JPS601225B2 - Transparent laminated film container with excellent dimensional stability and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated film container with excellent dimensional stability and a method for manufacturing the same, and more specifically, the present invention relates to a laminated film container with excellent dimensional stability and a method for manufacturing the same, and more specifically, a nylon film whose molecules are oriented in the Nito direction and a crystalline oleftine resin layer are The present invention relates to a container using a laminated film bonded with a thermal adhesive without losing orientation, and a method for manufacturing the same.

Taking advantage of the properties of nylons, which have excellent mechanical strength and gas barrier properties, and polyolefins' excellent moisture resistance and heat sealing properties, a transparent laminated film container is created by laminating a polyolefin layer and a nylon layer. However, since polyolefin and nylon have poor mutual adhesion, it is necessary to use some kind of bonding method that can withstand harsh treatments such as tort sterilization during the production of laminated films. There must be.

The most common method for bonding an olefin resin layer and a nylon layer is the so-called dry lamination method, in which a preformed olefin resin film and nylon film are bonded using a thermosetting adhesive such as a polyurethane adhesive.
When this dry lamination laminated film is used as a sealed film container for retort sterilization, some problems arise in terms of flavor retention of the food contents. In other words, polyurethane resin is a complex thermosetting resin composition containing uncondensed monomers and relatively low molecular weight condensates, and in the packaging described above, the thermosetting adhesive layer is made of high barrier nylon. Because it is always located inside the layer, harsh treatments such as retort sterilization tend to cause the aforementioned uncondensed substances and low-molecular striped polymers to migrate into or interact with the food contents. be.

In addition, the above-mentioned thermosetting adhesives are generally provided in a diluted form with organic solvents such as toluene, ethyl acetate, methyl ethyl ketone, etc. Such thermosetting adhesives are used to bond nylon and crystals. When laminating polyolefin resin films, a step is taken in which the adhesive is applied to nylon, the solvent is dried in a hot air oven, and then the adhesive is laminated using pressure bonding.
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, packaging made of a laminated film in which a crystalline olefin resin layer and nylon, etc. are bonded together using a thermosetting adhesive has an excellent preservability, but is still lacking in terms of preserving the flavor of the food contents. The results were not completely satisfactory.In order to improve these drawbacks, numerous attempts have been made to directly thermally bond the olefin resin layer and the nylon layer without using a thermosetting adhesive or the like. Attempts are being made.

These attempts involved chemically modifying one or both of olefin resins and nylon resins, which do not have mutual thermal adhesive properties, or blending them with ionomers and modified olefin resins, and coextruding both to form laminate molded products. It consists of things. This method of producing a laminated film by coextrusion has the advantages of easy operation and relatively good interlayer adhesion between the olefin resin layer and the nylon layer, but the resulting laminated film is Properties such as mechanical strength L, dimensional stability, transparency and gas barrier properties are still not fully satisfactory. In other words, it is known that the various properties mentioned above, such as mechanical strength, dimensional stability, transparency, and gas barrier properties, are significantly improved by biaxial molecular orientation of nylon. In the extrusion method, it is extremely difficult to impart biaxial molecular orientation to the nylon layer, and the resulting film container 0 is inevitably inferior in these properties.

As a method for producing a laminated film comprising an olefin resin layer and a nylon layer, a method of thermally bonding a pre-formed double-stretched nylon film and an olefin resin film via a thermoplastic resin adhesive has not yet been proposed. It seems very strange that there is no such thing, but the reason for this is thought to be due to the fact that nylon, in its unmolten state, does not exhibit sufficient adhesion to most thermoplastic resin adhesives such as modified olefin resins and ionomers. 0 The present inventors interposed a thermal adhesive layer containing a nylon-modified olefin resin in parallel positions in a molten state between a biaxially oriented nylon film and a crystalline olefin resin layer. In some cases, ``the nylon film can be thermally bonded without substantially losing its molecular orientation, and when the laminated film thus formed is used in the production of film containers, ``it has excellent delamination resistance. It has been found that a transparent laminated film container having excellent strength, dimensional stability, transparency, gas barrier properties, printability, etc. can be obtained.

According to the present invention, “the laminated film material constituting the container is
An outer layer made of a nylon film with molecules oriented in the two-koji direction, an inner layer made of a crystalline olefin resin layer, and a thermal adhesive layer interposed between both layers, and this thermal adhesive layer is located on the nylon film side. The carbonyl group content located on the unoriented nylon resin layer and crystalline olefin resin layer is at a concentration of 1 to 60 "eq. 100" and the constituent olefin units are the same type as the crystalline olefin resin. A transparent laminated film container with excellent dimensional stability is provided, which is characterized by being comprised of a modified olefin resin layer.

