Low-temperature-resistant, high-barrier and puncture-resistant aluminum foil composite film and food packaging bag

Abstract

The utility model discloses a low-temperature-resistant, high-barrier and puncture-resistant aluminum foil composite film and a food packaging bag, the aluminum foil composite film comprises a heat sealing layer, a first protective layer, a barrier layer, a second protective layer and a printing layer which are laminated in sequence, and the layers are bonded with one another; wherein the heat sealing layer comprises a PE film, the first protective layer and the second protective layer respectively comprise a PA film, the blocking layer comprises an Al film, the printing layer comprises a PET film, and the thickness of the heat sealing layer is larger than that of other layers. The aluminum foil composite film disclosed by the utility model is good in barrier property, can keep good mechanical property in an extremely low-temperature environment, has high barrier property and puncture resistance, can avoid low-temperature fracture, and better plays a role in protection.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of food packaging material, concretely relates to a kind of low-temperature-resistant high-barrier puncture-resistant aluminium foil composite film and food packaging bag. BACKGROUND

[0002] In order to keep food clean and sanitary, it is usually necessary to package food during food storage and transportation. Traditional food packaging materials use aluminum foil, plastic and other materials, and by setting multiple functional layers such as barrier layers, impact-resistant layers and other additional functional layers to improve the barrier performance and protective performance of the food packaging material, oxygen, water vapor and other harmful substances are blocked from entering the inside of the food packaging, thereby improving the quality of food preservation and extending the shelf life of food.

[0003] However, in extremely low temperature environments below -55°C, the barrier performance of existing food packaging materials to oxygen and water vapor cannot provide better barrier performance and freeze resistance, and cannot meet the diverse needs of food preservation.

[0004] Under extremely low temperature conditions, the impact resistance of food packaging bags is poor, and they are easily damaged by external forces during transportation, handling and shelf placement, making it easy to break or open the bag. This is because the interlayer peeling strength of the packaging bag is small, the breaking force is not enough, and the mechanical properties of the packaging bag are poor, causing the packaging bag to delaminate and not being able to achieve the desired load-bearing effect, thus not being able to effectively protect the contents. Chinese patent application CN222022340U discloses a high-temperature-resistant and low-temperature-resistant composite film, which includes an oxygen barrier layer, an antibacterial layer, a temperature-resistant protective layer and an inner layer, each layer being bonded to each other; the oxygen barrier layer includes a PA surface layer, an EVOH barrier layer, a PA middle layer and a PE layer; the antibacterial layer includes a BOPP layer and two layers of bamboo charcoal film layer; the temperature-resistant protective layer includes a low-temperature-resistant protective layer and a high-temperature-resistant protective layer. The utility model can improve the puncture resistance and strength of the film, and prevent the film from being easily damaged. However, the mechanical properties of the composite film still need to be improved.

[0005] The cold resistance of the food packaging material does not meet the requirements, and under low temperature conditions, the material cannot maintain its original properties, the packaging material is brittle, the mechanical strength of the packaging material decreases, causing the packaging bag to break and crack, and the protection of the contents is even more difficult to meet. The puncture resistance of the packaging bag also decreases, and after freezing, food is generally hard, especially fish and meat products, which contain bones and hard objects. During transportation and stacking, the product is easily squeezed, which can cause the packaging bag to be punctured, damaging the sealing of the packaging bag, and causing dry consumption and freezing of the food.

[0006] In order to minimize this phenomenon, reduce the frequency of the influence of the extremely low temperature environment on the mechanical strength of the packaging material, and ensure the safety of food, it is necessary to provide a food packaging material with high barrier, low temperature resistance and puncture resistance.

[0007] Therefore, the utility model provides a kind of low temperature resistant high barrier puncture resistant aluminium foil composite film. Utility model contents

[0008] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art, provide a low temperature resistant high barrier puncture resistant aluminium foil composite film, which can maintain the original performance of the material under extremely low temperature environment, has high barrier performance, puncture resistance, avoids rupture, and well protects the contents.

