Aluminum-coated wide-narrow segmented easy-to-peel double-cavity facial mask bag and preparation method thereof

Abstract

The application discloses an aluminized wide-narrow segmented easy-to-open double-cavity facial mask bag and a preparation method thereof, and belongs to the field of packaging materials. The product is a PET / VMPET / PE three-layer composite double-cavity structure, a wide straight support middle seal and a narrow wavy easy-to-open middle seal are arranged between the two cavities, and a fracture indentation and an angular limiting hole are arranged in the narrow segment. The preparation is divided into three steps: first, modified extrusion is used to prepare a functional PET film and a three-layer co-extrusion easy-to-open modified PE film; then, differentiated gluing is performed by using a partition micro-concave roller, step speed-up compounding, segmented pre-solidification and constant temperature curing are performed to eliminate the film stress; finally, double-temperature-zone controlled heat sealing is performed to form. Through the synergistic regulation of substrate modification, gradient gluing and differentiated heat sealing, the wide segment has high edge sealing tearing strength and can prevent leakage during storage and transportation; the narrow segment has low opening force and can be connected with the double cavities by light pressing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of packaging materials, and particularly relates to a plated aluminum type wide-narrow segmented easy-to-uncover double-cavity mask bag and a preparation method thereof. BACKGROUND

[0002] The double-cavity dry-wet separation mask bag can store mask cloth and essence separately, can reduce the addition of preservatives in skin care products, can maintain the activity of essence, and has become a mainstream packaging of high-end masks. The industry mainstream adopts a PET / VMPET / PE plated aluminum composite structure, relies on a VMPET plated aluminum layer to realize high water permeability and oxygen barrier effect, and guarantees long-term storage stability of essence. The plated aluminum thin film is difficult to replace as a high-end packaging solution.

[0003] The existing plated aluminum composite production process has the following technical defects which are difficult to eliminate: Firstly, the VMPET plated aluminum layer has poor wettability and weak interfacial adhesion. Traditional high internal stress adhesive, one-time high-temperature curing, and high-speed composite production mode can easily cause the plated aluminum layer to peel, migrate, fall off, and have white spots on the surface. This not only reduces the appearance grade of the packaging, but also greatly reduces the film layer peeling strength. The product is prone to delamination, liquid leakage, and bag breakage during transportation and pressing. The production yield is low. Secondly, the traditional composite process has uneven glue coating, unbalanced tension, and single temperature control gradient. The processing process can easily cause micro-cracks in the plated aluminum layer, resulting in continuous decay of the barrier properties of the thin film. Thirdly, the traditional mask is only provided with a single-section uniform strength middle seal, and the mechanical properties cannot be controlled in different zones. If the overall middle seal strength is low, the middle seal is prone to damage and liquid leakage during transportation. If the overall strength is high, the user needs to exert a lot of effort to open the mask, and the concentrated stress is prone to cause the whole seal edge to tear and the bag to burst, resulting in poor user experience. Fourthly, the traditional mask bag does not have a wide-narrow segmented differential easy-to-uncover structure design. The adhesion of the bag body around and the whole middle seal edge has no difference, and it is impossible to simultaneously realize the functions of "high-strength sealing and anti-leakage around, high-strength anti-pressing in the middle support section, and pre-set narrow section easy-to-uncover and tear". The tearing strength fluctuates greatly, and the whole seal edge is prone to tear and the plated aluminum layer is prone to fall off with the seal edge during peeling. The use feels unstable.

[0004] At present, the industry only makes simple improvements by adjusting the glue ratio and reducing the production speed, but cannot solve the problem of plated aluminum layer falling off from the root. The conventional single-section middle seal packaging structure also cannot simultaneously meet the three requirements of high-strength anti-leakage during transportation, comfortable opening feeling, and stable and controllable easy-to-uncover peeling. It is difficult to realize the support section 20-25N protection strength, easy-to-open section 5-10N light and soft pressing force in different zones. Therefore, there is an urgent need in the market for a wide-narrow segmented middle seal double-cavity mask bag complete preparation process which retains the high barrier properties of the VMPET plated aluminum layer, completely solves the defect of plated aluminum layer falling off, simultaneously improves the storage stability, use feeling, and controllable easy-to-uncover performance. SUMMARY

[0005] TECHNICAL PROBLEM The traditional process of the existing PET / VMPET / PE structure double cavity mask bag adopts a single section uniform strength middle seal, and has multiple defects such as easy peeling of the aluminum plating layer, attenuation of the barrier property, large composite internal stress, inability to partition control the opening force of the sealing edge, easy leakage and bag breakage during transportation, poor use experience, and the inability to balance the sealing strength and easy tearing performance, and it is difficult to simultaneously realize the three core requirements of high barrier storage stability, comfortable low force extrusion opening, and high strength resistance to storage and transportation extrusion of the middle support section.

[0006] Technical content In order to solve the above technical problems, the present application provides an aluminum plated wide and narrow segmented easy-to-open double cavity mask bag and a preparation method thereof. The aluminum plated wide and narrow segmented easy-to-open double cavity mask bag is a double cavity mask bag with a PET / VMPET / PE three-layer aluminum plated composite structure. The inner part of the bag body is separated into an independent mask cavity and an essence cavity. A wide and narrow two-section type separation middle seal is arranged between the two cavities, including a high-strength wide edge straight support middle seal and a low-force easy-to-open narrow edge wave section. The narrow edge easy-to-open middle seal is provided with a breakable indentation line, and the end of the indentation line is provided with an angular limiting hole. The whole process includes eight major procedures of raw material pretreatment and automatic proportioning, melt extrusion precision filtration, die stretching and shaping, cooling and winding, online intelligent detection, aluminum film compounding and curing, constant temperature cutting, and integrated bag forming. The easy-to-open modified PE inner layer, zoned gradient coating, and dual-temperature zone differentiation heat sealing innovative process are matched, and the bag body is accurately sealed around the edge. The wide edge straight middle seal can realize a high-strength seal of 20-25N, and the middle narrow edge wave middle seal can realize a constant 5-10N soft easy-to-open force.

[0007] To achieve the above purpose, the present application adopts the following technical scheme: a preparation method of an aluminum plated wide and narrow segmented easy-to-open double cavity mask bag, comprising the following steps: S1, preparing a PET functional film and an easy-to-open modified PE film Prepare the PET film raw material, the easy-to-open modified PE film outer layer, the middle layer, and the inner layer raw material. Dust all the raw materials, and perform constant temperature drying and water removal treatment. Accurately proportion and mix the raw materials through a full-automatic batching system, and uniformly stir in a sealed manner. After the raw materials of each formula are melted through five-stage gradient temperature control of an extruder, and three-stage precision filtration, the materials are extruded through a die, and then subjected to bidirectional stretching, constant temperature cooling and shaping, and tension adjustment and winding, to respectively prepare PET films and easy-to-open modified PE films with uniform thickness.

