JPS5827107B2 - Method for manufacturing laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminate of an aluminum foil or sheet and a crystalline polypropylene resin layer, and more specifically, the present invention relates to a method for producing a laminate of an aluminum foil or sheet and a crystalline polypropylene resin layer, and more specifically, both of these layers have excellent low-temperature thermal adhesion properties and are suitable for retort sterilization. The present invention relates to a method for producing a laminate that is thermally bonded through a specific resin blend adhesive layer that can withstand such harsh hot water treatments.

Conventionally, for use in sealed packages for retort sterilization, a crystalline olefin resin layer for heat sealing was provided on one surface of an aluminum foil or sheet, and a heat-resistant resin layer such as polyethylene terephthalate was provided on the other surface. Laminated sheets are widely used.

These laminated sheets are stacked together and then heat-sealed to form a bag, filled with contents such as salt, degassed, sealed, and then stored in a heat-sterilized state in a sterilizer called a retort. packaging as possible.

Normal retort sterilization is generally carried out at a temperature of up to 120°C for a relatively long time, but in recent years, improvements have been made to improve the flavor preservation of food contents and to prevent the structure, pigments, vitamins, etc. of food contents from being overcooked. In order to avoid destruction, high temperature short-term sterilization (HTST), which carries out short-term sterilization at high temperatures of 125 to 160'C, is becoming increasingly popular.

Such f (in a laminate for TST, the heat-sealable olefin resin layer, which is the innermost material, has heat resistance,
Polypropylene is exclusively used from the standpoint of extraction resistance.

The crystalline propylene polymer used as the sealant and inner surface material is generally inert, and since the package is subjected to harsh heat sterilization treatment, urethane is used exclusively to bond the propylene polymer layer to the aluminum foil or sheet. This is done using a thermosetting adhesive such as an incyanate adhesive or an epoxy adhesive.

Although the above-mentioned thermosetting adhesives are generally satisfactory for the purpose of forming adhesive bonds with excellent heat resistance and hot water resistance, they are still unsatisfactory for the purpose of preserving the flavor of food contents after retort sterilization. It wasn't a kimono.

That is, thermosetting resins are complex resin compositions containing uncondensed monomers and relatively low molecular weight condensation polymers, and
In the above-mentioned package, the thermosetting adhesive layer is always located inside the impermeable metal aluminum layer, so harsh treatments such as retort sterilization can cause decondensation of the uncondensed substances and low molecules mentioned above. The coalescence tends to migrate into or interact with the food contents.

Further, the above-mentioned thermosetting adhesive is generally provided in a diluted form with an organic solvent such as toluene, ethyl acetate, or methyl ethyl ketone.

When laminating aluminum foil and crystalline propylene polymer film using such a thermosetting adhesive, there is a step of applying the adhesive to the aluminum foil, drying the solvent with hot air, and then pressing and laminating. is taken.

However, it is difficult to completely remove the organic solvent by oven drying, and this residual organic solvent may migrate into the food contents during retort sterilization treatment and may significantly impair the flavor of the food contents.

Due to these reasons, although packages made of laminated sheets made by bonding a crystalline propylene polymer layer and aluminum foil etc. with a thermosetting adhesive have excellent preservability, they do not retain the flavor of the food they contain. In this respect, it was still not completely satisfactory.

Conventionally, it has been known to use a modified olefin resin modified with an unsaturated carboxylic acid or the like as a thermoplastic resin adhesive for thermally bonding a polyolefin layer onto a metal substrate.

However, it has been found that when a modified propylene resin is used for thermal bonding between a crystalline propylene polymer and aluminum foil, various disadvantages occur.

First, modified propylene-based resins do not form adhesive bonds of sufficient strength when removed at considerably high temperatures, such as 180°C or higher, and the materials to be laminated must be heated to high temperatures. There are operational disadvantages such as insufficient production speed and high cost for heat treatment.

Not only that, but most importantly, because the thermal bonding operation is carried out at high temperatures such as 180°C or higher, the crystalline propylene-based resin layer tends to shrink significantly before and after the thermal bonding operation, and the resulting Another drawback is that the laminate curls.

The present inventors have determined that the carbonyl group content is 1 to 600 m
eq/ At least one crystalline modified ethylene polymer or modified ethylene-propylene polymer rubber having the same carbonyl group content as above is added to the crystalline modified propylene polymer at a concentration of 100♂ polymer. When a composition in which seeds are blended in a specific ratio is used as the adhesive layer described above, thermal bonding can be performed at a relatively low temperature such as 160° C. or less, and the various drawbacks described above are eliminated. In addition, it has been found that this adhesive layer exhibits excellent resistance to severe hot water treatment such as the above-mentioned high-temperature short-time sterilization.

The present inventors have found that when the thus obtained laminated sheet is used as a sealed package for retort sterilization, it significantly improves the flavor retention properties of the food contents and improves the dimensional and shape stability of the package. I found out that it can be done.

That is, an object of the present invention is to provide a method for producing a laminate that can thermally bond an aluminum foil or sheet to a crystalline propylene polymer layer at a low temperature.

Another object of the present invention is to provide a method for producing a laminate that can suppress the curling tendency of an aluminum foil-propylene polymer laminate due to shrinkage of the crystalline propylene polymer.

Still another object of the present invention is to provide a method for producing a laminate including a novel thermoadhesive resin composition as an adhesive layer.

Still another object of the present invention is to provide a method for producing a laminate that is particularly useful for use as a sealed package that can be sterilized at high temperatures.

According to the present invention, in the method for producing a laminate which prohibits thermally adhering an aluminum foil or sheet and a crystalline propylene polymer layer through an adhesive layer of a thermoplastic resin, the adhesive layer is Capacity carbonyl group content is 1 to 60
0meq/100? (B) a crystalline modified ethylene polymer with a carbonyl group content of 1 to 600 meq/1001 polymer; (B) a crystalline modified ethylene polymer with a carbonyl group content of and at least one polymer selected from the group consisting of modified ethylene-propylene copolymer rubber at a concentration of 1 to 600 meq/100 ft of polymer, and per 100 parts by weight of said polymer A). Polymer B
A method for producing a laminate is provided, characterized in that it consists of a blend in which 3 to 30 parts by weight of 3 to 30 parts by weight of c) are present.