[0009] To solve the above technical problems, the basic idea of the technical scheme of the utility model is:

[0010] The utility model provides a kind of low temperature resistant high barrier puncture resistant aluminium foil composite film, including heat sealing layer, first protective layer, barrier layer, second protective layer and printing layer that are sequentially laminated, and each layer is mutually adhered;Wherein, the heat sealing layer includes PE film, the first protective layer and the second protective layer include PA film respectively, the barrier layer includes Al film, the printing layer includes PET film, and the thickness of the heat sealing layer is greater than that of other layers.The low temperature resistant high barrier puncture resistant aluminium foil composite film of the utility model includes heat sealing layer, first protective layer, barrier layer, second protective layer and printing layer that are sequentially laminated.In the five-layer composite film structure, the barrier layer is located in the middle, one layer of protective layer is arranged on the both sides of the barrier layer, the heat sealing layer is arranged on the innermost side, and the outermost layer can be printed with ink.The barrier layer can play a good barrier role, and both sides are protected to avoid the influence of light and heat.

[0011] The barrier layer is aluminum film, has excellent barrier property;The printing layer is PET, has good barrier property, high strength and high temperature resistance and low temperature resistance;The two protective layers are PA film, have strong mechanical property, high toughness, impact resistance and tear resistance;The heat sealing layer is PE film, is waterproof and moistureproof, and has good toughness.Through the arrangement of the structure and the mutual cooperation between the performance of each layer of film material, the composite film as a whole has high barrier property, can prevent water vapor and oxygen from penetrating through, and also has the advantages of high toughness, tear resistance, impact resistance, puncture resistance and extremely low temperature resistance.

[0012] Further scheme, the thickness of the heat sealing layer is 70-120 microns.

[0013] Further scheme, the thickness of the first protective layer is 12-15 microns.

[0014] Further scheme, the thickness of the barrier layer is 7-9 microns.

[0015] In a further aspect, the second protective layer has a thickness of 12-15 microns.

[0016] In a further aspect, the printing layer has a thickness of 12-15 microns.

[0017] In a further aspect, the first protective layer, the second protective layer and the printing layer have the same thickness.

[0018] In a specific preferred embodiment, the heat-seal layer has a thickness of 70 microns, the first protective layer has a thickness of 15 microns, the barrier layer has a thickness of 7 microns, the second protective layer has a thickness of 15 microns, and the printing layer has a thickness of 15 microns.

[0019] The aluminum foil composite film of the utility model discloses, the adjacent each layer between all is equipped with adhesive. Adhesive can adopt the conventional adhesive in prior art. As an alternative way, adhesive is polyurethane polyol mixture, adapts low temperature environment. The adhesive gumming amount is 4.2~4.5g / square meter.

[0020] In a further aspect, the surface of each layer of film that contacts the other layer of film is subjected to corona treatment, and then the layers are combined by dry or wet lamination.

[0021] The utility model discloses still provide a kind of food packaging bag, which is made of the low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film, and from inside to outside includes heat-seal layer, first protective layer, barrier layer, second protective layer and printing layer which are sequentially laminated.

[0022] After the above technical solution is used, the utility model has the following beneficial effects compared with prior art:

[0023] 1. The low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film comprises a heat-seal layer, a first protective layer, a barrier layer, a second protective layer and a printing layer which are sequentially laminated. In the five-layer composite film structure, the barrier layer is located in the middle, one protective layer is arranged on each side of the barrier layer, the innermost side is provided with a heat-seal layer, and the outer surface of the outermost layer can be printed with ink. The barrier layer is an aluminum film, which has excellent barrier properties. The printing layer is PET, which has good barrier properties, high strength, and resistance to high and low temperatures. The two protective layers are PA films, which have strong mechanical properties, high toughness, impact resistance and tear resistance. The heat-seal layer is PE, which is waterproof, moisture-proof and has good toughness. Through the arrangement of the structure and the mutual cooperation between the properties of the film materials, the composite film as a whole has high barrier properties, can prevent water vapor and oxygen from penetrating through, and also has the advantages of high toughness, tear resistance, impact resistance, high temperature resistance and extremely low temperature resistance.

[0024] 2. The low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film has reasonable thicknesses set according to the properties of the layers of materials, and meets the requirements of high barrier, puncture resistance and low-temperature resistance at the same time.