[0008] S2, multi-layer dry compounding and curing treatment Adopting two-component polyurethane glue as composite glue, the glue is prepared according to the preset ratio and vacuum degassing is completed; adopting PET film, VMPET aluminized film and three-layer composite structure of easy-to-peel modified PE film, differential gluing process is adopted by partitioning micro-concave roller to glue the whole PET film and to glue the VMPET aluminized film and PE film in the differential areas of wide straight middle sealing area and narrow wave easy-to-open middle sealing area; dry composite is completed by adopting stepwise speed-up mode to control the composite speed, oven temperature, hot roller temperature and composite tension; after the composite is completed, pre-curing, constant temperature curing and normal temperature cooling stress relief treatment are sequentially performed to obtain the composite film base material.

[0009] S3, slitting and segmented heat sealing bag forming The composite film after cooling stress relief is cut to remove the waste edges and is slitted into standard specification film rolls; full-automatic double-temperature-zone middle sealing bag machine is adopted to control the heat sealing process parameters in different areas to respectively complete the heat sealing forming of the outer peripheral sealing of the bag body, the wide straight middle sealing and the middle narrow wave easy-to-open middle sealing; wide and narrow two-section partition middle sealing structure is arranged at the double-cavity partition position, fracture indentation lines are arranged at the narrow easy-to-open section, and angular limiting holes are arranged at the end of the indentation lines, and finally the aluminized type wide and narrow segmented easy-to-peel double-cavity surface film bag is obtained.

[0010] Further, the PET film raw material formula in step S1 includes, by mass percentage, 90-92% food-grade PET virgin particles, 3.0-4.0% functional barrier aid, 4.5-5.5% toughening aid, and 0.30-0.40% slip aid; wherein the food-grade PET virgin particles are selected from Hainan Yisheng YS W01, the functional barrier aid is selected from Mitsubishi MXD6S6007, the toughening aid is selected from Arkema AX8900, and the slip aid is selected from INNOSLIP SE stearyl erucamide.

[0011] Further, the PET film preparation drying temperature in step S1 is 55-65°C, and the drying time is 3.5-4.5h; the five-section gradient temperature control melting temperatures are 175-185°C for the feeding preheating section, 230-240°C for the melting zone one, 245-255°C for the melting zone two, 240-248°C for the homogenization section, and 238-245°C for the die flow section; the three-stage filtration adopts 70-90 mesh coarse filter screen, 280-320 mesh medium filter screen and 1100-1300 mesh ultra-fine sintered filter screen in sequence; the longitudinal stretching ratio is 2.8-3.1 times, and the transverse stretching ratio is 3.2-3.6 times, and the PET film thickness is 25-80μm, and the thickness uniformity deviation is ≤±5μm.

[0012] Further, the modified PE film in step S1 is a three-layer co-extrusion structure, and the mass percentage of the raw materials of the outer layer, the middle layer and the inner layer is as follows: the outer layer formula: 65-75% LLDPE, 26-30% LDPE, 1.2-1.8% general blown film opening master batch, 0.15-0.25% 1010 / 168 antioxidant compound aid; the middle layer support layer formula: 75-85% LLDPE, 15-25% HDPE; the inner layer easy-to-open heat sealing layer basic formula: 65-75% LDPE, 16-20% PB 1, 8-12% mLLDPE, 1.5-2.1% food-grade smooth opening master batch, 0.15-0.25% composite antioxidant; to adapt to different easy-to-open requirements, the inner layer heat sealing layer can add 0-1.2% linear low density polyethylene easy-to-open master batch, corresponding to PB 1 The content is adjusted synchronously to 16.8-18%.

[0013] Further, the LLDPE is selected from Fushun Petrochemical DFDA 7042, the LDPE is selected from Yanshan Petrochemical 2420H, the HDPE is selected from Baofeng 23050, and the PB 1 is selected from LyondellBasell PB8640M, and the mLLDPE is selected from ExxonMobil 1018HA; the prepared easy-to-open modified PE film has a thickness of 25-80 μm, and the thickness uniformity deviation is ≤±5 μm.

[0014] Further, in step S2, the mass ratio of the main agent and the curing agent of the two-component polyurethane adhesive is 4.5:1-5.5:1, and the adhesive solid content is 32%-38%; the adhesive dispensing process is constant temperature stirring for 4.5-5.5 min at 140-160 r / min in a negative pressure environment, and vacuum degassing for 25-35 min after closed standing.

[0015] Further, in step S2, 120-line partition micro-concave roller coating is adopted, and the total dry adhesive amount of the PET film is 2.1-2.45 g / m 2 ; the dry adhesive amount of the bag body four-side sealing edge, the straight middle sealing area of the wide side and the PET total adhesive amount are consistent, and the dry adhesive amount of the narrow side wavy easy-to-open middle sealing area is 1.9-2.0 g / m 2 .

[0016] Further, in step S2, the composite process parameters are as follows: the composite basic speed is 62-68 m / min, the three-stage oven temperature is 70-80℃, 80-90℃ and 90-100℃ in turn, the hot roller temperature is 60-70℃, and the composite tension is 0.08-0.12 MPa; the stepwise speed-up process is as follows: winding at 75-85 m / min for 450-550 m, then winding at 90-110 m / min for 800-1000 m, and then increasing the speed to 280-320 m / min for mass production without defective products.

[0017] Furthermore, the curing process in step S2 is as follows: pre-curing at 22~28℃ for 3.0~5.5h, followed by constant temperature curing at 53~58℃ for 22~26h, and then standing at 22~28℃ for 22~26h after curing to eliminate the internal stress of the film.

[0018] Furthermore, in step S3, the composite film is cut to a size of 18cm × 22cm; the heat-sealing process parameters are as follows: outer perimeter seal and wide-edge straight center seal: mold temperature 136~140℃, pressure 0.21~0.24MPa, holding pressure 0.3~0.5s, heat-sealing tear strength 20~25N / 15mm; narrow-edge wavy easy-open center seal: mold temperature 120~124℃, pressure 0.10~0.12MPa, holding pressure 0.2~0.3s, narrow-edge tear force 5~10N / 15mm, and the final double-cavity mask bag has an overall extrusion opening force of 5~10N.

[0019] Furthermore, the aluminized, segmented, easy-open dual-cavity mask bag prepared by this method exhibits a firmly adhered aluminized layer, free from migration, whitening, mottled appearance, and peeling defects, with no delamination between film layers; the product's water permeability is ≤1.6 g / (m²). 2 •24h), oxygen permeability ≤2.2cm 3 / (m 2 (24h·0.1MPa), stable barrier performance, clear distinction between wide and narrow sections, no leakage or cracking of sealing edges during storage and transportation, uniform peeling of narrow sections without bag bursting or residual adhesive stringing.

