JPH02279531A - Improvement of appearance of recovered glass vessel - Google Patents

Abstract

PURPOSE:To restore a recovered glass vessel with scratches on the outer surface to the former condition at a low cost without causing thermal deformation by heating the vessel to a specified temp. and then heating only the scratched part to a specified temp. CONSTITUTION:A recovered glass vessel with scratches on the outer surface such as a beer bottle is heated to 500 to 650 deg.C, preferably 570 to 620 deg.C at 5 to 100 deg.C/min, preferably 10 to 50 deg.C/min heating rate with a heater such as a tunnel furnace. Only the scratched part is then heated to a temp. close to the softening point of the glass vessel, e.g. to 620 to 770 deg.C, preferably 630 to 700 deg.C. By this heating, the scratched part is half-melted to vanish the scratches and the appearance of the glass vessel is improved.

Description

[Detailed description of the invention] [Background of the invention] Concerning a method for improving the appearance of recycled glass containers.

<Prior Art and its Problems> Conventionally, containers made of glass have been used for accommodating liquid beverages such as beer, soft drinks, and milk from the viewpoint of hygiene and strength.

These glass containers are repeatedly collected and used, so
Scratches consisting of numerous fine scratches occur on the outer surface of the container. Such scratches on glass containers can be caused by collisions and pushing of glass containers at the bottler, contact between the containers and various equipment, conveyor guides, etc., or by consumers who drink liquid beverages packed in such glass containers. Transfer to
This occurs on the outer surface of glass containers due to collisions between containers during truck transportation for re-collection. Such scratches increase as the number of times the container is used increases, and they not only impair the beauty of the container itself, but also
This can significantly reduce the strength of the container itself and reduce its commercial value.

In addition, among these glass containers, glass containers that contain liquid carbonated beverages such as beer, cola, and ramune, in which carbon dioxide gas is dissolved, are relatively difficult to use because the carbon dioxide gas is sealed inside the container. held under high pressure. Therefore, if a glass container is damaged, it will be more likely to burst even with the slightest impact.

Therefore, in order to prevent the occurrence of such dangers such as container rupture, and to prevent the decline in product value due to damage to the beauty of the container itself, we are trying to remove severely damaged glass containers from among the recycled glass containers that have been used repeatedly. A certain percentage of containers are disposed of as waste. However, since many containers of this type are on the market and in use, the number of glass containers that are disposed of is also extremely large.

In order to prevent such deterioration of the appearance of the container, conventionally,
Attempts have been made to prevent the occurrence of scratches by coating the outer surface of the container with various types of emulsion-based and silicone-based polymer coating agents for scratch-shielding, and polyester films.

However, in the method of coating the outer surface of the container with a scratch-shielding coating agent, the coating agent peels off during hot alkaline washing in the washing process, so the coating must be recoated every time the container is collected, and the scratches can be prevented. When the shielding coating agent is water-soluble, it has the disadvantage of being slightly sticky, which causes a hygienic discomfort.

In addition, the glass container reinforced by coating the outer surface of the container with a polyester film can absorb some impact due to the polyester film,
Although it has the effect of preventing broken glass pieces from scattering when a container ruptures, it is quite troublesome because the polyester film coated on the outside of the container must be replaced every time it is collected. And the cost was also very high.

[Summary of the invention]

Summary> The inventors of the present invention have conducted extensive research in view of the above-mentioned problems, and as a result of analyzing the scratches that occurred on the outer surface of the collected glass containers, they discovered that they were minute cracks or chipped parts. If you try to improve the appearance by rapidly heating and melting these scratched parts, the minute cracks and chipped parts will expand and eventually lead to damage to the entire container. If this is done in two stages, the second stage is at a temperature that does not deform the bottle, and the second stage is where only the scratched area is heated locally for a short period of time at a temperature close to the softening point, the glass can be The present invention was completed based on the knowledge that scratches on the outer surface of the container can be eliminated.

That is, in the method for improving the appearance of a collected glass container according to the present invention, the entire collected glass container with scratches on the outer surface is
After heating to a temperature of ~650°C, the abraded area was heated to 620°C.
It is characterized by heating to a temperature of ~770°C.

Effect> According to the two-stage heating method according to the present invention, the scratched part in question can be heated to a temperature at which the scratched part disappears without causing any heating deformation of the target glass bottle. The disadvantages observed in conventional methods can be avoided. That is, the method for improving the appearance of collected glass containers of the present invention, which involves two-step heat treatment to remove scratches on the outer surface of collected glass containers that have been repeatedly used, is similar to the method of coating with a scratch-shielding coating agent. There is no need to coat it each time it is collected, and it does not become sticky, so it is hygienic and does not cause discomfort to consumers. In addition, unlike the method of coating polyester film, there is no need to replace the film every time it is collected, which saves time and costs.

Furthermore, since the repaired glass container has the effect of improving the scratched parts into shiny, transparent glass and improving the appearance of the glass container to be similar to a brand new glass container, it is recommended that the glass container be stored in the same glass container. The value of the product will increase. Therefore, the recovered glass container that has been repaired can be used again.

[Detailed description of the invention]

Recovered Glass Containers Targeted in the method for improving the appearance of glass containers according to the present invention include alcoholic beverages such as beer, tsuiski, and sake, seasonings such as soy sauce and vinegar, cola, ramune,
Typical examples include glass containers for soft drinks such as juice and liquid drinks such as milk. The effects of the present invention are best enjoyed in darkly colored glass containers such as beer, and the remarkable effects can be seen in such colored types.

