CN219114975U

CN219114975U - Novel transparent high-barrier fresh-keeping vacuum packaging composite material structure

Info

Publication number: CN219114975U
Application number: CN202222538687.7U
Authority: CN
Inventors: 辜伟悦
Original assignee: Zhuhai Hengqin Huizefeng Packaging Technology Co ltd
Current assignee: Zhuhai Hengqin Huizefeng Packaging Technology Co ltd
Priority date: 2022-09-24
Filing date: 2022-09-24
Publication date: 2023-06-02
Anticipated expiration: 2032-09-24

Abstract

The utility model provides a novel transparent high-barrier fresh-keeping vacuum packaging composite material structure, which comprises a natural cellulose film layer, an RCPP cooking film layer and an adhesive layer clamped in the natural cellulose film layer, wherein the natural cellulose film layer, the adhesive layer and the RCPP cooking film layer are bonded together through a composite technology. The utility model prepares a tough, puncture-resistant and impact-resistant transparent composite packaging material structure by compounding the natural cellulose film layer with excellent printing adaptability and oxygen resistance and the RCPP cooking film layer with strong water resistance, boiling resistance, cooking resistance, acid resistance, alkali resistance and grease resistance and heat sealing performance, can be prepared into packaging bags for filling foods, and can be subjected to vacuumizing, boiling, high-temperature sterilization or cooking treatment without layering and breaking bags; the natural vitamin film layer replaces the BOPA film, compensates for the low oxygen resistance of the BOPA film, provides a negative pressure low oxygen environment after vacuumizing and sealing, isolates air, ensures that food under vacuum has longer preservation period than general storage, and provides a better solution for the field of food packaging.

Description

Novel transparent high-barrier fresh-keeping vacuum packaging composite material structure

Technical Field

The utility model relates to the technical field of composite materials, in particular to a novel transparent high-barrier fresh-keeping vacuum packaging composite material structure.

Background

At present, a common high-temperature steaming type multilayer composite packaging bag in the flexible packaging market has transparent and opaque choices, and a consumer can more clearly see the live condition of packaging contents through the transparent packaging bag, so that the consumer is further attracted to purchase, the transparent multilayer composite packaging bag material structure basically consists of a BOPA film (nylon film) and an RCPP steaming film, and the BOPA film has the defect that the oxygen resistance is insufficient in practical application and is unfavorable for the preservation of foods with high barrier requirements. In order to increase the barrier property, a water-blocking and oxygen-blocking coating is generally coated on the surface of the transparent packaging film, but the transparent packaging film is not enough to meet the high-strength performance requirements of vacuumizing, high-temperature sterilization and high-temperature cooking.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art, and to realize the exertion of the high-barrier property of the transparent composite material in high-temperature cooking, the high-temperature cooking film with a more transparent structure and barrier property can be obtained by carrying out new combination on cellulose and RCPP, so that the fresh-keeping property of food can be kept.

In order to achieve the above purpose, the technical scheme provided by the utility model is as follows: the utility model provides a novel transparent high separation vacuum packaging composite material structure, composite structure includes natural cellulose rete, RCPP cooking rete and the adhesive layer of centre gripping wherein, laminate together through compound film forming technique between natural cellulose rete, adhesive layer and the RCPP cooking rete.

Preferably, a printing layer is further arranged between the natural cellulose membrane layer and the RCPP cooking membrane layer, and the printing layer is arranged on the inner surface of the natural cellulose membrane layer.

Preferably, a BOPA layer is further arranged between the natural cellulose film layer and the RCPP cooking film layer, the adhesive layer is respectively clamped between the natural cellulose film layer, the BOPA layer and the RCPP cooking film layer, and the natural cellulose film layer, the BOPA layer, the RCPP cooking film layer and the adhesive layer are attached together through a composite film forming technology.

Preferably, a PVDC barrier coating or an acrylic barrier coating may be provided on the natural cellulose film layer.

Preferably, the RCPP retort film may be replaced by a high temperature retort PE film.

The utility model prepares a tough, puncture-resistant and impact-resistant transparent composite packaging material structure by compounding a natural cellulose film with excellent printing adaptability and oxygen resistance with an RCPP cooking film with strong water resistance, cooking resistance, acid resistance, alkali resistance and grease resistance and heat sealing performance, can be prepared into packaging bag filling foods, and can be subjected to vacuumizing, cooking, high-temperature sterilization or cooking treatment without layering and breaking.