[0020] Beneficial effects 1. Solve the industry problem of aluminum plating layer peeling: Adopt low internal stress adhesive, negative pressure degassing, segmented pre-curing + stepped curing process to eliminate the pulling of the aluminum plating layer by the internal stress of curing, prevent the aluminum plating layer from whitening, migrating, delamination and peeling, greatly improve the composite peel strength, and make it less likely to leak and break the bag when squeezed in logistics, and significantly improve the product yield.

[0021] 2. Stable and long-lasting high barrier properties: It fully retains the high barrier advantage of the VMPET aluminum coating, avoids the generation of micro-cracks in the aluminum coating during processing, and significantly reduces the permeability of water vapor and oxygen. It can effectively isolate water vapor and oxygen, retain the active ingredients, reduce preservatives, and extend the shelf life of the mask.

[0022] 3. Segmented mechanical structure balances storage and transportation strength with a comfortable, low-force opening feel: The wide and narrow two-section separation design of the center seal, with the wide straight support center seal and the four sides of the seal providing 20~25N high-strength protection against accidental opening due to transportation compression; the narrow easy-open section has a tearing force of 5~10N, and with the wavy indentation and angular limiting holes, the two cavities can be connected with a light pressure, solving the defects of traditional single-section center seals that are either difficult to open or prone to bag breakage during storage and transportation.

[0023] 4. Strong weather resistance and storage stability: After high and low temperature cycling, long-term accelerated aging, and repeated compression fatigue tests, the wide-side high-strength support structure has no cracks or leaks, and the narrow-side is easy to peel off with minimal force fluctuations, making it less prone to failure during cross-regional storage and transportation.

[0024] 5. Excellent economic efficiency for industrial mass production: Fully automated production with a wide process parameter window and high fault tolerance, significantly reducing the appearance defect rate; increased production line capacity, reduced material loss and rework costs, no need to replace expensive base materials, energy-saving and environmentally friendly, suitable for large-scale mass production.

[0025] 6. Controllable segmented and balanced easy-open peel performance, completely solving the contradiction between sealing and easy tearing: Through the three-in-one coordinated control of easy-open masterbatch modified PE inner layer, wide and narrow area gradient adhesive coating, and dual-temperature zone differentiated heat sealing, a layered and controllable mechanical structure is formed; the bag body is supported by a 20~25N high-strength seal around the perimeter and the middle wide section to resist leakage due to logistics compression; the tearing force of the narrow section easy-open seal is constant at 5~10N, and the compression force is concentrated only in the narrow section, ensuring that the wide edge seal is intact and does not tear, without defects such as sudden local bag bursting or aluminum coating peeling; after high and low temperatures and 90 days of long-term storage, the force fluctuation of both wide and narrow sections is ≤±1N, and the easy-open feel is uniform and stable, solving the industry pain point that the sealing strength and easy-open feel of traditional single-section seals are incompatible. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a dual-cavity mask bag with wide and narrow sections. The dual-cavity mask bag is divided into an essence cavity and a mask cavity. It has a high-strength outer edge seal, a wide straight support center seal and a narrow wavy easy-open center seal, and an angular limiting hole at the end.

[0027] Figure 2 This is a schematic diagram of a heat seal strength / segment tear force testing device. The tear force for a narrow-edge easy-open center seal is 5~10N. Detailed Implementation

[0028] The VMPET aluminized film used below is a commercially available product. This film uses biaxially oriented polyester (BOPET) as the substrate and employs a high-vacuum evaporation process to deposit an ultra-thin high-purity aluminum layer on the film surface, making it a high-barrier functional film.

[0029] Example 1: A method for preparing an aluminum-plated, wide-narrow segmented, easy-open dual-cavity facial mask bag. (1) Preparation of PET film and easy-to-peel modified PE film The raw material formula of PET film is as follows: 91.15wt% food-grade virgin PET particles (Hainan Yisheng YS-W01), 3.50wt% functional barrier additive (Mitsubishi Chemical MXD6S6007), 5.00wt% toughening additive (Arkema AX8900), and 0.35wt% slip additive (INNOSLIP-SE stearyl erucamide).

[0030] The PET film preparation process is as follows: The raw materials are first subjected to dust removal treatment and then dried at a constant temperature of 60℃ for 4 hours to remove moisture and impurities. Afterwards, a fully automated batching system is used to precisely mix each component, and the mixture is stirred in a sealed environment until the material is homogeneous. The mixture is then conveyed to an extruder for melt extrusion and filtration, employing a five-stage gradient temperature-controlled melting process: preheating section (175-185℃), melting zone 1 (230-240℃), melting zone 2 (245-255℃), homogenization section (240-248℃), and die confluence section (238-245℃). The molten material is then sequentially passed through an 80-mesh coarse filter, a 300-mesh medium filter, and a 1200-mesh ultrafine sintered filter for three-stage precision filtration. An automated hydraulic screen changer is used to remove impurities online, ensuring a clean melt free of coke particles and agglomerated impurities. The melt is then extruded through a high-precision die and fed into a biaxial stretching unit for stretching. The longitudinal stretching ratio is controlled at 2.8~3.1 times, and the transverse stretching ratio is controlled at 3.2~3.6 times. Uniform stretching at a constant speed yields a PET film with a thickness of 25~80μm, and the thickness uniformity deviation is ≤±5μm. The stretched film preform is then shaped by a 22℃ water-circulating constant-temperature cooling roller assembly. An intelligent tension system dynamically adjusts the winding parameters, ensuring smooth low-speed winding to prevent wrinkles and deformation. Throughout the production process, online thickness detection and visual defect detection systems are activated to monitor film quality in real time and automatically fine-tune process parameters.

[0031] The raw material formulation of the easy-peel modified PE film is as follows: the outer layer formulation consists of 70% LLDPE (Fushun Petrochemical DFDA-7042) and 28.3% LDPE (Yanshan Petrochemical 2420H), combined with 1.5% general blown film opening masterbatch and 0.2% 1010 / 168 antioxidant compound additive; the middle support layer formulation uses 80% LLDPE (Fushun Petrochemical DFDA-7042) and 20% HDPE (Baofeng 23050) to ensure film rigidity and processing stability; the inner easy-peel heat-sealing layer formulation consists of 70% LDPE (Yanshan Petrochemical 2420H), 18% poly-1-butene PB-1 (Ryndall Basel PB8640M), 10% mLLDPE (ExxonMobil 1018HA), plus 1.8% food-grade slip opening masterbatch and 0.2% composite antioxidant. This formula relies on the two-phase island-island incompatible structure of PE and PB-1 to achieve clean peeling of the interface after heat sealing, with no stringing or residue. It has a wide heat sealing window and stable peel strength, making it suitable for high-end food sealing applications such as PP food containers and cup lids. It is a mature and stable mass production formula in the industry.