According to the present invention, the nylon resin and the carbonyl group content of 1 are further bonded between the nylon film whose molecules are oriented in the bifocal direction and the preformed crystalline olefin resin film.
A modified olefin resin having a concentration of 60 skin eq/10M polymer and whose constituent olefin units are the same type as the crystalline olefin resin is placed in a parallel position, with the nylon resin layer facing the nylon film and the modified olefin resin layer facing the olefin resin. Provided is a method for producing a transparent laminated film container with excellent dimensional stability, characterized by performing simultaneous melt extrusion and sandwich lamination so that the resin film is located on the resin film side, and molding the formed laminated film into the shape of the container. Ru.

The invention will be explained in detail below.

In FIG. 1 showing the cross-sectional structure of the laminated film used in the present invention, the laminated film consists of a nylon film 2 with molecules oriented in biaxial directions, a crystalline olefin resin layer 3, and a thermal adhesive layer applied between the two. It consists of 4 and 5.

This thermal adhesive layer consists of a nylon layer 4 located on the nylon film side and a modified olefin resin layer 5 located on the crystalline olefin resin layer side, and is between the nylon film 2 and the crystalline olefin resin layer 3. A distinctive feature of the present invention is that thermal bonding is performed by intervening in a molten state. First, when the modified olefin resin layer 5 is interposed alone in a molten state between the nylon film 2 and the crystalline olefin resin layer 3, as shown in Comparative Example 1 described later, the Only very weak interlayer adhesion occurs, and in order to obtain a satisfactory interlayer adhesion strength of 500°/1.5° or higher, the nylon film 2 must be heated to a temperature of at least 2000°C or higher.

Due to such heating, the nylon film 2 shrinks significantly, and furthermore, there is a drawback that the molecular orientation that has been given so much effort is relaxed. In contrast, according to the present invention, the modified olefin resin and nylon are simultaneously melt-extruded in parallel positions, and sandwich laminated so that the nylon layer is on the nylon film 2 side and the modified olefin resin layer is on the crystalline polyolefin layer 3 side. Sometimes 500 between both layers
It is possible to form an interlayer bond with an adhesive strength of 1.5 cm or more, and it is also possible to maintain the dual molecular orientation of the nylon film substantially as it is. Examples of the polyamide constituting the nylon film include various homopolyamides, copolyamides, and blends thereof.

Such polyamides include, for example, the following amide repeating unit, i.e., one CO-R-NH-
......'1} or -CO-RI-CONH-
R2-NH-……. ．． ．． Mention may be made of homopolyamides, copolyamides, or blends thereof having an amide repeating unit of the formula {2}, in which R, RI and R2 each represent a linear alkylene group or a xylylene group.

From the viewpoint of gas barrier properties against oxygen, carbon dioxide, etc., homopolyamides, copolyamides, or these polyamides in which the number of amide groups per 100 carbon atoms in the polyamide is in the range of 3 to 3, particularly 4 to 2. It is preferable to use a blend of. Examples of suitable homopolyamides are polycapramide (nylon 6) poly-aminoheptanoic acid (nylon 7) poly-aminoheptanoic acid (nylon 7) polyundecaneamide (nylon 11) polylaurinlactam (nylon 12)
) Polyethylenediamine adipamide (nylon 2,6) polytetramethylene adipamide (nylon 4,6) polyhexamethylene adipamide (nylon 6,6) polyhexamethylene sebacamide (nylon 6,10) ) polyhexamethylene dodecamide (nylon 6,12) polyoctamethylene adipamide (nylon 8,6) polydecamethylene adipamide (nylon 10,6) polydodecamethylene sebaamide (nylon 10,8) These include taxylylene adipamide, polymethaxylylene beramid, polymethaxylylene sebamide, polymethaxylylene decanedionamide, and the like.

