JP2929140B2 - Inner container for bag-in-box made of synthetic resin - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an interior container for a bag-in-box made of a soft and thin synthetic resin housed in an exterior container known as a bag-in-box. In particular, the present invention relates to an interior container for a bag-in-box made of synthetic resin, which extremely suppresses generation of pinholes and does not cause peeling at a fused portion.

(Conventional technology and problems to be solved) A container in which a soft thin synthetic resin is housed in an outer box such as a cardboard box is conventionally called a bag-in-box, and is excellent in convenience and economy. Therefore, it is widely used as a container for various kinds of liquids such as alcoholic beverages, vinegar, and developing solutions.

A soft thin synthetic resin inner container used in such a bag-in-box (hereinafter, this container is simply referred to as an inner container) is such that the synthetic resin can be joined on the diagonal surface of the container immediately after being melt-extruded. It is manufactured by molding a half of the container by means of pressure molding or blow molding using a mold having a shape, and then joining them.

Before use, the inner container is folded for transportation efficiency, handling, and the like, that is, inserted into one container half so as to overlap the other container half. I have.

By the way, as a synthetic resin for manufacturing such a container, a synthetic resin having the following characteristics is required.

(I) using a synthetic resin having a high melting point to prevent cracking (peeling) at the fusion-bonded portion; Prevent the occurrence.

However, using a synthetic resin with a high melting point poses a problem in the suitability of resin extrusion during molding, and it is not easy to process the container. As a result, it becomes impossible to maintain the original function of the container as a bag-in-box.

For this reason, bag-in-box interior containers have traditionally been made of highly flexible synthetic resin compositions containing EVA mixed with ethylene-vinyl acetate copolymer (EVA) or linear polyethylene to maintain folding properties. Things are used.

However, since EVA has a low melting point, there is a drawback in that the fusion-bonded portion at the time of molding is weak, and after the contents are filled in the inner container, the fusion-bonded portion is peeled off by repeated vibrations.

(Problem to be solved) The present inventor has improved the above-mentioned drawbacks, has good folding characteristics, and does not produce any pinholes or cuts even if the interior container is filled with the contents and transported over a long distance. The present invention has been completed as a result of various studies on a soft and thin-walled container having no soft and thin-walled container, and an object of the present invention is to provide a soft and thin-walled container which can be easily folded without generating a pinhole.

(Means for Solving the Problems) That is, the gist of the present invention is to provide a foldable resin obtained by blending 35 to 45 parts of low density polyethylene with 55 to 65 parts of linear polyethylene. This is an interior container for resin bag-in-box.

That is, in the present invention, when a linear polyethylene is 55 parts or less, a low-density polyethylene is more than 45 parts when a resin composition is used, pinholes are easily generated, and
When a resin composition having a linear polyethylene content of 65 parts or more and a low density polyethylene of 35 parts or less is used, the resin extrusion suitability is poor, which is not preferable.

As the preferred resin composition in the present invention, a resin composition comprising about 60 parts of linear polyethylene and about 40 parts of low density polyethylene is preferable.

The linear polyethylene used in the present invention has an MFR of 0.
The low-density polyethylene has an MFR of 1.0 to 2.0 and a density of 0.917 to 0.921.

In the present invention, other conventional resin compounding agents such as an antioxidant and a processing stabilizer may be added.

Next, the present invention will be described more specifically with reference to examples.

(Example) An interior container of a bag-in-box containing 20 is molded using the following resin composition. At this time, the minimum thickness of the container was 0.13 mm. For comparison, an interior container is similarly molded using a resin composition using EVA which has been conventionally used.

In order to examine the performance of these obtained containers, the following actual tests were performed.

(1) Pour a 30% aqueous solution of a surfactant, and add 0.1k
A pressure of g / cm ² was applied, the solution was stored at 50 ° C., and peeling from the welded portion was measured.

(2) Water was filled, and a vibration test was performed at 20 ° C. under the conditions of 10 mm, 10 mm, and 1 G.

Example 1 A resin composition consisting of 60 parts of linear low-density polyethylene (MFR0.8) and 40 parts of low-density polyethylene (MFR1.5) can be joined on the diagonal surface of the container immediately after melt extrusion. The interior container was formed by vacuum forming using a mold having such a shape.

The obtained container was tested by the test method described above. Table 1 shows the results.

Example 2 In the same manner as in Example 1, 65 parts of linear low-density polyethylene (MFR 0.8) and 65 parts of low-density polyethylene (MFR 0.8) were used.
1.5) An interior container was molded using the resin composition consisting of 35 parts.

The obtained container was tested by the test method described above. Table 1 shows the results.

Example 3 In the same manner as in Example 1, 55 parts of linear low-density polyethylene (MFR 0.8) and 55 parts of low-density polyethylene (MFR 1.5)
An interior container was molded using the resin composition consisting of 45 parts.

The obtained container was tested by the test method described above. Table 1 shows the results.

Comparative Example 1 An interior container was molded in the same manner as in Example 1 using EVA (6.5 wt% containing VA, MFR 1.2), and the obtained container was tested according to the test method described above. The result is
It is shown in the table.

Comparative Example 2 An interior container was molded using a resin composition consisting of 50 parts of EVA (4.0 wt% of VA, MFR 0.5) and 50 parts of linear low density polyethylene (MFR 1.2). The obtained container was tested by the test method described above. Table 1 shows the results.

As is clear from the results in Table 1, the comparative example (conventional product)
In each case, peeling occurred in the fused portion and breakage occurred in about one and a half hours, but the products of the examples according to the present invention did not cause peeling in the fused portion, and the vibration test Again, the products of the examples according to the present invention did not break.

(Effects) As described above, the resin composition for a flexible thin-walled container according to the present invention does not cause a peeling phenomenon because it is firmly fused at a fusion bonded portion, and also has a resistance to breaking. It has resistance and has extremely good properties as a resin composition for a soft thin-walled container.

Claims (1)

(57) [Claims] 1. A synthetic resin bag-in-box interior container formed by folding a resin obtained by blending 35 parts to 45 parts of low density polyethylene with 55 parts to 65 parts of linear polyethylene.