JPH04280833A - Borosilicate glass - Google Patents

Abstract

PURPOSE:To provide the title glass of low thermal expansion coefficient, excellent in resistance to chemicals and corrosion, also low in working or meltting temperature, suitable for medicinal bottles, nursing bottles, boiler water gauges, etc. CONSTITUTION:The objective glass comprising (A) 69.5-73.0wt.% of SiO2, (B) 13.0-15.0wt.% of B2O3, (C) 4.5-6.0wt.% of Al2O3, (D) 0.5-1.5wt.% of CaO, (E) 0.5-2.5wt.% BaO, (F) 5,5-7.0wt.% of Na2O, (G) 0-1.5wt.% of K2O, and (H) 0.3-2.5wt.% of ZrO2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to borosilicate glass used for pharmaceutical bottle glasses, baby bottle glasses, water level gauge glasses for boilers, and the like.

0002

[Prior Art] Borosilicate glass, which has good chemical durability and corrosion resistance, and has a thermal expansion coefficient of 55 x 10-7/°C or less, is used for medical bottle glass, baby bottle glass, and boiler glass. It is used for various purposes such as water level gauge glass. A typical example of borosilicate glass used in these applications is SiO2-
There is B2O3-Al2O3-CaO-Na2O-based borosilicate glass.

0003

[Problems to be Solved by the Invention] However, the borosilicate glass disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 64-18939 has
Although this glass has low expansion and good chemical durability and corrosion resistance, it is difficult to form due to the high working temperature. Further, since the viscosity of the glass is high in a high temperature range, the melting temperature is high and there is a problem that bubbles are difficult to break.

An object of the present invention is to provide a borosilicate glass that has low expansion, excellent chemical durability and corrosion resistance, and has a low working temperature and low melting temperature.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present inventors conducted various studies and found that the content of SiO2 was increased to 73% in order to lower the working temperature and melting temperature.
．． 0% or less, adjust B2 O3 to 13.0% or more,
Furthermore, it has been found that high chemical durability can be maintained by containing BaO and ZrO2 as essential components, and this is proposed as the present invention.

That is, the borosilicate glass of the present invention has a weight percentage of SiO2 of 69.5 to 73.0%, B2 O3
13.0-15.0%, Al2O3 4.5-6.0
%, CaO 0.5-1.5%, BaO 0.5-2.
5%, Na2O 5.5-7.0%, K2O
0 to 1.5% and ZrO2 0.3 to 2.5%.

[0007]

[Operation] The reason why the composition range of the borosilicate glass of the present invention is limited as described above will be described below.

[0008] SiO2 is a glass-forming oxide, and its content is 69.5-73.0%. When SiO2 is more than 73.0%, the meltability of the glass deteriorates, and 69
．． If it is less than 5%, chemical durability will deteriorate.

B2 O3 is a component that improves the meltability of glass, and its content is 13.0 to 15.0%. If B2 O3 is more than 15.0%, the chemical durability will be poor, and if it is less than 13.0%, the melting temperature will be high, making it difficult to break bubbles, or the working temperature will be too high, making it difficult to mold.

[0010] Al2 O3 suppresses devitrification of glass,
It is a component that improves corrosion resistance and chemical durability, and its content is 4.5 to 6.0%. Al2O3 is 6
．． If it is more than 0%, the meltability of the glass will be poor and striae, bubbles, etc. will be likely to occur, and if it is less than 4.5%, the chemical durability will be poor.

[0011] CaO is a component that improves the meltability and chemical durability of glass, and its content is 0.5 to 1.5%.
It is. If CaO is more than 1.5%, glass melting becomes difficult, and if it is less than 0.5%, the above effects cannot be obtained.

BaO is a component that improves chemical durability, suppresses phase separation of glass, and improves meltability, and its content is 0.5 to 2.5%. If BaO is more than 2.5%, glass melting becomes difficult;
If the amount is less, the above effects cannot be obtained.