[0032] The preparation process of the easy-to-peel modified PE film is as follows: referring to the preparation process of PET film, three kinds of melts are prepared by the outer layer formula, the middle support layer formula and the inner easy-to-peel heat-sealing layer formula. Then, the three melts are co-extruded and stretched to obtain a food contact easy-to-peel functional PE film with a thickness of 25~80μm. The thickness uniformity deviation of the PE film is ≤±5μm.

[0033] (2) Composite processing and bag forming of aluminum-plated wide and narrow segmented easy-open double-cavity mask bags A two-component polyurethane adhesive was used for dry lamination, with the adhesive base and curing agent mixed in a 5:1 mass ratio. During preparation, the adhesive was diluted to a solid content of 35%, and stirred at a constant temperature for 5 minutes under negative pressure at 150 rpm. The mixture was then sealed and allowed to stand for 30 minutes to complete vacuum degassing. The composite structure consisted of a PET film, a VMPET aluminized film, and an easy-peel modified PE film. During preparation, the adhesive was first applied to the entire surface of the PET film at a ratio of 2.25 g / m². 2 The VMPET aluminized film is laminated; the VMPET and PE lamination section uses a 120-line segmented micro-grooved roller for segmented adhesive application, with a dry adhesive application rate of 2.25g / m² for the bag's perimeter sealing and the wide, straight center seal area. 2 Narrow-edged, wavy, easy-to-open, centrally sealed molding area: 2.0g / m² of dry adhesive application. 2 This achieves a narrow, locally low-adhesion, easily peelable interface.

[0034] The lamination speed was 180 m / min, and the oven temperature was set sequentially to 75℃, 85℃, and 95℃, with the hot roller temperature at 65℃ and the lamination tension at 0.1 MPa. Production employed a stepped speed-up method: first, 500 m was wound at 80 m / min, then adjusted to 100 m / min for 900 m. After confirming no defective products, the speed was increased to 300 m / min for mass production. The laminated film was pre-cured at 25℃ for 4 hours, followed by curing at 55℃ for 24 hours.

[0035] After curing, the composite film is cooled at 25℃ for 24 hours, the waste edges are removed, and it is cut into 18cm×22cm film rolls. The rolls are then formed in one piece using a fully automatic dual-temperature zone center-sealing bag-making machine. The specific process is as follows: Four-sided outer perimeter seal + wide-edge straight center seal: mold temperature is 138℃, pressure is 0.22MPa, holding pressure is 0.4s, and the heat seal / tear strength of this area is 23.7N / 15mm; Narrow-edge wavy easy-open center seal: An independent mold is used, with a mold temperature of 122℃, a pressure of 0.11MPa, and a holding pressure of 0.22s. The actual measured tear force of the narrow-edge center seal after molding is 8.7N / 15mm. A two-section dividing seal with a wide and a narrow section is set between the two cavities. The narrow side easy-open section is equipped with a fracture indentation line, and an angular limiting hole is opened at the end of the indentation line. Finally, a controllable segmented easy-open aluminum-plated double-cavity mask bag is made, with an overall extrusion opening force of 8.2N for the double cavities.

[0036] (3) Product performance testing Performance tests were conducted on the aluminized wide and narrow segmented dual-cavity mask bag prepared in this embodiment. The results showed that the VMPET aluminized layer was firmly adhered, with no aluminum layer migration, whitening, or mottled defects, and the interlayer composite strength of the film was excellent. The aluminized film had stable barrier performance, with no significant attenuation of the barrier index. Only 8.2N of extrusion force was required to break the narrow side center seal and smoothly connect the two cavities. The wide side straight support center seal and the four sides of the seal were intact without tearing. The narrow segment peeled off evenly without bursting or aluminum layer falling off. There were no problems such as leakage or seal cracking during storage and transportation. The overall performance was significantly better than that of the traditional single-segment center-sealed aluminized composite mask bag.

[0037] Example 2: A method for preparing an aluminum-plated, wide-narrow segmented, easy-open dual-cavity facial mask bag. (1) Preparation of PET film and easy-to-peel modified PE film The raw material selection and preparation process of the PET film are consistent with those in Example 1.

[0038] The preparation process of the easy-open modified PE film is consistent with that of Example 1. The difference in raw material selection compared to Example 1 is that 1.0 wt% of linear low-density polyethylene easy-open masterbatch is added to the inner easy-open heat-sealing layer formulation. Specifically, it consists of: 70% LDPE (Yanshan Petrochemical 2420H), 17% poly-1-butene PB-1 (Ryndell Basel PB8640M), 10% mLLDPE (ExxonMobil 1018HA), 1.0 wt% linear low-density polyethylene easy-open masterbatch, plus 1.8% food-grade slip-opening masterbatch and 0.2% composite antioxidant.

[0039] (2) Composite processing and bag forming of aluminum-plated wide and narrow segmented easy-open double-cavity mask bags A two-component polyurethane adhesive was used for dry lamination, with a 5:1 mass ratio of adhesive base to curing agent. The adhesive was diluted to a concentration of 32% and stirred at a constant temperature of 150 rpm for 5 minutes under negative pressure, followed by vacuum degassing after 30 minutes of sealed standing. The composite structure consisted of a PET film, a VMPET aluminized film, and an easy-peel modified PE film. 2.1 g / m³ of adhesive was applied to the entire PET layer. 2 The VMPET and PE bonding section uses a 120-line zoned coating roller for zoned coating. The dry coating amount is 2.1g / m² around the bag body and in the wide, straight center seal area. 2 The narrow-edge, easy-to-open center seal has a dry adhesive application rate of 1.9g / m². 2 This achieves a narrow, locally low-adhesion, easily peelable interface.

[0040] The laminating speed was 68 m / min, the oven temperatures were set at 75℃, 85℃, and 95℃ respectively, the hot roller temperature was 65℃, and the laminating tension was 0.08 MPa. Production employed a stepped speed-up method: first, 500 m was wound at 80 m / min, then adjusted to 100 m / min for 900 m. After confirming no defects, the speed was increased to 300 m / min for mass production. The laminating film was pre-cured at 25℃ for 3.5 hours, followed by curing at 53℃ for 24 hours.

