JPS59106928A - Preparation of laminated body - Google Patents

Abstract

PURPOSE:To obtain a laminated body for a container wall part having a part to be formed into an easily openable mouth part, by laminating the metal foil layer side of a web having pervious orifices formed thereto and a heat sealable polyolefin film through a melt extrusion layer of olefin resin having fusion bonding capacity to both of them. CONSTITUTION:A web 1' consisting of a metal foil layer 1'b, an outer layer 1'a and an adhesive layer 1'c and having a large number of pervious orifices 2 formed thereto by punching is wound around a cooling roll 6 so as to contact the outer layer 1'a with said cooling roll 6 while a polyolefin film 5 is supplied to a nip roll 7 in a contacted state. A melt extrusion layer 4 of olefin resin is supplied to a V-shaped part 10 from above and directly pressed by the nip roll 7 and, at the same time, cooled and solidified by the cooling roll 6 to form an olefin resin layer 4' fusion bonded to the adhesive layer 1'c and the polyolefin film 5 while a laminate 11 consisting of the web 1', the olefin resin layer 4' and the polyolefin film 5 is formed to the side of the cooling roll 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminate, and more particularly to a method for manufacturing a laminate for a container wall (herein referred to as the container wall including the lid).

A laminate consisting of a base layer containing metal foil and a heat-sealable polyolefin film, which has a hole in the base layer to serve as a pouring spout or drinking spout, for example, is made so that the polyolefin film is on the inner side. When the polyolefin film is used as a container lid member and the sealing tab is thermally bonded to the I-lyolefin film portion in the hole to cover the hole, the polyolefin film is used directly to heat seal the container body and the lid. In addition, it contributes to the protection of the contents on the inner surface of the lid member and the end surface of the hole, and furthermore, when opening, the polyolefin film in the hole is torn by pulling up the seal tab, making opening easier. Since the lid member has a metal foil layer, it has the advantage of excellent gas barrier properties and long shelf life of the contents.

The present invention relates to a method for manufacturing such a laminate, but when attempting to manufacture this type of laminate using a conventional method, the following problems occur.

That is, when bonding the metal foil in the base layer and the polyolefin film via a urethane adhesive, the bonding must be performed while the urethane adhesive is still in a sticky state. However, it is extremely difficult to industrially apply a urethane adhesive to the metal foil in the base layer, form holes (i.e., through holes) while the adhesive is in a sticky state, and then adhere a polyolefin film. It is. Another possible method is to attach a layer of molten polyolefin formed by melt extrusion directly to the metal foil of the base layer in which the holes are formed, using a cooling metal roll and a nip roll (made of silicone rubber). In this case, even if the molten polyolefin is adhered to the cooling roll and the base layer is in contact with the nip roll, it is difficult to obtain a satisfactory laminate in which the molten polyolefin passes through all the holes and adheres to the nip roll. Similarly, it is difficult to apply a urethane adhesive to the metal foil of the base layer in which holes are formed.

The present invention aims to solve the above-mentioned technical problems.

In order to achieve the above object, the present invention provides a method for manufacturing a laminate for a container wall, which has a portion that is to be an easy-to-open mouth portion and whose inner surface is made of a heat-sealable polyolefin film, the first surface being After forming a through hole in a web consisting of a metal foil layer or an adhesive layer covering the metal foil layer at a position corresponding to the portion that should become the opening, both the first surface and the polyolefin film are An olefin resin having heat-fusible properties is melt-extruded in a layer between the web and the polyolefin film with the second side of the web in contact with a cooling roll and the polyolefin film in contact with a nip roll. The present invention provides a method for manufacturing a laminate for a container wall, which is characterized by laminating layers.

The present invention will be described below with reference to the drawings.

In FIG. 1, a web 1 includes a metal foil layer 1b (for example, aluminum foil, iron foil, tin foil, etc.), an outer layer 1a, and an adhesive layer 1c. The outer layer 1a is provided to protect the metal foil layer 1b or to reinforce the web 1, and depending on the purpose of use, it may be made of a coating film (e.g., epoxy/phenol baking film), a plastic film (e.g., biaxially oriented polypropylene, polyethylene), etc. (made of terephthalate, polyamide, etc. and adhered to the metal foil layer 1b via an adhesive layer (not shown)), paper, a composite thereof, or the like may be used as appropriate.

The adhesive layer 1c is provided to increase the adhesive strength between the olefin resin layer 4' formed by melt extrusion described later and the metal foil layer 1b, and is made of, for example, an acid (for example, maleic anhydride).
It consists of a two-layer body of modified polyolefin, ionomer, or urethane adhesive (on the metal foil side) and polyolefin (on the melt-extruded olefin resin layer side). Further, an organic titanium-based or incyanate-based anchoring agent may be used (in this specification, the anchoring agent is also referred to as an adhesive).

