O ₃ was not added.

Table 1-1 Example glass composition 1 2 3 4 5 6 SiO ₂ 73.5 73.5 73.5 73.5 73.5 73.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 0. 6 CaO 10.8 10.8 10.8 10.8 10.8 10.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 0.3 CeO ₂ 0.1 0.5 1.0 Fe ₂ O ₃ 0.3 0.5 1.0 Before irradiation (%) 90 88 86 80 80 77 70 Visual colorless transparent Colorless transparent Colorless transparent Colorless transparent Slightly green transparent Green transparent After irradiation (%) 23 77 85 85 34 47 60 Visually slightly transparent Color Transparency Some slightly slightly brown transparent brown transparent brown transparent green transparent change rate (%) 74 12 1 58 39 14

Table 1-2 Example glass composition 7 8 9 10 11 12 12 SiO ₂ 73.5 73.5 73.5 73.5 73.5 73.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 0. 6 CaO 10.8 10.8 10.8 10.8 10.8 10.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 CeO ₂ 0.1 0.5 1.0 1.0 0.1 0.5 1.0 Fe ₂ O ₃ 0.1 0.1 0.5 0.5 0.1 0. _{1 0.1 V 2 O 5 0.1 0.5} 1.0 before irradiation (%) not I 88 87 80 80 82 82 visual colorless colorless slightly colorless slightly Green transparent Green transparent green transparent after irradiation (%) 33 87 80 28 82 82 visual Some colorless colorless slight green slightly slightly brown transparent brown transparent transparent green transparent change rate (%) 63 0 0 65 0 0

Table 1-3 Example glass composition 13 14 15 16 17 18 SiO ₂ 65.0 70.0 75.0 73.5 73.5 73.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Na ₂ O 13.5 12.3 12.3 12.3 12.3 12.3 K ₂ O 1.6 0.6 0.6 0.6 0.6 0.6 0. 6 CaO 11.8 10.8 10.8 10.8 10.8 10.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 CeO ₂ 0.1 0.5 1.0 1.0 0.1 0.5 1.0 Fe ₂ O ₃ 0.1 0.1 0.5 V ₂ O ₅ 0 .1 0.5 1.0 Before irradiation (%) 88 87 80 80 80 82 82 Visually colorless transparent Transparent colorless slightly colorless transparent slightly slightly green transparent After color transparent green transparent irradiation (%) 33 87 80 28 82 82 visual Some colorless colorless slightly slightly slightly brown transparent brown transparent green transparent green transparent change rate (%) 63 0 0 65 0 0

Table 1-4 Comparative example glass composition 1 2 3 4 5 6 SiO ₂ 73.5 73.5 73.5 76.5 76.5 76.5 Al ₂ O 2.0 2.0 2.0 2.0 0.0 2.0 2.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 0.6 CaO 10.8 10.8 10.8 7.8 7.8 7.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SO ₃ 0.5 0.3 0 0.3 0.3 0.3 0.3 Nb ₂ O ₅ 0.5 1.0 PbO 0.1 0.5 1.0 Before irradiation (%) 84 84 84 83 83 83 83 Visual colorless colorless transparent colorless colorless colorless colorless Transparent Colorless Transparent Colorless Transparent After irradiation (%) 7 7 7 7 5 8 8 Visual brown opaque brown opaque brown opaque brown opaque brown opaque brown opaque Change (%) 92 92 92 94 90 90

Table 1-5 Comparative Example Glass Composition 7 8 9 10 11 12 SiO ₂ 73.5 73.5 80.0 73.5 73.5 77.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 0. 6 CaO 10.8 10.8 10.8 10.8 10.8 6.0 B ₂ O ₃ 0.3 0.3 0.3 0.3 1.3 1.3 1.3 1.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 0.3 V ₂ O ₅ 0.1 0.5 1.0 CeO ₂ 0.01 0.1 Fe ₂ O ₃ 0.1 Before irradiation (%) 82 79 74 84 84 90 Visually colorless colorless slightly slightly colorless transparent colorless transparent colorless transparent green transparent green transparent after irradiation (%) 5 8 13 7 11 18 visual brown Transparent brown opaque brown clear tea opaque brown transparent brown transparent change rate (%) 94 90 82 92 87 80

(Examples 2 to 18) Using an electron beam and under the same conditions as in Example 1, the compositions of Examples shown in Table 1 were
The experiment was repeated. The results are shown in Table 1 and some of FIGS.

