JP2003154614A - Co-extrusion composite film for deep draw packaging and deep draw package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a co-extrusion composite film for deep draw packaging suitable for packaging block ham or the like having large inner volume and reducing the curl of a flange (seal part) even if a package is boiled especially in secondary sterilization or the like, and a deep draw package. SOLUTION: The co-extrusion composite film for deep draw packaging has successively laminated layered constitution of 610 nylon/adhesive resin/polyamide resin/gas barrier resin/adhesive resin/sealable resin or 610 nylon/adhesive resin/ gas barrier resin/polyamide resin/adhesive resin/sealable resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to deep-drawing packaging of foods, which is suitable for packaging block ham or the like having a large content,
In particular, the present invention relates to a coextruded composite film for deep-drawing packaging and a deep-drawing packaging body in which the flange portion (seal portion) is less curled even when the packaging body is boiled by secondary sterilization or the like.

[0002]

2. Description of the Related Art Conventionally, in order to prevent curling of a flange portion after boil, a composite film having a layer structure in which an outer layer resin of a bottom material and a lid material is a non-stretched polypropylene resin (CPP) has been used. For applications such as block ham where pinhole resistance is important, bottom material using 6 nylon as the outer layer or 1
The bottom material using 2 nylon as the outer layer was often used.

[0003]

The bottom material of the CPP outer layer product, which attaches importance to curling prevention, has poor pinhole resistance at low temperatures and is unsuitable for block hams having a relatively heavy weight. Further, if CPP is used for the outer layer of the lid material, since it is unstretched, the heat resistance is poor and a so-called hot plate peeling phenomenon that melts at the time of sealing and adheres to the sealing hot plate is likely to occur, so that the sealing temperature cannot be raised. There was a problem. If the sealing temperature cannot be raised, the melting point of the resin in the sealing layer must be set low. Especially, if the melting point of the sealing material is lowered, the peeling point (seal of the seal) Since the hot plate of No. 2 was hollowed out to prevent the film from being heated during sealing, there was a problem that the applied unsealed portion) was fused during boiling.

Further, in the type in which the pinhole resistance is important, a composite film using 6 nylon or 12 nylon as the outer layer is used as the bottom material, but a biaxially stretched polyester resin is used as the outermost layer as the lid material. When a composite film having the above is used, the film is extremely curled to the bottom side after boil, which causes a problem in the appearance of the packaged product. The same curling problem was encountered even when a composite film having a biaxially stretched polyamide resin was used as a lid material. Therefore, a lid material having a biaxially oriented polypropylene resin as an outer layer has been studied, but similarly, the problem of curling after boiling as described above could not be solved.

[0005]

DISCLOSURE OF THE INVENTION The present invention has found a coextrusion composite film for deep drawing packaging and a deep drawing packaging body capable of solving the above problems, and the gist thereof is that the layer constitution is 610 nylon / adhesive resin / polyamide resin / gas barrier resin / adhesive resin / sealable resin, or 610 nylon / adhesive resin / gas barrier resin / polyamide resin / adhesive resin / sealable resin in this order It is a co-extrusion composite film for deep-drawing packaging characterized by the following.

It also includes a deep-drawing package obtained by packaging the above-mentioned coextruded composite film as a bottom material and using a lid material having a biaxially oriented polypropylene film as an outer layer.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The basic construction of the bottom material for deep-drawing packaging of the present invention has a 610 nylon layer as an outer layer. This is particularly effective in preventing curling after boiling when the lid material is a biaxially oriented polypropylene film (OPP) outer layer product. It is valid. Conventionally, there has been a problem in that a package made of a bottom material having an outer layer of a 6 nylon layer has a large tendency to shrink due to crystallization when boiled and the flange portion of the lid material curls toward the bottom material. On the other hand, the 12 nylon outer layer product had a tendency to curl to the lid material side. When the curl occurs, not only the appearance is deteriorated, but also the automatic labeler for attaching a label to the package causes a problem that the curl portion interferes with the machine and the machine does not work properly.

