JPS5993645A - Glass vessel, outer surface thereof is protected with heat-shrinkable film, and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for covering the outer surface of a glass container, such as a bottle, with a heat-shrinkable film, and to a glass container obtained thereby.

Conventional methods for protecting the surface of glass containers with heat-shrinkable films include a method using a non-foaming shrinkable film 1 and a method using a foaming shrinkable film. The latter has a scattering prevention effect but lacks cushioning properties; the latter has scratch prevention and cushioning properties but does not have a scattering prevention effect
All of them have their advantages and disadvantages, and the current situation is that they do not provide sufficient protection.

The present invention solves this problem, and provides a glass container that has sufficient cushioning properties compared to conventional products and has excellent scratch-prevention and shatter-prevention effects, and a method for manufacturing the same. It is.

The glass container of the present invention has a heat-shrinkable film interposed on the outer surface of the glass container via a foamed cushion material layer. The foamed cushion material layer is usually provided over the entire container, but in containers with long bodies such as beer bottles, it is placed in three places, for example, in the upper and lower parts of the body, in the form of bands. For example, it may be provided in a band shape only at one location where the maximum value is maximum. - Here, the foamed cushioning material layer is a foamed cushioning material layer obtained by heating and foaming after applying a foaming paint, and the heat-shrinkable film is a foamed cushioning material layer obtained by heating and foaming after applying a foaming paint. This is a film layer obtained by heating and shrinking.

The foaming paint used in the present invention has a foaming agent uniformly dispersed in various emulsions, and if necessary, a surfactant,
Added thickener and coloring agent. A typical blowing agent is a microsphere having a shell wall made of vinylidene chloride and acrylonitrile copolymer and containing a low-boiling hydrocarbon (butane gas, etc.).

As various emulsions, resin emulsions in which fine particles of acrylic resin, vinyl acetate, ethylene-vinyl acetate copolymer, urethane resin, styrene resin, epoxy resin, olefin resin, etc. are dispersed in water are used. The resin solids content is about 50-60%. However, the proportion of resin solid content can be changed as appropriate depending on the type of resin, performance, etc.

The proportion of the blowing agent is 5% based on the resin solid content in the emulsion.
~30%, preferably about 10%.

The surfactant is added to improve the wettability of the paint to the glass container, and both anionic and cationic surfactants can be used, and the amount added is preferably 1 volume or less.

The viscosity of the above paint is 500 to 10,000 centivoise. All dyes and pigments can be freely used as colorants.

The paint is applied to an appropriate area depending on the shape of the container, the application method, and the desired buffer properties. The coating method may be sponge coating, roller coating, screen coating, spray coating, or dipping. The thickness after coating and drying is preferably about 10 to 100 microns.

Next, the ink is foamed, usually at a temperature of 100 to 200°C.
Blow hot air for 30 seconds to 5 minutes to heat the
A foamed cushion material layer is formed by foaming to 0μ. At this time, it is particularly preferable to use an infrared heater instead of hot air as the heating means, since the heating time can be greatly shortened (to about 15 seconds). Furthermore, if a solvent is used instead of water in the resin emulsion, the foaming temperature can be lowered to a lower temperature. Alternatively, a foamable paint may be applied, heated and dried, and then covered with a heat-shrinkable tube to cause foaming to occur simultaneously with heat-shrinking.

This drying process is performed at a lower temperature than the foaming process; for example, when the thickness is 30 μm, the drying process is performed at 65° C. or lower for about 2 to 3 minutes by blowing hot air. This treatment can also be performed using preheating before covering the tube. Furthermore, if you use a foaming agent that foams at 40 to 80°C/m, it can be foamed while preheating the container before covering it with the heat-shrinkable tube in the next process, which can simplify the process. be.

A heat-shrinkable film is then formed on the outer surface of the glass container with the foam cushioning layer formed thereon using a heat-shrinkable tube.

The heat-shrinkable tube used in the present invention includes polyvinyl chloride, low-density and high-density polyethylene, polypropylene,
A stretched tube (either -axial stretching or biaxial stretching may be used) made of polystyrene, polyethylene terephthalate resin, polyamide resin, ethylene-vinyl acetate copolymer, etc.
The film may be seamless or may have both ends of the film overlapped and joined. In the case of biaxial stretching,
When the container is covered, the stretching ratio is small in the axial direction and large in the circumferential direction, usually 2 in the circumferential direction relative to the axial direction.
It is better to have at least double that. In either case, the stretching ratio in the circumferential direction is preferably 1.5 times or more. Thickness is IO~500
Although a wide range of μ can be used, 30 to 100 μ is particularly preferred.