The high oxygen resistance of natural vitamin film possesses and prevents oxygen nature replacement BOPA membrane, has compensatied the low oxygen resistance of nylon (PA) membrane, provides the low oxygen environment of negative pressure after the evacuation is sealed, has isolated air, and food under the vacuum is longer than general storage fresh-keeping period, provides a novel, more environmental protection packaging solution for food packaging field.

Description of the drawings:

FIG. 1 is a schematic diagram of a composite structure of an embodiment 1 of the present utility model;

FIG. 2 is a schematic diagram of a composite structure of embodiment 2 of the present utility model;

FIG. 3 is a schematic view of a composite structure of embodiment 3 of the present utility model;

FIG. 4 is a simplified schematic diagram of the process flow of the dry composite method of the present utility model;

fig. 5 is a simplified schematic diagram of the process flow of the solvent-free compounding method of the present utility model.

Detailed Description

The utility model is further illustrated by the following examples:

example 1:

as shown in fig. 1, the novel transparent high-barrier fresh-keeping vacuum packaging composite material structure in the embodiment comprises a natural cellulose film layer 1, an RCPP cooking film layer 2 and an adhesive layer 3 clamped in the natural cellulose film layer 1, the adhesive layer 3 and the RCPP cooking film layer 2, which are attached together through a composite film forming technology.

The transparent packaging bag can enable consumers to more clearly see the live condition of package contents, so that the consumers are further attracted to purchase, the transparent multilayer composite packaging bag material structure basically consists of a BOPA film (nylon film) and an RCPP steaming film, and the BOPA film has the defect that the oxygen resistance is insufficient in practical application and is unfavorable for the preservation of foods with high barrier requirements. In order to increase the barrier property, a water-blocking and oxygen-blocking coating is generally coated on the surface of the transparent packaging film, but the transparent packaging film is not enough to meet the high-strength performance requirements of vacuumizing, high-temperature sterilization and high-temperature cooking.

Therefore, the natural cellulose film layer 1 with excellent printing adaptability and oxygen resistance and the RCPP cooking film layer 2 with strong water resistance, boiling resistance, cooking resistance, acid resistance, alkali resistance and grease resistance and heat sealing performance are compounded to prepare a tough, puncture-resistant and impact-resistant composite structure, and the composite structure can be prepared into packaging bags for filling foods, and can be subjected to vacuumizing, boiling, high-temperature sterilization or cooking treatment without layering and breaking after being subjected to packaging bags

The natural vitamin film has high oxygen resistance to replace a BOPA film, so that the low oxygen resistance of a nylon (PA) film is compensated, a negative pressure low oxygen environment is provided after vacuumizing and sealing, air is isolated, and the food under vacuum has longer preservation period than general storage.

The natural cellulose membrane layer 1 is commonly called cellophane, is synthesized by two words of cellulose and diaphane, and has good printing adaptability. It was invented by a textile engineer, brancher, switzerland in 1905. The natural cellulose membrane with high transparency and luster, also called as regenerated cellulose membrane, is prepared by using dissolving pulp prepared from natural fibers such as cotton linters, chemical wood and the like as raw materials through a viscose method. The term "regenerated" does not mean reused, but means a cellulose film produced by a viscose method and by rearranging molecular chains.

The production method of the natural cellulose membrane layer 1 (glass paper) is different from papermaking, and is similar to a rayon process, cotton linter dissolving pulp or refined chemical wood pulp with high alpha-cellulose content is adopted as a raw material, alkali cellulose is prepared through the processes of alkalization (18% sodium hydroxide), squeezing, crushing and the like, and then the alkali cellulose is aged and then added with carbon disulfide to yellow into cellulose xanthate, and the cellulose xanthate is dissolved by sodium hydroxide solution to prepare the orange cellulose viscose. The viscose is prepared by ripening at 20-30 deg.C, filtering to remove impurities and bubbles, extruding in a narrow and small gap in a film forming machine, flowing into coagulating bath of sulfuric acid and sodium sulfate mixture to form film (regenerated cellulose film), washing with water, desulfurizing, bleaching, desalting, softening (glycerine and ethylene glycol, etc.), adding color, and drying. In the production process, chemicals such as acid, alkali, carbon disulfide and the like are used, but the treated products do not contain any chemicals.