[0041] After curing, the composite film is left to stand at 25℃ for 24 hours to eliminate internal stress. After removing the waste edges, it is cut into standard 18cm×22cm rolls. It is then formed in one piece by a fully automatic dual-temperature zone sealing bag making machine. The outer perimeter seal + wide-edge straight center seal mold is heated at 136℃, 0.21MPa, and held for 0.4s, with a heat seal strength of 21.8N / 15mm in this area. The middle narrow-edge wavy easy-open center seal mold is heated at 120℃, 0.10MPa, and held for 0.22s, with a measured tear force of 7.9N / 15mm. The two cavities retain a wide and narrow section separating center seal, a narrow section fracture indentation line, and an angular limiting hole structure, resulting in an aluminized segmented easy-open double-cavity mask bag with a double-cavity extrusion opening force of 7.2N.

[0042] (3) Product performance testing Performance tests were conducted on the aluminized dual-cavity mask bag with wide and narrow sections prepared in this embodiment. The results showed that the product could completely retain the high gloss and high barrier properties of the VMPET aluminized layer, and there were no phenomena such as whitening, peeling, or mottled aluminized layer; the opening extrusion force of the dual cavities was 7.2N, the tear strength of the wide straight center seal and four-sided seal was 21.8N / 15mm, and the tear strength of the narrow easy-open section was 7.9N / 15mm; the water permeability was 1.53g / (m³). 2 •24h), oxygen permeability 2.18cm 3 / (m 2 • 24h • 0.1MPa); the film layers are firmly bonded together, with no delamination, leakage, or edge damage. The aluminum plating layer has stable performance without degradation. The narrow section is easy to peel off with a uniform feel, and the wide section has sufficient support strength to meet storage and transportation requirements. Its overall performance is significantly better than products prepared by traditional single-section center-sealing aluminum plating processes.

[0043] Example 3: A method for preparing an aluminum-plated, wide-narrow segmented, easy-to-peel dual-cavity facial mask bag. (1) Preparation of PET film and easy-to-peel modified PE film The raw material selection and preparation process of the PET film are consistent with those in Example 1.

[0044] The preparation process of the easy-open modified PE film is consistent with that of Example 1. The difference in raw material selection compared to Example 1 is that 1.2 wt% of linear low-density polyethylene easy-open masterbatch is added to the inner easy-open heat-sealing layer formulation. Specifically, it consists of: 70% LDPE (Yanshan Petrochemical 2420H), 16.8% poly-1-butene PB-1 (Ryander Basel PB8640M), 10% mLLDPE (ExxonMobil 1018HA), 1.2 wt% linear low-density polyethylene easy-open masterbatch, plus 1.8% food-grade slip-opening masterbatch and 0.2% composite antioxidant.

[0045] (2) Composite processing and bag forming of aluminum-plated wide and narrow segmented easy-open double-cavity mask bags A two-component polyurethane adhesive was used for dry lamination, with a 5:1 mass ratio of adhesive base to curing agent. The adhesive was diluted to a concentration of 38% and stirred at a constant temperature of 150 rpm for 5 minutes under negative pressure, followed by vacuum degassing after 30 minutes of sealed standing. The composite structure consisted of a PET film, a VMPET aluminized film, and an easy-peel modified PE film; 2.45 g / m² of adhesive was applied to the entire PET layer. 2 The VMPET and PE bonding section uses a 120-line zoned gluing roller for zoned gluing, with 2.45g / m² applied to the perimeter and wide-edge straight center sealing area. 2 The narrow-edge, easy-to-open center seal corresponds to an area with a g / m² content of 2.1 g / m². 2 .

[0046] The laminating speed was 62 m / min, the oven temperatures were set at 75℃, 85℃, and 95℃ respectively, the hot roller temperature was 65℃, and the laminating tension was 0.12 MPa. Production employed a stepped speed-up method: first, 500 m was wound at 80 m / min, then adjusted to 100 m / min for 900 m. After confirming no defects, the speed was increased to 300 m / min for mass production. The laminating film was pre-cured at 25℃ for 5 hours, followed by curing at 58℃ for 24 hours.

[0047] After curing, the composite film is left to stand at 25℃ for 24 hours to eliminate internal stress. After removing the waste edges, it is cut into standard 18cm×22cm rolls. It is then formed in one piece by a fully automatic dual-temperature zone sealing bag making machine. The outer perimeter seal + wide-edge straight center seal mold is heated at 140℃, 0.24MPa, and held for 0.4s, with a heat seal strength of 24.2N / 15mm in this area. The middle narrow-edge wavy easy-open center seal mold is heated at 124℃, 0.12MPa, and held for 0.22s, with a measured tear force of 9.6N / 15mm. The two cavities are separated by a wide and narrow center seal, a narrow-section fracture indentation line, and an angular limiting hole structure, resulting in an aluminized segmented easy-open double-cavity mask bag with a double-cavity extrusion opening force of 9.4N.

[0048] (3) Product performance testing Performance tests were conducted on the aluminized, segmented, dual-cavity mask bag prepared in this embodiment. The results showed that the aluminized layer was intact, without any peeling or cracking defects; the dual-cavity opening compression force was 9.4 N, the wide-side support section and four-sided sealing strength was 24.2 N / 15 mm, and the narrow-side easy-open section tear force was 9.6 N / 15 mm, all within their respective optimal usage ranges; the water permeability was 1.45 g / (m³). 2 •24h), oxygen permeability 2.05cm 3 / (m 2 (24h, 0.1MPa). Even within the critical range of process parameters, this solution clearly distinguishes between the wide and narrow pressure sections, effectively overcoming the defect of aluminum plating layer peeling off. It exhibits stable and excellent barrier performance with minimal fluctuation in peeling pressure.

[0049] Comparative Example 1 (1) Substrate preparation Commercially available conventional PET film and ordinary PE film (without easy-peel masterbatch and without barrier toughening additives) are selected as composite substrates. The raw materials are only food-grade PET virgin particles and food-grade PE virgin particles, without any additives.

[0050] (2) Composite processing and bag forming A two-component polyurethane adhesive is used for dry lamination, with a 5:1 ratio of adhesive base to curing agent. During preparation, the adhesive is diluted to a solid content of 35%, and stirred at a constant temperature for 5 minutes under negative pressure at 150 rpm. Afterward, it is allowed to stand in a sealed environment for 30 minutes to complete vacuum degassing. The composite structure consists of a PET film, a VMPET aluminized film, and a regular PE film. There is no wide or narrow zone coating design; a traditional 100-line coating roller is used uniformly across the entire width, with the dry adhesive application rate controlled at 1.8~2.0 g / m². 2 .

