JPH0454628B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel glass surface treatment method. Glass surface treatments include those that improve physical strength such as breaking strength, those that improve added value such as decorativeness, and those that increase chemical durability. For example, in the case of bottles used for medical purposes such as for intravenous fluids and intravenous drips, the glass should be protected from being eroded by the liquid inside and sodium, calcium, etc. in the glass would not be eluted into the liquid, or A high degree of chemical durability is required to minimize the There have been various methods of treating the surface of such glass to improve its chemical durability, and treatment using sulfur dioxide gas is common. In this case, sulfur dioxide gas is injected into the lehr immediately after the glass bottle is molded or inside the lehr, but because the reaction rate is slow, a relatively large amount of gas is required. product stains due to rust,
Problems include deterioration of the working environment. Furthermore, the chemical durability of glass can also be improved by treatment with fluorinated hydrocarbon gas such as chlorofluorocarbon gas and Freon gas (trade name). In this case, only a small amount of gas is required and the reaction speed is fast, so the working environment will not be degraded, but since the product after treatment is transparent (no reaction products adhered to it), it is difficult to manage it. Moreover, when the amount of gas increases, there are problems such as the formation of a cloudy cloud that cannot be removed even by washing with water. The present inventors discovered that when treating glass products with sulfur dioxide gas and fluorinated hydrocarbon gas in combination, it was possible to obtain glass products with a high level of chemical durability that could not be obtained by either treatment alone. The present invention has been made based on this finding. Thus, the present invention provides a container-shaped glass product immediately after molding that is maintained at a temperature in the range of 550 to 750°C.
Inject 0.5 to 2.5 ml of fluorinated hydrocarbon gas and 2 to 20 ml of sulfur dioxide gas per 500 ml of internal volume of the container,
The present invention provides a method for surface treatment of glass, which is characterized in that the obtained mixed atmosphere of both gases is applied to the glass product, and then the glass product is gradually cooled. To explain the present invention in more detail, in the present invention, the surface of a glass container such as a medicine bottle immediately after being formed is treated with sulfur dioxide gas and fluorinated hydrocarbon gas. This treatment is performed during the several tens of seconds that the material is loaded and sent to the slow cooling furnace. Processing is done by keeping the injection gas at a constant pressure.
This is done by injecting the inside of the glass container from a nozzle under the volume. Sulfur dioxide gas and fluorinated hydrocarbon gas may be injected in that order, vice versa, or at the same time, but both gases are mixed inside the container-shaped glass product to form a mixed atmosphere. to be done. It is preferable that the temperature of the glass container be maintained in the range of 550 to 750° C. during the processing after molding and before being transferred to the slow cooling furnace via a conveyor. If the temperature exceeds this temperature, there is a risk of clouding that cannot be removed even by washing with water, and if the temperature is below this temperature, an appropriate treatment effect cannot be obtained and it is not practical. Freon-12 is generally used as a fluorinated hydrocarbon gas.
(CCl ₂ F ₂ ), Freon 14 (CF ₄ ), Freon 116 (CF ₃ −
Although some products are commercially available under trade names such as CH ₃ ) and Freon 152A (CH ₃ CHF ₂ ), in the present invention, a gas that does not contain chlorine, such as Freon Gas 152-A, is preferred. The amount of sulfur dioxide gas or fluorinated hydrocarbon gas to be introduced varies depending on the volume, shape, or surface area of the glass container, or depending on the glass material, but if the amount of fluorinated hydrocarbon gas is too large, it will lead to clouding. 0.5-2.5ml per glass bottle with normal internal volume of 500ml
Even if the amount of sulfur dioxide gas used in combination with fluorinated hydrocarbon gas is reduced to about 1/4, that is, 2 to 20 ml, the amount is the same as that of sulfur dioxide gas treatment alone. chemical durability can be obtained. Furthermore, by adjusting the amount of each gas, durability can be increased four times compared to when used alone. The ratio of fluorinated hydrocarbon gas to the full capacity of the glass container is 2×10 ^-3 ~
5×10 ^-3 is a range in which durability can be improved without causing cloudiness that impairs the appearance. The present invention will be further explained by showing test examples below. Internal volume 500ml made from soda lime glass
Ringer bottle (usually filled with 400ml Ringer's solution)
After molding, the sample is collected on a machine conveyor that transports it to a slow cooling furnace, placed on a heat insulating board prepared in advance, and a fixed amount of Freon 152-A is injected with a syringe.
The inner surface temperature of the bottle at this time is approximately 700°C. Approximately 1
After allowing the bottle to stand for a second, sulfur dioxide gas is injected into the bottle using a syringe under certain conditions. The bottle was placed on the upper left end of the net of a lehr (slow cooling furnace), and a sample was taken at the leir end. Here, the amounts of the two gases injected were adjusted in various ways, and the chemical durability of the combinations was tested. That is, the amount of sulfur dioxide gas is 0, 2, 5, 10,
20, 40ml, while the amount of fluorinated hydrocarbon gas is 0,
Test by changing the combinations to 0.5, 1.0, 2.5, 5.0, and 10.0ml. In the present invention, chemical durability was tested by the following method. (1) Clean the sample bottle three times with tap water and rinse it three times with pure water. Next, add 100 ml of 0.9% NaCl aqueous solution containing 1 ml of 0.02N potassium chloride solution.
After capping with a Ringer bottle rubber cap + aluminum shell, autoclave at 121°C for 1 hour. After adding an indicator to the resulting sample solution, titrate with 1/50 normal hydrochloric acid to measure the amount of hydrochloric acid required for neutralization. (2) The test method in (1) above is relatively harsh and clearly shows differences between samples, but in the present invention, apart from this, eluted fluorine ions, etc. are quantified by absorption analysis. . That is, as mentioned above, 3 times with tap water.
After washing twice and rinsing with pure water three times, it is filled with pure water to 90% of its full capacity, capped, and subjected to the same autoclave treatment to obtain a sample solution. After dividing this, one is after doing the necessary processing.
The eluted fluorine ions were quantified by absorbance measurement at 620 nm, and the eluted Na ₂ O was determined by atomic absorption spectrometry.
Quantify the amount of The results of the test using method (1) are shown in Table 1.
The results of the test using method (2) are shown in Tables 2 and 3. All are shown as the average value of the results obtained for each 8 samples, and in Table 1, they are expressed by the amount (ml) of titrated 1/50N hydrochloric acid,
In Table 3, the amounts are shown in mg per bottle. In any case, when this value is small, the amount of alkali or fluorine eluted is small and it can be said that the chemical durability is high.

