JPH11245973A - Manufacture of packaging material for retort pouch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a packaging material for retort pouch wherein a polypropylene resin is turned to a film and at the same time the film is laminated to a substrate film, and a packaging material for retort pouch manufactured by the manufacturing method. SOLUTION: After an adhesive is applied to the surface of a barrier layer of a laminated film in which a substrate layer and the barrier layer are combined, the adhesive is dried and the laminated film is sent into between a pair of nip rolls 30 to laminate the laminated film. On the other hand, a polypropylene resin is extruded from an extruder onto the outer circumferential surface of a cooling revolving roll 52 at a non-oxidizing temperature, not lower than a softening temperature, and cooled in a close contact state to form a sealant layer of film-like shape and one of the sides of the layer is treated and then the sealant layer is passed through between the nip rolls 30 to bring the treated side of the layer into contact with the adhesive applied surface of the laminated film to combine the layer and the laminated film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a packaging material used for a retort pouch.

[0002]

2. Description of the Related Art Conventionally, as a packaging material used for retort pouches, polyester film (PET) / aluminum foil (Al) / unstretched polypropylene film (CP)
P), PET / nylon film (Ny) / Al / CP
A laminated film having a structure such as P is used. And C
A PP film is dry-laminated using an adhesive or heat-laminated to form a packaging material for a retort pouch.

[0003] In order to form a CPP film neatly, the film thickness, the softness of the resin, the roughness of the film surface, and the amount of various additives such as lubricants are affected. In addition, since there is a certain amount of time until bonding after film formation, deterioration of the processing degree due to bleed-out of the lubricant on the surface of the CPP film, deterioration due to oxidation of the surface of the CPP film, and decomposition odor of the resin generated due to sufficient discharge treatment are performed. Or occur. In addition, resin loss occurs when the resin is formed into a film and wound.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems relating to a packaging material for a retort pouch produced by laminating a polypropylene film and a base film, and is made of polypropylene resin. It is an object of the present invention to provide a method for producing a packaging material for a retort pouch, which is formed into a film and bonded to a base film, and a packaging material for a retort pouch produced by this production method.

[0005]

Means for Solving the Problems A first invention of the present invention is:
A method for producing a packaging material for a retort pouch comprising a film in which a substrate layer, a barrier layer, and a sealant layer are sequentially laminated, wherein an adhesive is applied to the barrier layer surface of the laminated film in which the substrate layer and the barrier layer are laminated. Thereafter, the adhesive is dried, and the laminated film is fed to a pair of nip rolls to be bonded, while the polypropylene resin is extruded from the extruder at a softening temperature or higher at a non-oxidizing temperature to the outer peripheral surface of a cooling rotary roll and closely cooled, A package for a retort pouch, wherein a sealant layer formed in a film shape is formed, and after one surface thereof is surface-treated, the processed surface is passed through the space between the nip rolls so as to be brought into contact with the adhesive applied surface of the laminated film. It is a method of manufacturing a material.

A second aspect of the present invention is a packaging material for a retort pouch produced by the production method of the first aspect.

As described above, according to the present invention, the polypropylene resin is extruded from the extruder to the outer circumferential surface of the cooling rotary roll at a softening temperature or higher and at a non-oxidizing temperature to be closely cooled, and one surface thereof is surface-treated. , So that the treated surface is in contact with the adhesive-coated surface of the laminated film so that the treatment is not degraded and a stable laminate strength is obtained. In addition, since the surface treatment does not deteriorate with the passage of time, a relatively weak treating power is sufficient, and the odor due to corona discharge treatment is small. By laminating the polypropylene resin with the substrate film layer immediately after forming the film into an extruded film, the polypropylene film is hardly oxidized, the film can be prevented from being deteriorated, and the impact resistance and the functionality are improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. In the packaging material apparatus shown in FIG. 1, a laminated film 13 in which a base material layer 11 and a barrier layer 12 are bonded together.
Is fed from the supply roll 21 with the barrier layer surface inside, and an adhesive application machine 23 including a tank 24 containing an appropriate adhesive, an application roll 25, and a holding roll 26 is applied with an appropriate amount of adhesive on the barrier layer surface. Then, it passes through a dryer 27 to dry the surface to which the adhesive is applied. The laminated film 13 passes between a pair of nip rolls 30 including a rubber roll 28 and a metal roll 29 from a dryer.

On the other hand, in order to form the sealant layer 14 to be laminated on the laminated film, a polypropylene resin is
The resin is melted at about 300 ° C., plasticized, extruded from the extrusion die 51, formed into a film, and transferred to and contacted with the outer peripheral surface of the cooling rotary roll 52. The extruded film is brought into close contact with the cooling rotary roll by an air knife 53 or the like near the contact point with the cooling rotary roll and cooled. The surface of the cooled CPP film 14 is subjected to a surface treatment by a surface treatment device 54 such as a corona discharge treatment device at an appropriate location between the cooling rotary roll and the nip roll.

The surface-treated CPP film 14 is brought into contact with the adhesive-coated surface of the laminated film 13 between a pair of nip rolls 30 each composed of a rubber roll and a metal roll, and both are tightly adhered to each other so that the packaging material 10 (Figure 2
reference).

In the nip roll, a rubber roll and a metal roll apply a pressure necessary for bonding the two films. The laminated film and the CPP film as the sealant layer are configured such that the traveling speed can be adjusted by a feed roll 31, respectively, and the laminated packaging material is wound up by a take-up roll 32.