The natural cellulose film layer 1 has certain air permeability and larger elongation, is not fire-resistant but high-temperature resistant, can not deform at a high temperature of more than 190 ℃, can be sterilized at a high temperature together with food in food packaging, and is very beneficial to the fresh-keeping and preservation activities of the food; the water-absorbing type water-absorbing agent has strong resistance to oily, alkaline and organic solvents, is not easy to permeate through a natural fiber membrane layer, has high oil-blocking property, is made of natural fibers, and can absorb water and be easily decomposed during waste treatment; static electricity is not generated, dust is not sucked, the high transparency of the anti-moisture anti-dust coating enables the goods to be clearly contained, and the surface of the anti-moisture anti-dust coating has a moisture-proof function after being provided with a barrier coating.

The cellophane (1) is degradable: tests of Zhejiang university show that when the film product is buried in soil for 45 days, the film is extremely severely broken, and when the film product is excavated, the film is cracked together with the soil, so that the film can not be obtained for measuring the degradation weight loss rate; (2) no toxicity, no smell, no smoke and no malodor when the film product burns; (3) the printing ink has good insulativity (surface resistance is 8.2 multiplied by 107 omega), is not electrified and is not easy to be stained with dust, and has good printing adaptability; (4) has good air permeability: the average oxygen permeability is 67.018 cc/square meter day, and the film is porous and breathable due to the fact that the film is made of cellulose, and the film is suitable for fresh-keeping storage of fruits, vegetables and the like. (5) High temperature resistance: the oven is maintained at 200 ℃ for 24 hours without deformation. The thickness of the natural cellulose membrane layer 1 applied to the composite structure is between 10UM and 50 UM.

The RCPP steaming film layer 2 has excellent tensile strength, heat sealing strength and impact resistance, and can keep excellent puncture resistance and packet breaking resistance in a steaming environment with high temperature and high pressure. The packaging bag has the advantages of being suitable for the type selection of high-temperature steaming and boiling resistance at 121 ℃ and 135 ℃ respectively, ensuring the puncture resistance of the packaging bag, along with good heat sealing strength, high peeling strength, low breaking rate and safe food contact in packaging applications requiring sterilization or steaming and boiling in different high-temperature and high-pressure environments, such as packaging of sharp contents such as shelled eggs, bones and the like. The conventional high-temperature cooking packaging film structures are respectively provided with a plurality of layers of composite structures such as PET/RCPP, BOPA/RCPP, BOPA/AL/RCPP and the like, wherein one important basic substrate is the RCPP cooking film, but the conventional structures in the market are all plastic films, static electricity is easy to accumulate on the surfaces, dust is easy to adsorb, and the composite structures of different materials are not easy to separate and not degradable, so that the recycling is not facilitated.

The adhesive layer 3 can be polyurethane adhesive, and the natural fiber film layer and the RCPP cooking film layer 2 can be adhered into a whole through a traditional dry type compounding or solvent-free compounding process. The polyurethane adhesive is an environment-friendly adhesive which can adapt to high-temperature cooking, and has heat resistance and cold resistance which can bear the requirements of high-temperature and high-pressure environment of boiling and cooking after filling the bag and also can bear the environmental requirements of low-temperature refrigeration or freezing preservation (lower embrittlement temperature); can bear the erosion of various media in the content and the environment, is nontoxic and odorless, has good fluidity and leveling property, and has good adhesive force to the composite substrate.

The RCPP steaming film layer 2 has poor printing adaptability, but has excellent heat sealing strength, peeling strength, high-temperature steaming resistance and water boiling resistance; although the natural cellulose film layer 1 has poor ductility and heat sealing performance, the printing adaptability is excellent, the heat resistance is good, the performances are complementary and enhanced after the natural cellulose film layer 1 and the natural cellulose film layer are bonded and formed by a composite process, and the prepared composite packaging product can be subjected to the performance requirements of vacuumizing, water boiling resistance, high temperature sterilization and high temperature boiling resistance; the natural cellulose film layer 1 has excellent oxygen resistance, and after being combined with the RCPP cooking film layer 2, the water resistance and oxygen resistance of the natural cellulose film layer are higher than those of the conventional BOPA/RCPP composite packaging structures; in addition, the natural cellulose membrane is free from static electricity, does not adsorb dust, is not easy to enter bacteria, is easy to decompose and degrade after being dissolved in water, and has wider popularization value in the field of flexible packaging.