The present invention will be explained in detail below.

In FIG. 1 showing the cross-sectional structure of an example of a laminated sheet according to the present invention, a laminated sheet 1 has an aluminum foil or sheet 2 bonded to one surface thereof with a blend layer 3 mainly composed of modified propylene resin. The heat-resistant resin layer 6 is bonded to the crystalline propylene-based resin layer 4 and the other surface via the adhesive layer 5.

An important feature of the present invention is that the base resin constituting the adhesive layer has a carbonyl (-C-) group content of 1 to 600.
Select a crystalline modified propylene polymer in the range of meq (milli-equivalent)/10oz polymer, especially 10-300meq/1001 polymer, and apply a similar carbonyl group content to this base resin. At least one crystalline modified ethylene polymer or modified ethylene-propylene polymer is added to the base resin 10.
0 parts by weight to 3 to 30 parts by weight, particularly 7 to 20 parts by weight.

First, the carbonyl group content of the modified propylene polymer is 1 meq/100? If the crystallinity is lower than that of the polymer or if it is not substantially crystalline, significant delamination will occur when this material is exposed to a high temperature hot water or hot steam atmosphere such as in retort sterilization, and such a tendency The same is true when the base resin of the adhesive is made of a modified ethylene polymer.

Furthermore, if the carbonyl group content of the modified propylene resin is higher than the amount specified in the present invention, the flavor after retort sterilization will be significantly reduced due to the influence of what is considered to be a thermal decomposition product.

In contrast, according to the present invention, by selecting the type of constituent olefin monomer, crystallinity and carbonyl group content of the resin as the base resin constituting the adhesive within the above-mentioned ranges, retort sterilization is possible. When this laminate is used in packaging while still forming a durable interlayer bond, it becomes possible for the first time to improve the flavor retention properties of the food contents after retorting.

In addition, crystalline modified ethylene polymers and modified ethylene
If propylene-based polymer rubber is not added or the amount added is lower than the above range, it will be difficult to form an adhesive bond with sufficient strength at a relatively low temperature such as 160°C or lower. High-temperature thermal bonding causes curling of the formed laminate, while low-temperature thermal bonding causes delamination during retort sterilization or a significant decrease in the strength of the heat-sealed portion of the package.

Furthermore, crystalline modified ethylene polymers and modified ethylene
If the amount of the propylene polymer rubber exceeds the above range, the hot water adhesive strength and oil resistant adhesive strength of the laminate will significantly decrease.

Furthermore, even if unmodified crystalline ethylene polymer or ethylene-propylene polymer rubber is blended into the base resin, little improvement in low-temperature thermal adhesion can be expected; If the amount is outside the above range, the disadvantages described above with respect to modified propylene polymers will occur.

Modified propylene polymer In the present invention, the modified propylene polymer is an olefin monomer composed of a known carbonyl group-containing ethylenically unsaturated monomer by means such as graft copolymerization, block copolymerization, or terminal treatment. More than 80 mol% of the mass is □
Among those introduced into the main chain or side chain of the olefin resin, which is pyrene, those that satisfy one of the above conditions are used.

As the carbonyl group-containing ethylenically unsaturated monomer, carbonyl (-C-) groups based on carboxylic acids, carboxylates, carboxylic anhydrides, carboxylic esters, carboxylic amides, imides, aldehydes, ketones, etc. may be used alone. in,
Or one or more O/ethylenically unsaturated monomers possessed in combination with a cyano (-C3N) group; a hydroxy group; an ether group; an oxalane (-C-C-) ring, etc. Combinations can be used, suitable examples of which are as follows.

A, ethylenically unsaturated carboxylic acid nialic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, 5-norbornene-2,3-dicarboxylic acid.

B, ethylenically unsaturated carboxylic anhydride: maleic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride.

C, ethylene vesicle tl ester: ethyl acrylate, methyl methacrylate, acrylic acid 2
-Ethylhexyl, mono- or di-ethyl maleate, vinyl acetate, vinyl propionate, propyl r-hydroxymethacrylate, ethyl β-hydroxyacrylate, glycidyl acrylate, glycidyl methacrylate, β
-N-ethylaminoethyl acrylate.

D. Ethylenically unsaturated amide or imide: acrylamide, methacrylamide, maleimide.

E. Ethylenically unsaturated aldehydes or ketones: acrolein, methacrolein, vinyl methyl ketone, vinyl butyl ketone.

In the present invention, among the above-mentioned monomers, ethylenically unsaturated carboxylic acids and ethylenically unsaturated carboxylic anhydrides are particularly preferred, and these monomers may be used alone or in combination with other monomers. Used in combination to modify propylene polymers.

These carbonyl group-containing monomers are used as the main component of the propylene polymer in such a way that the concentration of carbonyl groups is within the above-mentioned range and the modified propylene polymer is crystalline, that is, its crystallinity is at least 15%. attached to a chain or side chain.

Other olefins that can be contained in the propylene polymer include one or a combination of two or more of ethylene, butene-1, pentento-4-methylpentene-1, and the like.

In order to modify the propylene polymer so as to satisfy the above-mentioned conditions, for example, in the case of graft treatment, the raw material propylene polymer should be a highly crystalline one,
In particular, it is necessary to select an olefin resin with a crystallinity higher than 30% and to carry out the grafting treatment under conditions such that the crystallinity of the product does not fall below 15%.

Therefore, as the backbone polymer, highly crystalline ones among tactical polypropylene and ethylene-propylene copolymers are preferably used.

In addition, in this specification, the crystallinity degree is defined in the Journal of Polymer Science (J, Polym.

Sci.) Volume 18, pp. 17-26, 1955 (S.
L, Aggarwal and G, D, T 11
1g) as measured by the X-ray diffraction method.

The above-mentioned grafting process can be carried out under conditions known per se, except for the above-mentioned limitations.

