JPH0257557A - Heat-weldable paper bag such as envelope - Google Patents

Abstract

PURPOSE:To seal a paper bag easily at low cost without making a hand filthy, and in addition, to keep the confidentiality of a letter by equipping heat-weldable resin films which are provided corresponding with both bonding surfaces at the sealing part of a paper bag such as envelope, etc. CONSTITUTION:For this envelope 1, a heat-weldable plastic film is coated at the sealing part shown by shaded portions 2, 3. At the time of usage, a tongue shaped pat, that is, a lid 4, is folded, and the heat-welding surfaces coated with a heat-weldable plastic film are placed face to face, and heat-welding is conducted by a heat-sealer 5. When the heat-welded surface are tried to separate by adding heat again after the heat welding, the heat-welded plastic sheets are not separated, but the coated surface to the envelope main body is peeled. Therefore, the application of reheat-welding is difficult, and the confidentiality of the letter can be kept.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention generally relates to paper bags such as envelopes, and particularly relates to seals for paper bags such as envelopes.

In particular, paper bags such as envelopes can be easily sealed, and once sealed, they can be attached to paper bags such as envelopes with heat welding properties that create a seal that cannot be easily peeled off.

[Prior Art] Conventionally, the main types of seals for paper bags such as envelopes are as follows.

■ First, some old and typical envelopes are sealed by applying glue to the lid of the envelope.

■Next, there is a method where water-soluble glue is applied to the lid of an envelope or the like in advance, and water is applied to the lid just before sealing.

(2) Then, there are those that apply adhesive plastic glue to the lid and corresponding parts of envelopes, etc. in advance, and then stick the coated surfaces together as they are.

[Problem B to be Solved by the Invention] These drawbacks are as follows: ■ The above-mentioned first method of applying glue and pasting is difficult to apply when you are in a hurry or when you want to seal a large amount. It's a hassle. Or, if you apply glue with your fingertips, you may be concerned about stains.

■ If the second water-soluble glue mentioned above is applied to an envelope etc. in advance, then water is applied to it immediately before sealing.If the adhesive is to be pasted, expose the sealing surface to steam or apply a chemical that will peel off the adhesive surface. This allows the adhesive portion to be easily peeled off. Then, it can be re-paired without leaving any trace that it was opened.

Therefore, it becomes difficult to maintain the confidentiality of letters.

■ Even if the above-mentioned third adhesive plastic glue is applied to an envelope etc. in advance and the coated surfaces are stuck together, it can be easily removed with a release agent.
As with Section 2, there is a problem with maintaining the confidentiality of letters.

Therefore, it would be ideal as a method for sealing envelopes if it could be done easily and inexpensively without getting one's hands dirty, and if it could also maintain the secrecy of the letter.

[Means for Solving the Problems] In consideration of the above points, the thermofusible paper bag such as an envelope according to the present invention uses a thermoreversible resin as its adhesive.

The specific structure of the heat-weldable paper bag such as an envelope according to the present invention will be described in detail below.

First, the structure of the first invention, a paper bag such as a heat-fusible envelope, will be described. First, there are paper bags such as envelopes. Next, there is a heat-fusible resin film. This heat-fusible resin film is
This is provided to correspond to both adhesive surfaces of the sealed portion of the paper bag such as the envelope mentioned above.

Next, the structure of the heat-weldable paper bag of the second invention will be described. First, there are paper bags whose entire surface is coated with plastic film. Next, there is a heat-fusible resin film. This heat-fusible resin film is provided inside the lid portion of the paper bag.

[Function] The specific structure of the heat-weldable paper bag such as an envelope according to the present invention will be described below.

First, we will describe the function of the first invention, a paper bag such as a heat-sealable envelope. This is because heat-fusible resin films are provided corresponding to both adhesive surfaces of the sealed portion of a paper bag such as an envelope, so that when the lid portion is folded, the heat-fusible resin films overlap. Since this resin film is heat-fusible, it is welded by heating it.

Next, the function of the heat-weldable paper bag of the second invention will be described. First, a heat-fusible resin film is provided inside the lid of the paper bag. On the other hand, because the entire surface of this paper bag is coated with plastic film,
By folding the lid portion, the heat-fusible resin film overlaps the plastic film coating. Since this resin film is heat-fusible, heating it welds it to the plastic film coating.

[Example] Therefore, we searched for an ideal seal and invented a paper bag such as a thermally weldable envelope, which will be described next.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a paper bag such as a thermally weldable envelope according to the present invention will be described in detail using one embodiment thereof with reference to the accompanying drawings.

FIG. 1 shows a back view of an embodiment of a paper bag such as a heat-weldable envelope according to the present invention.

First, as shown in FIG. 1, the hatched areas 2 and 3, which are the sealed areas of the envelope l, are coated with a heat-fusible plastic film. When in use, the tongue-shaped portion, that is, the lid 4, is bent as shown in FIG. 2, the heat-welding surfaces coated with a heat-fusible plastic film are overlapped, and heat-welding is performed using a heat sealer 5 as shown in FIG.

Recently, paper bags for home delivery use have been made available whose entire surface is coated with a plastic film for waterproofing purposes, but in this case, the coating is only on the surface and cannot be heat welded as is. Therefore, as shown in FIG. 4, a heat-fusible film may be coated in advance on the hatched area 3a, which is the inner area of the lid 4a of the paper bag 1a coated with the plastic film.

[Effects of the Invention] According to the results of experiments, when applying heat again after heat welding and trying to peel it off, the heat welded plastic sheets do not peel off from each other, but the surface coated on the envelope body peels off.

Therefore, it became difficult to perform heat welding again, making it possible to maintain the secret of the meeting.

Furthermore, from a cost perspective, applying adhesive glue to an envelope and coating it with a heat-fusible sheet are considered to be almost the same when comparing material prices and processes. In addition, items coated with adhesive glue tend to attract other substances or dust before being sealed, so care must be taken when handling them.

This method requires a heat sealer as a device for adhesion, but this is an inexpensive product for sealing polyethylene bags, so-called plastic bags, and is easily available.

[Brief explanation of the drawing]

FIG. 1 shows a back view of an embodiment of a paper bag such as a heat-weldable envelope according to the present invention. FIG. 2 shows a perspective view of the heat-welded portion being folded together. FIG. 3 is a perspective view showing the method of sealing. FIG. 4 shows a perspective view of an embodiment of a paper bag coated with a plastic film. l...Envelope 1a...Plastic film coated paper bag 2
．． 3... Sealing part 5... Heat sealer 4... Lid Figure 1 Figure 2

Claims (2)

[Claims] (1) A heat-fusible paper bag such as an envelope, characterized by being composed of a paper bag such as an envelope, and a heat-fusible resin film provided corresponding to both adhesive surfaces of the sealed portion of the paper bag such as an envelope. . (2) A heat-fusible paper bag comprising: a paper bag whose entire surface is coated with a plastic film; and a heat-fusible resin film provided inside the lid of the paper bag.