(Comparative Examples 1 to 12) Using electron beams and under the same conditions as in Example 1, the compositions of Comparative Examples shown in Table 1 were as follows:
The experiment was repeated. The results are shown in Table 1 and FIGS.
And 6 are shown.

(Examples 19 to 27) γ instead of the electron beam
The experiment was repeated for the compositions of the examples shown in Table 2 under the same conditions as in Example 1 except that the rays were irradiated at 25 kGry. The results are shown in Table 2 and partial FIGS.

(Comparative Examples 13 to 24) Instead of the electron beam,
The experiment was repeated for the composition of the comparative example shown in Table 2 using γ rays under the same conditions as in Example 19. The result is
Shown in Table 2 and partial Figures 7 and 9.

Table 2-1 Example glass composition 19 20 21 22 22 23 SiO ₂ 73.5 73.5 73.5 73.5 73.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2 0.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 CaO 10.8 10.8 10.8 10. 8 10.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 0.3 0.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 CeO ₂ 0.1 0.5 1. 0 Fe ₂ O ₃ 0.5 1.0 Before irradiation (%) 90 88 86 77 77 70 Visual colorless transparent Colorless transparent colorless transparent Slightly a little green transparent Green transparent After irradiation (%) 20 75 86 35 63 Visually a little colorless transparent colorless Transparent Slightly Slight brown Transparent Brown transparent Green transparent Change rate (%) 78 1 0 55 10

[0046]

Table 2-3 Comparative example glass composition 13 14 15 16 17 18 18 SiO ₂ 73.5 73.5 73.5 73.5 73.5 73.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 0. 6 CaO 10.8 10.8 10.8 10.8 10.8 10.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 0.3 Nb ₂ O ₅ 0.5 1.0 1.0 PbO 0.1 0.5 1.0 Before irradiation (%) 84 84 84 85 85 85 85 Visual colorless transparent colorless transparent colorless transparent Colorless transparent Colorless transparent Colorless transparent After irradiation (%) 6 4 9 5 7 11 Visually Brown opaque Brown opaque Brown opaque Brown opaque Brown opaque Brown opaque Change rate (%) 93 95 89 94 91 91 87

Table 2-4 Comparative example glass composition 19 20 21 22 23 24 24 SiO ₂ 73.5 73.5 73.5 73.5 76.5 73.5 Al ₂ O ₃ 2.0 2.0 2.0 2.0 2.0 2.0 Na ₂ O 12.3 12.3 12.3 12.3 12.3 12.3 K ₂ O 0.6 0.6 0.6 0.6 0.6 0.6 0. 6 CaO 10.8 10.8 10.8 10.8 7.8 10.8 B ₂ O ₃ 0.3 0.3 0.3 0.3 1.3 1.3 1.3 SO ₃ 0.5 0.3 0.3 0.3 0.3 0.3 V ₂ O ₅ 0.1 0.5 1.0 CeO ₂ 0.01 0.1 Fe ₂ O ₃ 0.1 Before irradiation (%) 84 84 84 84 88 84 Visual inspection Transparent colorless colorless transparent colorless transparent colorless transparent colorless transparent colorless transparent after irradiation (%) 6 6 5 11 17 8 visual brown opaque brown brown Transparent Brown opaque Brown opaque Brown opaque Brown opaque Change rate (%) 92 92 94 87 81 90

[0049]

EFFECTS OF THE INVENTION According to the present invention, (1) it has an excellent effect of preventing discoloration for applications such as radiation sterilization, (2) it has a low high-temperature viscosity when melted, and has good workability ( 3)
High chemical stability, (4) High glass density, (5)
In addition, it has become possible to provide a radiation-induced discoloration-preventing glass having high transparency.

Furthermore, a predetermined amount of CeO ₂ and F is added.
e ₂ O ₃ or V ₂ O ₅ in combination, SiO ₂ ,
Na ₂ O, CaO, Al ₂ O ₃ , K ₂ O, B ₂ O ₃ , S
O ₃ etc. or SiO ₂ , Na ₂ O, CaO, Al
By adding to ₂ O ₃ , K ₂ O, B ₂ O ₃ , SO ₃ , etc., it becomes possible to provide a more excellent radiation irradiation discoloration preventing glass.