Examples of suitable copolyamides include caprolactam/laurinlactam copolymer, caprolactam/hexamethylene diammonium adipate copolymer, lauryl lactam/hexamethylene diammonium adipate copolymer, hexamethylene diammonium Adibate/hexamethylene diammonium sebacate copolymer, ethylene diammonium adipate/hexamethylene diammonium adipate copolymer "cabrolactam/hexamethylene diammonium adipate/hexamethylene diammonium sebacate" -Copolymer~ Polymethacrysilene/
Paraxylylene adipamide copolymer Z polymer, polymethacrylic IJ
Silennopara-xylylene pimeramide copolymer "polymethaxylylene/para-xylylene veramide copolymer, poly
Examples include metaxylylene/paraxylylene sebamide copolymer, polymethaxylylene/paraxylylesodecanedionamide copolymer, and metaxylylene/polyxylylene adipamide/caprolactam copolymer.

These homopolyamides and copolyamides can also be used in the form of so-called blends, such as blends of polycaprolactam and polyhexamethylene adipamide, polycaprolactam and caprolactam nohexamethylene diammonium adipamide copolymers. Blends of polymethaxylylene/paraxylylene adipamide copolymer and polycaprolactam can all be used for the purpose of the present invention.The molecular weight of these polyamides is also generally within a range that allows film forming ability. ``It can be used without any particular restrictions, but the relative viscosity (rel.
)but】. A range of 8 to 3.5 is generally desirable.

These polyamides are used in the form of biaxially molecularly oriented films.

Generally, the molecular orientation of polymers is expressed by the molecular orientation coefficient,
The nylon film used in the present invention has an in-plane orientation coefficient, that is, the sum of the meandering coefficient x in the longitudinal direction (machine direction) of the film and the meandering coefficient y in the transverse direction, which is generally 0.65 or more, particularly 0.7.
It is important that the ratio is set within the range of 0 to 0.95. Such orientation is generally obtained by simultaneous double stretching, sequential biaxial stretching in the vertical direction, or sequential double direction stretching in the transverse and total directions, but it can also be obtained by self-directed crystallization during melt molding of the film. It is also possible. Further, rolling can also be used as a means for molecular orientation. In this specification, "orientation coefficient" refers to the degree of orientation of a film in a specific direction determined by birefringence measurement.
, when the orientation coefficient in the transverse direction is expressed as y and the orientation coefficient in the thickness direction of the film is expressed as z, the value is determined so that ×1yy1z=1.

Details of the method for calculating the orientation coefficient are as follows.

It is well known that, in general, polymers have different refractive indexes in the long-axis and short-axis directions of the molecules. Therefore, when a polymer film or sheet is stretched, the molecular chains become oriented in the stretching direction, and the refractive index is different in the direction of orientation and in the direction perpendicular to it, and the difference in these refractive index values is called birefringence. Defined. Here, orthogonal three-dimensional coordinates (x, y; z)
, where the x direction is the longitudinal direction of the film, the y direction is the horizontal direction, the x direction is the thickness direction, and the refractive index in each direction is nx, ny, nz, then the following formula n
i=(nn-n,)iten, (i=x,y,z).・…
．． ....

6} In the formula, n is the refractive index in the direction from the vehicle when the sample is completely oriented, and n. is the refractive index in the direction perpendicular to the axial direction in the case of completely uniaxial feeding orientation, and i (i=X, y-shaped Z) is the refractive index of R. S. These are the orientation coefficients in each direction defined by STEIN et al.

0 is established.

Each of nn and n has a unique value depending on the thermoplastic resin.

Therefore, birefringence, △x=nZ−ny 亨△n=nZ−n
If any two of the five values of x'△Z=nx-ny are measured, RS. STEIN report (J.polyme
The orientation coefficient t×'y'z is determined based on rSci, 24 "383 (1957)).

Examples of crystalline olefin resins include known olefin resins that are heat-sealable and can withstand suitable tort sterilization, such as low, medium to high density polyethylene, isotactic polypropylene, polybutene-1, 4-
Methylbentene-1, polyolefin of ethylene-propylene copolymer, or blends thereof are used.

In order to improve the impact resistance and, in some cases, the blocking property of the polyolefin, a small amount of an elastomer such as polyisobutylene, butyl rubber, styrene butadiene rubber, ethylene propylene rubber, etc., for example, 1 to 3% by weight, is blended with the crystalline olefin resin. can do. The molecular weight of the crystalline olefin resin may be sufficient as long as it can form a film, and generally the melt index (MI) is 0.
．． 2 to 50 evenings/10 minutes, especially 2 to 25 evenings/cape minutes, is preferably used.

