JPH0323494B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a glass bottle that has both mechanical strength and chemical durability, and a method for manufacturing the same. The present invention relates to a soda-lime glass bottle that has been chemically treated to form a low-alkali layer on its inner surface through a dealkalization reaction. (Prior Art) An ion exchange method is known as one effective method for improving the mechanical strength of conventional soda-lime glass bottles. This creates a compressive stress layer on the glass surface by replacing the sodium ions on the surface of the soda lime glass with potassium ions that have a larger ionic radius. It is well known that this contributes to On the other hand, when soda lime glass is used as a glass bottle for filling medicines, foods, etc., it is necessary to improve the chemical durability of the glass surface, that is, chemical resistance, water resistance, etc. A known method for improving this chemical durability is generally a dealkalization method in which sulfur dioxide gas, ammonium chloride, or the like reacts with an alkali component on the glass surface to form a low-concentration alkali layer. However, since dealkalization treatment to improve the chemical durability of the glass surface is aimed at removing alkaline components from the glass surface, the above-mentioned ion treatment, which assumes the presence of alkali ions on the glass surface, It is generally believed that strengthening the glass surface by replacement treatment is mutually exclusive. In other words, the glass bottles currently used for liquid pharmaceuticals are dealkalized with ammonium chloride, sulfur dioxide gas, etc. to reduce the amount of alkaline elution. If an ion exchange treatment is performed for the application, there is a problem with the amount of alkali eluted after ion exchange, and a sufficient dealkalization effect cannot be expected. Additionally, if a strong dealkalization treatment is applied to the surface of a tempered glass bottle that has been subjected to ion exchange treatment, the compressive stress layer obtained through ion exchange will be removed, resulting in the loss of its function as tempered glass. This will result in Looking at it this way, ion-exchanged tempered glass bottles are inferior in chemical durability, so the fields in which they can be used are naturally limited, while in fields where chemical durability is required. As a result, it is not possible to promote the reinforcement and weight reduction of glass bottles. (Problems to be Solved by the Invention) As a result of repeated efforts in this situation, the inventor of the present invention focused on the shape of a glass bottle.
The inner surface of the bottle, where the contents are filled, is treated with dealkalization to improve chemical durability, and the outer surface of the bottle, which is exposed to contact with other objects and impacts, forms a compressive stress layer through ion exchange. This paper proposes to increase its mechanical strength. In other words, in the process leading to this invention, the inventor learned that it is sufficient to strengthen only the outer surface of the bottle against damage from the outer surface of the bottle, especially for what is called a one-way bottle. It has been found that mechanical strength almost equivalent to that obtained by ion exchange treatment on both the inner and outer surfaces can be obtained by ion exchange treatment only on the outer surface, since there is less chance of damage to the inner surface. Then, the outer surface of the bottle is subjected to ion exchange treatment, and one inner surface is subjected to dealkalization treatment, but these ion exchange treatment and dealkalization treatment are performed separately over time. When combined, there is the difficulty in processing technology that it is necessary to control and adjust the surface treatment of the other according to the purpose due to the difference in the degree of surface treatment of one, and furthermore, Even in such cases, the disadvantage is that the effect of the surface treatment carried out earlier is reduced by the subsequent treatment steps. In addition, there are economic disadvantages such as equipment and work efficiency due to multiple steps. In this invention, the above-mentioned technical difficulties and economic efficiency are solved all at once by performing the dealkalization treatment on the inner surface of the bottle body and the ion exchange treatment on the outer surface simultaneously in a single heat treatment process. I was able to do that. (Means for Solving the Problems) That is, in the present invention, a chemical is applied to the outer surface of a base glass bottle to perform an ion exchange treatment, and a chemical is put into the bottle to perform a dealkalization treatment. The base glass bottle is heat treated in a heat treatment furnace, and in one heat treatment process, a compressive stress layer is formed on the outer surface of the stool by ion exchange treatment, and a low alkaline layer is formed on the inner surface by dealkalization treatment. The present invention relates to a method for manufacturing a glass bottle that has both mechanical strength and chemical durability. (Example) The details of the present invention will be explained below along with experimental examples. The present invention relates to a glass bottle container, which is characterized in that a compressive stress layer is formed on its outer surface by ion exchange, and its inner surface is chemically treated by a dealkalization reaction. Such a glass bottle can be obtained by the following process. First, after a slow cooling process of the molded base glass bottle, in order to perform ion exchange treatment only on the outer surface of the glass bottle, a highly concentrated aqueous solution of, for example, a mixed salt of potassium chloride and potassium nitrate or a mixed salt of potassium sulfate and potassium nitrate, etc. The drug is applied by appropriate means such as dipping or spraying. On the other hand, sulfur dioxide gas or a chemical such as ammonium chloride or ammonium sulfate is injected into the inner surface of the base glass bottle to perform a dealkalization treatment inside the glass bottle container. The base glass bottle is then transferred to a heat treatment furnace at a temperature that does not damage the bottle, and is gradually heated. Generally, ion exchange between sodium ions in glass and potassium ions having a larger ionic radius is limited to a glass temperature of 300 to 350°C, and dealkalization reactions occur at temperatures lower than this. Then, as shown in FIG. 1 of the accompanying drawings, the temperature is maintained at 400 to 500° C. for about 1 hour, and then the temperature drops. In this heat treatment step, dealkalization treatment proceeds independently on the inner surface of the base glass bottle, and ion exchange treatment proceeds independently on the outer surface. Of course, in this heat treatment step, the heat treatment furnace is actually filled with sulfur dioxide gas in order to dealkalize the surface of the bottle, but if the ion exchange treatment proceeds at the same time, this sulfur dioxide gas The fact that it does not have a very negative effect on ion exchange on the external surface of the body is that
This is clearer than the experimental examples described later. In addition, regarding the base glass bottle treated by the above invention, this base glass bottle is generally an untreated glass bottle after molding, but it has been subjected to the following hot end coating treatment or has already been treated. A glass bottle that has been subjected to dealkalization treatment may be selected as the base glass bottle. In other words, in the former method, compounds such as tin and titanium are applied to the hot bottle immediately after production in a bottle making machine to form an oxide film of these metals on the bottle surface, thereby increasing the abrasion resistance of the glass surface. However, a compressive stress layer may be further formed by ion exchange on the glass surface which has been subjected to this hot end coating treatment. The latter is used for chemical bottles that require strict chemical durability such as chemical resistance, and in the slow cooling process after the bottle is formed, sulfur dioxide gas or other is sprayed on the bottle, and the inner surface of the bottle is dealkalized as a pretreatment. Since the latter is subjected to two dealkalization treatments, the amount of alkali eluted from the inner surface of the bottle is extremely small, which is particularly advantageous for medicine bottles. Next, a comparative experimental example of a glass bottle according to an embodiment of the present invention will be shown. The glass composition of the soda lime glass bottle used in the following experimental examples is as follows; SiO ² ...71.0%,
_Al2O3 ... _2.3 %, _Fe2O3 ... _0.220 %, CaO...10.0%,
MgO…0.8%, _Na2O …14.2%, _K2O …1.2%. Further, in the glass bottle A according to the present invention, a 30% aqueous solution of potassium nitrate and potassium sulfate mixed at a ratio of 3:1 is applied to the outer surface of an untreated bottle, and after sulfur dioxide gas is introduced into the inner surface, that is, inside the bottle, heat treatment is performed. It was transferred to a furnace and heat treated at a maximum temperature of 480°C for 1 hour. Bottle B, which was subjected to ion-exchange treatment on the inner and outer surfaces used for comparison in the mechanical strength test, was treated with a 30% aqueous solution of potassium nitrate and potassium sulfate mixed at a ratio of 3:1 on the entire inner and outer surfaces of the untreated bottle, as described above. After applying the heat treatment, it is transferred to a heat treatment furnace where the maximum temperature
It was heat treated for 1 hour. Experimental example 1 Test using normal test method

