JPH066340B2 - Film for container sealing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a film for sealing a container, and more specifically, when a film is formed into a roll without an adhesion preventing slip sheet (hereinafter, simply referred to as a slip sheet). The present invention relates to a film for sealing a container which does not cause blocking.

[Conventional technology]

The film for container sealing is a film made of synthetic resin that exhibits adhesiveness by cold drawing and easily adheres to glass, metal, ceramics, etc. Since this adhesive film can be peeled off, it can be used in laboratories, hospitals, etc. It is used to prevent water from scattering in containers such as beakers and petri dishes, to isolate odors, to prevent pollution from the atmosphere, and for fixing grafts. By the way, the container sealing film has a composition of polyisobutylene, polyethylene and paraffin wax (for example, USP2,339,958, USP2,876,20).
4, USP 3,046,238, JP-A-51-122153, JP-A-58-18744
4 etc.), the film itself does not have much tackiness, but as described above, the tackiness appears due to cold stretching,
It has the property that it appears sticky during rolling or during storage and causes blocking with each other. Therefore, it is usually sold as a roll using interleaving paper to prevent adhesion.

However, when the interleaving paper is stacked on the container sealing film to form a roll, the process and the device are complicated, and the yield of the product is poor. It is expensive and wastes resources. In addition, depending on the environmental conditions at the distribution stage (transportation, storage, etc.) or storage by consumers, the film and interleaving paper may block, and peeling may be difficult during use. there were.

As a means for preventing such blocking, Japanese Patent Publication Sho 39
Japanese Laid-Open Patent Application No. -12498 discloses a technique for embossing a film. The embossing roll used in this technique has a rough surface formed by spraying a steel grid or the like, and the difference in surface irregularities is 10 to 13 μm at the maximum.

However, when the surface roughness is 10 to 13 μm, the above blocking preventing effect is not sufficient, and especially when a self-adhesive synthetic resin film made of polyisobutylene, polyethylene and paraffin wax is used, Blocking occurred when it was made into a body, and there was also a problem in peelability during use.

[Problems to be solved by the invention]

An object of the present invention is to provide a container-sealing film that solves the problem of using the above-mentioned interleaving paper and suppresses blocking to improve the take-out property during use.

[Means for solving problems]

The present inventors have conducted extensive studies to achieve the above object, and finally completed the present invention.

That is, the present invention provides an embossed pattern satisfying the following conditions on at least one surface of a synthetic resin film in which the mixing ratios of polyisobutylene, polyethylene and paraffin wax are 30 to 60% by weight, 10 to 30% by weight and 20 to 40% by weight, respectively. A film for sealing a glass container, which comprises:

(Conditions for embossed pattern) Difference in unevenness is 30 to 80 μm. A plurality of pattern units composed of a combination of parallel lines and meridians or a combination of parallel lines, meridians and diagonal lines can be identified. Polyisobutylene in the present invention, Polyethylene and paraffin wax are used. As these resins and paraffin waxes, those described in the above-mentioned documents are preferably used, and the compounding ratio thereof and the method for producing a film raw material may be determined according to these documents.

That is, as polyisobutylene, not only homopolymer of isobutylene but also other copolymerizable monomer (10 wt%
The following can also be used as a copolymer.

As polyethylene, any of low density polyethylene, high density polyethylene and linear low density polyethylene can be used, but low density polyethylene and linear low density polyethylene are preferable.

The paraffin wax has various properties depending on, for example, the content of isoparaffin, but any of polyisobutylene and polyethylene can be used by appropriately selecting it.

The mixing ratio of these three is usually 30 to 60% by weight of polyisobutylene, 10 to 30% by weight of polyethylene, and 20 to 40% by weight of paraffin wax. Good and easy to handle.

The embossed pattern, which is a feature of the present invention, has a plurality of pattern units consisting of a combination of parallels and meridians or a combination of parallels, parallels and diagonals, and the length of the film can be identified by counting the pattern units. For this, a configuration that appropriately combines geometric patterns and arabesque patterns is adopted. In addition,
Some examples of these are shown in FIGS.