For example, a modified propylene polymer can be easily obtained by bringing the backbone polymer of a propylene polymer into contact with a carbonyl group-containing ethylenically unsaturated monomer in the presence of a radical initiator or radical initiation means. be able to.

The backbone polymer and the monomer can be brought into contact with each other in a homogeneous solution system, a liquid or solid-liquid homogeneous system, or a melt homogeneous system.

Examples of initiators include organic peroxides such as dicumyl peroxide, t-butyl hydroperoxide, dibenzoyl peroxide, and dilauroyl peroxide, and azonitrile such as azobisisobutyronitrile and azobisinopropionitrile. etc. are used in catalytic amounts known per se.

Radical initiation means include ionizing radiation such as X-rays, r-rays, and electron beams; ultraviolet rays or a combination of ultraviolet rays and a sensitizer; mechanical radical initiation means such as kneading (mastication) and ultrasonic irradiation. is used.

For example, in a homogeneous solution reaction, a propylene polymer,
Grafting is performed by dissolving monomers and initiators in an aromatic solvent such as toluene, xylene, or tetralin, and the resulting modified propylene polymer is recovered as a precipitate.

In a heterogeneous reaction, grafting is carried out by bringing a propylene polymer powder into contact with a monomer or a diluted solution of the monomer under irradiation with ionizing radiation.

Furthermore, in a homogeneous melt reaction, a blend of a propylene polymer, a monomer, or an initiator is melt-kneaded in an extruder, kneader, or the like to obtain a modified propylene polymer.

In any of these cases, the resulting modified propylene polymer can be subjected to purification treatments such as washing and extraction in order to remove unpolymerized monomers, homopolymers, initiator residues, and the like.

Furthermore, the particle size of the produced modified propylene polymer can be adjusted by subjecting it to the recrystallization operation in the aromatic solvent described above and changing the crystallization conditions at that time.

The modified propylene polymer thus obtained can be used for the purpose of the present invention as it is, or after being uniformly blended with an unmodified crystalline propylene polymer to adjust the carbonyl group content.

The molecular weight of the modified propylene polymer used may be sufficient to form a film, and generally has a melt index (MI) of 0.2 to 501/10 minutes, particularly 2.
20 f/10 minutes is preferably used.

Modified ethylene polymer In the present invention, as the crystalline modified ethylene polymer, 80 mol% or more of the constituent olefin monomers are ethylene. Of the carbonyl group-containing ethylenically unsaturated monomers introduced by graft copolymerization, block copolymerization, terminal treatment, etc., those satisfying the above conditions are used.

The raw material ethylene polymer is highly crystalline,
In particular, high-density polyethylene is advantageously used, but under mild grafting conditions where the decrease in crystallinity is virtually unstoppable, medium-density polyethylene, low-density polyethylene, or with an ethylene content of 80 mol% or more may be used. Crystalline ethylene-propylene copolymers can also be used.

The type of carbonyl group-containing ethylenically unsaturated monomer used for producing the modified ethylene polymer and the modification means may be exactly the same as those described in detail for the modified propylene polymer.

The degree of crystallinity of the modified ethylene polymer is preferably 15% or more, and its melt index may also be in the same range as described for the modified propylene polymer.

Modified ethylene-propylene polymer rubber In the present invention, the modified ethylene-propylene polymer rubber includes a carbonyl group-containing ethylene known per se in the main chain or side chain of an ethylene-propylene polymer rubber known per se. Among those into which system unsaturated monomers are introduced by means such as graft copolymerization, block copolymerization, or terminal treatment, those satisfying the above conditions are used.

The raw material ethylene-propylene polymer rubber is:
20 to 79 mol% of the constituent olefin monomers are propylene, and the remainder is ethylene or ethylene and butene.
A rubber composed of a combination with another α-olefin such as 1 or a conjugated or non-conjugated diolefin is used.

As the diolefin, for example, butadiene, isoprene, 1,4-hexadiene, vinylnorbornene, etc. are used.

The type of carbonyl group-containing ethylenically unsaturated monomer used in the production of the modified ethylene-propylene polymer and the means for modification can be the same as those described in detail regarding the modified propylene polymer.

According to the present invention, as described above, at least one of (B) modified ethylene polymer length ψQ modified ethylene-propylene polymer rubber is added to (A) modified propylene polymer. The seeds are incorporated in an amount of 3 to 30 parts by weight, especially 7 to 20 parts by weight.

For applications where the oil-resistant adhesive strength of the laminate is a problem, for example, applications for sealed packages for retort sterilization of oil-based foods, the amount of modified ethylene-propylene polymer rubber (C) blended is 1.
It is preferable that the amount is 0 parts by weight or less.1. Generally, it is desirable to use it in combination with the modified ethylene polymer B).

These polymer components can be easily blended by melt-kneading, and for this purpose, pelletizers,
An extruder, roll, kneader, etc. can be used.

In the case of flexible sealed packaging bodies such as bag-shaped containers, aluminum foil or sheet such as aluminum foil generally has a thickness of 6 to 80 mm.
In the case of rigid or semi-rigid containers such as squeeze containers and press-formed containers, foils or sheets with a thickness of 9 to 500 microns are used.

Even if the surface of the aluminum foil or sheet is untreated,
Alternatively, it may be subjected to a known surface treatment.

For the purpose of the present invention, it is desirable to use an aluminum foil or sheet having an alumina hydrate layer of 10 to 1 OOO millimicrons, and a modified propylene polymer is preferably used in a position adjacent to this alumina hydrate layer. It is preferable to provide a blend layer containing the main component.

Crystalline propylene polymer layer The crystalline propylene polymer may be a crystalline propylene polymer that can be heat sealed and is resistant to retort sterilization, especially tactical polypropylene, or 1 to 8 mol%, especially 3 to 6 mol%. A crystalline ethylene-propylene random or block copolymer containing mole percent ethylene is used.

In order to improve the impact resistance and, in some cases, blocking properties of polypropylene, polyisobutylene, butyl rubber, styrene-butadiene rubber,
A small amount of nidistomer such as ethylene propylene rubber can be blended.