[0008] A bottom material having a linear low-density polyethylene resin layer (LL) as an outer layer loses luster when the molding portion shrinks due to boil treatment, and furthermore, LL having no polar group has poor adhesion at the time of label sticking. was there. Therefore, in the present invention, a bottom material having 610 nylon as an outer layer is used, and such a 610 nylon outer layer product is curled after boil treatment especially when an OPP outer layer product (OPP // coextruded film) is used as a lid material. Has the effect of preventing As the layer structure of the film, 610 nylon of the outer layer imparts luster, heat resistance and curl suitability, and a polyamide resin is used for the intermediate layer.
A gas barrier layer is arranged.

That is, the layer constitution is 610 nylon / adhesive resin / polyamide resin / gas barrier resin / adhesive resin / sealable resin, or 610 nylon / adhesive resin / gas barrier resin / polyamide resin / adhesive It is necessary to laminate the resin / sealable resin in this order. Here, two or more polyamide resin / gas barrier resin layers may be arranged. 610 nylon is 6 nylon (6 Ny)
Compared with, the copolymerization has an effect that the crystallinity is low and the gloss is as good as 12 nylon. In addition, since the raw material unit price is almost the same as 6 Ny in terms of cost,
It also has the effect of reducing costs. The thickness of the outer layer 610 nylon is preferably 1/10 to 1, more preferably 1/10 to 1/2 of the thickness of the intermediate polyamide resin from the viewpoint of preventing curling and improving pinhole resistance. If it is less than 1/10, the strength of the outer layer 610 nylon tends to be weak, and when the label is attached to the molded part of the package and then peeled off by re-adhesion or the like, the 610 nylon layer may be broken and peeled off. On the other hand, if the thickness ratio exceeds 1, the outer layer 610 nylon is not preferable because it has the property of drying during refrigeration to deteriorate the pinhole resistance.

610 nylon is generally obtained by polycondensation of hexamethylenediamine and sebacic acid, and its properties are well balanced in terms of water absorption rate as compared with 6Ny and 12Ny used for other deep drawing bottom materials. However, it is useful. Generally, in polyamide resins, the lower the concentration of amide groups in the molecule, the lower the water absorption. 6Ny has a water absorption of about 1.8% when immersed in water for 24 hours, while 12Ny has a water absorption of about 0.25%. 610 nylon has a water absorption rate of about 0.5%, which is between 6 Ny and 12 Ny. This point is very effective when used as the outer layer resin of the deep drawing packaging bottom material, and it is possible to prevent extreme bottom material side curl and lid material side curl due to the difference in moisture absorption rate during boiling.

Although 610 nylon has good gloss, it deteriorates slipperiness. Therefore, 610 nylon contains an inorganic filler in an amount of 100 to 3000 ppm, and more preferably 200 to 20 ppm.
It is effective to add 00 ppm. If it is less than 100 ppm, it is difficult to obtain the effect of improving slipperiness, and 3000 pp
If it exceeds m, the surface irregularities become strong and the gloss may be extremely lowered, and the appearance of the package is deteriorated, which is not preferable. The type of inorganic filler is not particularly limited, but silica-based ones that are effective in improving slippage can be preferably used.

The second adhesive resin (AD) layer from the outermost layer is effective for pinhole resistance of the intermediate polyamide resin layer and for preventing whitening of the gas barrier resin during boiling. The pinhole resistance serves as a buffer layer and is effective in preventing the polyamide resin from drying. Further, a gas barrier resin, usually a saponified product of ethylene-vinyl acetate copolymer (EVOH), is whitened if it absorbs too much water during boil treatment. Therefore, it is necessary to provide a moisture-proof layer on the outer layer side of EVOH.
Since the polyamide resin has no moisture-proof effect, the moisture-proof property can be imparted by disposing a polyolefin-based adhesive resin. The thickness of the adhesive resin (AD) layer is 5 to 5
It is desired that the thickness is 0 μm, more preferably 10 to 30 μm, but if it is less than 10 μm, the moisture resistance becomes insufficient, and the effect tends to be insufficient in terms of imparting pinhole resistance and preventing whitening of EVOH. Further, if it exceeds 50 μm, it is disadvantageous in terms of cost. The polyolefin-based adhesive resin used here is not particularly limited, but in terms of moisture resistance and pinhole resistance, moisture permeability is 20 [g / ■ · 24 hr] or less (JIS K
7129 40 ° C. × 90% RH 30 μm) LL can be preferably used.