[0025] The specific embodiments of the utility model will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings are part of the utility model, which is used to provide further understanding of the utility model, and the illustrative embodiments of the utility model and the description thereof are used to explain the utility model, but do not constitute improper limitation on the utility model. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0027] Figure 1 is a sectional view of the low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film of the utility model.

[0028] In the figure: 1, heat sealing layer, 2, first protective layer, 3, barrier layer, 4, second protective layer, 5, printing layer.

[0029] It should be noted that these drawings and textual descriptions are not intended to limit the scope of the concept of the utility model in any way, but to illustrate the concept of the utility model to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model more clear, the technical scheme in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the utility model. The following embodiments are used to illustrate the utility model, but not to limit the scope of the utility model.

[0031] In the description of the utility model, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the utility model.

[0032] In the description of the utility model, it is necessary to explain that, unless there are definite provisions and limitations, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, can also be detachable connection, or integrally connected, can be mechanical connection, can also be electrical connection, can be directly connected, also can be indirectly connected through intermediate medium.

[0033] As Figure 1 Indicated, the utility model provides a kind of low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film, including heat-seal layer 1, first protective layer 2, barrier layer 3, second protective layer 4 and printing layer 5 that are sequentially laminated, each layer is mutually adhered;Wherein, the heat-seal layer 1 includes PE film, the first protective layer 2 and the second protective layer 4 include PA film respectively, the barrier layer 3 includes Al film, the printing layer 5 includes PET film, the thickness of the heat-seal layer 1 is greater than other layers.Specifically:

[0034] Heat-seal layer is PE film, specifically low-density polyethylene LDPE, with good moisture resistance, can prevent water vapor and the like from permeating;It also has good low-temperature heat-seal performance.Therefore can prevent water and damp, and good toughness.

[0035] First protective layer and second protective layer are PA film, PA macromolecular material has better low-temperature resistance, puncture resistance and air barrier and the like, so PA film has high toughness, tear resistance, impact resistance, high-temperature resistance advantage, has very strong mechanical property, prevent the damage of external force to food, the effect of protecting food.

[0036] Barrier layer is AL film layer, AL film barrier is very good, and waterproof and moistureproof, but it has higher reflection to light and heat, the disadvantage is low strength, not resistant to tension.

[0037] Printing layer includes PET film, PET has good barrier property, can prevent water vapor and oxygen and the like from permeating, is important aroma-retaining material;Cold resistance and heat resistance are good;BOPET film has the characteristics of high strength, good rigidity, transparency, glossiness and the like;No smell, no taste, no color, no toxicity, outstanding toughness;It has excellent wear resistance, folding resistance, pinhole resistance and tear resistance and the like;Heat shrinkage is very small, only shrinks 1.25% after 15 minutes;It has good heat resistance, excellent puncture resistance, low-temperature freezing resistance, good oil resistance and chemical resistance and the like.

[0038] The utility model discloses a low temperature resistant high barrier puncture resistant aluminium foil composite film, including heat sealing layer, first protective layer, barrier layer, second protective layer and printing layer of setting up in turn. Thus, aluminium foil composite film is five layer's composite structure, and barrier layer is located in the middle, and one layer protective layer is arranged on the both sides of barrier layer, and heat sealing layer is arranged in the most inside, and the outer surface of printing layer can print ink. Thus, on one hand, barrier layer is located in the middle, and two layers of protective layer and the inner layer and outer layer can all play the protection effect to the barrier layer in the middle, avoid the influence of light heat to barrier layer performance, improve the barrier property of composite film from the physical structure. On the other hand, barrier layer is aluminium film, and the barrier property is very good, and printing layer is PET, and the barrier property is good, and the strength is high, and resistant to high temperature and low temperature, and two layers of protective layer are PA film, and have very strong mechanical property, and high toughness, and impact resistance, and tear resistance, and heat sealing layer is PE, and waterproof and moistureproof, and good toughness. PE and PA high molecular material all have good low temperature resistance, puncture resistance and air barrier property, and the performance of each layer of film material can cooperate with each other, make the composite film whole have high barrier property, can prevent water vapor and oxygen and the like from permeating through, also have high toughness, impact resistance, tear resistance, puncture resistance, resistant to extremely low temperature advantage.