Protective Coating Resin Layer The protective coating resin used to coat the other surface of the aluminum foil etc. is generally a thermoplastic resin or thermosetting resin having a higher melting temperature or decomposition temperature than the crystalline propylene polymer mentioned above. Polymer resins are preferably used.

Heat-resistant thermoplastic resins include polyesters such as polyethylene terephthalate, nylon 6, and nylon-6.
Examples of thermosetting resins include polyamides, polycarbonates, cellulose esters, fluororesins, etc. such as 6. , a heat-resistant polymer containing a heterocyclic ring such as a thiazole ring, such as polyimide, polyamideimide, polyesterimide, polyamideimide ester, polyesteramideimide, polyimideimidazopyrrolone, etc. can be used.

Or in addition, epoxy/phenolic resin paint, phenolic resin paint, unsaturated polyester resin paint,
Oleogenous paints and the like can also be used.

Heat-resistant thermoplastic resins can be easily made into unstretched or biaxially stretched films by hand, and these films can be attached to aluminum foil or sheets using known adhesives such as epoxy adhesives and polyurethane adhesives. Laminated, heat-infusible heat-resistant resins are formed by applying a solution of a precursor polymer of these resins to the foil or sheet and then baking.

Lamination operation In the method of the present invention, the lamination operation itself is known per se, except that the above-mentioned composition is used as the thermal adhesive layer to thermally bond aluminum foil or the like to the crystalline olefin polymer layer. It can be carried out by any operation such as extrusion lamination, extrusion coating method, heat lamination, etc.

That is, a crystalline propylene-based polymer layer is melt-extruded and coated on a modified blend resin layer of aluminum foil or a sheet on which a modified blend resin layer has been previously provided by means such as melt extrusion or electrostatic powder coating. It can be pressure bonded to a preformed crystalline propylene polymer film.

It is also possible to melt and extrude a modified blend resin between a preformed crystalline propylene polymer film and an aluminum foil or sheet, and then press them together to form a laminated sheet.

Alternatively, the modified blend resin layer and the crystalline propylene polymer layer may be simultaneously melt-extruded, and the extrudate may be fused in a position where the modified blend resin layer is adjacent to the aluminum foil or sheet to form a laminated sheet.

Further, the modified blend resin layer of the coextruded laminated film having the modified blend resin layer and the crystalline propylene polymer layer formed in advance and the aluminum foil or sheet are faced to each other,
A laminated sheet can also be made by thermocompression bonding.

In addition, if sufficient adhesive strength is not obtained during the lamination process, heat rolls, post ovens, high frequency induction heating devices,
The adhesive strength can be increased by subjecting this laminate to heat treatment using an infrared heater or the like.

Further, if necessary, the adhesive strength can be increased by post-curing the laminated sheet obtained in the lamination process in an oven after bag making.

The modified olefin resin layer can be provided as a single layer or as a plurality of layers.

For example, a layer with a relatively high carbonyl group content can be provided on the aluminum foil or sheet side, and a layer with a relatively low carbonyl group content can be provided on the crystalline propylene polymer layer side.

According to the present invention, by using the modified blend resin having the above-mentioned composition as the adhesive layer, the thermal bonding temperature is 160° C. or lower, compared to 180° C. or higher when the modified propylene polymer alone is used. In particular, lamination can be performed at a thermal bonding temperature of 140 to 160°C, which significantly increases the production speed of the laminate, and also suppresses the thermal shrinkage of the crystalline propylene polymer layer to completely eliminate the curling tendency of the laminate. It becomes possible to suppress the

Instead of providing a crystalline propylene polymer layer only on one side of the aluminum foil through a modified blend layer, it is possible to provide a crystalline propylene polymer layer on both sides of the aluminum foil through a modified blend layer. Such laminates can be used in various fields as cylindrical containers with lap seams.

Alternatively, a layer of crystalline propylene-based polymer can be provided between two sheets of aluminum foil or the like through a modified blend layer, respectively, to form a laminate in which the outer surface of the circle is a metal surface. The body is useful in fields such as decorative containers and container lids.

The thickness of the crystalline propylene polymer layer is preferably 10 to 300 microns, particularly 30 to 100 microns from the viewpoint of heat sealing, while the thickness of the modified blend resin layer is 1 to 50 microns from the viewpoint of adhesive properties. , especially preferably from 5 to 20 microns.

Application The thus produced laminated sheet is made by laminating the two pieces so that the crystalline propylene polymer layer is on the inside,
The three peripheral parts can be heat-sealed to form a flexible bag-like container.

Heat sealing can be easily performed using a heating bar, heating knife, heating wire, impulse seal, ultrasonic seal, induction heating seal, etc.

Further, the laminated sheet can be drawn or press-formed so that the crystalline propylene polymer layer is on the inside to form a rigid or semi-rigid container equipped with a heat-sealing flange.

Fill these containers with perishable foods, especially liquid foods, and remove air or other gases that are harmful to storage if necessary.
For example, after removing the gas by a vacuum degassing method, a hot filling method, a steaming degassing method, a steam injection method, a degassing method by deforming the container, or the like, the filling port is sealed by the heat sealing method described above.

Next, this package was filled into a retort device and heated to 100°C.
Above, heat sterilization is performed particularly at a temperature of 125° C. or higher.

The retort sterilization sealed package using the laminate according to the present invention does not cause any change in the flavor of the contents even during heat sterilization, and there is no change in the flavor of the contents not only after sterilization but also when subjected to drop impact, etc. It has the remarkable advantage of not causing peeling.

'The present invention will be explained below by way of examples.

Example 1 A biaxially oriented polyethylene terephthalate film with a thickness of 12μ and an aluminum foil with a thickness of 9μ were laminated using a urethane adhesive.

Also, the melting point is 159℃ and the density is 0.90? /cdl,
MI is 7. Of/10-, ethylene content is 4 mol%
ethylene propylene block copolymer with a diameter of 50 mm
Melt extrusion was performed through a single layer die using an extruder having a mmφ screw, and a film with a thickness of 50 μm was obtained by an inflation method.