TABLE 1 comparison of Single Membrane Material and partial composite Material Performance

As shown in Table 1, from the comparison of the data from the single-layer natural cellulose film, BOPA film, RCPP cooking film to the natural cellulose/RCPP composite film, the composite film product prepared from the combination of the natural cellulose film and the RCPP cooking film of the utility model has higher and more stable oxygen resistance. The oxygen is an important factor influencing the quality of food in the shelf life, and the oxygen quantity contacted with the food is reduced as much as possible, so that the method is an effective means for ensuring the quality of the food and prolonging the shelf life.

The thickness of the composite structure manufactured by the method is between 60UM and 250UM, and the composite structure can be applied to food packaging bags (the composite strength is more than or equal to 1.5N), fresh-keeping bags, vacuum-pumping bags, water-boiling bags and high-temperature boiling bags (the heat-sealing strength is more than or equal to 20N and the oxygen-blocking performance is between 2 and 5).

Example 2:

the difference from example 1 is that: as shown in fig. 2, a printing layer 5 is disposed between the natural cellulose membrane layer 1 and the RCPP cooking membrane layer 2, the printing layer 5 is disposed on the inner surface of the natural cellulose membrane layer 1, and the natural cellulose membrane layer 1 has better printing adaptability compared with a conventional BOPA membrane (nylon membrane). Characters, patterns and the like are printed on the inner surface of the natural cellulose film layer 1 and then are compounded with the RCPP cooking film layer 2, and as the ink is clamped between the film layers, the ink layer is prevented from being damaged by direct friction, scratch and various corrosive substances, so that the problem that commodity information is lost due to the fact that the ink layer is subjected to external friction fading and scratching is solved well, and potential safety hazards caused by direct contact of the ink with contents are avoided.

If the printing layer 5 has a requirement on corona intensity, the surface of the natural cellulose film layer 1 can be additionally subjected to corona treatment, so that the adhesive force of the printing ink is enhanced, the printing quality is improved, and the production loss is reduced.

Example 3:

the difference from example 1 is that: as shown in fig. 3, in order to expand the application scenario of the composite structure, a BOPA film layer 4 is further added between the natural cellulose film layer 1 and the RCPP cooking film layer 2. The adhesive layer 3 is respectively clamped between the natural cellulose membrane layer 1, the BOPA membrane layer 4 and the RCPP cooking membrane layer 2, and the natural cellulose membrane layer 1, the BOPA layer, the RCPP cooking membrane layer 2 and the adhesive layer 3 are bonded together through a composite membrane forming technology.

In the above composite structure, the purpose is to use the BOPA film layer 4 as a functional layer, further improve the puncture resistance and impact resistance of the composite packaging product, and improve the bearing load of the composite packaging product, so as to adapt to the packaging field with larger capacity, such as packaging field requiring high-temperature sterilization, retooling, or packaging field requiring higher strength and harsher conditions, as shown in table 1.

Example 4:

the difference from example 1 is that: in order to obtain more multifunctional application, a high-barrier coating can be added on a single-layer substrate, and an aluminum oxide coating, PVDC or acrylic coating can be added outside the natural cellulose film layer 1 and then the natural cellulose film layer is composited with other substrates to meet the application requirement of higher barrier performance, as shown in table 1.

Example 5:

the difference from example 1 is that: the RCPP retort film 2 can be replaced by a high temperature retort PE film and also can provide the same effects as the RCPP retort film 2, as shown in table 1.

The polyurethane adhesive properties employed in the composite adhesive should meet, but are not limited to, the following health and safety regulations:

● Additive regulations for Chinese food packaging materials GB9685-2008

● U.S. Food and Drug Administration (FDA) 21CFR175.300

● Restriction of harmful substances by European Union ROHS

The compounding process related by the utility model is dry compounding and solvent-free compounding respectively.

The dry compounding process is the most common method in plastic package compounding, and is a process of coating adhesive on one layer of film under the conditions of certain temperature, tension, speed and the like, drying by an oven, and hot-pressing and bonding with another layer of film to form a composite film. It is suitable for various base material films, can be compounded with any kind of film, and can be used for synthesizing various packaging materials with excellent performances according to the purpose requirements instead of different contents.

Solvent-free compounding is another compounding process applied in the plastic flexible packaging industry. And (3) a composite mode that a solvent-free adhesive and special solvent-free composite equipment are adopted to enable film substrates (or paper, aluminum foil and the like) to be mutually attached, and then all layers of substrates are bonded together after chemical reaction curing treatment of the adhesive.

