Chicken packaging film facilitating detachment from chicken skin and method for preparing the same

Abstract

The application relates to the field of food packaging technology, in particular to chicken meat packaging film convenient to separate from chicken skin and a preparation method thereof. The packaging film comprises, from the outer layer to the inner layer, a PA layer, a TIE layer, a PA layer, an EVOH layer, a PA layer, a TIE layer, a PE layer and a heat-sealing layer. The heat-sealing layer is modified, the modified heat-sealing layer contains 20% mLLDPE, 73.5%-76.5% EVA-18, 2%-5% SiO2, 1% dispersant and 0.5% antioxidant; the heat-sealing layer is suitable for contacting with chicken skin, and the polarity of the heat-sealing layer material repels the non-polarity of the chicken skin tissue. The heat-sealing layer is modified by using a polar material, the heat-sealing layer keeps the self polarity while ensuring the repulsion between the heat-sealing layer and the chicken skin tissue, so that the adhesion degree with the chicken skin is reduced, the packaging film can be easily separated from the chicken skin when being torn.

Description

Technical Field

[0001] This invention relates to the field of food packaging technology, specifically to a chicken packaging film that is easy to separate from chicken skin and its preparation method. Background Technology

[0002] Chicken meat refers to the meat of a chicken. Chicken meat is tender and flavorful. The market offers a wide variety of packaging bags for chicken, but choosing vacuum-sealed, sterilized chicken packaging bags is the most beneficial option, ensuring food safety and extending shelf life. This allows consumers to enjoy a higher quality of life.

[0003] A Chinese patent with publication number CN 104843212 A discloses a manufacturing process for vacuum-sealed chicken packaging bags. It describes the process of preparing chicken packaging bags through refining plastic masterbatch, rinsing, drying, mixing with a mixing machine, blowing film, and vacuuming. The process is simple and easy to implement, and the produced chicken packaging bags have good vacuum and can be recycled.

[0004] However, current packaging films are prone to wrinkling or tearing after sterilization, causing moisture from the chicken inside to escape and resulting in loose packaging. Alternatively, the packaging film may adhere too closely to the chicken skin, making it difficult to separate from the skin when unpacking, and may even tear the skin off the chicken meat. Summary of the Invention

[0005] The purpose of this invention is to provide a chicken packaging film that is easy to separate from chicken skin and a method for preparing the same, so as to solve the problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a chicken packaging film that is easy to separate from chicken skin, wherein the packaging film comprises, from the outer layer to the inner layer, a PA layer, a TIE layer, a PA layer, an EVOH layer, a PA layer, a TIE layer, a PE layer, and a heat-sealing layer; the PA layer and the EVOH layer, and the PE layer and the heat-sealing layer, are adapted to be connected by multi-layer co-extrusion; the heat-sealing layer is modified and contains 20% mLLDPE, 73.5%–76.5% EVA-18, 2%–5% SiO2, 1% dispersant, and 0.5% antioxidant; the heat-sealing layer is adapted to contact chicken skin, and the polarity of the heat-sealing layer material is repelled by the non-polarity of the chicken skin tissue.

[0007] Furthermore, the heat-sealing layer preferably contains 20% mLLDPE, 74.5% EVA-18, 4% SiO2, 1% dispersant and 0.5% antioxidant.

[0008] Furthermore, the thickness of the TIE layer is 10–20 μm.

[0009] Furthermore, the PE layer is made of LLDPE.

[0010] Furthermore, the dispersant is an ethylene bis-stearamide.

[0011] Furthermore, the antioxidant is a substance composed of hindered phenols and phosphites.

[0012] Based on the same technical problem, the present invention further provides the following technical solution: a method for preparing a chicken packaging film that is easy to separate from chicken skin, the specific steps of which are as follows:

[0013] S1. Film blowing and cooling: Multiple hoppers are provided in front of the extruder. The raw materials are added to each hopper in the order of PA layer, TIE layer, PA layer, EVOH layer, PA layer, TIE layer, PE layer and heat-sealing layer. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channel of the hopper. The preform is then extruded from the extruder and the melt is rapidly cooled by a water cooling device.

[0014] S2, Shaping: The film obtained in step S1 is pulled to the herringbone clamp and flattened to form a barrel film;

[0015] S3, Annealing: The film obtained in step S2 is drawn to the annealing and stretching system, and preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0016] Furthermore, the heat-sealing layer in step S1 is modified by the following method: 20% mLLDPE, 73.5%~76.5% EVA-18, 2%~5% SiO2, 1% dispersant and 0.5% antioxidant are fed, melted, mixed, extruded and cooled, and finally pelletized to obtain the material particles of the heat-sealing layer.