[Table] Experimental Example 2 Mechanical strength test after damage Bottle A treated according to the present invention and bottle A treated with inner and outer surfaces ion exchange treated were tested on a rocking tester that made 40 reciprocations per minute with a rocking distance of 100 mm. Arrange 20 untreated bottles such as B, A, and B under the same conditions,
This is a comparison result regarding the mechanical strength of each bottle that was damaged by 30 reciprocating motions. Each item is the average value of 20 items.

【table】

[Table] As is clear from the above experimental examples, the bottle in which only the outer surface has been subjected to ion exchange treatment according to the present invention has almost the same mechanical properties as a conventional bottle in which ion exchange treatment has been carried out on both the inside and outside surfaces. It exhibits excellent physical strength, and there is no visible influence from the dealkalization treatment on the inner surface, which is a concern. It also shows sufficient effects as a dealkalization treatment. Effects According to the present invention, the special shape of the bottle-like container is used to chemically treat the inner surface through a dealkalization reaction, and to form a compressive stress layer on the outer surface through ion exchange treatment. Because it is,
It has become possible to improve both the chemical durability of the contents and the mechanical strength of the bottle. Further, according to the manufacturing method of the present invention, it is possible to provide the easiest, most effective, and economical method. This invention greatly contributes to the need to strengthen and reduce the weight of glass bottles that require chemical durability, and because it eliminates ion exchange treatment on the inner surface of the glass bottle, there is no need to worry about contamination on the inner surface. Process and economic advantages can also be enjoyed, such as simplifying the post-cleaning process. This invention has a great effect on medicinal bottles such as vials and drink bottles, which are particularly sensitive to even the slightest amount of dirt, and at the same time greatly contributes to reducing the weight of these bottles.

[Brief explanation of drawings]

FIG. 1 is a temperature-time curve showing a heat treatment process in an embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. A chemical is applied to the outer surface of a base glass bottle for ion exchange treatment, while a chemical is put into the bottle for dealkalization treatment, and this base glass bottle is placed in a heat treatment furnace. The bottle is heat-treated, and is characterized by forming a compressive stress layer on the outer surface of the bottle through ion exchange treatment and forming a low-alkali layer on the inner surface through dealkalization treatment in one heat treatment step. A method for manufacturing a glass bottle that has both mechanical strength and chemical durability. 2. A method for manufacturing a glass bottle having both mechanical strength and chemical durability as set forth in claim 1, wherein the base glass bottle has a metal oxide coating on its outer surface by hot-end coating treatment. .