As a material for such a glass container, soda lime glass, borosilicate glass, etc. are generally used, preferably soda lime glass.

When such recycled glass containers are filled with contents, they are subject to collisions and pushing between the containers at the bottler, contact between the containers and various equipment, conveyors, guides, etc., or
When the liquid carbonated drinks packed in the containers are transported by truck to consumers and then collected again, scratches occur on the outer surface of the containers due to collisions between containers and containers.

As mentioned above, such scratches increase as the number of times the container is used increases, and not only impairs the beauty of the container itself, but also significantly impairs the strength of the container itself.

Analysis of the scratches on the outside surface of the recovered glass containers revealed that they were minute cracks or chips.

Two-stage heat treatment> (a) - Stage heat If you try to improve the appearance by rapidly heating and melting the scratched parts on the outer surface of the recovered glass container, the difference in thermal expansion caused by the temperature difference will result in fine scratches. The abrasion caused by the cracked or chipped area will expand and eventually damage the entire container.

The first stage of the two-step heat treatment in the method for improving the appearance of recycled glass containers of the present invention is performed at a temperature that avoids rapid temperature increases and does not deform the bottle, i.e., heats the entire recycled glass container for 5 to 10 minutes. , preferably at 10-b to raise the final temperature to a temperature of 500-650°C, preferably 570-620°C.

Such heating can be carried out in a tunnel furnace or other suitable heating device.

(b) Second-stage heating The second-stage heating performed subsequent to the above-mentioned -stage heating is as follows:
In contrast to the first stage heating, only the scratched portion is heated to a temperature near the softening point of the glass container, 620 to 770°C, preferably 630 to 700°C. Local heating at this temperature for a short period of time can semi-melt and eliminate scratches on the outer surface of the glass container without deforming the entire glass container, thereby improving the overall appearance of the glass container. The localized heating that should be performed at this stage is aimed at the scratches that have occurred on the outer surface of the glass container, but in reality, it is applied to the parts corresponding to the upper and lower parts of the body of the glass container. There are many cases. For example, for a large beer bottle, there are about 140 dragons and about 2 dragons from the bottom.
This is the 0th point. In the second stage heating, the glass container is rotated and passed between heaters placed on both sides at the height of the upper part of the glass container and the lower part of the body, or An annular electric heater is inserted and energized to heat only the scratched area for usually 10 to 600 seconds, preferably 30 to 150 seconds to soften it. This local heating is desirably carried out in a tunnel furnace such as that used in the -stage heating.

When the scratched area is softened in this way, the surface tension of the glass smooths out the scratched area, which consists of fine irregularities and cracks, and suppresses the diffused reflection that makes the scratches noticeable. As a result, the appearance of the collected glass container improves. will be done.

The recovered glass container whose appearance has been improved in this way is generally treated with
It is taken out after being cooled at ~b and subjected to slow cooling treatment.

The attached FIG. 1 shows an example of a device for performing second-stage heating, and is a cross-sectional view perpendicular to the direction in which the bottle travels (for details, please refer to the examples below). ) <Example> Example 1 (a) Beer dog breed 1 collected after 30 rotations in the heat treatment market (
Scratch disposal site) 10 pieces have approximately 140mm from the bottom 1a and 2
The degree of scratches around the heights H and h of 01 is grade E.
Abrasions 2as and 2b were present in a concentrated manner. In addition, 1
．． Symbols such as 1a are those in FIG.

Put Beer Dog Type 1 out of these into the electric furnace one by one.
The bottle was heated for 00 minutes to bring the temperature of the bottle to 580°C (-stage heating).

Next, the scratched area 2a as shown in FIG. 1 is removed in the same furnace.
, an alloy resistance heating element 3a with a power of about 600W per round that can intensively heat only 2b, and a distance M between the s3b and the bottle.
4 is placed at a distance of 15 mm, and the heating elements 3a and 3b are installed in upper and lower two stages at heights H%h of approximately 1401 and 201 from the bottom 1a of the bottle 1. Only the scratched portions 2a and 2b were heated intensively to a temperature of 680° C. for 100 seconds to perform second heating. The appearance of the recovered glass container 1 was improved by softening only the scratched portions 2a and 2b by heating in the second stage 1'', and changing the scratched portions 2a, 2b to glossy transparent glass.

At this time, the temperature of the surface 1b of the bottle at the middle part of the upper and lower heating elements rose only to 620° C., so the bottle was hardly deformed.

(b) Evaluation of results The evaluation results were as shown in Table 1 below.

Table 1 Sample number 1 2 3 4 5 6 7 8 9
10 Appearance grade BBABBBBBAB BThe above evaluation was performed in the following four stages.

Grade A: Close to residual limb condition with no abrasion) Grade D;
A few scratches remain.

Grade C: Some scratches remain.

Grade D=Significant scratches remain.

Grade E: Significant scratches remain.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a heating device for intensively heating only the scratched area in an electric furnace used in an embodiment of the present invention. 1... Beer dog breed, 1a... Bottom, 1b... Surface of bottle at middle part of heating element, 2a, 2b... Scratched area, 3a, 3b... Heating element, 4... Distance, 5...
・Heating device.

Claims (1)

[Claims] The entire recovered glass container with scratches on the outer surface was
heated to a temperature of 650°C and then heated the scratched area to 620°C.
A method for improving the appearance of a collected glass container, characterized by heating it to a temperature of ~770°C.