Next, the laminated aluminum sheet is heated and maintained at 160°C using a high-frequency induction heating device, and an ethylene-propylene block copolymer with an ethylene content of 5 mol% is placed between the laminated sheet and the propylene copolymer film. A polymer with a carbonyl group concentration of 180 meq/1001 to which maleic anhydride is grafted, a crystallinity of 62%, a melting point of 153°C, a Vicat softening point of 140°C, and an MI of 19.
．． 0? Polymer with a carbonyl group concentration of 180 meq/100′y, in which maleic anhydride is grafted onto a 710 m1n modified propylene copolymer of 44% by weight and an ethylene-propylene random copolymer with an ethylene content of 5 mol%, and a carbonyl group concentration of 180 meq/100′y. 44% by weight of a modified propylene copolymer with a melting point of 147°C, a Vicat softening point of 135°C, and an MI of 20.0P710m, and an average carbonyl group concentration of 140 meq/100 in which maleic anhydride is grafted to low density polyethylene. ? Polymer, crystallinity 62%, melting point 108°C, MI 8. A blend of OS'/10 with 12% by weight of modified low-density polyethylene with a diameter of 65 mm
Melt extrusion was carried out through a T-die with a width of 650 mm using an extruder with a screw of 40,000 mm and a diameter of 00 m 1 φ, with the resin temperature at the die section being 260 °C, and the temperature was maintained at 70 °C and 155 °C, respectively. After being crimped with a pair of crimping rolls, it was cooled to room temperature using a cooling roll with a diameter of 400 mm to form a laminated sheet with a composition of 12μ polyethylene terephthalate layer/9μ aluminum foil/20μ modified propylene polymer blend layer and 150μ propylene copolymer layer. Obtained.

The peel strength between the aluminum foil and the propylene copolymer layer of this laminated sheet was measured and was 730f/1.5.
It was cIIL.

From the laminated sheet thus obtained, 130 m1 x 1701
Cut two rectangular pieces with a size of 1 trIL, place them facing each other so that the propylene copolymer layer is on the inside, and heat-compress the three peripheral parts at 270°C, 3 kg/cni, and 1.0 seconds. I got a bag by doing this.

200 shrimp curry for this? was filled, and the filling port was heat-sealed under the same conditions as above.

This was subjected to retort sterilization treatment at 135° C. for 10 minutes under pressure of 2.1 kg/crrt.

At this time, there was no damage to the bag due to peeling between each layer or peeling of the seal part, and the peel strength between the aluminum foil and the propylene copolymer layer after retorting was measured to be 1070P/1.5.
It was cm.

In addition, the sterilized shrimp curry was delicious, especially the flavor, which was almost the same as before sterilization.

Example 2 A biaxially stretched polyethylene terephthalate film with a thickness of 12μ and an aluminum foil with a thickness of 9μ were laminated using a urethane adhesive.

Also, the melting point is 162°C1 the density is 0.91? /cri
Isotactic polypropylene with t and MI of 7.0 g/l Q min was melt-extruded from a single-layer die using an extruder with a screw having a diameter of 50 mmφ, and a film with a thickness of 55 μm was produced by the inflation method. I got it.

Next, the laminated aluminum sheet was heated and maintained at 170°C using a high frequency induction heating device, and an ethylene film having an ethylene content of 4 mol% was placed between the laminated sheet and the polypropylene die. -Propylene block copolymer grafted with maleic anhydride and fumaric acid and has a carbonyl group concentration of 230 meq/1 oo? Heavy body, crystallinity 63%, melting point 156°C, MI 22
．． OS'/10m modified propylene copolymer 84% by weight
Ethylene-propylene copolymer rubber (EPR) with a propylene content of 35 mol% and a carbonyl group concentration of 200 meq/100?
Polymer, characteristic ethylene-propylene copolymer rubber with an average molecular weight of 100,000 8% by weight and maleic anhydride grafted to low density polyethylene with an average carbonyl group concentration of 140 meq/100? Polymer, crystallinity 62%,
Melting point is 108℃, MI is 8.0? /10m1n of a blend of 8% by weight of modified low density polyethylene was melt-extruded through a T-die with a width of 650mm under conditions where the resin temperature at the die part was 250°C using an extruder having a screw with a diameter of 65mm. is so 'c and 155℃
After crimping with a pair of crimping rolls with diameters of 400 mmφ and 200 mmφ, which were held in the same position, the mixture was cooled to room temperature with a cooling roll with a diameter of 400 mmφ, and the composition was a 12μ polyethylene terephthalate layer/9μ aluminum foil/15μ modified propylene polymer blend. A laminated sheet of 155μ polypropylene layer was obtained.

The peel strength between the aluminum foil and polypropylene layer of this laminated sheet was measured and was 670 to 71.5 c.
It was m.

From the thus obtained laminated sheet, 130 mm x 170
Cut two rectangular pieces of the same size, place them facing each other so that the polypropylene layer is on the inside, and then
A bag was obtained by thermocompression bonding at 70° C. and 3 kg/c for 4.1.0 seconds.

This was vacuum-degassed and filled with 150 y of grilled eel, and the filling opening was heat-sealed with an impulse sealer.

This was subjected to retort sterilization treatment at 135° C. for 10 minutes under a pressure of 2.1 kg/cnl.

At this time, there was no damage to the bag due to peeling between each layer or peeling of the seal, and the peel strength between the aluminum foil and polypropylene layer after retorting was measured to be 920 f? / 1.5
It was CrrL.

In addition, the sterilized eel kabayaki was delicious, especially the flavor was good, and was almost the same as the one before sterilization.

Comparative Example 1 In Example 1, instead of the modified propylene copolymer used as the adhesive resin, an ethylene-propylene block copolymer with an ethylene content of 5 mol% was grafted with maleic anhydride and the carbonyl group concentration was 0.5meq/
100? When a polymer with a low degree of modification was used,
The resulting laminated sheet had low interlayer peel strength, and significant peeling occurred during retort treatment.

