JP2000153585A - Raw material for laminated tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rew material for producing a laminated tube having permeation resistance. SOLUTION: A raw material for a laminated tube is constituted by forming polyethylene layers to both surfaces of an aluminum foil being a core material through adhesive layers comprising an ethylene/carboxylic acid copolymer and interposing a co-extrusion sheet consisting of a core comprising an ethylene/vinyl alcohol copolymer resin and polyethylene between the adhesive layer on the surface corresponding to the inner surface side of the tube and the polyethylene layer. The co-extrusion sheet may be constituted by interposing nylon between the core and polyethylene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw material for producing a laminated tube used as a container for medicines, cosmetics, and other chemical substances.

[0002]

2. Description of the Related Art In recent years, a plastic film on which an inorganic oxide has been deposited is often used as a tube container. Particularly, in the case of pharmaceuticals, there is a case where perfect gas barrier properties and light-shielding properties are required. A laminate tube using Al foil as a material is considered to be most suitable.

[0003] Since the body of the laminated tube is formed by winding a flat laminated raw material into a tube and heat-welding the overlapped ends, the outermost layer and the innermost layer that overlap at the ends are generally formed as follows. Are made of the same material. The innermost layer is a polyolefin-based plastic from the viewpoint of chemical stability against contact with the contents, heat sealing properties, workability, etc.
Particularly, polyethylene is used. Therefore, polyethylene is also used for the outermost layer.

[0004] The most suitable Al foil as a substrate and a barrier layer,
The most suitable polyethylene as the innermost layer (and the outermost layer) does not usually adhere to each other, so it is necessary to interpose some kind of adhesive layer between them in order to bond them and obtain sufficient strength for practical use. is there. As the most preferable adhesive layer, an ethylene-carboxylic acid copolymer (EMAA or EAA) is well known, and this is an extremely common adhesive layer interposed between an Al foil and a polyethylene layer in a raw material for a laminated tube. Used in As another adhesive layer, for example, an adhesive of a two-liquid reaction type or the like may be used. In this method, although the initial adhesive strength is obtained,
The adhesive layer is easily damaged by penetration and attack of the content component, and particularly when the content is filled with a large amount of the solvent component, the adhesive layer is often broken and causes delamination.

[0005] It is considered that the permeation of the contents penetrates the innermost layer and the adhesive layer, stops at the interface of the Al foil layer, and stays there. As a result, as described above, the interface between the Al foil and the adhesive layer, which is relatively difficult to adhere, is attacked, and eventually, delamination occurs at this portion. Means for improving the content-resistant component adhesion between the Al foil and the adhesive layer have been considered for some time,
The conventional method has not yet achieved a sufficient effect.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to protect the interface between an Al foil and an inner adhesive layer in a laminated tube so that delamination does not occur even with a highly permeable content.

[0007]

According to the present invention, an aluminum foil is used as a core material, and a polyethylene layer is formed on both surfaces thereof through an adhesive layer made of an ethylene-carboxylic acid copolymer. A raw material for a laminated tube, characterized in that a coextruded sheet of polyethylene with an ethylene vinyl alcohol copolymer resin as a core is interposed between the adhesive layer and the polyethylene layer on the surface to be coated.

[0008] The coextruded sheet with polyethylene having the above-mentioned ethylene-vinyl alcohol copolymer resin as a core shows chemical resistance and acts as a second barrier layer for Al foil. Therefore, the influence of the penetrating component on the bonding interface between the Al foil and the adhesive layer is reduced, and delamination at this most important portion is prevented. Then, it is considered that a strong stagnation of the penetrating component occurs at the interface between the second barrier layer and the polyethylene layer, and the delamination at the site is likely to occur. Since the polyethylene is bonded in advance, delamination between the second barrier layer and the polyethylene is prevented. In addition, since the core ethylene-vinyl alcohol copolymer resin and the polyethylene on both sides are co-extruded, the interface becomes fine and intricate, and the bond between them is also strong. Of course, if necessary, it is more effective to interpose an adhesive layer between the ethylene-vinyl alcohol copolymer resin and the polyethylene so as to more firmly bond the both. Further, when the co-extruded sheet is biaxially stretched, the barrier property is further enhanced.

Although this effect is based on various test results, since the second barrier layer does not have the perfect barrier property as Al foil, some components are slightly contained in the second barrier layer. It is considered that strong permeation such as the bonding interface between the Al foil and the adhesive layer does not occur because of the permeation of the layer, and the peeling action on each layer is alleviated through steps. The innermost layer of polyethylene can be extrusion-coated without special treatment. In this case, since the same kind of material is bonded by heat welding, this portion does not peel off.

[0010] The co-extruded sheet may be a sheet in which a nylon layer is interposed between each of polyethylene on both sides of an ethylene-vinyl alcohol copolymer resin. The chemical resistance is further improved by interposing the nylon layer.