If a heat-shrinkable tube is placed over a container at about 140°C immediately after the foam cushioning material layer is formed, defects such as film sagging and swelling will occur. This is done after cooling the container with an ox.

In order to heat-shrink the heat-shrinkable tube, a known heat-shrinking means can be used;
As described in the above issue, first, the tube of the body is pre-shrinked by blowing relatively low-temperature hot air only on the body of the container, and then relatively low-temperature air is blown only on the shoulders and bottom of the container. Particularly preferred is a method in which hot air is blown to pre-shrink the shoulder and bottom tubes, and finally, relatively high-temperature hot air is blown uniformly over the entire container for final shrinkage.

However, the present invention is not limited to the above-mentioned manufacturing method, and uses a heat-shrinkable tube whose inner surface is coated with foamable paint in advance. 1. This is placed over a glass container, and at the same time as the tube heat-shrinks, the paint is applied. It can also be foamed. According to this method, at the same time as forming the foam cushioning layer,
A heat-shrinkable film layer can be formed on the outside, simplifying the process.

Alternatively, you can heat and foam the foam paint applied to the inner surface, cover it with heat-shrinkable tubing, and heat-shrink it.

Next, the present invention will be explained by examples.

〔Example〕

Emulsion of 50% ethylene-vinyl acetate copolymer, 50% water, blowing agent 10% based on the above resin content, 1% volume of anionic surfactant, and 200% force/random/viscosity.
A foaming paint adjusted to 0 centipoise was prepared. This foaming paint was applied to the glass containers 1 shown in Figures 1 and 2 using the sponge coating method. was applied in a band 2 only to the center of the body with the largest diameter. The thickness after drying was 30μ.

Next, it was heated at 140°C for 1 minute to foam to about 100 tt to form a foamed cushioning material layer. Container at 60℃
After cooling to 100°C, cover with a polyvinyl chloride stretched tube with a thickness of 50μ, and heat the body first at 150°C for 1 second, then the shoulders and bottom at 100°C for 1 second, and finally at 350°C for 2 seconds. Heat the whole to heat shrink the tube, and
A glass container whose outer surface was protected with a heat shrink film 3 as shown in the figure was obtained.

These glass containers are less likely to be damaged due to double blows or collisions during handling, compared to glass containers that are protected only by heat-shrinkable film without a foam cushion layer. As expected, no debris was scattered at all.

As mentioned above, the glass container according to the present invention has a superior buffering effect compared to the conventional glass container coated only with a heat shrink film, so that damage during handling can be reduced on the other hand.
However, unlike glass containers with only a foam cushioning layer, broken pieces do not scatter, so they are safe enough to be used in vending machines, and can also be easily used during transportation. Materials, etc. can be omitted, and the volume of the box can be reduced, resulting in extremely significant effects.

[Brief explanation of the drawing]

Figures 1 and 2 show an actual bf using a glass container with a long body and a glass container with the largest diameter in the center of the body, respectively.
=Explanatory diagram of an example. 1...Glass container 2 Foamed cushion material layer 3...Heat shrinkage)・ILM agent Patent attorney Satoshi Sasaki

Claims (1)

[Scope of Claims] (1) A glass container whose outer surface is protected by a heat-shrinkable film, characterized by having a heat-shrinkable film on its outer surface via a foamed cushioning material layer. (2) A glass container according to claim 1, wherein a foam cushioning layer is provided over the entire body of the container. (3) A glass container according to claim 1, wherein the foamed cushion material layer is provided in a band shape above and below the body of the container. (4) A glass container according to claim 1, wherein a foamed cushioning material layer is provided in a band-like manner at the largest diameter portion of the container. (5) A method for manufacturing a glass container whose outer surface is protected with a heat-shrinkable film, which comprises heating a foamable paint applied to the outer surface of the glass container, and then covering it with a heat-shrinkable tube to shrink it by heating. (6) The method according to claim 5, wherein the foamable paint is heated and foamed and then covered with a heat-shrinkable tube. (Form) The method according to claim @5, in which the foamable paint is heated and dried, then covered with a heat-shrinkable tube, and the paint is foamed at the same time as the tube heat-shrinks. (8) The foamable paint is applied to the inner surface in advance. A method for manufacturing a glass container whose outer surface is protected by a heat-shrinkable film, the method comprising: covering a glass container with a heat-shrinkable tube and heat-shrinking the tube. (9) A patent claim for foaming a paint simultaneously with the heat-shrinking of the tube. The method according to claim 8. (fil') The method according to claim 8, wherein a heat-shrinkable tube made by heating and foaming a foamable paint is placed over a glass container.