A usual polyolefin resin can be used for the sealing resin layer, but the polyolefin resin layer / the cohesive failure type easy peel layer may be laminated in this order to impart the easy peel property. In this case, the thickness of the easy peel layer is 1 to 15 μm, more preferably 3 to 10 μm.
It is desirable to set m. If it is less than 1 μm, the stability of easy peel may occur, and conversely 1
If it exceeds 5 μm, stringing and the like are likely to occur, which may cause a problem in peeling appearance. The cohesive failure type easy peel material is not particularly limited, but LL and polybutene-1 (PB-1) based blend resin can be preferably used in consideration of heat resistance during boiling. Here, the melting point of LL is 120 ° C to 135 ° C, more preferably 120 to 130 ° C.
It is preferable that the blend ratio of LL is 50 to 80%. If the melting point is less than 120 ° C., the heat resistance during boil treatment is low, which may cause rupture of the boil bag and may cause the easy peel peeling portion (unsealed portion) to be fused. On the other hand, if the temperature exceeds 135 ° C., the sealing property will deteriorate, which is not preferable. The blend ratio of LL is 5
If it is less than 0%, the easy peel strength will be weak and the bag may break. On the other hand, if it exceeds 80%, it becomes too strong and the unsealing property is deteriorated, which is not preferable. Taking peeling resistance and opening resistance into consideration, the easy peel strength is 1.96 to 4.90.
The width is preferably N / 15 mm (200-500 gf / 15 mm width, tensile tester, tensile speed 200 mm / min).

Since the polyamide resin for the intermediate layer is arranged for imparting strength, it is not particularly limited as long as it can impart strength, but 610 nylon, which is the same as the outer layer excellent in deep drawability, can be preferably used. Also, EVOH
Although there is no particular limitation, the ethylene content of 32 to 44 mol% is preferably used in consideration of barrier properties, pinhole resistance, and moldability.

When the OPP outer layer product is used as the lid material by using the bottom material of the present invention, it is possible to make a good packaging body with a small curl after boiling. In particular, other than OPP, it is composed of an unstretched film. Since it is better to prevent curling, a lid material obtained by dry laminating OPP and a coextrusion film can be preferably used. As a co-extruded film, EVOH / Ny
/ AD / Seal layer, Ny / AD / Ny / EVOH / AD
A film having an oxygen barrier property of a / seal layer, a Ny / AD / EVOH / Ny / AD / seal layer structure, and a pinhole resistance can be preferably used. In the case of the easy peel type bottom material, the sealing material of the lid material is divided into two or more layers, and the melting point of the sealing material is 120 to 135 ° C, more preferably 12
It is desired to have an LL of 0-130 ° C. 120 ° C
If it is less than the above, the easy peeling part of the easy peel will be fused in the boil, making it difficult to open. Also, 135 ℃
If it exceeds, the problem that the sealing property is deteriorated tends to occur. Here, the purpose of dividing the seal layer into two or more layers is to prevent fusion of the easy peel part by placing LL having a high melting point and a high crystallinity on the surface of the seal layer. There is a drawback that transparency is deteriorated due to high degree of conversion. Therefore, in order to prevent fusion, it is preferable to use a resin having a high melting point for the surface layer and a resin having a low melting point and low crystallinity and good transparency for the other layers. It is desired that the heat-resistant resin on the surface layer of the seal be as thin as possible, and the thickness is 1 to 10 μm, more preferably 3 to 7 μm.
It is effective to set m.

The bottoming material film of the present invention is formed by coextrusion, which is advantageous in that the thickness of each layer can be optimally set and transparency and moldability are good. This is because. Further, since it is recommended that the lid material has OPP as the outermost layer, it is a laminated product such as dry laminate, but it is useful because it is possible to perform intermediate printing on the OPP. An OPP having a thickness of about 20 to 30 μm is generally used, but in the case of a printed product, it is 3 in view of pitch accuracy.
0 μm is preferred.