When the crystalline olefin resin layer is a preformed film, this film may be an unstretched film such as a so-called cast film, or a film stretched in the transverse direction. good. The modified olefin resin has a tocarponyl group content of 1 to 60 heq/1.
A modified olefin resin which is a 10 to 30 heq/100 multipolymer and whose constituent olefin units are substantially the same as the crystalline olefin resin is used. Preferably, as the modified olefin resin, a known carbonyl group-containing unsaturated monomer is added to the primary mirror or side of the olefin resin by means such as graft copolymerization, block copolymerization, random copolymerization, or terminal treatment. Among those introduced into the chain, those that satisfy the above conditions are used. Examples of carbonyl group-containing ethylenically unsaturated monomers include carboxylic acids, carboxylic acid salts, carboxylic acid anhydrides,
An ethylene unsaturated compound having a carboninyl group based on a carboxylic acid ester, a carboxylic acid amide or imide, an aldehyde, a ketone, etc. alone or in combination with a cyano (one C=N) group; a hydroxy group: an ether group; an oxirane ring, etc. One or a combination of two or more monomers can be used, suitable examples of which are as follows.

A Ethylenically unsaturated carboxylic acid: acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, 5-norbornene-273-dicarboxylic acid.

B Ethylenically unsaturated hydroruboxic acid anhydride: maleic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride.

C Ethylenically unsaturated ester: ethyl acrylate, methyl methacrylate, acrylic acid 2
-ethylhexyl, mono- or di-maleic acid.

Ethyl, vinyl acetate "vinyl propionate, propyl dihydroxymethacrylate, ethyl 8-hydroxyacrylate, glycidyl acrylate, glycidyl methacrylate, 8-N-ethylaminoethyl acrylate.○
Ethylenically unsaturated amides and imides: acrylamide, methacrylamide, maleimide.

B Ethylenically unsaturated aldehyde or ketone: acrolein, methacrolein, vinyl methyl ketone, vinyl butyl ketone.

In the present invention, among the above-mentioned monomers, ethylenically unsaturated carboxylic acid or ethylenically unsaturated hydroluponic acid is particularly preferred, and these monomers may be used alone or in combination with other monomers. Used in combination with to modify olefin resins.

These carbonyl group-containing polymers are bonded to the royal chain or side chain of the olefin resin in such a way that the concentration of the polar group is within the above-mentioned range, and more preferably, the crystallinity of the modified olefin resin is at least 15%. be done.

Examples of the olefin include one or a combination of two or more of ethylene, propylene, butene-1, bentene-1,4-methylbentene-1, etc., which satisfy the above-mentioned conditions.

In order to modify an olefin resin so as to satisfy the above-mentioned conditions, for example, in the case of graft treatment, an olefin resin with a degree of crystallinity higher than 15% is selected as the raw material olefin resin, and the olefin resin is It is necessary to carry out the grafting treatment under conditions such that the degree of crystallinity does not fall below 15%.

For this purpose, high-crystalline materials such as high-density polyethylene, isotactic polypropylene, or ethylene-propylene copolymers are preferably used as the backbone polymer, and furthermore, there is virtually no decrease in crystallinity. Under such mild grafting conditions, medium density polyethylene or low density polyethylene with a degree of crystallinity greater than 15% may also be used. The above-mentioned grafting process can be carried out under conditions known per se, apart from the above-mentioned limitations.

For example, a modified olefin resin can be easily produced by bringing a backbone polymer consisting of an olefin resin into contact with a carbonyl group-containing ethylenically unsaturated monomer in the presence of a radical initiator or radical initiation means. The polymer and monomer can be brought into contact in a homogeneous solution system, a solid-liquid or solid-liquid heterogeneous system, or a molten homogeneous system. Examples of initiators include dicumyl/di-oxide, t-butylhydronogoxide, Organic peroxides such as dibenzoylnoglyoxide (dilauroyl peroxide) and asonitriles such as azobisisofuthyronitrile and azobisisopropionitrile are used in catalytic amounts known per se. Radical initiation Examples of methods include ionizing radiation such as X-rays and beam electron beams; ultraviolet rays or a combination of ultraviolet rays and a sensitizer; and two mechanical radical initiation methods such as mastication and ultrasonic irradiation. For example, in a homogeneous solution reaction, the olefin resin, monomer, and initiator are
Even if toluene is dissolved in an aromatic solvent such as xylene or tetralin and grafted, the modified olefin resin produced is precipitated and recovered.

