JPH02153846A - Production of low-alkali glass container - Google Patents

Abstract

PURPOSE:To prevent an alkaline metal compound remaining on the inner surface of a glass vessel by cutting a glass tube, then forming the mouth and bottom parts of the glass vessel, subsequently washing and drying the interior of the vessel according to a specific method and annealing the vessel. CONSTITUTION:A low-alkali glass vessel is obtained by the following steps (a) to (d). That is step (a) for forming and working the mouth part (1a) of the glass vessel 1; step (b) for inserting a washing nozzle 4 from the mouth part (1a) of the glass vessel 1 into the interior thereof and jetting a washing substance from the nozzle 4; step (c) for inserting an air nozzle 5 from the mouth part (1a) of the glass vessel 1 into the interior thereof, blowing air from the nozzle 5 and drying the interior and step (d) for removing the inner residual moisture while removing strain of the glass vessel 1. Distilled water which is washing water or steam produced by increasing temperature of pure water is used as the washing substance. An acid or alkali may be added to the washing water.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for manufacturing a low-alkali glass container.

(Prior Art) Tubes, ampoules, test tubes, etc. are made by molding the mouth and bottom of tubes made of hard glass (borosilicate glass) with low alkali elution. During this molding process, the alkali metal compound (alkali boric acid, sodium) volatilizes and forms a layer on the inner surface of the glass container due to heat processing at a temperature of approximately 650 to 1200°C. this is,
This is noticeable when forming the bottom part. This alkali metal compound adhering to the inner surface of the container is baked onto the inner surface during the slow cooling (annealing) step, which is the final step to remove distortion from the glass container. For this reason, even though the glass container is made of hard glass, its inner surface is rich in alkaline content. Therefore, when a chemical solution of physiological saline or distilled water is filled, alkaline content is dissolved into the solution, raising the pH and causing alkali elution.

Conventionally, therefore, the blow method, which uses air, inert gas, or cooling of these gases to remove the alkali metal compounds that volatilize inside the glass container during the molding process of the bottom, etc., and the suction method, which simultaneously removes them using vacuum, have been used. There was a law.

(Problem to be Solved by the Invention) However, the removal effect of the conventional example is insufficient, and the alkali metal compound remains on the inner surface of the glass container. Therefore, when a solution or the like is filled, the pH increases, This will cause alkaline elution.

An object of the present invention is to prevent alkali metal compounds from remaining on the inner surface of a glass container.

(Means for Solving the Problems) The manufacturing method of the present invention is characterized by a step of molding the mouth part 1a and the bottom part of the glass container 1, and a cleaning process by inserting a cleaning nozzle 4 into the inside of the glass container from the mouth part. A cleaning process in which a cleaning body is injected from a nozzle, a drying process in which the air nozzle 5 is inserted into the inside of the glass container from the mouth and air is blown from the air nozzle, and an annealing furnace is used to remove the strain in the glass container while cleaning the inside of the glass container. and a gradual cooling step for removing residual moisture. The cleaning body includes cleaning water or purified water turned into steam at an elevated temperature, and distilled water may be selected as the cleaning water. As a cleaning step, it is also possible to add acid or alkali to the cleaning water for cleaning.

(Example) An embodiment of the present invention will be described below.

After cutting the glass tube to a predetermined length, the mouth and bottom of the glass container are formed.

Next, as shown in FIG. 1, the glass container 1 is turned downward, the mouth 1a is held by the tubular mouth fixture 2, and the glass container is turned upside down. In FIG. 1, the dotted portion is an alkali metal compound that adheres to the inner surface of the glass container 1 during the molding process.

Then, as shown in Fig. 2, with the glass container 1 clamped and fixed on both the upper and lower sides by the presser 3 and the fixture 2, the cleaning nozzle 4 is inserted into the glass container from the opening 1a, and the cleaning water is applied from the cleaning nozzle. The inside of the glass container 1 is cleaned by spraying some distilled water.

After cleaning, as shown in FIG. 3, a drying air nozzle 5 is inserted into the inside of the glass container from the mouth 1a of the glass container 1, and clean air, which is drying air, is blown from the drying air nozzle.
Dry the inside of the glass container.

Thereafter, as shown in FIG. 4, the glass container 1 is set in a slow cooling furnace, and the residual moisture inside is removed while the glass container is strained in the slow cooling furnace.

As a result, as shown in FIG. 5, a low-alkali glass container is manufactured in which the alkali metal compound adhering to the inner surface of the glass container 1 has been removed during the molding process.

(Experiment example) Using a 5ml vial as a sample, a sulfur-treated product, a hydrofluoric acid-treated product, a product of the present invention produced by the manufacturing method of the present invention, and a regular product without any treatment were used as examples, and a PH meter was used. The pH value was measured for eluted Na+ by atomic absorption spectrophotometry. The results of IIF1 determination are shown in the graphs shown in Figures 6 and 7, and Figure 6 shows the elution N
a+, and FIG. 7 shows PH. In Fig. 6.7, the graph ``■'' is the sulfur-treated product, the graph ``■'' is the hydrofluoric acid-treated product, the graph ``■'' is the product of the present invention, and the graph ``■'' is the conventional product.

For the measurement, 528 samples were prepared for each example, and 264 of them were filled with 3 ml of pure water for Na'ffi measurement using a dispenser, and the rest were filled with 3 ml of physiological saline for PH value measurement. ml, each sealed with a rubber stopper and an aluminum cap, and then placed in an autoclave for 12 hours.
It was sterilized at 1°C for 1 hour.

The measurement items are filling, sterilization, 1st day, 4th day, and each week from 1st week to 7th week.

As is clear from the graph in Figure 6, the N
The a+ amount draws a graph close to that of the hydrofluoric acid-treated product over time, and the PH value of the product of the present invention is higher than that of the sulfur-treated product and the hydrofluoric acid-treated product, as shown in Figure 9; It was found that the value did not exceed the permissible value of 7, and therefore it could be used satisfactorily.

(Effects of the Invention) As explained above, according to the present invention, it is possible to prevent an alkali metal compound from remaining on the inner surface of a glass container using a simple method.

[Brief explanation of the drawing]

Fig. 1 to Fig. 5 are front views showing the main parts of the manufacturing method according to the present invention step by step; Fig. 6 is a graph showing the change over time in the amount of Na'' in the experimental example; Fig. 7 is the PH in the experimental example. It is a graph showing changes over time. 1... Glass container, 1a... Mouth part, 4... Cleaning nozzle, 5... Air nozzle.

Claims (1)

[Claims] 1. A step of molding the mouth and bottom of the glass container; a cleaning step of inserting a cleaning nozzle into the inside of the glass container from the mouth and spraying a cleaning body from the nozzle; The method includes a drying process in which an air nozzle is inserted into the container through its mouth and air is blown from the nozzle, and an annealing process in which residual moisture inside the glass container is removed while removing strain in the glass container in an annealing furnace. A unique manufacturing method for low-alkali glass containers. 2. A method for producing a low-alkali glass container according to claim 1, characterized in that the cleaning body is steam obtained by heating distilled water or pure water as cleaning water. 3. A method for producing a low-alkali glass container according to claim 2, characterized in that washing is carried out by adding an acid or an alkali to washing water.