[0017]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. The films of Examples 1 and 2 and Comparative Examples 1 to 4 were formed by a coextrusion method and evaluated.

(Example 1) Layer structure: 610 nylon / AD / 6-66Ny / EVOH / AD
/ EVA / EP (10μm / 15μm / 60μm / 20
μm / 10μm / 8Oμm / 5μm) * EP (Easy peel layer): LL (60% by weight) + P
P (40% by weight) 610 Nylon: Amilan CM2001 (manufactured by Toray Industries, Inc.) AD: Admer NF528 (manufactured by Mitsui Chemicals, Inc.) EVOH: Soarnol AT4403 (manufactured by Nippon Synthetic Chemical Co., Ltd.) EVA: Novatec EVA LV350 (Nippon Polychem Co., Ltd.) LL: Novatec LL UF240 (Nippon Polychem Co., Ltd.) PP: Novatec PP FW3E (Nippon Polychem Co., Ltd.)
Co., Ltd.) A coextrusion film was formed by the T-die method using the raw material resin having the above composition.

(Example 2) Layer structure: 610 nylon / AD / EVOH / Ny / AD /
EVA (20 μm / 20 μm / 10 μm / 50 μm / 10
μm / 90 μm) Ny: Novamid 1020 (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) EVA: Novatec EVA LV350 (manufactured by Nippon Polychem Co., Ltd.) Others are the same raw materials as in Example 1. A coextrusion film was formed by the T-die method using the raw material resin having the above composition.

(Comparative Example 1) Layer structure: 6Ny / AD / 6-66Ny / EVOH / AD / EVA
(10 μm / 15 μm / 60 μm / 20 μm / 10 μm / 85 μ
m) 6Ny: Novamid 1030 (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) Other than that, the same raw material as in Example 1. A coextrusion film was formed by the T-die method using the raw material resin having the above composition.

(Comparative Example 2) Layer structure: 12Ny / AD / 6-66Ny / EVOH / AD / EV
A (10 μm / 15 μm / 60 μm / 20 μm / 10 μm / 85
μm) 12Ny: Daiamide L1940 (manufactured by Daicel Degussa Co., Ltd.) The same raw material as in Example 1 except for the above. A coextrusion film was formed by the T-die method using the raw material resin having the above composition.

(Comparative Example 3) Layer structure: LL / AD / 6-66Ny / EVOH / AD / EVA
(30 μm / 15 μm / 60 μm / 20 μm / 10 μm / 65 μ
m) LL: Novatec LL SF941 (manufactured by Nippon Polychem Co., Ltd.) Other than that, the same raw material as in Example 1. A coextrusion film was formed by the T-die method using the raw material resin having the above composition.

(Comparative Example 4) Layer structure: 610 nylon / EVOH / 6-66Ny / AD / EV
A (10 μm / 20 μm / 60 μm / 10 μm / 100 μ
m) The same raw materials as in Example 1 except for the above. A coextrusion film was formed by the T-die method using the raw material resin having the above composition.

<Evaluation Method> Using each of the above films, a package was prepared with a deep-drawing packaging machine “FV6300” (manufactured by Omori Machinery Co., Ltd.), and then boiled at 95 ° C. for 20 minutes to carry out evaluation. went. Curl property: The curl of the face seal portion after boil is evaluated. The one that was almost flat was marked (○). Boil aptitude: The one that did not whiten boil was rated as (◯). -Mitsuzawa: After the boiling, the good gloss of the part containing the content was rated as (○).