1' in FIGS. 2 and 3 shows the web (5) after punching out a large number of through holes 2 when this web 1 is used as a material for an easy-to-open lid 21 (see FIG. 6). This is what is shown. The circular portion 3 surrounded by the one-dot chain line corresponds to a portion to be punched out to become a lid blank after the polyolefin film 5 is laminated to form a laminate 11 (see FIG. 5) as shown later.

Next, the metal foil layer 1'b of the web 1' with the through holes 2 formed therein.
A heat-sealable polyolefin film 5 is laminated on the side, but since it is difficult to directly adhere the adhesive layer 1'c and the polyolefin film 5, a melt-pressed layer of olefin resin having heat-sealability is applied to both. Both are laminated via 4.

Figure 4 shows this lamination process, where 6 is a cooling metal roll (internally water-cooled), 7 is a nip roll (
(for example, made of silicone rubber) is wound around the cooling roll 6 so as to be in contact with the roll 6. The polyolefin film 5 is in contact with the nip roll 7, and the web 1'
and polyolef (6) The in-film 5 is supplied in a seven-figure shape.

The molten extruded layer 4 of olefin resin is supplied to the V-shaped portion 10 from above and immediately pressed in the direction of the cooling roll 6 by the nip roll 7, and simultaneously cooled and solidified by the cooling roll 6 to form the adhesive layer 1. An olefin resin layer 4' is formed by heat-sealing the web 1', the olefin resin layer 4', and the polyolefin film 5 (by melting only a very thin layer on the inner surface side of the film). A laminate 11 is formed on the cooling roll 6 side.

FIG. 5 shows a cross section of the laminate 11, in which the holes 2' of the web 1' are separated by the olefin resin layer 4' and the polyolefin film 5 on the metal foil layer 1'b side. The hole 2' forms a mouth (not shown) after opening of the lid 21 (FIGS. 6 and 7), which is easy to open.

In the above process, the melt extrusion layer 4 and the nip roll 7
Since the polyolefin film 5 is interposed between the layers, the melt-extruded layer 4 is less likely to adhere to the nip roll 7. The resin of the melt-extruded layer 4 protrudes into the through hole 2 (fifth
Although not shown in the figure, this protrusion occurs in reality)
Even if it comes into contact with the cooling roll 6, the surface of the protruding portion is immediately cooled and solidified, so there is no risk of it sticking to the cooling roll 6. On the other hand, if the web 1 is fed so as to be in contact with the nip rolls 7, the molten resin that overflows will adhere to the nip rolls 7, making it impossible to continue production.

Adhesive layer 1'c1 melt extrusion layer 4 and heat sealability, J? Examples of combinations of materials forming IJ olefin 5 are shown in Table 1.

Table 1 (9) Note: (1) Polyethylene (low density, medium density, high density polyethylene) (2) Ethylene/vinyl acetate copolymer (3) Acid modified polyethylene (carboxylic acid, acid anhydride, acid ester, (4) Polynolopyrene (5) Acid-modified polyzoropyrene (6) For example, Surlyn (trade name, manufactured by DuPont) Among the above, acid-modified, f IJ olefin is melt-extruded. 4
In 5.7.12.15 used as a polyolefin film, the resin protruding into the through hole 2 adheres to the end surface 1'b of the metal foil layer 1'b, protecting the end surface 1'b1 (polyolefin film 5 and This is preferable in terms of corrosion caused by acidic liquid components that have penetrated into the olefin resin layer 4'f and entered the through holes 2).

The preferred thicknesses of the olefin resin layer 4' and the polyolefin film 5 are approximately 20 to 40 μm and 3 μm, respectively.
It is 0 to 100 μm.

In the above example, the adhesive layer IC was formed on the surface of the metal foil layer 1b (10) of the web 1, but the application (i.e., strong adhesive force between the metal foil layer 1b and the olefin resin layer 4' is not required). Depending on the application), the metal foil layer 1b and the melt-extruded layer 4 may be directly bonded to each other, although not shown, without necessarily forming the adhesive 1c.

Examples of the olefin resin forming the melt-extruded layer 4 in this case include low-density polyethylene, ionomer, acid-modified polyethylene (low density, medium density, or high density), and acid-modified polypropylene.

The laminate 11 manufactured as described above is, for example, a second
It is punched out along the dashed line in the figure to form a lid blank.
Next, the lid 21 is formed into an easy-to-open lid 21 as shown in FIGS. 6, 7, and 8, and is heat-sealed to the open end 30a of the container body 30.

In FIGS. 7 and 8, reference numeral 5' indicates a heat-sealing layer consisting of the polyolefin film 5 and the olefin resin layer 4'. The end edge 21a of the lid 21, which has a substantially U-shaped cross section, seals the open end 30a via the heat seal layer 5' and the heat seal layer 30a+ of the open end 30a. 22 is a seal tab, and as shown in FIG. 8, for example, it is composed of an inner layer 22X1 having heat-sealable properties with the olefin resin layer 4', an intermediate layer 22y1 made of metal foil, and an outer layer 22z made of a protective coating or plastic film. In the hole 2', the inner layer 22x is thermally fused to the olefin resin layer 4' to form a thermally fused portion 23. In addition, the inner layer 22x preferably includes (
It is thermally bonded to the outer layer 1/a of the web 1' to such an extent that it can be easily peeled off.