[0051] The lamination speed was 180 m / min, and the oven temperature was set sequentially to 75℃, 85℃, and 95℃, with the hot roller temperature at 65℃ and the lamination tension at 0.1 MPa. Production employed a stepped speed-up method: first, 500 m was wound at 80 m / min, then adjusted to 100 m / min for 900 m. After confirming no defective products, the speed was increased to 300 m / min for mass production. The laminated film was pre-cured at 25℃ for 4 hours, followed by curing at 55℃ for 24 hours.

[0052] After curing, the composite film is cooled at 25℃ for 24 hours, the waste edges are removed, and it is cut into film rolls of 18cm×22cm specifications. The bag making machine has a heat sealing mold without dual temperature differentiation, and the middle is a single-segment equal-width corrugated center seal. The heat sealing parameters are uniform throughout, and the heat sealing strength of the perimeter reaches 28N / 15mm.

[0053] (3) Product performance description This comparative example is a mainstream traditional production solution on the market. It does not modify the PET / PE substrate, does not have wide and narrow zone gradient adhesive coating, and does not have a dual-temperature zone differentiated heat-sealing and easy-open design. The middle section is only a single-segment equal-width seal and cannot be zoned to control the mechanical strength. This is used as a control sample to carry out various performance comparison tests with the wide and narrow segmented easy-open aluminum-coated double-cavity mask bags prepared in Examples 1 to 3.

[0054] Performance testing and data comparison To verify the innovative technological advantages of this invention, including wide and narrow segmentation, easy-to-peel modification, zoned adhesive coating, and differentiated heat sealing at dual temperatures, a comparative test was conducted on the traditional single-segment equal-width aluminized mask bag of Comparative Example 1 and the wide and narrow segmented easy-to-peel aluminized dual-cavity mask bags of Examples 1-3 under the same testing environment (temperature 25℃, humidity 50%RH) and the same testing standards. This test provides evidence of the comprehensive advantages of this invention in solving the problems of aluminized layer peeling, stable barrier, and segmented controllable easy peeling.

[0055] 1. Core barrier performance test The test results were obtained by referring to GB / T1037-2021 "Determination of Water Vapor Transmission Rate of Plastic Films and Sheets" and GB / T1038-2021 "Test Method for Gas Transmission Rate of Plastic Films and Sheets". The results are shown in Table 1 below: Table 1

[0056] Test conclusion: Comparative Example 1 uses only pure PET and pure PE virgin particles to make the film, without any functional barrier additives. The film itself has weak basic barrier ability. Microcracks are easily generated during composite processing, which further damages the integrity of the VMPET aluminum coating layer. Water vapor and oxygen can easily penetrate the film bag, causing the essence to oxidize and deteriorate.

[0057] The core innovation of this invention lies in the compounding of functional barrier additives during the preparation of PET and PE substrates. This enhances the basic water and oxygen barrier capabilities of the film itself. Combined with a low-stress composite process, it protects the aluminum-plated layer from damage and peeling, forming a multi-layer synergistic barrier system. The overall water and oxygen permeability is reduced by about 20%, providing a double-strengthened long-lasting freshness-locking effect and solving the industry's shortcoming of insufficient barrier properties inherent in traditional pure substrate films.

[0058] 2. Structural mechanics and sealing performance testing The heat seal strength, composite peel strength, and tear resistance were tested according to GB / T21302-2007 "General Rules for Composite Films and Bags for Packaging". The results are shown in Table 2 below: Table 2

[0059] Test conclusions: The pure PET and pure PE films used in Comparative Example 1 have poor toughness and high internal stress, weak bonding force with the adhesive interface, and no high-strength support partition in the middle single-section seal. Under stress, the aluminum coating layer is prone to transfer and delamination. The heat sealing toughness is insufficient, and the seal is prone to cracking and leakage due to bumpy logistics.

[0060] This invention adds toughening agents and easy-peel masterbatches to PET and PE raw materials, simultaneously improving the tensile and tear resistance and controllable peel characteristics of the film. The slip agent improves the surface uniformity and corona stability of the film, ensuring sufficient wetting at the interface with the adhesive and the VMPET aluminized layer. Combined with low-stress adhesive and segmented curing to eliminate interlayer tensile forces, the peel strength of all embodiments is much higher than that of traditional samples and there is no aluminized peeling. The heat-sealing strength of the four sides and the wide edge straight center seal is stably maintained at 20~25N / 15mm, and the transportation damage rate is greatly reduced. Relying on the modified substrate and segmented high-strength support structure, the overall mechanical stability of the composite structure is improved from the root.

[0061] 3. Start the hand-feel extrusion pressure performance test The critical force for opening the double-chamber pouch was tested by placing the finished double-chamber pouch containing essence and a mask under a press and squeezing it. When the double-chamber pouch easily opened and the central seal ruptured, i.e., the two chambers merged into one, the press reading was recorded. 50 samples were tested in each group, and the average value was taken. The results are shown in Table 3 below. Table 3

[0062] Test conclusions: Traditional pure PE film has high rigidity and poor resilience, lacks easy-peel modification, and the stress is concentrated overall after the single-segment equal-width center seal is subjected to force, resulting in excessive opening force and violent fluctuations. During extrusion, the entire center seal is prone to tearing and bursting. This invention adds toughening, slip, and easy-peel modification additives to the PE substrate, improving the flexibility and buffering capacity of the PE heat-sealing layer. Combined with the wide and narrow segmented center seal and the narrow segment indentation stop structure, the modified PE layer forms a low peel interface only in the narrow edge area, evenly dispersing the extrusion force and stabilizing the opening force within the comfortable range of 5~10N. The wide edge and high-strength edge seals around the perimeter prevent accidental opening and leakage during transportation. The easy-peel modification of the substrate and the segmented structure are the basic guarantees for achieving controllable force zoning.

[0063] 4. Special test on tear force of segmented separator center seal A universal tensile testing machine was used to test the peel tear force of the narrow-side easy-open center seal and the wide-side support center seal. The average value of 50 samples in each group was taken. (Table 4) Table 4

[0064] Test conclusions: Comparative Example 1, lacking easy-peel modified PE, wide and narrow zone gradient adhesive application, and dual-temperature differentiated heat sealing, exhibited uniformly high adhesion across the entire middle seal, with a tear force exceeding 27.4N. Forceful compression easily tore the entire middle seal, and the aluminum plating layer peeled off along with the sealing edge. This invention, through the synergistic effect of easy-peel masterbatch modified inner layer, low adhesive content matching in narrow sections, and low-temperature, low-pressure, short-pressurization heat sealing on narrow edges, maintains the tear force of the narrow-edge middle seal within a low-strength range (5~10N), while maintaining a high-strength range (20~25N) around the perimeter and wide-edge straight middle seal. The compressive force is concentrated only in the preset narrow section, and the wide-edge support structure remains intact without tearing, completely solving the industry pain point of traditional single-section middle seals where "sealing strength" and "easy-peeling" cannot be simultaneously achieved.