Furthermore, even in a heterogeneous reaction, grafting is carried out by bringing the olefin resin powder into contact with the monomer or a diluted solution of the monomer under irradiation with ionizing radiation. Furthermore, in a homogeneous melt system reaction, a blend of three olefin resin monomers or an initiator is melted and mixed in an extruder or kneader to obtain a modified olefin resin. In any of these cases,
The resulting modified olefin resin can be subjected to purification treatments such as washing and extraction to remove unpolymerized monomers, homopolymers, initiator residue, etc.3. The particle size of the resin can also be adjusted by subjecting it to the aforementioned recrystallization operation in an aromatic solvent and changing the crystallization conditions at that time.Thus,
The modified olefin resin 4 used in the present invention can be easily obtained.

Another example of the modified olefin resin having the above-mentioned carbonyl group content concentration is polyethylene oxide.

As the oxidized polyethylene used in the present invention, polyethylene oxide that satisfies the above-mentioned requirements is used, which is obtained by oxidizing polyethylene or a copolymer mainly composed of ethylene, if desired, in a melt or solution state. be done.

In the present invention, the above-mentioned modified olefin resins can be used alone or in the form of a blend of two or more types.

Moreover, this modified olefin resin can also be used in the form of a blend with a crystalline olefin resin. In any of these cases, it is sufficient that the final resin composition has a carbonyl group content and a main composition of olefinic monomers within the range specified in the present invention. The molecular weight range of the modified olefin resin is the same as that of the crystalline olefin resin. As the nylon used as the thermal adhesive layer, the same polyamide, copolyamide, or polymer blend as in the case of the nylon film is used.

In this case, it is desirable for the polyamide constituting the film and the polyamide used as the thermal adhesive to share the same main amide repeating unit from the viewpoint of thermal adhesion. There is no problem in incorporating an amide repeating unit different from the amide repeating unit in the form of a copolyamide or a polymer friend into the thermal adhesive. Furthermore, the molecular weight of the polyamide used as a thermal adhesive may be the same as that of the film. It is distinguished by the fact that the molecules are oriented in the direction of the bag, whereas the latter is essentially non-oriented due to the fact that it is applied in the melt. Mechanical strength to transparency The fact that dimensional stability etc. are improved is a remarkable fact to those skilled in the art, and the fact that gas barrier properties are improved is that the oxygen gas permeability of unstretched 6/6 year copolymerized nylon is 048×10-11cc'c Jc Toru.

secGc (3700,0%RH), while that of biaxially oriented 6/66 degree polymerized nylon is 0.33
×10-11cc〆Skin'c Tiger Gsec3c Hg (37
00.0%RH).

The thickness of the nylon film is i in terms of the required physical properties.
It is desirable that the crystalline olefin resin has a heat sealing property of 20 to 100 degrees, and the modified olefin resin and the nylon thermal adhesive layer each have a range of 5 to 30 degrees.

In one embodiment of the invention, a biaxially oriented nylon film and a preformed crystalline olefin resin film are used, wherein the nylon resin and the carbonyl group content are between 1 and 60. A modified olefin resin having a concentration of heq/100g polymer and having constituent olefin units of the same type as the crystalline olefin resin is placed in a parallel position, with the nylon resin layer facing the nylon film and the modified olefin resin layer facing the olefin resin film. Sandwich lamination is performed by simultaneous melt extrusion so that the Simultaneous melt extrusion can be easily accomplished by using an extruder for the nylon and an extruder for the modified olefin resin and extruding the molten resin streams from both extruders through a multi-layer, multiple die.

As for multiple multilayer dies, a method of overlapping within the die is desirable from the viewpoint of adhesion, but a method of overlapping outside the tally can of course also be adopted.

Sandwich lamination is easily performed by supplying a molten resin layer between an olefin resin film and a nylon film that are supported by a pair of rolls, and pressing the two films together with the rolls through the resin layer. Although a special heating mechanism is not normally required for the pressure roll, there is no problem in heating the roll surface to a temperature within a range that does not inhibit the orientation of the nylon film. Prior to sandwich lamination, the surface of the film, particularly the surface of the crystalline olefin resin film, can be subjected to corona discharge treatment, ozone treatment, flame treatment, etc. to activate the film surface.

In another embodiment of the present invention, a nylon resin, a crystalline olefin resin, and a carbonyl group content of 1 to 60 molecules are coated on a biaxially oriented nylon film.
A modified olefin resin having a concentration of q/100g polymer and whose constituent olefin units are the same type as the crystalline olefin resin are placed in parallel positions, and the nylon resin layer is on the nylon film side. The nylon resin layer and the crystalline olefin resin layer are simultaneously melted and extruded so that they are interposed between the nylon resin layer and the crystalline olefin resin layer, and extrusion coating is performed.