<Packing conditions> Lid material: OPP // EVOH / Ny / AD / EV
A / LL (30 μm / 10 μm / 20 μm / 5 μm / 20 μm
/ 5μm) ・ Molding temperature: 90 ℃ ・ Seal temperature: 140 ℃

[0026]

[Table 1]

From Table 1, it can be seen that Examples 1 and 2 using the composite film of the present invention are excellent in all performances. On the other hand, in Comparative Example 1, the 6Ny layer contracted during boiling, so the flange portion curled toward the bottom material. In Comparative Example 2, curling was applied to the lid material side during boiling. In Comparative Example 3, since the bottom material is the LL outer layer product, LL is caused by shrinkage during molding and boiling.
Of the Ny outer layer product, resulting in a less glossy package. In Comparative Example 4, curling of the flange portion occurred on the bottom material side, and EVOH was whitened due to moisture absorption in the boil.

[0028]

As described above, the composite film of the present invention is a coextruded composite film for deep-drawing packaging and a deep-drawing packaging in which the flange portion (sealing portion) has little curl even when the package is boiled by secondary sterilization or the like. The body is obtained.

Continued front page    F-term (reference) 3E067 AA13 AB05 BA33A BB14A                       BB16A BB18A BB25A BC03A                       CA04 CA05 CA17 CA24 EA13                       EA35 EB27 EE48 FA01 FB02                       FC01 GC01 GD07                 3E086 AA21 AB01 AC07 AD07 AD24                       BB41 BB51 BB55 BB58 BB85                       CA04                 4F100 AK01B AK01C AK01E AK03B                       AK03E AK46D AK48A AK48D                       AK62E AK68E AK69C BA05                       BA10A BA10E BA15 DA01                       EH20 GB16 GB23 JA04E                       JC00 JD02C JJ03 JL04                       JL11B JL11E JL12E JL14E                       YY00A YY00B YY00D YY00E

Claims (11)

[Claims] 1. A layer structure of 610 nylon / adhesive resin / polyamide resin / gas barrier resin / adhesive resin /
A coextruded composite film for deep-drawing packaging, characterized in that a sealing resin or 610 nylon / adhesive resin / gas barrier resin / polyamide resin / adhesive resin / sealable resin is laminated in this order. 2. The coextruded composite film for deep-drawing packaging according to claim 1, wherein the thickness of 610 nylon is 1/10 to 1/1 of the thickness of the polyamide resin. 3. The coextruded composite film for deep-drawing packaging according to claim 1, wherein the adhesive resin is a polyolefin-based adhesive resin and the layer has a thickness of 5 μm to 50 μm. 4. The sealing resin layer comprises a polyolefin resin layer / a cohesive failure type easy peel layer, and the easy peel layer is the outermost layer, and the thickness of the easy peel layer is 1 to 15 μm. The coextrusion composite film for deep-drawing packaging according to any one of claims 1 to 3, characterized in that: 5. The deep drawing package according to any one of claims 1 to 4, wherein the second layer of the adhesive resin is a polyolefin-based adhesive resin, and the layer has a thickness of 5 to 50 μm. Extruded composite film. 6. A melting point of 120 ° C. to 13 in the easy peel layer.
The co-extruded composite film for deep-drawing packaging according to claim 4, which comprises 50 to 80% by weight of an ethylene-α-olefin copolymer at 5 ° C. 7. A deep-drawing package obtained by packaging the coextruded composite film according to claim 1 as a bottom material and using a lid material having a biaxially oriented polypropylene film as an outer layer. . 8. The deep-drawing package according to claim 7, wherein the biaxially oriented polypropylene film is used as an outermost layer and a co-extruded film is dry-laminated for packaging. 9. A biaxially oriented polypropylene film / saponified ethylene / vinyl acetate copolymer / polyamide resin /
The deep-drawing package according to claim 8, which is packaged by using a lid material in which an adhesive resin / seal layer is laminated in this order. 10. A lid material laminated in the order of biaxially oriented polypropylene film / polyamide resin / adhesive resin / polyamide resin / saponified ethylene / vinyl acetate copolymer / adhesive resin / seal layer is used for packaging. The deep-drawing package according to claim 8, wherein 11. The lid sealing layer is divided into two or more layers,
The deep-drawing package according to claim 8, which is packaged by using a lid material in which a linear low-density polyethylene resin having a melting point of 120 to 135 ° C is arranged on the surface of the seal layer.