The solvent-free composite adhesive is different from the solvent-free dry composite adhesive in that the solvent-free composite adhesive does not contain any solvent, the whole process is pollution-free, the product has no solvent residue, and the production process has no potential safety hazard. Compared with the dry type compounding of solvent type and water-based glue, the solvent-free compounding has obvious advantages in the aspects of glue coating cost, energy conservation and emission reduction.

Dry type composite technology

As shown in figure 4, a novel dry type composite operation method of a transparent high-barrier fresh-keeping vacuum packaging composite material structure comprises (1) firstly, packaging a paper cylinder on a rolling shaft, then, packaging a first substrate film roll, penetrating a film according to the direction designated by equipment, packaging a second substrate film roll, and then, lifting a group of rollers of a glue roller to prevent the substrate from being contacted with the glue roller.

(2) The adhesive is added into the rubber plate 6, a drying tunnel heater 9 is started, an auxiliary transmission motor is started, and the pressure between the gravure roller 7 (a rubberizing roller) and the rubber press roller I (an anilox roller) 8 is regulated, so that a thin and uniform layer of adhesive is coated on the gravure roller 7 (the rubberizing roller). When the temperature of the drying tunnel reaches the requirement, cooling water is turned on, an air blower and an exhaust fan are started, an auxiliary motor is turned off, a rubber press roller II 10 on the heating steel roller 11 is put down, the first base material is pressed to the heating steel roller 11, and a host machine is turned on, so that the second base material 1 is adhered to the first base material 2 for compounding.

(3) And adjusting the film tension and the composite pressure. Tension control is one of the most important conditions in the compounding process, and if the tension control is improper, film curling or film curling wrinkling can occur, so that a series of problems such as difficult bag making, reduced peeling strength, bag deformation and the like occur. The tension is set by the type, width, thickness of the substrate, temperature and humidity of the oven, and the like. The composite pressure should increase the temperature and pressure of the composite roll as much as possible without damaging the film, helping to increase the fluidity of the adhesive, promoting the adhesive to wet the second substrate rapidly and enter the micropores of the substrate surface, thereby increasing the composite strength. The compounding temperature is generally 70 to 90 ℃.

(4) The drying temperature and the wind speed are adjusted. Drying is an important factor in dry compounding, and drying directly affects the peel strength, transparency, and contributes to increase in initial adhesion of the composite film. The first, second and third sections of the drying tunnel are generally at 50-60 ℃, 60-70 ℃, 70-80 ℃ and the temperature must be increased step by step. The temperature of the first stage cannot be too high, so that the solvent gradually overflows, otherwise, the surface of the adhesive is hardened, and the solvent of the inner layer remains in the adhesive to greatly influence the strength and the transparency of the composite film. For the composite film for composite cooking, the upper limit of the three-stage temperature can be adopted, the drying tunnel must have enough length, usually not less than 8-9 m, so as to facilitate thorough drying of the adhesive, otherwise, the composite speed can only be reduced.

Another control point of the drying is the wind speed, and the wind speed directly influences the residual amount of the solvent. The wind speed is set to be 25m/s at the lowest, and the wind speed is measured at an air outlet nozzle, preferably 35m/s, so that a wind shovel can be formed, and heat can reach the depth of the base film, thereby being beneficial to thoroughly drying the adhesive. In addition, the balance of air inlet and air outlet is quite important, otherwise, the vibration of the film is easy to cause, the wrinkle is caused, and the pre-air suction is required to be opened during production.

(5) The novel transparent high-barrier fresh-keeping vacuum packaging composite material structure is obtained by bonding a first substrate 2 and a second substrate 1, then passing through a cooling roller 12 to obtain a composite material 14, curing the composite material 14, and fully solidifying.

Solvent-free composite process

The solvent-free compounding process is to compound two kinds of base materials together with solvent-free adhesive in a solvent-free compounding machine. The solvent-free composite polyurethane adhesive has the solid content of 100% and contains no organic solvent and no stoving unit.

As shown in fig. 5, a novel transparent high-barrier fresh-keeping vacuum packaging composite material structure comprises:

(1) unreeling: firstly, a paper cylinder is arranged on a winding shaft, then a first substrate film roll is arranged, films are penetrated according to the direction designated by equipment, and a second substrate film roll is arranged.