[0017] Furthermore, in step S3, the annealing temperature range is 75℃~90℃, and the annealing roller pressure is 0.1~0.25MPa.

[0018] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: Chicken skin tissue is composed of unsaturated fatty acids, which are non-polar substances and tend to adhere to ordinary metal PE. This invention uses polar materials to modify the heat-sealing layer. While maintaining its own polarity, the heat-sealing layer also ensures repulsion between itself and the chicken skin tissue, thereby reducing adhesion to the chicken skin and allowing the packaging film to easily detach from the chicken skin when torn. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the product structure layers of the present invention;

[0021] Figure 2 This is a flowchart of the preparation method of the present invention.

[0022] In the diagram, 1 is the PA layer; 2 is the TIE layer; 3 is the EVOH layer; 4 is the PE layer; and 5 is the heat-sealing layer. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1 A chicken packaging film that is easy to separate from chicken skin, comprising, from the outer layer to the inner layer, PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4, and heat-sealing layer 5. PA layer 1 and EVOH layer 3, as well as PE layer 4 and heat-sealing layer 5, are suitable for being connected by multi-layer co-extrusion.

[0025] The first, second, and third PA layers can all be made of PA; the EVOH layer 3 is made of EVOH; the PE layer 4 is made of LLDPE. The TIE layer 2 is made of TIE, and the thickness of the bond formed by the TIE layer 2 is 10–20 μm.

[0026] The first PA layer provides puncture strength, while the second and third PA layers protect the EVOH layer from moisture. The EVOH layer exhibits excellent barrier properties against chicken odor and oil. The PE layer, made of LLDPE, provides good moisture sealing for the chicken. The heat-sealing layer is in direct contact with the chicken skin.

[0027] The heat-sealing layer 5 is modified, containing 20% ​​mLLDPE, 73.5%–76.5% EVA-18, 2%–5% SiO2, 1% dispersant, and 0.5% antioxidant. The dispersant is an ethylene bis-stearamide (EBS) compound; the antioxidant is a complex of hindered phenols and phosphites, specifically B215. The modification method is as follows: modification is performed via twin-screw extrusion, specifically through conventional steps such as feeding, melting, mixing, extrusion, cooling, and pelletizing.

[0028] The polarity of EVA-18 provides repulsion to chicken skin, making it less likely for the packaging film to stick to the skin. Its softening point is relatively low, and a content of 73.5%–76.5% is preferred. Too much EVA-18 can lead to the following problems: 1. Adhesion during annealing; 2. The heat-sealable layer may peel off during sterilization.

[0029] Please see Figure 2 A method for preparing a chicken packaging film that is easy to separate from chicken skin, the specific steps of which are as follows:

[0030] S1. Film blowing and cooling: Multiple hoppers are provided in front of the extruder. The raw materials are added to each hopper in the order of PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4 and heat-sealing layer 5. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channel of the hopper. The preform is then extruded from the extruder. The melt is rapidly cooled by a water cooling device.

[0031] S2, Shaping: The film obtained in step S1 is pulled to the herringbone clamp and flattened to form a barrel film;

[0032] S3, Annealing: The film obtained in step S2 is drawn to the annealing and stretching system, and preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0033] Example 1

[0034] The structure of packaging film one is: PA / TIE / PA / EVOH / PA / TIE / PE / heat-sealing layer; wherein, the modified formulation of the heat-sealing layer is as follows: 20% mLLDPE + 76.5% EVA-18 + 2% SiO2 + 1% dispersant + 0.5% antioxidant. The heat-sealing layer is modified by twin-screw extrusion, specifically through conventional steps such as feeding, melting, mixing, extrusion, cooling, and pelletizing.

[0035] The preparation process of packaging film 1 is as follows: S1, film blowing and cooling: Multiple hoppers are provided in front of the extruder. Raw materials are added to each hopper in the following order: PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4, and heat-sealing layer 5. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channel of the hopper. The extruded material is then extruded into a preform tube from the extruder. The melt is rapidly cooled by a water-cooling device. S2, shaping: The film obtained in step S1 is drawn to a herringbone clamp and flattened to form a barrel film. S3, annealing: The film obtained in step S2 is drawn to an annealing and stretching treatment system, where it is preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0036] Example 2

[0037] The structure of packaging film two is: PA / TIE / PA / EVOH / PA / TIE / PE / heat-sealing layer; wherein, the modified formulation two of the heat-sealing layer is as follows: 20% mLLDPE + 75.5% EVA-18 + 3% SiO2 + 1% dispersant + 0.5% antioxidant. The same modification method as in Example 1 is used.