[0039] The aluminium foil composite film of the utility model, the adhesive is arranged between each layer. The adhesive can adopt conventional adhesive in the prior art. As an alternative, the adhesive is a polyurethane polyol mixture, which is suitable for low temperature environment. The adhesive amount of the adhesive is 4.2-4.5 g / m2.

[0040] The thickness of the heat sealing layer 1 is 70-120 microns. The thickness of the first protective layer 2 is 12-15 microns. The thickness of the barrier layer 3 is 7-9 microns. The thickness of the second protective layer 4 is 12-15 microns. The thickness of the printing layer 5 is 12-15 microns.

[0041] In the utility model, the heat sealing layer is located at the most inside, and the thickness is the largest, and the thickness of the first protective layer and the second protective layer can be the same or different. If the thickness of the first protective layer and the second protective layer is set to be the same, the double-sided protection of the barrier layer can be realized, and no special distinction is needed.

[0042] As an alternative, the thickness of the first protective layer, the second protective layer and the printing layer is set to be the same. As a specific preferred embodiment, the thickness of the heat sealing layer is 70 microns, the thickness of the first protective layer is 15 microns, the thickness of the barrier layer is 7 microns, the thickness of the second protective layer is 15 microns, and the thickness of the printing layer is 15 microns. Experiments prove that the tensile strength and toughness of the aluminium foil composite film of the structure are very good in extremely low temperature and high temperature environment.

[0043] The preparation process comprises:

[0044] (1) First, each layer of film is made by blowing film or casting;

[0045] (2) The surface of each layer of film which contacts each other is treated by corona, and the composite film is obtained by dry or wet composite process on the composite machine. The composite film obtained by the multi-layer composite process is heat-sealed and cut to obtain the aluminum foil composite film.

[0046] The aluminum foil composite film has excellent performance, and meets the requirements of light shielding, high barrier, low temperature resistance, puncture resistance, low temperature heat sealing, etc.

[0047] Example 1 (PET15 / PA15 / AL7 / PA15 / PE70)

[0048] The low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film of the embodiment comprises, from the inside to the outside, a heat-sealing layer 1, a first protective layer 2, a barrier layer 3, a second protective layer 4 and a printing layer 5 which are sequentially stacked, and each layer is adhered to each other. The heat-sealing layer is a PE film with a thickness of 70 microns; the first protective layer is a PA film with a thickness of 15 microns; the barrier layer is an Al film with a thickness of 7 microns; the second protective layer is a PA film with a thickness of 15 microns; and the printing layer is a PET film with a thickness of 15 microns.

[0049] Example 2 (PET15 / PA12 / AL7 / PA12 / PE100)

[0050] The low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film of the embodiment comprises, from the inside to the outside, a heat-sealing layer 1, a first protective layer 2, a barrier layer 3, a second protective layer 4 and a printing layer 5 which are sequentially stacked, and each layer is adhered to each other. The heat-sealing layer is a PE film with a thickness of 110 microns; the first protective layer is a PA film with a thickness of 12 microns; the barrier layer is an Al film with a thickness of 7 microns; the second protective layer is a PA film with a thickness of 12 microns; and the printing layer is a PET film with a thickness of 15 microns.

[0051] Example 3 (PET12 / PA15 / AL9 / PA15 / PE115)

[0052] The low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film of the embodiment comprises, from the inside to the outside, a heat-sealing layer 1, a first protective layer 2, a barrier layer 3, a second protective layer 4 and a printing layer 5 which are sequentially stacked, and each layer is adhered to each other. The heat-sealing layer is a PE film with a thickness of 115 microns; the first protective layer is a PA film with a thickness of 15 microns; the barrier layer is an Al film with a thickness of 9 microns; the second protective layer is a PA film with a thickness of 15 microns; and the printing layer is a PET film with a thickness of 12 microns.

[0053] Comparative Example 1 (PET15 / AL7 / PA15 / PE70)

[0054] Compared with Example 1, the present comparative example changes the double PA structure into a single PA structure, and the aluminum foil composite film lacks the second protective layer PA.

[0055] Specifically, from inside to outside, the aluminum foil composite film comprises, in sequence and by layer, a PE film layer with a thickness of 70 microns, a PA film layer with a thickness of 15 microns, an Al film layer with a thickness of 7 microns, and a PET film layer with a thickness of 15 microns.