That is, in this embodiment, the crystalline olefin resin layer is melt-extruded at the same time as the thermal adhesive layer, and the nylon thermal adhesive layer and the nylon film layer are subsequently thermally bonded. The thus produced laminated film is made by stacking the two pieces with the crystalline olefin resin layer on the inside and heat-sealing the three peripheral parts to form a visible bag-like film, as shown in Figure 2. It can be a 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-molded so that the crystalline olefin resin layer is on the inside to form a rigid or semi-rigid container equipped with a heat-sealing flange. These containers are filled with perishable foods, especially liquid foods, and if necessary, gases such as air that are harmful to storage are removed by vacuum degassing, hot filling, steam degassing, or steam injection. After removing the gas by a method such as degassing 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 1000
It can be heat sterilized at a temperature of 0 or higher. The film container according to the present invention does not change the flavor of the contents even during heat sterilization, and has excellent dimensional stability.
Transparency and mechanical strength are maintained, and of course after sterilization,
It has the remarkable advantage of not causing delamination even when subjected to a drop impact or the like.

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

Example 1 A biaxially stretched nylon 6 film with a thickness of 15 mm and an in-plane orientation coefficient (x+y) of 0.80 and an ethylene content of 4
A 50 mm thick blown film of mol% ethylene-propylene floc copolymer with a relative viscosity of 2.5, a melting point of 21,500, and a density of 1.
Using a first extruder having a screw with a diameter of about 50 mm, nylon 6 with a diameter of 14 mm was used to obtain a polymer having an average carbonyl group concentration of 25 eq/100 molar groups, in which maleic anhydride was grafted onto ysotactic polypropylene. Modified polypropylene 4 with a melting point of 161°C and a melt index (MI) of 10.0% by weight and a density of 0.
90 ta', melting point 154℃, MI 25.0/1■
hin, 53% by weight ethylene-propylene flock copolymer with 5 mol% ethylene content and melting point 109o
A blend of 7% by weight of low-density polyethylene with a density of 0.919 ta' and an MI of 12.0 m/1 hjn was heated to 23,000 m Co-extrusion was carried out through a T-shaped two-layer double die of medium 650℃ maintained at a temperature of 5,000℃, and a metal roll with a diameter of 400℃ maintained at a temperature of 5000℃ and a silicone roll with a diameter of 20℃. By pressure bonding, a laminated film having a composition of 15 French Nifuji stretched nylon 6 film layer / 10 French nylon 6 layer / 10 A modified polypropylene blend layer / 50 mountain ethylene-propylene flock copolymer film layer was obtained. .

This laminated film is biaxially stretched.

The peel strength between the Nylon 60 film layer and the Nylon 6 layer was measured and was found to be 750/1.5 skin. Two rectangular pieces with the size of 13 x 170 willows were cut out from the laminated film thus obtained, and placed facing each other so that the propylene copolymer layer was the inner layer.
A bag was obtained by thermocompression bonding under the conditions of , 3 kg' flow, and 1.0 seconds.

This was filled with 120-year-old hamburger steak, and the filling port was heat-sealed under the same conditions as above. This is 135qo
Retort sterilization was performed under pressure of 2.1k9K for 0 minutes. At this time, there was no damage to the bag due to peeling between layers or peeling of the seal portion. In addition, the sterilized hamburger steaks were delicious, and the flavor of the hamburger steaks in particular was good, almost the same as before sterilization. Separately, a bag filled with 180 cc of distilled water made of the laminated film, and a structure using the 70 ethylene-propylene flock copolymer film and urethane adhesive were 15 biaxially oriented nylon 6, film layer/70 Distilled water 180c made of a laminated film of ribropylene copolymer layer
A bag filled with c was made.

As a control, a glass ampoule sealed with distilled water was prepared and subjected to retort treatment in the same machine as above, along with the two types of bags. When the water was taken out and a flavor test was conducted by a panel of 25 people, the results shown in Table 1 were obtained, and the product of the present invention was superior. Table 1 Number of panels that answered that it was worse than the control water (n〒25) Examples 2 to 4 A laminated film with the structure shown in Table 2 was prepared using the materials shown in Table 2 and the same method as in Example 1. I got it.