【table】

【table】

[Table] The following can be considered from these tables. (A) Regarding Table 1, () Current treatment with normal sulfur dioxide gas is 0.200ml, but if used together,
For example, a value of 0.055 ml was obtained with 2 ml of sulfur dioxide gas and 2.5 ml of chlorofluorocarbon gas, and it is clear that the durability was approximately four times greater by this combined treatment. () Similarly, when using only sulfur dioxide gas, 40ml
When used together, a value of 0.175 ml was obtained, but by using only 0.5 ml of fluorocarbon gas in combination, sulfur dioxide gas can be obtained in a small amount of 10 ml, which is 1/4 of the amount when using it alone. . () As the amount of Freon gas input increases, the durability reaches its maximum value. This trend is the same regardless of the amount of sulfur dioxide gas added next to the fluorocarbon gas. In other words, the amount of fluorocarbon gas is 2.5
Durability increases rapidly as the amount increases up to ml, but as the amount exceeds that amount, durability tends to gradually decrease. (B) Regarding Tables 2 and 3, () Fluorine ions are detected when 5 ml or more of Freon is treated, which causes white turbidity, but in other samples, it is below the detection limit (0.04 mg/piece). It is clear that the treatment of fluorinated hydrocarbon gas does not leave any fluorine ions on the glass surface and is safe. () The elution of Na ₂ O will also be less than when treating with sulfur dioxide gas alone, provided that _the treatment does not result in white turbidity.
It is clear that the combined treatment is effective. In addition, to mention a few things about the appearance, it is observed that when the amount of Freon gas added is 5 ml or more, a white turbidity occurs that does not come off even when washed with water. This was also true in the case of treatment with chlorofluorocarbon gas alone without adding sulfur dioxide gas. However, when the amount of Freon gas input was 2.5 ml or less, no abnormality was observed in appearance after washing with water. As is clear from the above test examples, if glass surface treatment is carried out using both sulfur dioxide gas and fluorinated hydrocarbon gas in combination according to the present invention, a very small amount of sulfur dioxide gas and a fluorinated hydrocarbon gas can be used to treat the surface of the glass. It is possible to obtain a good glass product which has chemical durability and can be suitably used as a medical bottle such as a liquid-ring bottle or an infusion bottle, or a bottle for alcohol. Thus, the present invention provides a truly effective glass surface treatment method. The movement of the fluorinated hydrocarbon gas and sulfur dioxide gas used in this process is not fully understood, but when a small amount is added at the temperature specified in the present invention, the heat between the molecules on the glass surface and the gas It is thought that gas molecules are contained inside the glass due to the reaction, contributing to improved chemical durability, and are not eluted or spouted to the outside.

Claims (1)

[Claims] 1 Inside the container-shaped glass product immediately after molding, which is maintained at a temperature in the range of 550 to 750℃, the inner volume of the container is
It is characterized by injecting 0.5 to 2.5 ml of fluorinated hydrocarbon gas and 2 to 20 ml of sulfur dioxide gas per 500 ml, allowing the resulting mixed atmosphere of both gases to act on the glass product, and then gradually cooling it slowly. , glass surface treatment method.