Therefore, when the knob 22ae of the seal tab is pulled up, the hole 2
The portion 5'a of the heat sealing layer 5' at the hole 2
It is easily torn along the periphery of the ring and removed together with the sealing tab 22 to form a spout through which the liquid gold content can be poured out.

If a seal tab is attached to the hole 2' and the outer surface around it in the same manner as shown in FIG. 8, the hole 2' will be opened by peeling off the seal tab.
A straw can be easily inserted into the pouch.

When the laminate 11 includes paper material, this blank (with one hole 2') is bent and formed, and then heat-sealed to form a rectangular cylindrical container (with the hole 2' on the top wall). ), and a seal tab is attached to the outer surface of the hole 2' and its surroundings, thereby making it possible to manufacture a container that is easy to open.

According to the present invention, a heat-sealable polyolefin film is laminated without causing any trouble on the metal foil side of a web having a metal foil layer and having through holes formed therein, so that the portion that should become an easy-to-open mouth part Examples will be described below that have the effect of being able to manufacture a laminate for a container wall having the following properties.

EXAMPLE Outer layer 111% made of nitrocellulose-based oxide having a thickness of 3 μm, metal foil layer 1b made of aluminum foil having a thickness of 100 μm, and anhydrous male resin having a thickness of 20 μm.
13) A web 1 consisting of an adhesive layer IC made of inic acid-modified low density polyethylene was manufactured as follows.

First, a nitrocellulose-based overcoat agent was completely coated on an aluminum foil web using a gravure roll coating method, and then dried in an oven. Next, maleic anhydride-modified low-density polyethylene was coated on the surface not coated with the overcoating agent by an extrusion coating method to obtain a temporary laminate. This temporary laminate is heat-treated with a heat roll maintained at 200°C, and then cooled with a cooling roll to form a web 1 with sufficient adhesive strength between the aluminum foil and the areic anhydride-modified low-density polyethylene. Obtained.

As shown in FIGS. 2 and 3, the outer layer 1a of the web 1' is attached to a cooling roll 6 (made of steel with a chrome-plated surface, diameter 500 m, circumferential speed 80 m).
The nip roll 7 (outer layer silicone rubber, dia. 200fi) and a cooling roll 6 to obtain a laminate 11. There were no troubles during the work, and the adhesive strength between the metal foil layer 1'b of the laminate 11 and the polyolefin film 5 was 1500! i
' / 15 w + m, which was satisfactory.

For comparison, the same procedure as above was carried out except that the melt-extruded layer 4 was not flowed down, but the polyolefin film 5 did not adhere to the web 1' at all.

For comparison, an attempt was made to perform the same operation as above except that the outer layer 1a of the web 1' was brought into contact with the nip roll 7 and the polyolefin film 5 was brought into contact with the cooling roll 6, but the The resin of the melt-extruded layer 4 stuck to the nip roll 7, and the operation had to be stopped immediately.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an example of the web applied to the present invention, FIG. 2 is a plan view of the web in FIG. 1 with through holes formed, and FIG. 4 is an explanatory longitudinal sectional view showing an example of the method of the present invention for manufacturing a laminate using the web of FIG. 2, and FIG. 5 is a longitudinal sectional view taken along the line; FIG. Longitudinal cross-sectional view of an example of a laminate, No. 6
The figure is a plan view of a container with an easy-to-open lid formed from the laminate shown in Fig. 5 and heat-sealed, and Fig. 7 is a plan view of a container shown in Fig. 6.
FIG. 8 is an enlarged longitudinal sectional view of section A in FIG. 7. 1... Web, 1'... Web in which through-holes are formed,
1'al...Outer surface of outer layer (second layer), 1b...Metal foil layer, 1c...Adhesive layer, 2...Through hole, 2'...
- Holes, 4... Melt extrusion layer, 4'... Olefin resin layer, 5... Heat-sealable polyolefin film, 6... Cooling roll, Patent applicant: Kishimoto
Akira

Claims (1)

[Claims] (1) A method for producing a laminate for a container wall, which has a portion that should become an easy-to-open mouth and whose inner surface is made of a heat-sealable polyolefin film, the first surface being a metal foil layer or After forming a through hole in the web, which is the adhesive layer covering the metal foil layer, at a position corresponding to the portion that is to become the opening, heat-fusible gold is applied to both the first surface and the polyolefin film. a second olefin resin of the web.
With the surface of the web in contact with the cooling roll and the polyolefin film in contact with the Nizzo roll, melt-extrude the web and the polyolefin film in a layered manner,
A method for producing a laminate for a container wall, which comprises laminating layers.