Comparative Example 2 In Example 1, instead of the modified propylene copolymer used as the adhesive resin, maleic anhydride was added to an ethylene-propylene block copolymer with an ethylene content of 95 mol% and a propylene content of 5 mol%. The concentration of carbonyl group grafted is 180 meq/100? When a modified ethylene polymer was used as the polymer, the interlayer peel strength between the modified ethylene polymer blend layer and the propylene copolymer layer of the obtained laminated sheet was weak, and significant peeling occurred during retort treatment.

Comparative Example 3 In Example 1, instead of the ternary blend of modified propylene copolymer used as the adhesive resin, a binary blend consisting only of a modified propylene copolymer to which no modified low-density polyethylene was added was used. Since the interlayer peel strength of the obtained laminate sheet was low, the sealing strength of the bag made of this laminate was extremely low, making it unsuitable for use as a retort pouch.

Comparative Example 4 In Example 1, instead of the ternary blend of modified propylene copolymers used as the adhesive resin, each resin was the same, but the proportion of the blend was 35% by weight of modified ethylene-propylene-block copolymer. When a blend with a high content of modified low-density polyethylene, which is 30% by weight of modified ethylene-propylene random copolymer and 35% by weight of modified low-density polyethylene, was used, the laminated sheet obtained had sufficient lamination strength before retorting. However, the temperature was 135℃/
Peeling occurred between the layers after 10 minutes of retort treatment.

Comparative Example 5 In Example 2, instead of the modified propylene copolymer ternary blend used as the adhesive resin, only the modified propylene copolymer was used without adding modified ethylene-propylene copolymer rubber or modified low-density polyethylene. When used, the sealing strength of the bag made of this laminate was extremely weak due to the low interlayer peel strength of the obtained laminate sheet, making it unsuitable for use as a retort pouch.

Comparative Example 6 In place of the modified ethylene-propylene/copolymer ternary blend used as the adhesive resin in Example 2, each resin was the same, but the proportion of the blend was 65% by weight of modified ethylene-propylene random copolymer. %, modified ethylene-propylene copolymer rubber 20% by weight, modified low density polyethylene 15%
% by weight, the resulting laminated sheet had sufficient lamination strength before retorting, but delamination occurred after retorting at 135° C. for 10 minutes.

In particular, this laminate had poor oil resistance, and when it was filled with salad oil, there was a tendency for delamination even when retorted at 125° C. for 30 minutes.

Example 3 A biaxially stretched polyethylene terephthalate film with a thickness of 12μ and an aluminum foil with a thickness of 9μ were laminated using a urethane adhesive.

Next, a polymer with a carbonyl group concentration of 120 meq/1001 and a crystallinity of 6 was prepared by grafting maleic anhydride and citraconic anhydride onto isotactic polypropylene.
4%, melting point 163°C, MI 10.01/10771
Maleic anhydride and citraconic anhydride are grafted onto an ethylene-propylene random copolymer containing 40% by weight of modified polypropylene of No. 171 and 5 mol% ethylene content, and the carbonyl group concentration is 350 meq/100? Polymer, crystallinity 52%, melting point 154°C, MI 16.0
P/10- modified propylene copolymer 40% by weight, medium density polyethylene grafted with maleic anhydride and citraconic anhydride, carbonyl group concentration 250 meq/
100 tiI heavy body, crystallinity 61%, melting point 11
8℃, MI 10.0? 710ml modified medium density polyethylene 10% by weight and ethylene content 62mol%
, maleic anhydride and citraconic anhydride were grafted onto ethylene fluoropylene-diene copolymer (EPDM) with a 35 mol% fluoropylene content and 3 mol% 1,4-hexadiene content, and a carbonyl group concentration of 280 meq. /
1009 polymer, modified EP with an average molecular weight of 100,000
A blend containing 0% DMI was produced using a first extruder having a screw with a diameter of 50 mm, and a blend with a melting point of 154
°C1 density is 0.90P/c11t, MI is 10.0
P/10 - 92% by weight ethylene-propylene block copolymer with 5 mol% ethylene content and an average molecular weight of 1
00,000, ethylene content is 62 mol%, propylene content is 35 mol%, 1,4-hexadiene content is 3 mol%
ethylene-propylene-diene copolymer (EPDM)
The 8% by weight blend was coextruded using a second extruder with a screw with a diameter of 65 mm and 1φ, and a T-shaped two-layer double die with a width of 650 threads kept at a temperature of 240°C. The two-layer laminate and the aluminum laminate, which had been previously heated and maintained at 180°C by a high-frequency induction heating device, were heated to 50°C and 150°C, respectively, and had a diameter of 400°C.
After crimping with a pair of crimping rolls of mmφ and 200 mmφ,
Cooled to room temperature using a cooling roll with a diameter of 400vtmφ, and the composition was 12μ polyethylene terephthalate layer/9μ.
A laminated sheet of aluminum foil/10μ modified propylene polymer blend layer/60μ propylene polymer blend layer was obtained.

The peel strength between the aluminum foil and the propylene polymer blend layer of this laminated sheet was measured and was 83M'/1.
It was 5.

130miX170r from the thus obtained laminated sheet
Cut two rectangular pieces with a size of ltm, place them facing each other so that the propylene polymer blend layer is on the inside, and prepare the three peripheral parts at 270°G, 3k19/crrc, 1.0
A bag was obtained by thermocompression bonding under conditions of 2 seconds.

Chicken potage soup and 200 yen for this? Fill it with
The filling port was heat sealed under the same conditions as above.

This was subjected to retort sterilization treatment at 135° C. for 10 minutes under a pressure of 2.1 to 9/crA.

At this time, there was no damage to the bag due to peeling between each layer or peeling of the seal part, and the peel strength between the aluminum foil and the propylene polymer blend layer after retorting was measured to be 920S'/
It was 1.5 crrL.

In addition, the pasteurized chicken potage soup was delicious, especially the flavor, which was almost the same as before pasteurization.

