JPH0217866Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a heat-sealing lid material that completely adheres to the mouth of the container to prevent spillage of the contents or liquid inside the container against the uneven surface that occurs on the upper surface of the mouth of the container as a result of molding. Many commercially available plastic containers for pudding, jelly, and the like are sealed with lids, but due to the molding process, the upper surface of the mouth part is inevitably uneven. Therefore, in order to prevent the contents or liquid inside the container from spilling, various measures have been taken in the area of lids. In order for the lid to seal tightly against the uneven surface of the container opening, it is desirable to have a lid that has a cushioning action that follows the uneven surface.In this regard, conventional lid materials have a thick adhesive layer on the bottom side of the lid. However, this method required a large amount of adhesive and was expensive.
In addition, in order to overcome this drawback and have the above-mentioned cushioning effect, an adhesive mediating layer is provided between the base material of the lid and the adhesive layer, but in order to enhance the cushioning effect, the adhesive mediating layer is made soft. was. However, in the manufacturing process of the lid, before the adhesive layer is provided, that is, at the time when the adhesive layer is provided on the base material, the soft adhesive agent is once rolled up and then rewound to provide the adhesive layer. There is a drawback that a so-called blocking phenomenon occurs, such as part of the layer transferring to the base material, or deformation of the base material when the two layers are peeled off during unwinding. As a result of various experiments, the present inventor has hereby provided a heat-sealable lid material that completely eliminates the various drawbacks of conventional products.
This was also the purpose of this idea. That is, this invention has an adhesion assisting layer 2 on the bottom surface of the base material 1.
A heat-sealable adhesive layer 3 is provided on the lower surface of the adhesion-assisting layer 2, and the adhesion-assisting layer 2 is made of polyethylene 7 or EVA 8 and has a foaming ratio of 1.1.
It concerns a heat-sealing lid material that is a low-foaming resin of ~2.3. An embodiment of this invention will be explained according to the drawings.
As shown in FIG. 1, aluminum foil 4 is used as the base material 1, or a heat-resistant resin film 5 is used as a cheaper material.For example, in the case of polyester, polypropylene, nylon, etc. It is preferable as the base material 1 because it is possible to dry-laminate a low-foam resin sheet containing EVA8 as a main component.
Furthermore, even if the base material 1 is a paper 6 as shown in FIG. 2, if molten polyethylene is applied to the underside of the paper 6, the low foam resin sheet can be dry laminated onto the polyethylene 6'. It is possible. In addition, in recent extrusion lamination technology, instead of creating a low-foam resin sheet and laminating it on a base material using the dry lamination method as mentioned above, extrusion lamination is performed in which the surface of the base material is treated to promote adhesion. Lamination in which a low-foaming resin layer is provided directly on the treated surface is also fully possible. It goes without saying that at the same time, it is possible to provide an extruded adhesive resin layer on the outer layer using a composite extrusion method. In addition, the adhesion promotion treatment performed in this case includes a corona treatment method using electron impact, a chemical treatment using acid or alkali, a method using organic titanium or other coupling agents, and an anchor treatment layer using urethane resin, etc. Either method of making it can be used effectively. Below is an experimental example of the incidence of liquid leakage in containers with and without foaming in the adhesion promoting layer. However, the adhesion assisting layer used in the experimental example was formed into a film and then dry laminated. Furthermore, although polyethylene is used as the adhesion-promoting resin in the example, almost the same results can be obtained with EVA. 1. Rate of leakage The base material is soft aluminum foil with a thickness of 40μ, and the adhesive layer is a hot melt agent mainly composed of EVA and paraffin wax.

[Table] Next, we will show an experimental example of the rate of leakage in containers by changing the expansion ratio of foamed polyethylene. However, although the resin of the adhesion promoting layer used in the experimental example was polyethylene, almost the same results were obtained even if EVA was used. 2 Leakage rate depending on foaming ratio Soft aluminum foil with a thickness of 40μ was used as the base material, and EVA manufactured by Mitsui Polychemicals was used as the adhesive layer.
(a mixture of #360, #460, and #550) was used as the adhesive for dry laminating the aluminum foil and the adhesion support layer. EPS71 (2.5
g/m ² solids). The container used in the experiment was a high-impact styrene container.