[0013] Na2O is a component that improves the meltability of glass, and its content is 5.5 to 7.0%. Na
If the content of 2 O is more than 7.0%, the chemical durability will decrease, and the coefficient of thermal expansion will become too high, resulting in a decrease in heat resistance. On the other hand 5
．． If it is less than 5%, glass melting becomes difficult.

[0014] The content of K2O is 0 to 1.5%. If K2O is more than 1.5%, glass melting becomes difficult.

ZrO2 is a component that significantly improves the chemical durability and corrosion resistance of glass, and its content is 0.
It is 3 to 2.5%. When ZrO2 is more than 2.5%, glass melting becomes difficult and unmelted substances remain, and when it is less than 0.3%, the above-mentioned effects cannot be obtained.

[0016] The borosilicate glass of the present invention contains As2 O3 as a refining agent based on 100 parts by weight of the above composition.
, Sb2O3, and NaCl in a total amount of up to 1.0%.

[0017]

EXAMPLES The borosilicate glass of the present invention will be explained below based on examples.

Table 1 shows examples of the present invention (sample No. 1 to
4) and a comparative example (sample No. 5).

[0019]

[Table 1]

Each sample in the table was prepared as follows.

[0021] First, glass raw materials were prepared so as to have the composition shown in the table, and then put into a platinum crucible, melted at 1570°C for 7 hours, and molded into the necessary shape for measurement of each characteristic.

As is clear from the table, sample No. 1, which is an example of the present invention. 1 to 4 have a thermal expansion coefficient of 43.0 to 4
5.0×10-7/℃, alkaline elution amount 0.09-0
．． 10ml, corrosion amount 4.0-4.4mg/cm2,
Softening point is 776-782℃, working temperature is 1133-11
The temperature was 51°C, and the melting temperature was 1515-1540°C.

On the other hand, sample No. 1, which is a comparative example, 5
has a coefficient of thermal expansion of 46.0 x 10-7/℃, an amount of alkali elution of 0.07 ml, an amount of corrosion of 4.3 mg/cm2,
Although the softening point was 780°C, which was almost the same value as the example, the working temperature was 1175°C and the melting temperature was 1590°C.
℃, respectively 24-42℃ and 50℃ compared to the example.
It was ~75°C higher.

These facts indicate that the borosilicate glass of the present invention has low expansion, excellent chemical durability and corrosion resistance, and has a low working temperature and low melting temperature.

[0025] The coefficient of thermal expansion in the table is approximately 5φ×50
Measurements were made using an average linear thermal expansion meter using a sample molded into a mm rod. Alkali elution amount is Japanese Industrial Standard R
-3512, and the amount of corrosion was measured based on Japanese Industrial Standard B-8211 at a test pressure of 50 kgf/cm2.
It was measured with The softening point was measured based on Japanese Industrial Standard R-3104. In addition, the working temperature and melting temperature are determined using a viscosity measuring device that measures the viscosity of the glass by pulling up a platinum ball suspended in the glass melt, and the working temperature is the temperature of the glass when the viscosity shows 104.0 poise. 102.5
The temperature at which poise was exhibited was defined as the melting temperature.

[0026]

As explained above, the borosilicate glass of the present invention has a low coefficient of thermal expansion and is excellent in water resistance and corrosion resistance, so it can be used as glass for pharmaceutical bottles, glass for baby bottles, and water level gauges for boilers. Suitable for glass etc. Furthermore, since the working temperature is low, it is easy to mold, and the melting temperature is low, so bubbles are easily removed, and therefore it can be manufactured at a high yield and at low cost.

Claims (1)

[Claims] Claim 1: SiO2 in weight percentage 69.5-7
3.0%, B2 O3 13.0-15.0%, Al2
O3 4.5-6.0%, CaO 0.5-1.5
%, BaO 0.5-2.5%, Na2O 5.
5-7.0%, K2O 0-1.5%, ZrO2
A borosilicate glass characterized by comprising 0.3 to 2.5%.