Example 4 Biaxially oriented polyethylene terephthalate with a thickness of 12μ
The film and aluminum foil with a thickness of 9 μm were laminated using a urethane adhesive.

Next, maleic anhydride, fumaric acid, and vinyl acetate were grafted to an ethylene-propylene random copolymer with an ethylene content of 5 mol%, and the carbonyl group concentration was 240.
meq/100? Polymer, 88% by weight of a modified propylene copolymer with a degree of crystallinity of 57%, a melting point of 154° C., an MI of 6.01lii'710m and an ethylene-propylene copolymer rubber (EPR) with a propylene content of 35 mol%. The concentration of carbonyl groups grafted with maleic anhydride, fumaric acid, and vinyl acetate is 240 meq/100? Polymer, modified EPR 12% by weight with an average molecular weight of 100,000
Using a first extruder having a screw with a diameter of 50 mmφ, a blend of
0g/-1MI is 7. Of/10 - ethylene content is 4
Mol% of ethylene-propylene block copolymer was extruded using a second extruder with a screw having a diameter of 6511 LrrLφ, and the temperature was kept at 250°C.
Coextrusion was carried out using a double gouer for layers, and a two-layer coextruded film with a thickness of 70 μm was obtained by the T-die method.

Next, this two-layer coextruded film and the aluminum laminate are combined, and the diameter of the film is maintained at 160°C.
After crimping with a pair of rolls of 00 mrrtφ and 150 m1φ, it was cooled to room temperature using a cooling roll with a diameter of 400 mmφ, and the composition was 12μ polyethylene terephthalate layer/9
A laminated sheet of μ aluminum foil/10 μ modified propylene polymer blend layer/60 μ propylene copolymer layer was obtained.

The peel strength between the aluminum foil and propylene copolymer layer of this laminated sheet was measured and was 710 f/1.5c.
It was rrL.

From the thus obtained laminated sheet, 1301m x 170cm
Cut out two rectangular pieces of size, place them facing each other so that the propylene copolymer layer is on the inside, and thermocompress the three peripheral parts under the conditions of 270°C, 3 kg/lsl, and 1.0 seconds. Got a bag by doing that.

This was filled with hamburger steak No. 1202, and the filling opening was heat-sealed under the same conditions as above.

This was subjected to retort sterilization treatment at 135°C for 12 minutes under a pressure of 2.1 kg/cat.

At this time, there was no damage to the bag due to peeling between each layer or peeling of the seal part, and the peel strength between the aluminum foil and the propylene copolymer layer after retorting was measured to be 8201/1.5c.
It was frL.

Also, sterilized hamburger steaks are delicious.
The flavor was particularly good, almost the same as before sterilization.

Example 5 A biaxially stretched polyethylene terephthalate film with a thickness of 12μ and an aluminum foil with a thickness of 9μ were laminated using a urethane adhesive.

Also, the melting point is 159℃ and the density is 0.90f/cr? L,
MI is 7. Off/101ru! 1. An ethylene propylene block copolymer with an ethylene content of 4 mol% was melt-extruded from a single layer gouer using an extruder having a screw with a diameter of 50 mm, and a film with a thickness of 50 μ was obtained by the inflation method. .

Next, the laminated aluminum sheet was heated and maintained at 170°C using a high-frequency induction heating device, and an ethylene content of 5 mol%, a melting point of 154°C, an MI is 14. Og/1
39% by weight ethylene propylene floc copolymer, ethylene content 4 mol%, melting point 148°C, MI
39% by weight of ethylene-propylene random copolymer with 20.0 t/10%, melting point 109°C, MI 1
0. Ot? / 10m1IL low density polyethylene 12
Ethylene-propylene copolymer rubber 10 having a weight% and propylene content of 35 mol% and an average molecular weight of 100,000
The average concentration of carbonyl groups grafted with maleic anhydride to the blend by weight% is 250 meq/100? The modified blend of polymers was melt-extruded through a T-die with a width of 650 mm under the condition that the resin temperature at the die part was 250 °C using an extruder having a screw with a diameter of 6511LrILφ, and the temperature was maintained at 80 °C and 155 °C, respectively. After crimping with a pair of pressure rolls with diameters of 400mm and 200mm, the mixture was cooled to room temperature using a cooling roll with a diameter of 400mm, and the composition was 12μ polyethylene terephthalate layer/9μ aluminum foil/20μ modified propylene polymer. A laminated sheet having a blend layer of 150μ propylene copolymer layer was obtained.

When the peel strength between the aluminum foil and the propylene copolymer layer of this laminated sheet was measured, it was 730 P/1.
It was 5CrrL.

Two rectangular pieces measuring 130 mm x 170 mm were cut out from the laminated sheet thus obtained, and placed facing each other so that the propylene copolymer layer was on the inside. A bag was obtained by thermocompression bonding for 0 seconds.

This was filled with mapo tofu base 1201, and the filling opening was heat-sealed under the same conditions as above.

This was subjected to retort sterilization treatment at 135° C. for 10 minutes under a pressure of 2.1 kg/ca.

At this time, there was no damage to the bag due to peeling between each layer or peeling of the seal part, and the peel strength between the aluminum foil and propylene copolymer layer after retorting was measured to be 8101/1.5C.
It was IrL.

In addition, the flavor of the sterilized mapo tofu base is good,
It was almost the same as before sterilization.

Example 6 A biaxially stretched polyethylene terephthalate film with a thickness of 12μ and an aluminum foil with a thickness of 30μ were laminated using a urethane adhesive.

Also, the melting point is 146℃ and the density is 0.90? /cd, M
An ethylene-propylene random copolymer with an I of 7.0 f/10 m and an ethylene content of 4 mol% was melt-extruded from a single-layer die using an extruder having a screw with a diameter of 50 mm, and the inflation method was performed. Thickness by 50
A film of μ was obtained.