[Brief description of drawings]

FIG. 1 is a measurement chart of light transmittance of Comparative Examples 1 and 13 (basic glass composition) before irradiation with electron beams and γ rays.

FIG. 2 shows a measurement chart of light transmittance of Comparative Example 1 (basic glass composition) after electron beam irradiation.

FIG. 3 is a measurement chart of light transmittance of Examples 1 to 3 and 19 to 21 (0.1, 0.5, and 1.0 parts by weight of CeO ₂ added) before irradiation with electron beams and γ rays. Show.

FIG. 4: Examples 1-3 (CeO ₂ 0.1, 0.5,
The measurement chart of the light transmittance after electron beam irradiation of (1.0 part by weight added product) is shown.

FIG. 5: Examples 5, 6 and 22, 23 (0.5 and 1.0 parts by weight of Fe ₂ O ₃ added product) and Comparative Examples 11 and 24 (0.1 parts by weight of Fe ₂ O ₃ added product) 3) shows a measurement chart of light transmittance before irradiation with electron beams and γ-rays.

FIG. 6 After electron beam irradiation of Examples 5 and 6 (product with addition of 0.5 and 1.0 parts by weight of Fe ₂ O ₃ ) and Comparative Example 11 (product with addition of 0.1 part by weight of Fe ₂ O ₃ ). 3 shows a measurement chart of light transmittance in FIG.

FIG. 7 shows a light transmittance measurement chart of Comparative Example 13 (basic glass composition) after γ-ray irradiation.

FIG. 8: Examples 19-21 (CeO ₂ at 0.1, 0.
5 shows a measurement chart of the light transmittance after γ-ray irradiation of (5, 1.0 parts by weight added product).

FIG. 9: Examples 22, 23 (Fe ₂ O ₃ of 0.5, 1.
0 parts by weight of the additive) and Comparative Example 24 (Fe ₂ O ₃ were added in an amount of 0.
The measurement chart of the light transmittance after γ-ray irradiation of 1 part by weight added product) is shown.

Claims (7)

[Claims] 1. SiO ₂ : 65.0 to 8 in terms of parts by weight.
0.0, Na ₂ O: 12.0 to 15.0, CaO: 1
_{0.0~12.0 Al 2 O 3: 0.5~5.0,} CeO 2: 0.1~3.
_{0, K 2 O: 0.1~2.0,} B 2 O 3: 0.1~2.
0, SO ₃ : 0.1-2.0, and a radiation-induced discoloration-preventing glass, which is composed of a glass composition. 2. The glass composition contains F in terms of parts by weight.
The radiation irradiation discoloration preventive glass according to claim 1, further comprising e ₂ O ₃ : 0.3 to 3.0. 3. SiO ₂ : 65.0 to 8 in terms of parts by weight.
0.0, Na ₂ O: 12.0 to 15.0, CaO: 1
_{0.0~12.0 Al 2 O 3: 0.5~5.0,} Fe 2 O 3: 0.3~
_{3.0, K 2 O: 0.1~2.0,} B 2 O 3: 0.1~
A radiation-induced discoloration-preventing glass, which is composed of a glass composition containing 2.0 and SO ₃ : 0.1 to 2.0. 4. The radiation discoloration prevention according to claim 1, wherein the glass composition contains CeO ₂ : 0.5 to 2.0 in terms of parts by weight. Glass. 5. The glass composition comprises V in terms of parts by weight.
₂ O _5: 0.5 to 3.0 further irradiation discoloration glass according to claim 1, characterized in that it comprises a. 6. The radiation is an electron beam, and the radiation is 15 to 2
After irradiating the electron beam with a dose of 5 KGY, 600 nm
Change of the light transmittance in the wavelength of is less than 80% compared with the said light transmittance before irradiation, The radiation irradiation discoloration prevention of any one of Claims 1-5 characterized by the above-mentioned. Glass. 7. The radiation is gamma rays, and 20 to 30
The change in light transmittance at a wavelength of 600 nm after irradiation with the γ-ray of a dose of kGy is less than 80% as compared with the light transmittance before irradiation. 5. The radiation irradiation discoloration preventing glass according to any one of 5 above.