JPH01111651A - Glass bottle excellent in original shape retention - Google Patents

Abstract

PURPOSE:To reduce the required amount of resin material, yet permitting the retention of almost perfect original shape in the case of the breakage by forming a resin film excellent in elongation rate and tensile strength and high in recovery rate after elongation on the exterior surface of a bottle. CONSTITUTION:A resin film 1 characterized by possessing an elongation rate of not less than 250%, a tensile strength of not less than 400kg/cm<2> and a recovery rate of not less than 50% after 200% elongation is formed on the exterior surface of a bottle 2 in a thickness of 5-50mum. The resin film 1 satisfying such characteristics is formed on the exterior peripheral surface of the bottle 2 from the lower part of a neck 3 to a bottom corner 4. In practical application, urethane series resins are suitable. Also, static electrodeposition painting method or spray method is preferable to efficiently form the thickness as thin as 5-50mum and the applied resin becomes thermosetting in a short period of time of ordinary temperatures or not more than 300 deg.C. The destruction test carried out by applying inner pressure to the glass bottle with this resin film 1 formed thereon indicates that the original shape of the bottle is retained almost perfectly by the resin film 1, eliminating the possible scattering of the fragments.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a glass bottle that has excellent original shape retention and can almost completely maintain its original shape without scattering fragments even when broken.

(Prior Art) As one of the methods for strengthening glass bottles, it is widely known to form a reinforcing film by coating the outer surface of the bottle body with urethane resin or the like and drying it. As shown in Publication No. 52-48875, etc., the tensile strength is 50 kg/am” or more and the elongation is 100%.
Since the above resin was selected, the thickness of the coating was set to 200 μm.
A sufficient scattering prevention effect could not be obtained unless it was done before and after. For this reason, the amount of resin required for each glass bottle increases, making the cost of the resin extremely high.In addition, the processing is very time-consuming to form a thick coating, which has the disadvantage of not increasing productivity. .

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, reduces the amount of resin required, and can be manufactured at low cost and at high speed. It was developed with the aim of creating a glass bottle that maintains its original shape almost perfectly.

(Means for Solving the Problems) As a result of repeated research to solve the above problems, the present inventor found that in order to obtain excellent original shape retention with a film that is much thinner than before, it is necessary to It has been found that it is necessary to use a resin that not only has excellent tensile strength but also has a high return rate after elongation. Here, the return rate is the value measured by stretching the resin up to 200% (that is, up to 3 times the original size), releasing the tension, and measuring how much it returns to the stretched length. Even if the elongation rate is high, if this value is small, the glass fragments will not return to their original position when the bottle is broken.
The present invention was completed based on such knowledge, and has an elongation rate of 250% or more, a tensile strength of 400ksr/am or more, and a return rate of 50% or more after 200% elongation. A resin coating having the following characteristics is formed on the outer surface of the bottle body to a thickness of 5 to 50 microns.

The type of resin used in the present invention is not particularly limited as long as it satisfies the above three properties, but urethane resins are suitable for practical use. Also, to apply this resin to the outer surface of the glass bottle body, use the deimping method. Any method such as painting or spraying can be used, but electrostatic coating or spraying is preferable in order to efficiently form a thin film of 5 to 30 μm, and the applied resin should be kept at room temperature or below 300°C. Hardens in a short time by heat curing.

The reason why the elongation rate of the resin used in the present invention is set to 250% or more is that when the glass bottle is broken due to internal pressure, it reliably holds the pieces that are about to scatter outward, and the breaking energy is transferred to the potential energy of the coating and the pieces. This is because it is necessary for absorption. In addition, its tensile strength is 400kg/3”
The above values are necessary to prevent the coating from tearing at the time of fracture; if either the elongation rate or tensile strength is below these values, the coating will not be able to withstand the fracture energy and fragments will scatter. It will be necessary to do so. Further increase the return rate to 50
% or more is because, as mentioned above, it is necessary to pull the fragments displaced outward due to fracture energy back to their original position and maintain the original shape, and if this value is 80% or more, it is more preferable to maintain the original shape. You can get sex.

A resin coating (1) that satisfies these characteristics is formed to a thickness of 5 to 50 μm on the outer peripheral surface of the bottle body (2) from the bottom neck (3) to the bottom corner (4) as shown in Figure 1. Ru. This film thickness is extremely thin for a protective coating for this type of glass bottle, but if it exceeds 50 μm, the cost advantage decreases, and if it is less than 5 μm, it becomes difficult to apply uniformly and the anti-scattering effect decreases. Even points will be insufficient. 5~50μ like this
The results of a destructive test by applying internal pressure to a glass bottle on which a resin coating (11) with a thickness of
The original shape is almost completely maintained. Next, examples of the present invention will be shown.

(Example) Content 130 resin coatings with various characteristics shown in the following table.
It was formed to the thickness shown in the table on the outer surface of a glass bottle for carbonated beverages with a weight of 0 mjl and a weight of 170 gr. A destructive test was carried out on the resin-coated glass bottle by applying an internal pressure of 6 kg H1 at 40°C, and the scattering of fragments was investigated. It showed the ability to maintain its original shape.

(Effects of the Invention) As is clear from the above description, the present invention requires only a small amount of resin, prevents fragments from scattering in the event of breakage, and can almost completely maintain its original shape. Since the film is thin, it also has the advantage of being able to be manufactured at extremely high speed. Therefore, the present invention makes an extremely large contribution to the industry, mainly as a glass bottle suitable for use in carbonated beverages and excellent in maintaining its original shape.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is a front view showing the state at the time of failure. (1): Resin coating, (2): Bottle body.

Claims (1)

[Claims] A resin coating (1) having the characteristics of an elongation rate of 250% or more, a tensile strength of 400 kg/cm^2 or more, and a return rate of 50% or more after 200% elongation is applied to the outer surface of the bottle body (2) to a thickness of 5 to 50 μm. A glass bottle with excellent ability to maintain its original shape.