Next, the laminated aluminum sheet is heated and maintained at 160°C using a high frequency induction heating device, and an ethylene propylene random copolymer with an ethylene content of 5 mol% is placed between the laminated sheet and the propylene copolymer film. A carbonyl group concentration of 180 meq/1005' polymer to which maleic anhydride is grafted, a melting point of 147°C, M
I is 20.0? /10a I7+ modified propylene copolymer 83% by weight and ethylene propylene copolymer rubber (EPR) with a propylene content of 35 mol%, maleic anhydride grafted to a carbonyl group concentration of 200 meq/
100? Polymer, 7% by weight of modified ethylene-propylene copolymer rubber with an average molecular weight of 100,000 and a density of o,
93? /cft, Vicat softening point is 82°C, MI is 9
．． Or/10 theory, a blend of 10% by weight of an ethylene-acrylic acid copolymer with an acrylic acid content of 8% was produced using an extruder having a screw with a diameter of 65 mm at a resin temperature of 240°C at the die part. Width 650m
Melt extrusion was carried out from a T-die of m, and the temperature was 80℃ and 16℃.
After crimping with a pair of crimping rolls with diameters of 400 mm and 200 mm, each held at 0°C, it was cooled to room temperature using a cooling roll with a diameter of 400 mm, and the composition was 12μ polyethylene terephthalate layer/30μ aluminum foil. /20μ
A laminated sheet having a modified propylene polymer blend layer and a 150μ propylene copolymer layer was obtained.

The peel strength between the aluminum foil and the propylene copolymer layer of this laminated sheet was measured and was 841/1.5C.
It was m.

By drawing the thus obtained laminated sheet, a cylindrical container having a diameter of 8 tubes, a depth of 2 cm, and a flange was obtained.

This was filled with cheese, and the flange portion was heat-sealed with the lid material made of the laminated sheet.

This was subjected to retort sterilization treatment at 130°C for 15 minutes.

At this time, there was no peeling between the layers or peeling of the seal portion.

The pasteurized cheese was delicious, especially the flavor.

Example 7 A biaxially stretched polyethylene terephthalate film with a thickness of 12μ and an aluminum foil with a thickness of 9μ were laminated using a urethane adhesive.

Also, the melting point is 159℃ and the density is 0.90? /criL
An ethylene propylene block copolymer having an MI of 7.0 P/10# and an ethylene content of 4 mol% was melt-extruded using a single-layer die using an extruder having a screw with a diameter of 50 mgφ, and then the inflation method was performed. A film with a thickness of 50 μm was obtained.

Next, the laminated aluminum sheet is heated and maintained at 160° C. using a high-frequency induction heating device, and a block copolymer of ethylene propylene with an ethylene content of 5 mol% is placed between the laminated sheet and the propylene copolymer film. A carbonyl group concentration of 250 meq/100P polymer with maleic anhydride, fumaric acid and vinyl acetate grafted to the polymer, crystallinity of 56%, melting point of 151°C, MI of 12
．． 0? 2% by weight of acrylic acid was grafted onto a 90% hydrolyzate of 85% by weight of a modified propylene copolymer of 710ml1n and an ethylene-vinyl acetate copolymer with a vinyl acetate content of 33% by weight, with a melting point of 103°C and a density of 0.96f
A blend of 15 wt. Melt extrusion was performed using a T-die, and after crimping with a pair of pressure rolls with diameters of 400 mmφ and 200 mmφ held at temperatures of 70°C and 160°C, respectively, cooling rolls with a diameter of 400 mmφ cooled to room temperature, and the composition was made of 12μ polyester. A laminated sheet of modified ethylene terephthalate layer/9μ aluminum foil/20μ modified propylene polymer blend layer and 150μ propylene copolymer layer was obtained.

The peel strength between the aluminum foil and propylene copolymer layer of this laminated sheet was measured and was 640? /1.
It was 5cIrL.

130mm x 170m from the thus obtained laminated sheet
Cut out two rectangular pieces of size m, place them facing each other so that the propylene copolymer layer is on the inside, and heat the peripheral parts on three sides at 270°C and 3kg/c4. A bag was obtained by thermocompression bonding for 1.0 seconds.

This was filled with meat balls 1201, and the filling opening was heat-sealed under the same conditions as above.

This was retort sterilized at 135°C for 10 minutes under a pressure of 2.1 kg/crA.

At this time, there was no damage to the bag due to peeling between each layer or peeling of the seal part, and the peel strength between the aluminum foil and the propylene copolymer layer after retorting was measured and was 810? / 1.
It was 5crrL.

Also, the pasteurized meatballs were delicious, especially the flavor, which was almost the same as before pasteurization.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a laminated sheet according to the present invention. 1... Laminated sheet, 2... Aluminum foil or sheet, 3... Propylene resin blend layer, 4... Crystalline propylene resin layer,
5...Adhesive layer, 6...Heat-resistant wood layer.

Claims (1)

[Scope of Claims] 1. A method for producing a laminate comprising thermally adhering an aluminum foil or sheet to a crystalline propylene polymer layer via an adhesive layer of a thermoplastic resin, wherein the adhesive layer ( A) Carbonyl group content is 1 to 600 meq/
100? A crystalline modified propylene polymer at a concentration of the polymer and (B) a carbonyl group content of 1 to 60
From a crystalline modified ethylene polymer having a concentration of 0 meq/100 Si' polymer and a modified ethylene-furopylene copolymer rubber having a carbonyl group content of 1 to 600 meq/100r polymer (C) and at least one polymer selected from the group consisting of: a blend in which said polymer B) or (C) is present in an amount of 3 to 30 parts by weight per 100 parts by weight of said polymer A); A method for manufacturing a laminate, characterized in that it is made of a material. 2. The method according to claim 1, wherein the thermal bonding is carried out at a temperature of 140 to 160°C. 3. The method according to claim 1, wherein the blend is melt-extruded in layers between an aluminum foil or sheet and a pre-formed crystalline propylene polymer film to thermally bond the laminate. . 4 Co-melt extrusion of the blend and the crystalline propylene polymer in a layered manner, and thermally bonding the extrudate to an aluminum foil or sheet in a positional relationship where the blend layer faces the aluminum foil or sheet. A method according to claim 1.