[0056] Comparative Example 2 (PET15 / AL7 / PE12 / PA15 / PE115)

[0057] Compared with Example 1, the present comparative example changes one layer of PA into PE and thickens the heat-sealing layer PE.

[0058] The aluminum foil composite film of the present comparative example comprises, from inside to outside, in sequence and by layer, a PE film layer with a thickness of 115 microns, a PA film layer with a thickness of 15 microns, a PE film layer with a thickness of 12 microns, an Al film layer with a thickness of 7 microns, and a PET film layer with a thickness of 15 microns.

[0059] Comparative Example 3 (PA15 / AL7 / PA15 / PE115)

[0060] Compared with Example 1, the present comparative example removes the matte PET layer and thickens the heat-sealing layer PE.

[0061] The aluminum foil composite film of the present comparative example comprises, from inside to outside, in sequence and by layer, a PE film layer with a thickness of 115 microns, a PA film layer with a thickness of 15 microns, an Al film layer with a thickness of 7 microns, and a PA film layer with a thickness of 15 microns.

[0062] Comparative Example 4 (PET15 / GZVMPET12 / PA15 / PE115)

[0063] Compared with Example 1, the present comparative example changes the barrier layer Al into a vacuum aluminum-plated polyester film material GZVMPET, changes the double PA structure into a single PA structure, and thickens the heat-sealing layer PE.

[0064] The aluminum foil composite film of the present comparative example comprises, from inside to outside, in sequence and by layer, a PE film layer with a thickness of 115 microns, a PA film layer with a thickness of 15 microns, a GZVMPET film layer with a thickness of 12 microns, and a PET film layer with a thickness of 15 microns. The GZVMPET is a vacuum aluminum-plated polyester film material. The specific components of the GZVMPET include a polyester (PET) substrate and a vacuum aluminum-plated layer.

[0065] The aluminum foil composite films prepared in Example 1 and Comparative Examples 1-4 are subjected to performance detection, and the detection methods and results are as follows.

[0066] Test method: according to GB / T1040.3-2006.

[0067] The specific test results are shown in the following table:

[0068] Table 1

[0069]

[0070] Note: Lowercase letters represent that there is a significant difference (P<0.05) in the same index of different composite film materials, ** represents that there is a very significant difference (P<0.01) in the same index of the same composite film material at room temperature and after being frozen at-80℃ for 42h, and * represents that there is a significant difference (P<0.05) in the same index of the same composite film material at room temperature and after being frozen at-80℃ for 42h.

[0071] Result analysis:

[0072] The strength and toughness of the five-layer aluminum foil composite film of the utility model embodiment are better than those of the composite films in Comparative Examples 1-4 at room temperature and after being frozen at-80℃ for 42h. The breaking force (transverse and longitudinal), and the elongation at break (transverse and longitudinal) can be used as indexes for the performance decline of the composite material under the influence of temperature. PA nylon products are widely used in the field of low-temperature anti-freezing and anti-puncture, and the use of double nylon materials can significantly improve the anti-freezing performance of the packaging material.

[0073] Compared with Example 1, the four-layer composite film structure in Comparative Example 1 has a PET layer and an AL layer directly contacting each other, and lacks a PA film layer as a protective layer between the two layers. It can be seen that the breaking force, tensile strength, and elongation at break are all greatly reduced.

[0074] Compared with Example 1, although Comparative Example 2 is also a five-layer composite film structure, the PE layer is arranged in the middle, the Al layer is arranged between the PET layer and the PE layer, and the thickness of the innermost PE layer is 115mm. The breaking force, tensile strength, and elongation at break of the composite film of Comparative Example 2 are still lower than those of Example 1.

[0075] Compared with Example 1, the aluminum foil composite film of Comparative Example 3 is a four-layer composite film structure, lacks a PET film layer, and the thickness of the innermost PE layer is 115mm. However, the breaking force, tensile strength, and elongation at break are also lower than those of Example 1.