[0065] 5. Long-term storage stability test Both sets of samples were placed in a constant temperature and humidity aging chamber (temperature 45℃, humidity 65%RH) for accelerated storage for 90 days. The product condition was observed and the tear force of the wide and narrow middle seals was retested. Comparative Example 1: 12% of the samples showed mottled or migrated aluminum plating, a few samples had slight leakage at the sealing edge, and the essence showed slight oxidation and discoloration; the tearing force of the entire inner seal increased to over 35N, making it extremely difficult to tear.

[0066] Examples 1-3: No delamination, no leakage, no structural damage, intact membrane appearance, no significant changes in the color and activity of the essence; easy to peel and no decrease in support strength, excellent storage stability.

[0067] Test conclusions: Traditional unmodified PET / PE films exhibit inherent barrier defects that, combined with processing, lead to microcracks in the aluminized coating. During long-term storage, moisture and oxygen continuously penetrate the film, while the pure substrate experiences significant thermal expansion and contraction, resulting in continuous accumulation of interlayer stress. Ultimately, this leads to aluminized coating peeling, leakage, and deterioration; the tear strength increases continuously with storage time. This invention's barrier agent reduces temperature-induced fluctuations in film permeability and air / water permeability. The toughening and easy-peeling modifiers buffer interlayer stress during long-term storage. The modified substrate and the intact, undamaged aluminized layer form a long-lasting protective barrier. Even with long-term accelerated aging, the barrier and segmented mechanical properties show no significant failure, significantly extending the shelf life of the face mask.

[0068] 6. Extrusion fatigue test Test conditions: Simulate repeated squeezing and opening by users and vibration squeezing during logistics. Each group has 50 samples, and the samples are squeezed 30 times to test for damage, leakage, and aluminum plating peeling.

[0069] Comparative Example 1: After 30 cycles of reciprocating extrusion, 28% of the samples showed micro-cracks at the sealing edge, 16% showed peeling of the aluminum plating layer, and 8% showed micro-leakage, indicating poor fatigue stability.

[0070] Examples 1-3: The wide-side support with central and perimeter seals is free from cracks and leakage. The narrow-side easy-open section can be repeatedly squeezed and broken to restore its original shape. The aluminum plating layer is free from cracks, peeling, delamination, and structural damage. The tearing force of the two sections does not increase significantly. The extrusion fatigue resistance is significantly better than that of the traditional single-section aluminum plating process.

[0071] Test conclusions: Pure PET and PE films exhibit poor fatigue resistance. Single-segment, uniform-width seals lack high-strength support zones, and under repeated bending and extrusion, the film deformation cannot rebound. Stress concentration pulls on the aluminized interface, causing detachment and edge tearing. This invention modifies PET and PE substrates with toughening agents and easy-peeling additives to improve the film's resilience under repeated deformation. Slip-resistant additives reduce frictional loss between film layers, and a low-stress composite process lowers initial internal stress. The wide-narrow segmented structure disperses extrusion stress; the wide side bears the storage and transportation extrusion load, while the narrow side serves only as a weak point for opening. Under multiple extrusion cycles, the modified substrate buffers external forces, protecting the aluminized layer and high-strength edge seal, significantly improving the product's fatigue resistance and reliability during distribution and use, with long-term stable segmented strength.

[0072] 7. High and low temperature weathering stability test Test conditions: alternating high temperature of 60℃ and low temperature of -18℃, 12 hours per cycle, 15 cycles, and retesting the tear force fluctuation of the wide and narrow middle seals.

[0073] Comparative Example 1: The aluminum coating layer showed whitening, mottled appearance, and localized migration. The film's flexibility decreased, the opening force of the entire central seal fluctuated by more than ±3.5N, the tearing force fluctuated by more than 6N, and the feel was sometimes difficult and sometimes easy.

[0074] Example 1: No whitening, mottled, or peeling of the aluminum plating layer; no changes in appearance or interlayer delamination; the tearing force fluctuation of the narrow side center seal is only ±0.9N, and the fluctuation of the wide side support section is ±1.0N. Both sections maintain their respective standard ranges throughout the entire process. The performance of the aluminum plating layer and the segmented easy-to-peel structure is extremely stable under high and low temperature environments, making it suitable for transportation and sales in multiple climate regions across the country.

[0075] Test conclusions: Unmodified pure PET and PE films exhibit significant thermal shrinkage and low-temperature embrittlement. Under temperature cycling, interlayer stress repeatedly changes, continuously tearing the aluminized interface. Simultaneously, the film's barrier properties fluctuate drastically with temperature, and the tear strength of a single center seal varies considerably with temperature. This invention's barrier, toughening, and easy-to-peel composite modification system reduces the temperature deformation rate of PET and PE films, minimizes the difference in film dimensional changes under hot and cold environments, and reduces tensile stress between the aluminized layer and the substrate. The aluminized layer remains intact across the entire temperature range, with minimal fluctuation in tear strength at both the wide and narrow sections, making it suitable for warehousing and transportation in different climate regions across the country.

[0076] Comparing the traditional pure substrate single-segment equal-width, unpartitioned, easy-open aluminized mask bag in Example 1 with the product testing data of the wide-narrow segmented easy-open modified product of Examples 1-3, it can be seen that the core first layer innovation of this invention is the modification of PET and PE film with barrier, toughening, easy-open, and slip-resistant additives, which simultaneously improves the basic barrier, tear resistance, temperature change resistance, and controllable peel performance of the film substrate itself; the second layer is equipped with a wide-narrow segmented gradient differential adhesive coating process, which locally reduces interlayer adhesion in the narrow easy-open segment, while maintaining a high amount of adhesive coating on the wide edge and around the perimeter to ensure strong sealing. The third layer, combined with a dual-temperature zone independent mold for differentiated heat sealing, achieves high-strength protection of 20~25N for the four sides and wide-side straight center seal, and a gentle tear-resistant mechanical standard of 5~10N for the narrow-side center seal. This is further enhanced by low-stress adhesive, negative pressure degassing, stepped composite, and segmented pre-curing stress-relieving processes to fully protect the VMPET aluminized layer. Combined with a dedicated bag structure featuring wide and narrow segmented center seals, narrow-segment indentations, and angular limiting holes, this forms a complete and innovative three-in-one technical solution integrating substrate modification, wide and narrow segmented adhesive coating control, and dual-temperature zone segmented heat sealing.

