JPH0470263B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a glass container that can efficiently block ultraviolet rays while maintaining the transparency of soda lime glass. (Prior art) Glass that can block ultraviolet rays has been known for a long time, and glass containers such as Cr ⁶⁺ , Ce ³⁺ ,
Glass containing metal ions such as Ce ⁴⁺ and Fe ³⁺ was used to block ultraviolet rays and protect the contents. However, ultraviolet-blocking glass containers using Ce ³⁺ and Ce ⁴⁺ metal ions (Special Publications Showa)
45-17794), the colorless transparency could be maintained, but the UV blocking effect was insufficient.
Glass containers that use Cr ⁶⁺ metal ions have sufficient effect in blocking ultraviolet rays, but they coexist.
Due to Cr ³⁺ , it exhibited a dark green color, resulting in decreased transparency and the disadvantage that the color tone of the contents could not be seen from the outside. In addition, although glass containers using Fe ³⁺ metal ions have some degree of UV-blocking effect, they have the disadvantage that the green coloring becomes strong and the color tone of the contents cannot be seen from the outside. (Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, has a large ultraviolet blocking effect, can sufficiently protect contents from ultraviolet rays, and maintains high colorless transparency. It was completed with the aim of providing a glass container that allows the color tone of the contents to be clearly seen from the outside. (Means for solving the problem) In a glass whose body has a wall thickness of 1.0 to 10.0 mm, V ₂ O ⁵ and 0.07 of 0.01 to 1.0% by weight are added.
It is made of soda lime glass that contains less than % Fe ₂ O ³ and exhibits oxidizing properties, and is characterized by maintaining colorless transparency. In the present invention, a glass containing vanadium oxide (V ₂ O ₅ ) as a component that blocks ultraviolet rays is used in the composition _of ordinary soda lime glass.
O ₅ needs to be in the range of 0.01 to 1.0% by weight in the glass composition. If V ₂ O ₅ is less than 0.01% by weight, the UV blocking effect will be insufficient,
It becomes impossible to provide a glass container that can sufficiently protect the contents from ultraviolet rays. Meanwhile, _{V2O5 is} 1.0% by weight
If the color exceeds this value, the yellow-green color becomes deep and it becomes impossible to provide a glass container in which the color of the contents can be seen from the outside. Further, in the present invention, it is necessary that the glass be soda lime glass that exhibits oxidizing properties. The terms oxidizing glass and reducing glass are relative expressions and do not have precise definitions, but in the industry, attention is paid to the concentration of S in the glass as shown in Figure 1. , the glass with a higher concentration of S ⁶⁺ is referred to as an oxidizing glass, and the glass with a higher concentration of S ^2- is referred to as a reducing glass, so they will be used in this sense in this specification as well. . Common soda-lime glass that does not contain a colorant is an oxidizing glass, and its typical composition is as shown in the Examples below. V ₂ O ₅ normally exists as V ⁵⁺ , V ⁴⁺ , and V ³⁺ ions in glass, but it must exist as V ⁵⁺ ions in order to block ultraviolet rays while maintaining transparency. However, when it comes to reducing glass,
V ⁵⁺ ions are reduced and the presence of V ³⁺ ions increases, and as a result, the green color due to V ³⁺ becomes darker, making it difficult to maintain high transparency, and the color tone of the contents cannot be seen from the outside. It disappears. Therefore, it is necessary for the glass to maintain its oxidizing properties. Additionally, less than 0.07% by weight Fe ₂ O ³ is included to maintain transparency. If the content exceeds 0.07% by weight, the reaction 2Fe ²⁺ + V ⁵⁺ → 2Fe ³⁺ + V ³⁺ occurs, which not only impairs transparency as described above but also reduces the V ⁵⁺ content. Therefore, the ultraviolet blocking effect also decreases. In order to satisfy the present invention, the wall thickness of the body of the glass container must be within the range of 1.0 to 10.0 mm. If it is less than 1.0 mm, it will not be possible to maintain the required strength as a glass container;
If the thickness exceeds mm, the yellow-green color becomes intense throughout the wall thickness direction, making it difficult to see the color tone of the contents from the outside. In this way, the glass container of the present invention is made by adding a predetermined amount of V ₂ O ₅ to the usual soda lime glass composition and limiting the thickness of the body of the glass container. It can be mass-produced by slow cooling, efficiently blocks ultraviolet rays, and maintains high transparency. Therefore, it is possible to provide a glass container that can sufficiently protect the contents from ultraviolet rays and also allows the color tone of the contents to be seen as is from the outside. (Example) SiO ₂ : 71.0% (weight %, same below), Al ₂ O ₃ :
2.0%. , CaO: 10.5%, Na ₂ O: 14.0%, K ₂ O:
Soda lime glass having a composition of 1.5%, Fe ₂ O ₃ : 0.05%, and V ₂ O ₅ : 0.1% was melted and molded by a conventional method to produce a jam container (weight: 345 g, capacity: 820 c.c.).
The wall thickness of the body of this container was 3 mm, and when the jam was placed inside this container and viewed from the outside, the color tone of the jam could be seen as it was without any change. The transmittance curve (3 mm thickness) of the glass constituting this glass container is as shown in curve 1 in Figure 2.
Further, the ultraviolet blocking rate of this glass was as shown in Table 1. Furthermore, the transmittance curves when the content of V ₂ O ₅ in the soda lime glass is 0.3%, 0.5%, and 0.7% are defined as curves 2, 3, and 4, and as a comparative example, the transmittance curves when the content of V ₂ O ₅ is 0.3%, 0.5%, and 0.7%, and as a comparative example, The transmittance curve of flint glass is shown as curve A in FIG. Table 1 also shows the ultraviolet blocking rates of the glasses of Curve A and Curves 2, 3, and 4. As is clear from this table, the glass container of the present invention is more effective than the conventional glass container made of flint glass.
The UV blocking rate of 310~350nm is approximately twice as high, and the UV blocking rate of 360~
The UV blocking rate at 400 nm was approximately 2 to 8 times higher.

[Table] (Effects of the Invention) As explained above, the glass container of the present invention maintains high colorless transparency and allows the color tone of the contents to be seen from the outside, and also efficiently blocks ultraviolet rays. It can protect the contents from ultraviolet rays and can be easily manufactured using conventional processes. Therefore, the present invention greatly contributes to the development of industry as a glass container that blocks ultraviolet rays and eliminates the problems of the conventional products.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the S concentration in glass and the oxidizing and reducing properties of the glass, and FIG. 2 is a graph showing transmittance curves in Examples.

Claims (1)

[Claims] 1. In glass whose body has a wall thickness of 1.0 to 10.0 mm, V ₂ O ₅ of 0.01 to 1.0% by weight
A glass container that blocks ultraviolet rays and is made of soda lime glass that contains less than 0.07% Fe ₂ O ₃ and exhibits oxidizing properties, and maintains colorless transparency.