This figure is shown as an enlarged front view of the main part of each roller,
1 shows a roll and 2 shows an embossed pattern.

The embossed pattern does not necessarily have to be provided on both sides, and blocking can be sufficiently prevented even if only one side is provided.

Difference in unevenness of embossed pattern (value measured at the lowest point of the concave part using the surface roughness meter manufactured by Tokyo Seimitsu Co., Ltd., with the highest point of the convex part as the reference, with a probe tip radius of 5 μm ) Is 30 to 80 μm, preferably 40 to 60 μm. If it is less than 30 μm, blocking tends to occur when it is made into a roll, and if it exceeds 80 μm, the tackiness after cold drawing becomes poor.

The container-sealing film of the present invention is prepared by appropriately mixing various additives such as a stabilizer and a pigment with the above-mentioned raw materials, and forming the film by a known calendering method, an extrusion method, or the like. It can be manufactured according to a known method for manufacturing an embossed film using a roll made of metal or the like in which is marked.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Production example Production of film base Mixing 50 parts by weight of polyisobutylene having a weight average molecular weight of about 800,000, 20 parts by weight of polyethylene having a weight average molecular weight of about 50,000 and 30 parts by weight of paraffin wax having a melting point of about 60 ° C., a T-die extruder A film having a thickness of 120 μm was obtained at 150 ° C.

Examples 1 to 3 and Comparative Examples 1 and 2 The films obtained in the production examples are preheated to 60 ° C. and passed between the engraving roll and the rubber roll having the pattern shown in FIG. 1 to obtain the difference in unevenness shown in Table 1. Emboss with the pressure between the rolls,
It was a roll. The peel strength of the roll when the obtained roll was stored under the temperature conditions of 20 ° C., 40 ° C. and 60 ° C. for 48 hours, and the adhesion to the glass device after cold drawing was evaluated.

The results are shown in Table 1.

Method for measuring peel strength of rolls Attach a roll with a width of 10 cm to the upper fastener of the Tensilon tensile tester rotatably, fix the film partially fed from the roll to the lower fastener, and pull it at 500 mm / min. taking measurement.

Blocking of rolls It was investigated whether a roll with a width of 10 cm could be pulled out smoothly by hand.

◯: Practically no problem, ×: Practically unusable Adhesion after cold stretching The film was cut into an appropriate size and stretched about 2 times to check the adhesion to a beaker.

Good: Poor: Bad Example 4 Example 2 was repeated using a roll having the pattern shown in FIG. 2 as the engraving roll. The results are shown in Table 1.

Reference Example 1 An interleaving paper and a roll were produced using the film obtained in the production example, and the same test as in the example was conducted. The results are shown in Table 1.

Reference Example 2 Table 1 also shows the results when the film obtained in the Production Example was directly wound.

[Advantages of the Invention] The present invention is a container-sealing film that does not require a slip sheet that has been conventionally used, is extremely easy to manufacture a roll, and since there is no blocking between films, There is an advantage that it can be taken out easily.

Furthermore, since the uneven pattern that shows the length is attached,
There is also an advantage that a predetermined amount can be quickly cut during use.

[Brief description of drawings]

1 to 3 are diagrams showing an example of a concavo-convex pattern of an engraving roll used in the production of the film for sealing a container according to the present invention,
It is shown as an enlarged front view of the main part.

Claims (1)

[Claims] 1. A compounding ratio of polyisobutylene, polyethylene and paraffin wax is 30 to 60% by weight, respectively.
A film for sealing a glass container, comprising a synthetic resin film of 10 to 30% by weight and 20 to 40% by weight and having an embossed pattern satisfying the following conditions on at least one surface. (Conditions for embossed pattern) Difference in unevenness is 30 to 80 μm. Multiple pattern units consisting of a combination of parallels and meridians or a combination of parallels, meridians and diagonals. The length of the film can be identified.