JPS58209550A - Laminating material for easy-open sealing packing - 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 laminate material for easy-open sealed packaging.

There are two types of easy-open sealants: interfacial peeling type and cohesive failure type.

Generally speaking, when liquid contents are sealed and packaged and subjected to heat sterilization, the container is filled with the contents and sealed with as little air as possible to prevent the bag from breaking. . In other words, liquid sealing is performed through the five contents. In this case, it is difficult to achieve an easy-to-open seal using an interfacial peeling type sealant because it is difficult to obtain stable seal strength. On the other hand, with a cohesive failure type sealant, since the adhesive interface is completely fused, easy-to-open sealed packaging can be performed without fear of bag breakage.

However, hermetic seals using cohesive failure sealants currently have the following problems.

That is, polypropylene-high density polyethylene blend polymer is currently known as a material for cohesive failure type sealants.

However, because polypropylene and high-density polyethylene have poor compatibility, it is extremely difficult to form a polypropylene-high-density polyethylene blend polymer into a film, and the surface of the formed film tends to be uneven, and in the worst case, there are holes in the film. The film is formed in an open state.

When forming packaging materials for easy-open packaging, it is necessary to laminate a sealant on a base material of non-plastic resin film or metal foil, but due to the poor surface condition of the sealant, the space between the base material layer and the sealant layer The strength becomes extremely unstable. This interlayer strength greatly affects the peel strength when opening the package. In extreme cases, delamination occurs between the base material layer and the sealant layer, resulting in a filmy state and the contents not being able to come out.

Furthermore, the heat seal strength of the polypropylene-high density polyethylene blend polymer compared to polyethylene is stronger than the ideal heat seal strength for easy opening.

As a result of research to solve the above-mentioned drawbacks, the inventor of the present invention has found that by blending polypropylene with high-density polyethylene and low-density polyethylene to create a three-component blend polymer, the amount of resin discharged from the die can be reduced. Not only is it easy to form a film, but it is also preferable from a safety and health perspective, and can be performed without using additives (substrates, antioxidants, etc.), and is suitable for lamination. 4) A film with good surface smoothness is obtained, and by laminating this film to a base material, it can be easily peeled off to polypropylene and can be easily opened by heat-rolling with a heat seal strength of l/'R degree. It was found that a laminated material for sealed packaging can be obtained.

The present invention was completed based on this knowledge.

That is, 1. The gist of the present invention is that polypropylene 30 to 70% is used as the base material.
This is an easily openable laminate for sealed packaging made by laminating a sealant layer made of a blend polymer film of 20-60% by weight of high-density polyethylene and 10-30% by weight of low-density polyethylene.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a laminate material (3) for easy-open, sealed packaging according to the present invention.

A blend polymer film of 30-70% by weight of polypropylene, 20-60% by weight of high-density polyethylene and 10-30% by weight of low-density polyethylene (2% by weight) on a base material (11).
) is laminated. Therefore, in the present invention, the sealant layer is composed of a polypropylene-high-density polyethylene-low-density polyethylene blend polymer, and the blend polymer is This is because a film that is easy to form, has good surface smoothness, and is suitable for lamination can be obtained, and the blending ratio of each component is limited as described above for the following reasons.

Conventionally used polypropylene-high-density polyethylene blend polymers cause cohesive failure when polypropylene is 30 to 70% by weight and high-density polyethylene is 30% by weight.
In the case of a blending ratio of ~70% by weight, polypropylene is 30%
If it is less than % by weight, cohesive failure will not occur, the heat seal strength will be highly temperature dependent (the heat seal strength increases greatly as the heat seal temperature increases), and stable seal strength will not be obtained. do not have. On the other hand, voripropylene is 7
If the weight is 0 or more, cohesive failure will not occur and the container will be completely fused, making it impossible to open the container. Therefore, a sealant made of a blend polymer made by blending polypropylene and high-density polyethylene in the above-mentioned blending ratio range has been conventionally used. The ideal heat seal strength for easy opening is generally 2000g/15% width or more (800~15%).
00 Y-/15% width) Good size is large. By blending polypropylene with high density polyethylene and low density polyethylene, the heat sealing strength can be lowered.

The heat seal strength can be lowered by blending low-density polyethylene because its compatibility with polypropylene is poorer than that of high-density polyethylene.

This is because cohesive failure is more likely to occur.

In the HoIJ propylene-high-density polyethylene-low-density polyethylene blend polymer, the blending ratio of polypropylene must be 30 to 70% by weight, and cohesive failure will not occur when the blending ratio of polypropylene is 30 wtS or less. If it is less than 9, stable heat-sealing strength cannot be obtained, while if it is more than 70% by weight, it will completely fuse to the polypropylene, which is not preferable.

Next, the blending ratio of low density polyethylene is 10 to 30% by weight.
Therefore, when the blending ratio of low density polyethylene is less than 10% by weight, the effect of lowering the heat sealing strength cannot be achieved.On the other hand, when it is more than 30% by weight,
It is not suitable for practical use because delamination occurs between the base material and the sealant layer when the package is opened.

Next, the blending ratio of high-density polyethylene is 20-6011, as the blending ratio of polypropylene must be 30 to 70% by weight, and the blending ratio of low-density polyethylene must be 10 to 30% by weight. There must be.

Next, a sealant layer consisting of a polypropylene-high-density polyethylene-low-density polyethylene blend polymer is applied.
A value of 100μ is appropriate; a value of 3μ or less is undesirable because the heat-sealing strength after heat-sealing is below practical strength; a value of 100μ or more is undesirable because delamination occurs upon opening and costs increase.

Next, in the present invention, the base material is thermoplastic #I such as polyethylene, polypropylene, polyester, polyamide, polycarbonate, polystyrene, polyvinyl chloride, etc.
J-oil, aluminum foil, metal foil, paper, or a composite material thereof can be applied.

Next, the present invention will be specifically explained with reference to Examples.

The following polypropylene-high-density polyethylene-low-density polyethylene blend polymer (Al~3) was formed into a film with a thickness of 30 μm by the inflator method.

M I A Hill 2 3 Use this as a base material (polyester 12μ/aluminum 40μ
) is bonded to the aluminum foil and the inflated film using an isocyanate adhesive. The material was mowed down to form a stockpile.

Heat seal this onto a polypropylene plate (4
, 5% 0.75 sec) l, Peel strength was measured.

The measurement results were as shown in Figure 2, indicating good beer quality, and no change in beer strength was observed even after retort treatment at 110°C for 30 minutes.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the laminated material for easy-open sealed packaging of the present invention;
FIG. 2 is a graph showing the peel strength determined for the easy-open sealed packaging laminate of the present invention. (1) Base material (2) Sealant layer made of polypropylene-high-density polyethylene-low density polyethylene blend polymer Patent applicant: Dai Nippon Printing Co., Ltd. Company representative patent attorney Atsumi Konishi

Claims (1)

[Claims] 30~70% by weight of polypropylene as base material! = 20-60% by weight of ILF polyethylene and 1% of low density polyethylene
A laminate material for easily openable sealed packaging comprising a sealant layer made of 0 to 30% by weight blended polymer film.