When the polyethylene layer corresponding to the outer surface of the tube is a colored polyethylene layer or a transparent or translucent polyethylene layer on the outermost layer of the colored polyethylene layer, an arbitrary pattern can be formed by covering the ground color of the Al core material. Can be formed. Conversely, a transparent or translucent polyethylene layer can intentionally provide a decorative effect utilizing the ground color of Al. It is also effective to interpose a polyethylene terephthalate layer on the surface of the outer adhesive layer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on examples and comparative examples. The layer configuration of each example is as follows.

Example 1 L-LDPE was used as the innermost layer, and the following layer structure was adopted from the outermost layer side. PE / colored PE / EMAA / Al / EMAA / coextruded sheet (PE-EVOH-PE) / L-LDPE Example 2 PE and PE between the adhesive layer EMMA on the outer layer side and the colored PE
This is one in which a T layer is interposed. PE / colored PE / PE / PET / EMAA / Al / EM
AA / co-extruded sheet biaxially stretched (PE / Ny
/ EVOH / Ny / PE) / L-LDPE Comparative Example 1 PE / white PE / PE / EMMA / Al / EMMA / P
E In this layer configuration, the Al foil and the PE layer as the sealant layer are
It was bonded by MAA.

Comparative Example 2 PE / white PE / PE / EMAA / Al / PET / (ethylene-glycidyl methacrylate copolymer) / PE On the inner layer side of an Al foil, a PET layer having excellent resistance to penetration components was provided. Protect the foil. Furthermore, by using an ethylene glycidyl methacrylate copolymer resin as an adhesive layer between the PET layer and the PE layer serving as a sealant layer, delamination between the PET layer and the PE layer due to the influence of a penetrating component is prevented. In particular, it is used as a raw material for anti-inflammatory pain medicine.

Comparative Example 3 PE / white PE / PE / EMAA / Al / acid-modified PE /
As an adhesive layer between the PE Al foil and the PE layer which is a sealant layer,
By using the maleic anhydride-modified linear PE resin, delamination between the Al foil and the PE layer due to the influence of the penetrating component is prevented. It is especially used as a raw material for acne.

A laminate tube having a diameter of 20 mm was prepared from each of the raw materials of the above Examples and Comparative Examples, filled with four types of contents shown in Table 1, sealed, and heated at 40 ° C., 75%
RH was stored for 6 months in a constant temperature and humidity chamber to check for delamination, discoloration, and other corrosion. Table 1 shows the results.

[0017]

[Table 1]

As is evident from the results shown in Table 1, the embodiment of the present invention could solve the problem for all four types of contents, but the comparative example was different from the specific contents. Is effective in solving the problem or somewhat effective, but the components capable of exerting the effect are all selective and not versatile. In particular, those using the special adhesive resin of Comparative Examples 2 and 3 are technically difficult to laminate.
Unless a special processing method is adopted, a sufficient adhesive effect cannot be exerted, so that there remains a problem in the work surface and the associated cost in the production of the raw material. On the other hand, the embodiment can be manufactured by ordinary laminating processing, and there is no particular difficulty.

[0019]

According to the present invention, since the permeation resistance is improved by using a coextruded sheet having both sides made of PE, there is no need to go through any special steps in the laminating process, and the workability is improved by ordinary laminating. There is no inferiority to processing. The EVOH at the center of the co-extruded sheet has excellent barrier properties against permeation components and also has excellent non-adsorption (non-sorption) properties on hydrocarbon-based components and ester-based components. Therefore, it is effective for various contents such as foods, medicines, cosmetics and the like containing vitamin E, limonene and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 35/10 B65D 35/10 B // A61J 1/10 A61J 1/00 331C F-term (Reference) 3E065 BA02 BA12 BA16 BB03 4F100 AB07G AB10A AB33A AK04B AK04C AK04E AK42E AK48E AK63 AK69D BA05 BA07 BA10B BA10C BA10E CB00 EH20 GB16 JD01 JD14 JL10B JL10C JN01B

Claims (5)

[Claims] 1. An aluminum foil as a core material, a polyethylene layer formed on both sides of an adhesive layer made of an ethylene-carboxylic acid copolymer, and a polyethylene layer formed on the inner surface side of the tube by the polyethylene layer. A raw material for a laminated tube, wherein a coextruded sheet with polyethylene having an ethylene vinyl alcohol copolymer resin as a core is interposed between the layers. 2. The laminate tube material according to claim 1, wherein the coextruded sheet of polyethylene with an ethylene vinyl alcohol copolymer resin as the core is formed by interposing nylon between the core and the polyethylene on both sides. Anti. 3. The raw material for a laminated tube according to claim 1, wherein the polyethylene layer corresponding to the outer surface side of the tube is a colored polyethylene layer. 4. The raw material for a laminated tube according to claim 2, wherein the outermost layer of the colored polyethylene layer is a transparent or translucent polyethylene layer. 5. The raw material for a laminated tube according to claim 1, wherein a polyethylene terephthalate layer is interposed on the surface of the adhesive layer on the outer layer side.