(2) And (3) sizing and coating: after the first substrate 2 passes through a coating mechanism consisting of a rubber disc 6, a scraper, a coating roller 13 and a sizing press roller I8, the surface of the first substrate 2 is uniformly coated with adhesive.

(3) Compounding: after the process (2), the first base material 2 with the adhesive attached to the surface is sent to a hot pressing mechanism consisting of a heating steel roller 11 and a rubber press roller II 10 under the traction of a guide roller, and the first base material 2 and the second base material 1 are bonded together under the uniform pressure in a hot pressing mode. The temperature of the heating steel roller 11 is between 40 and 60 ℃, and the composite pressure of the hot pressing mechanism is increased as much as possible under the condition of not damaging the film, so that the composite strength of the composite film material can be improved.

(4) And (3) rolling: and (3) bonding the two layers of base materials, cooling the base materials by a cooling roller 12, and rolling the base materials under proper tension and rolling pressure to obtain the flat and uniform composite material 14.

(5) Curing: and (3) placing the composite coiled material in an environment with a certain temperature to enable the solvent-free adhesive to fully react, thereby obtaining the novel high-barrier fresh-keeping vacuum packaging material structure with expected composite strength.

The adhesive layer 3 can be adhered to the natural cellulose layer 1 and the RCPP retort film layer 2, respectively, because when the adhesive layer 3 is adhered to each substrate, adhesion is generated during drying and curing (solvent-free polyurethane adhesive) or heating and curing (solvent-free polyurethane adhesive), that is, during compounding, the adhesive layer 3 enters the pores of the natural cellulose film layer 1 and the RCPP retort film layer 2 under the condition of being heated and pressed to form mutual adhesion. The bonding effect is affected by factors such as speed, scraper distance, solvent formula, pressure distribution and the like in the compounding process, and the bonding effect needs to be adjusted according to actual conditions in actual operation so as to obtain an ideal compounding effect.

The composite material 14 obtained by the dry type composite process and the solvent-free composite process is subjected to a curing process, and the curing process can be carried out in a constant temperature chamber at 35-50 ℃ for more than 6 hours, and the chemical reaction speed can be accelerated under certain high-temperature conditions.

The curing reaction is beneficial to the curing of the adhesive layer and the acceleration of the phase reaction of-NCO groups in the adhesive and active hydrogen groups on the surfaces of the natural cellulose film layer 1 and the RCPP cooking film layer 2. Meanwhile, the adhesive layer 3 can be softened by heating, so that the wetting of the surfaces of the natural cellulose film layer 1 and the RCPP cooking film layer 2 is increased, the molecular movement is facilitated, the adhesive force is improved, the composite product can be rapidly subjected to subsequent processing, and the production period is shortened. The peel strength of the composite material 14 changes until the curing reaction is completed, a process that presents an increase-decrease-stabilization.

The curing reaction process can be continued for more than 48 hours in the natural environment at 25 ℃ to achieve the aim of full curing.

The peel strength of the cured composite material 14 can be up to 1.5N-2N.

Claims

1. The utility model provides a novel transparent high separation vacuum packaging combined material structure which characterized in that: the composite material structure comprises a natural cellulose membrane layer, an RCPP cooking membrane layer and an adhesive layer clamped in the RCPP cooking membrane layer, wherein the natural cellulose membrane layer, the adhesive layer and the RCPP cooking membrane layer are bonded together through a composite membrane forming technology.

2. The novel transparent high-barrier fresh-keeping vacuum packaging composite material structure according to claim 1, which is characterized in that: and a printing layer is further arranged between the natural cellulose membrane layer and the RCPP cooking membrane layer, and the printing layer is arranged on the inner surface of the natural cellulose membrane layer.

3. The novel transparent high-barrier fresh-keeping vacuum packaging composite material structure according to claim 1, which is characterized in that: the natural cellulose membrane layer and the RCPP cooking membrane layer are respectively clamped with the adhesive layer, and the natural cellulose membrane layer, the BOPA layer, the RCPP cooking membrane layer and the adhesive layer are bonded together through a composite membrane forming technology.

4. The novel transparent high-barrier fresh-keeping vacuum packaging composite material structure according to claim 1, which is characterized in that: a PVDC barrier coating or an acrylic barrier coating may be provided on the natural cellulose film layer.

5. The novel transparent high-barrier fresh-keeping vacuum packaging composite material structure according to claim 1, which is characterized in that: the RCPP retort film may be replaced by a high temperature retort PE film.