[0077] Compared to traditional processes that use only additive-free pure PET and PE virgin particles, uniform adhesive application across the entire surface, and uniform heat-sealing parameters for each segment, the products produced by this invention exhibit an overall reduction of approximately 20% in water and oxygen barrier performance, a significant improvement in composite peel strength, and complete elimination of defects such as aluminum plating layer peeling, migration, and white mottled appearance. The bag body features a perimeter seal around the four sides and a wide, straight-supported center seal with a stable heat-sealing strength of 20-25 N / 15 mm, meeting the requirements for leak prevention and compression resistance during long-distance storage and transportation. The narrow, wavy, easy-open center seal has a precisely locked tear force of 5-10 N, achieving gentle, low-force, and balanced easy peeling. The overall compression opening force of the dual cavities is synchronously and stably controlled within a comfortable range of 5-10 N. After long-term accelerated storage, reciprocating compression fatigue, and high and low temperature cycle weathering tests, all embodiments showed no delamination, leakage, aluminum plating damage, or significant fluctuations in force on both the wide and narrow sealing edges. The product's storage stability, circulation reliability, and user experience are all superior to traditional single-seal samples.

[0078] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing an aluminized, segmented, easy-to-open dual-cavity facial mask bag, characterized in that, Includes the following steps: S1. Preparation of PET functional films and easy-to-peel modified PE films PET film raw materials, easy-peel modified PE film outer layer, middle layer and inner layer raw materials are prepared, all raw materials are dusted, dried and stirred evenly, then each formula raw material is melted, filtered and extruded, then stretched, cooled and shaped, tension adjusted and wound up to obtain PET film and easy-peel modified PE film respectively. The easy-peel modified PE film has a three-layer co-extrusion structure. The raw materials for the outer, middle, and inner layers are formulated as follows by weight percentage: Outer layer formulation: 65~75% LLDPE, 26~30% LDPE, 1.2~1.8% general-purpose blown film opening masterbatch, 0.15~0.25% 1010 / 168 antioxidant compounding agent; Middle layer support layer formulation: 75~85% LLDPE, 15~25% HDPE; Inner layer easy-peel heat-sealing layer base formulation: 65~75% LDPE, 16~20% PB 1. 8~12% mL LDPE, 1.5~2.1% food-grade smooth open-ended masterbatch, 0.15~0.25% compound antioxidant; S2, Multi-layer dry compounding and curing treatment A two-component polyurethane adhesive is used as the composite adhesive, and vacuum degassing is performed. A three-layer composite structure is employed, consisting of PET film, VMPET aluminized film, and easy-to-peel modified PE film. A differentiated coating process using a 120-line segmented micro-grooved roller is used to coat the entire PET film, achieving a dry coating weight of 2.1~2.45 g / m². 2 For the bonding area between the VMPET aluminized film and the PE film, apply adhesive to the wide, straight center sealing area, with a dry adhesive application rate of 2.1~2.45 g / m². 2 For the narrow-edged, easily opened, corrugated, and easily sealed areas, the dry adhesive application rate is 1.9~2.0 g / m². 2 Dry lamination is completed using a stepped speed-up method, controlling the lamination machine speed, oven temperature, hot roller temperature, and lamination tension. After lamination, pre-curing, constant temperature curing, and room temperature cooling stress relief treatments are performed sequentially to obtain the composite film substrate. S3. Slitting and segmented heat sealing for bag forming After cooling and stress relief, the composite film is trimmed of waste edges and cut into standard-sized film rolls. A fully automatic dual-temperature zone center-sealing bag making machine is used to control the heat-sealing process parameters in different zones, and to complete the heat-sealing forming of the outer perimeter seal, the wide-side straight center seal, and the narrow-side wavy easy-open center seal of the bag body. A wide and narrow two-section center seal structure is set at the double-cavity separation position, and a fracture indentation line is set on the narrow easy-open section. An angular limiting hole is opened at the end of the indentation line, and finally, an aluminum-plated wide and narrow segmented easy-open double-cavity mask bag is produced.

2. The preparation method according to claim 1, characterized in that, The PET film raw material formulation in step S1 includes, by mass percentage: 90~92% food-grade virgin PET particles, 3.0~4.0% functional barrier agents, 4.5~5.5% toughening agents, and 0.30~0.40% slip agents.

3. The preparation method according to claim 1, characterized in that, In step S1, the melting temperatures are as follows: 175~185℃ in the preheating section, 230~240℃ in the first melting zone, 245~255℃ in the second melting zone, 240~248℃ in the homogenization section, and 238~245℃ in the die head confluence section. The filtration process uses 70~90 mesh coarse filter screen, 280~320 mesh medium filter screen, and 1100~1300 mesh ultrafine sintered filter screen.

4. The preparation method according to claim 1, characterized in that, In step S1, 0-1.2% of linear low-density polyethylene easy-to-remove masterbatch is added to the inner heat-sealing layer of the easy-to-remove modified PE film.

5. The preparation method according to claim 1, characterized in that, The PET film and easy-to-peel modified PE film prepared in step S1 have a thickness of 25~80μm and a thickness uniformity deviation of ≤±5μm.

6. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the two-component polyurethane adhesive main agent to the curing agent in step S2 is 4.5:1 to 5.5:1, and the solid content of the adhesive is 32% to 38%. The adhesive mixing process is to stir at a constant temperature of 140 to 160 r / min for 4.5 to 5.5 min under negative pressure, and then let it stand in a sealed environment for 25 to 35 min for vacuum degassing.

7. The preparation method according to claim 1, characterized in that, The composite process parameters in step S2 are as follows: the composite base speed is 62~68m / min, the three-section temperature of the drying oven is 70~80℃, 80~90℃, and 90~100℃ respectively, the hot roller temperature is 60~70℃, and the composite tension is 0.08~0.12MPa; the step-by-step speed-up process is as follows: first, wind up 450~550m at 75~85m / min, then wind up 800~1000m at 90~110m / min, and after there are no defective products, increase the speed to 280~320m / min for mass production.

8. The preparation method according to claim 1, characterized in that, The curing process in step S2 is as follows: pre-curing at 22~28℃ for 3.0~5.5h, followed by constant temperature curing at 53~58℃ for 22~26h, and then standing at 22~28℃ for 22~26h after curing to eliminate the internal stress of the film.

9. The preparation method according to claim 1, characterized in that, The heat-sealing process parameters in step S3 are as follows: outer perimeter seal and wide-edge straight center seal: mold temperature 136~140℃, pressure 0.21~0.24MPa, holding pressure 0.3~0.5s; narrow-edge corrugated easy-open center seal: mold temperature 120~124℃, pressure 0.10~0.12MPa, holding pressure 0.2~0.3s.

10. An aluminized, segmented, easy-open double-cavity mask bag with wide and narrow sections, prepared according to any one of claims 1 to 9, characterized in that, The opening force for the double-cavity mask bag is 5~10N.

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