The peel strength between the double-sided nylon film layer and the coextruded nylon layer of these laminated films was measured and was as shown in Table 2. Next, bags having a size of 13 ribs x 170 willows were prepared from these laminated films in the same manner as in Example 1, and these bags were filled with 120 pieces of hamburger steak and then sealed.

These were retort sterilized at 135°C for 10 minutes, but there was no damage to the bag due to peeling between each layer or peeling of the seal portion. In addition, the pasteurized hamburger steak was delicious, and the flavor was particularly good. Ship Comparative Example 1 In Example 1, only the modified polypropylene blend was used as the thermal adhesive layer and no coextrusion with nylon 6 was performed, but no coaxial stretching was achieved.

The peel strength between the Polypropylene 6 film layer and the modified polypropylene mother blend layer was a very low value of 60/1.5 skin, making it unsuitable as a packaging material for a retort. Comparative Example 2 In place of the biaxially stretched nylon 6 film Z in Example 1, nylon 6 having an in-plane orientation coefficient (x + y) of 0.60 was used.
A laminated film was prepared using the film, and a bag made of this laminated film was compared with the bag of Example 1. ``The bag of Example 1 was superior in terms of drop strength and oxygen gas barrier properties.

Comparative Example 3 In Example 1, when maleic anhydride-modified polypropylene with an average carbonyl group concentration of 0.8 meq/100 multipolymer was used as the modified polypropylene, the nylon layer and the modified polypropylene layer may peel off due to retort sterilization treatment. It was unsuitable as a packaging material for torts.

Comparative Example 4 Also in Example 1, maleic anhydride-modified polypropylene with a very high degree of modification, which is a female polymer with an average levonyl group degree of 65, was used as the modified polypropylene. Foaming was observed due to resin decomposition.

Furthermore, the flavor of the hamburger steak that was filled into a bag made of the obtained laminated film and then retorted and cocooned was poorer than that of Example 1. Comparative Example 5 In Example 3, metaxylylene/paraxylylene in the outer layer with amide repeat units as the nylon in the coextruded thermal adhesive layer.

When nylon 12, which is completely different from the adipamide copolymer, was used, the peel strength between the outer layer and the nylon 12 layer was weak, making it unsuitable as a packaging material for retorts. 4 with a relative viscosity of 2.5, a melting point of 21500, and a density of 1.14 ta'
Nylon 6 was prepared using a first extruder having a screw with a diameter of about 50 mm, and maleic anhydride was grafted onto isotactic polypropylene with an average carbonyl group concentration of 25 mm and a melting point of 16100 mm.
Modified polypropylene 40 with MI of 10.0 m/h
Weight % and density are 0.90 ta' mass, melting point is 15400, M
I is 25.09/1■h. jn, a blend of 6% by weight of ethylene-propylene floc copolymer 6 with an ethylene content of 5 mol% was produced using a second extruder with a screw on the 5th side in diameter to a density of 0.90 ta'. The melting point of
57℃, MI 12.0 pm/pond hm, ethylene-propylene floc copolymer with 4 mol% ethylene content in a 65mm diameter fence? Using a third extruder with a screw of By pressing a biaxially stretched nylon 61 film with an in-plane orientation coefficient of 0.80 between a metal roll with a diameter of about 400 and a silicone roll with a diameter of about 20 and kept at a temperature of 5000. , the composition is 15 layers of stretched nylon 6' film layer / 5 layers of nylon 6 layers /
10 French modified polypropylene.

A laminated film having a blend layer/55 ethylene-propylene flock copolymer layer was obtained. The peel strength between the double-stretched nylon 61 film layer and the nylon 6 layer of this laminated film was measured to 805/1. It was &. Next, a bag with a size of 130 x 170 mm was prepared from this laminated film in the same manner as in Example 1, and the bag was filled with 150 mm of meat poles and heat-sealed.