【table】

[Table] As is clear from the above experimental examples, when the actual amount of resin in the adhesion-promoting layer is small, the rate of leakage is lower for those with a low foaming ratio than for those with a high foaming ratio. This is because highly foamed films tend to break during heat sealing and the strength of the foamed film itself is low. From the above, the foaming ratio is low 1, 1 to 2,
In No. 3, it was found that the sheet did not leak when the thickness in the foamed state was in the range of 15 μm to 40 μm. In other words, by using a low-foaming polyethylene film or a low-foaming EVA film as the adhesion-facilitating layer of the lid material to the uneven surface of the container opening, the effect of eliminating liquid leakage inside the container is achieved. Furthermore, this low-foaming resin surface has an uneven surface, and has the advantage that even a flexible and viscous film does not suffer from the blocking phenomenon that occurs in the prior art.
In addition, the formation of the adhesive layer on the uneven surface is from 1,1 to
If the foaming adhesion promoting layer is about 2 or 3 times larger, the unevenness will be fine and there will be no problem in processing. In addition, polyester, which is a base material other than aluminum foil,
Polypropylene and nylon films (thickness approx.
25μ), experiments were conducted on the case where each film was printed on the back side. An OPP film (approximately 25 μm in thickness) was further dry-laminated on the back-printed side, and an adhesion assisting layer was provided on the underside of this OPP film under the same conditions as in Experimental Example 2. Almost the same results were obtained. Ta. In addition, if the base material is paper, if the adhesion assisting layer provided on the lower surface of the polyethylene layer formed by melt-extruding and coating polyethylene on the lower surface of the paper has a low foaming rate as described above, liquid leakage in the container will be eliminated. It is possible. In addition, printing is performed on the surface of soft 40μ aluminum foil using a commonly used method, and on the opposite side, a polyethylene film (Sumitomo Chemical manufactured by Sumikasen L705) or with a foaming ratio of 1 or 2,
An EVA film (Ultrasen UE625 manufactured by Toyo Soda) with a thickness of 20μ is adhered to the aluminum foil by dry lamination, and 40 parts of paraffin wax, 35 parts of EVA, and 15 parts of a polar group-containing synthetic resin are mixed on the lower surface of this film. Even with the lid coated with hot melt adhesive (16 g/m ² ), the uneven surface of the container opening was completely sealed and there was no leakage. Also, regarding the rolled product after dry lamination, since the adhesion promoting layer has an uneven surface, there is no adhesion of the resin to the printed overcoat surface of the aluminum foil surface.
Further, since there is no blocking phenomenon, winding and unwinding during the process of lid processing are smooth, and there is no problem in forming the bottom melt adhesive layer. As mentioned above, the lid of this invention has an adhesion support layer made of polyethylene or EVA with a foaming ratio of 1.1 to 2.3.
By providing a low-foaming resin as the intermediate layer between the base material and the adhesive layer, it ensures a sealing effect against the uneven surface of the container opening, and also eliminates all the conventional troubles in the production process of the lid, making it extremely practical. It was set as a high value.

[Brief explanation of the drawing]

1 and 2 are partially enlarged sectional views of an embodiment of this invention. DESCRIPTION OF SYMBOLS 1... Base material, 2... Adhesion assisting layer, 3... Heat sealable adhesive layer, 4... Aluminum foil, 5... Heat resistant resin film, 6... Paper, 7... Polyethylene, 8...
…EVA.

Claims (1)

[Claims for Utility Model Registration] 1. An adhesion-assisting layer 2 is provided on the lower surface of a base material 1, a heat-sealable adhesive layer 3 is provided on the lower surface of the adhesion-assisting layer 2, and the adhesion-assisting layer 2 is made of polyethylene 7. Or the foaming ratio made of EVA8 is 1,1~2,3
A heat-sealing lid material made of low-foaming resin. 2. The heat-sealing lid material according to claim 1, wherein the base material 1 is aluminum foil 4. 3. The heat-sealable lid material according to claim 1, wherein the base material 1 is a heat-resistant resin film 5. 4. The heat-sealing lid material according to claim 1, wherein the base material 1 is paper 6.