[0076] Compared with Example 1, the aluminum foil composite film of Comparative Example 4 is a four-layer composite film structure, the AL layer is replaced by a GZVMPET layer, and directly contacts the outermost PET layer. The results show that the breaking force, tensile strength, and elongation at break are also lower than those of Example 1.

[0077] Test Example 1

[0078] The aluminum foil composite film of Example 1 was used to make a five-layer aluminum foil composite bag, and then the performance was detected.

[0079] The sample size of the composite bag was 200mm x 205mm x 80mm unfolded with the bottom inserted, and the sample number was 100.

[0080] Detection environment: temperature: 23℃; humidity: 50%RH;

[0081] Detection basis: GB / T 10004-2008, GB / T 6673-2001, GB / T 8808-1988, QB / T 2358-1998, GB / T 1040.3-2006, QB / T 1130-1991, GB / T 8809-2015, GB / T 1037-2021, GB / T 1038-2000, GB 9683-1988, GB 31604.8-2021, GB 31604.2-2016, GB 31604.9-2016, GB 31604.23-2016, GB / T 21302-2007

[0082] Judgment basis: Refer to GJB 4122A-2015 Military Food Packaging Storage and Transportation Requirements

[0083] The specific test results are shown in the following table:

[0084] Table 2

[0085]

[0086]

[0087] Test conclusion: The sample meets the requirements of GJB 4122A-2015 standard.

[0088] Test Example 2

[0089] The aluminum foil composite film of Example 1 was used to make a five-layer aluminum foil composite bag, and then the puncture resistance performance was detected.

[0090] The sample size of the composite bag was 200mm x 205mm x 80mm unfolded with the bottom inserted, and the sample number was 100.

[0091] Detection environment: temperature: 23℃; humidity: 50%RH;

[0092] Detection basis: Refer to GB / T 21302-2007 General Requirements for Composite Film and Bag for Packaging

[0093] The specific test results are shown in the following table:

[0094] Table 3

[0095]

[0096] Therefore, the aluminum foil composite film is made into a five-layer aluminum foil composite bag, and the puncture resistance is good.

[0097] The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form, although the utility model has disclosed the above preferred embodiment, however, it is not used to limit the utility model, any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the technical scheme of the utility model, and equivalent embodiments of equivalent changes are made, but as long as the content of the utility model technical scheme is not deviated, according to the technical essence of the utility model, any simple modification, equivalent change and modification of the above-mentioned embodiments are still within the scope of the utility model scheme.

Claims

1. A low temperature resistant, high barrier, puncture resistant aluminum foil composite film, characterized by, The composite film comprises a heat-sealing layer, a first protective layer, a barrier layer, a second protective layer and a printing layer which are sequentially stacked and adhered to each other, wherein the heat-sealing layer comprises a PE film, the first and second protective layers each comprise a PA film, the barrier layer comprises an Al film, and the printing layer comprises a PET film, and the thickness of the heat-sealing layer is greater than that of the other layers; the surface of each film which contacts with the surface of another film is subjected to corona treatment, and then the films are compounded by dry or wet compounding process.

2. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film of claim 1, wherein, The thickness of the heat-sealing layer is 70-120 microns.

3. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film of claim 1, wherein, The thickness of the first protective layer is 12-15 microns.

4. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film of claim 1, wherein, The thickness of the barrier layer is 7-9 microns.

5. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film of claim 1, wherein, The thickness of the second protective layer is 12-15 microns.

6. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film of claim 1, wherein, The thickness of the printing layer is 12-15 microns.

7. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film according to any one of claims 1 to 6, characterized in that, The thicknesses of the first protective layer, the second protective layer and the printing layer are the same.

8. The low temperature resistant, high barrier, puncture resistant, aluminum foil composite film according to any one of claims 1-6, characterized in that, The thickness of the heat-sealing layer is 70 microns, the thickness of the first protective layer is 15 microns, the thickness of the barrier layer is 7 microns, the thickness of the second protective layer is 15 microns, and the thickness of the printing layer is 15 microns.

9. A food packaging bag characterized by The composite film is made of the low-temperature-resistant high-barrier puncture-resistant aluminum foil composite film according to any one of claims 1-8 and comprises a heat-sealing layer, a first protective layer, a barrier layer, a second protective layer and a printing layer which are sequentially stacked from inside to outside.

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