According to the method for manufacturing a packaging material of the present invention, the base material layer 11 is made of PET, polybutylene phthalate (P
BT), Ny, etc., and the barrier layer 12
For example, a vapor-deposited film obtained by vapor-depositing a thin film of silicon oxide, aluminum oxide, or the like on a substrate film of Al, PET, Ny, or the like by a method such as a vacuum vapor-deposition method at about 400 ° can be preferably used. P
For example, a film coated with a (VDC) resin, an ethylene vinyl alcohol copolymer resin (EVOH) film, or the like may be used.

An adhesive (not shown) for bonding the base layer 11 and the barrier layer 12 and an adhesive (not shown) for bonding the laminated film 13 and the sealant layer 14 are excellent in heat resistance having retort suitability. Any adhesive may be used. For example, a two-component reaction type urethane-based adhesive can be preferably used.

[0014]

EXAMPLES Examples of the present invention will be described below more specifically. Example 1 First, a 12 μm thick PE was used as the base material layer 11.
A 7-μm thick Al film is prepared as a barrier layer 12 on a T film, and the two are bonded together using a two-component reaction type urethane-based adhesive to produce a laminated film 13 of PET (12 μm thickness) / Al (7 μm thickness) configuration. did. A printing layer (not shown) may be provided on the surface of the PET film in contact with Al, if necessary.
May be provided.

The laminated film 13 is set on a supply roll 21 with the Al side facing inward, fed out as shown in FIG. 1, and passed through an adhesive applicator 23 set with a two-component reaction type urethane adhesive. An adhesive is applied to the Al surface of No. 13 and then the applied surface is dried by the dryer 27.

Separately, a polypropylene resin is charged into a hopper (not shown) of an extruder, melted at 250 to 300 ° C. to plasticize the polypropylene resin, extruded from an extrusion die 51, formed into a film, and cooled by a cooling roll 52. The transfer surface is brought into contact with the outer peripheral surface of. The extruded film is brought into close contact with the cooling rotary roll 52 by an air knife 53 or the like near the contact point with the cooling rotary roll 52 and cooled, and a 30 μm-thick CPP film serving as the sealant layer 14 is produced.

The surface of the cooled CPP film 14 is
The surface treatment is performed between the cooling rotary roll 52 and the nip roll 30 by a surface treatment device 54 such as a corona discharge treatment device.

In this manner, the treated surface of the CPP film 14 and the adhesive-coated surface of the laminated film 13 come into contact between the rubber roll 28 and the nip roll 30 composed of the metal roll 29, and the two adhere tightly to form the packaging material 10. It is wound on a winding roll 32.

Comparative Example 1 30 μm as sealant layer
PET (12 μm) / Al (7 μm) / CP using the same material as in Example 1 except that a thick CPP film was used.
A packaging material for retort pouches made of P (30 μm) was produced.

Using the obtained two types of packaging materials for retort pouches, a three-sided sealed bag having a size of 200 mm × 150 mm was prepared by a heat sealing method, and distilled water was added to the bag.
It was filled with 0 ml, sealed, and retorted at 120 ° C. for 30 minutes. Thereafter, the adhesion strength between the barrier layer (Al) and the sealant layer (CPP) before and after the retort treatment, the drop impact strength after the retort treatment, and the taste test were performed by the following methods. Table 1 shows the results. Adhesive strength: Measured with an Instron type peeling tester (tensile speed: 300 mm / min. Sample width: 15 mm,
(Unit: g / 15 mm width) Drop impact strength: 1.5 parts of retorted three-side seal bag
m from the height of m to the concrete floor once each in the vertical and horizontal directions, and visually observe the condition of the bag tearing and water leakage ○: no bag tearing, no water leakage ×; bag tearing, Water leakage occurs Taste inspection… Check the presence or absence of resin odor by including distilled water in the retort-treated three-way seal bag in the mouth (paneler: 10
Name) Total score of 10 people ○: No resin odor at all 2 points △: Slight resin odor 1 point ×: Resin odor 0 point

[0021]

[Table 1]

[0022]

As described above, according to the production method of the present invention, it is possible to produce a packaging material for retort pouches having performance equal to or higher than that of laminating a CPP film. In addition, since the packaging material can be manufactured from the resin in one step, the production efficiency can be increased, the loss can be reduced, and the thickness of the seatant layer can be reduced.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing an example of a manufacturing apparatus used in a method for manufacturing a packaging material for a retort pouch of the present invention.

FIG. 2 is an explanatory sectional view showing an example of a packaging material manufactured by the manufacturing method.

[Explanation of symbols]

 10 packaging material 11 base layer 12 barrier layer 13 laminated film 14 sealant layer, CPP film 21 supply roll 23 adhesive coating machine 24 tank 25 coating roll 26 mm Holder roll 27 mm Dryer 28 rubber roll 29 metal roll 30 nip roll 31 feed roll 32 windup roll 51 extrusion die 52 cooling rotary roll 53 air knife 54 ‥‥ surface treatment equipment

Claims (2)

[Claims] 1. A method for producing a packaging material for a retort pouch comprising a film in which a base material layer, a barrier layer, and a sealant layer are sequentially laminated, wherein the base material layer and the barrier layer are bonded to each other. After applying the adhesive, the adhesive is dried, and the laminated film is fed to a pair of nip rolls to be bonded, while the polypropylene resin is extruded from the extruder at the softening temperature or higher at a non-oxidizing temperature to the outer peripheral surface of the cooling rotary roll. Close-contact cooling, to form a sealant layer in the form of a film, after surface treatment on one side, and pasted between the nip rolls so that the treated surface is in contact with the adhesive applied surface of the laminated film, characterized in that Of producing packaging material for retort pouches. 2. A packaging material for retort pouches produced by the production method according to claim 1.