This was retort sterilized between each powder using 1360 ml, but there was no damage to the bag due to peeling between the layers or peeling off of the seal.In addition, the sterilized meat convex balls were delicious and had a particularly good flavor. Example 6 A rolled nylon 128 film with a thickness of 15 mm and an in-plane orientation coefficient of 0.73 was used as the outer layer, and a relative viscosity of 2.1 mm and a melting point of 17500 as the resin supplied to the first extruder. Density is 1.0
A 2-ta' female nylon 12/6 copolymer is co-supplied to the second extruder as a resin with a carbonyl group concentration of 24 heq/m, maleic anhydride grafted to low-density polyethylene ethylene.
100° polymer, melting point 116°, MI 8.0°/
40% by weight of modified polyethylene with a carbonyl group concentration of 21 heq/100 yen, a Zn partial salt of ethylene-methacrylic acid copolymer, a melting point of 990
0, MI is 5.0 m/1st hjn ionomer 0% by weight, density is 0.94 ta', MI is 9.0 m/1 hj
n, a blend of high-density polyethylene with a melting point of 13% and a cloud content of 4%, and a density of 0 as the resin supplied to the third extruder.
．． 94 c tiger, MI 9.0 tano 1 plate in, melting point 13
Using 2oC high-density polyethylene and using the same method as in Example 5, the structure was I5 French rolled.

A laminated film was obtained consisting of a 121 film layer, a 10-layer nylon 12/6 copolymer, a 10&modified polyethylene-ionomer blend layer, and a 50-layer high-density polyethylene layer.
The peel strength between the rolled nylon 12 film layer and the nylon 12/6 copolymer layer of this laminated film was measured and found to be 830/1.5 cases.

Next, from this laminated film, a bag with a size of 16 x 17 bags was made by heat sealing, and the resulting bag had 1509
Filled with shumai and heat sealed. This is 120o
Retort sterilization was performed for 30 minutes at ◯, but there was no damage to the bag due to peeling between layers or peeling of the seal portion. Also,
The pasteurized shumai was delicious, especially in flavor. - Comparative Example 6 Nylon 6 for extruded thermal adhesive in Example 5 was extruded using a first extruder having a screw diameter of 50 mm, and the modified polypropylene blend of Example 5 was extruded into a Using a second extruder with a screw, the ethylene-propylene floc copolymer in Example 5 was extruded with a diameter of 65 mm.
Using a third extruder with a side screw, melt extrusion was carried out through a triple circular die for three layers, and the composition was made by the inflation method: 6 layers of 20 renylon/10 layers of French modified polypropylene blend/55 layers of French ethylene. - A laminated film of a propylene block copolymer layer was obtained.

When the thus obtained laminated film was compared with the laminated film of Example 5 of the present invention, it was found that the dimensional stability was poor and the printability was insufficient.

In addition, "the oxygen gas barrier property was also inferior to that of Example 5.Furthermore, when a drop test was conducted on a bag using this laminated film, the bag breakage rate was higher than that of Example 5.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of a transparent laminated film according to the present invention, and FIG. 2 is a cross-sectional view of an example of a transparent sealed package of the present invention. 3 is a crystalline olefin resin layer L, 4 is a nylon layer, 5 is a modified olefin resin layer L, and 6 is a heat-sealed portion. Figure 1 Figure 2

Claims (1)

[Claims] 1. The laminated film material constituting the container includes an outer layer made of a nylon film with molecules oriented in biaxial directions, an inner layer made of a crystalline olefin resin layer, and a thermal adhesive layer interposed between both layers. The thermal adhesive layer has an unoriented nylon resin layer located on the nylon film side and a carbonyl group content of 1 to 60 located on the crystalline olefin resin layer side.
A transparent laminated film container with excellent dimensional stability, characterized by comprising a modified olefin resin layer having a concentration of 0 meq/100 g polymer and having constituent olefin units similar to those of the crystalline olefin resin. 2. Between the biaxially oriented nylon film and the pre-formed crystalline olefin resin layer film,
Nylon resin and carbonyl group content from 1 to 600me
A modified olefin resin having a concentration of q/100g polymer and having constituent olefin units of the same type as the crystalline olefin resin is placed in a parallel relationship, with the nylon resin layer facing the nylon film and the modified olefin resin layer facing the olefin resin film. 1. A method for producing a transparent laminated film container with excellent dimensional stability, which comprises simultaneously melting and extruding the film so as to be located at the same position, performing sandwich laminate, and molding the formed laminated film into the shape of the container. 3 On a nylon film with biaxial molecular orientation,
A nylon resin, a crystalline olefin resin, and a modified olefin resin having a carbonyl group content of 1 to 600 meq/100 g of polymer and having constituent olefin units of the same type as the crystalline olefin resin are placed in parallel positions, and the nylon resin is Simultaneously melt extrusion and extrusion coating so that the modified olefin resin layer is interposed between the nylon resin layer and the crystalline olefin resin layer on the nylon film side, and then molded into the shape of the laminated film container to be formed. A method for manufacturing transparent laminated film containers with excellent dimensional stability.