[0038] The preparation process of packaging film II is as follows: S1, film blowing and cooling: Multiple hoppers are provided in front of the extruder. Raw materials are added to each hopper in the following order: PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4, and heat-sealing layer 5. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channels of the hoppers. The extruded material is then extruded into a preform tube from the extruder. The melt is rapidly cooled by a water-cooling device. S2, shaping: The film obtained in step S1 is drawn to a herringbone clamp and flattened to form a barrel film. S3, annealing: The film obtained in step S2 is drawn to an annealing and stretching treatment system, where it is preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0039] Example 3

[0040] The structure of packaging film three is: PA / TIE / PA / EVOH / PA / TIE / PE / heat-sealing layer; wherein, the modified formulation three of the heat-sealing layer is as follows: 20% mLLDPE + 74.5% EVA-18 + 4% SiO2 + 1% dispersant + 0.5% antioxidant. The same modification method as in Example 1 is used.

[0041] The preparation process of packaging film 3 is as follows: S1, film blowing and cooling: Multiple hoppers are provided in front of the extruder. The raw materials are added to each hopper in the following order: PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4 and heat-sealing layer 5. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channel of the hopper. The extruded material is then extruded into a preform tube from the extruder. The melt is rapidly cooled by a water-cooling device. S2, shaping: The film obtained in step S1 is drawn to a herringbone clamp and flattened to form a barrel film. S3, annealing: The film obtained in step S2 is drawn to an annealing and stretching treatment system, where it is preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0042] Example 4

[0043] The structure of packaging film four is: PA / TIE / PA / EVOH / PA / TIE / PE / heat-sealing layer; wherein, the modified formulation of the heat-sealing layer four is as follows: 20% mLLDPE + 73.5% EVA-18 + 5% SiO2 + 1% dispersant + 0.5% antioxidant. The same modification method as in Example 1 is used.

[0044] The preparation process of packaging film four is as follows: S1, film blowing and cooling: Multiple hoppers are provided in front of the extruder. The raw materials are added to each hopper in the following order: PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4 and heat-sealing layer 5. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channel of the hopper. The extruded material is then extruded into a preform tube from the extruder. The melt is rapidly cooled by a water-cooling device. S2, shaping: The film obtained in step S1 is drawn to a herringbone clamp and flattened to form a barrel film. S3, annealing: The film obtained in step S2 is drawn to an annealing and stretching treatment system, where it is preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0045] Comparative Example 1

[0046] The structure of packaging film five is: PA / TIE / PA / EVOH / PA / TIE / PE / heat-seal layer; wherein, the unmodified composition of the heat-seal layer is as follows: 20% mLLDPE + 80% EVA-18. The two materials are blended using a twin-screw extruder. The blended material was tested by DSC, and the optimal initial shrinkage rate was found at the melting point of 85°C, ensuring both the material's polarity and preventing melt adhesion during annealing. Packaging film five can be used as a comparative example of the products in Examples 1-4.

[0047] The preparation process of packaging film 5 is as follows: S1, film blowing and cooling: Multiple hoppers are provided in front of the extruder. Raw materials are added to each hopper in the order of PA layer 1, TIE layer 2, PA layer 1, EVOH layer 3, PA layer 1, TIE layer 2, PE layer 4 and heat-sealing layer 5. After uniform mixing, the resin of each layer is melted at a melting temperature of 190-280℃ and extruded into the corresponding flow channel of the hopper. The preform is then extruded from the extruder and the melt is rapidly cooled by a water-cooling device. S2, shaping: The film obtained in step S1 is drawn to a herringbone clamp and flattened to form a barrel film. S3, annealing: The film obtained in step S2 is drawn to an annealing and stretching treatment system, and is preheated in an oven and repeatedly stretched and shaped by multiple rollers.

[0048] Experiment 1: Thermal Viscosity Test

[0049] The packaging films from Example 1, Example 2, Example 3, Example 4, and Comparative Example 1 were pasteurized at 80°C. This experiment was conducted according to the American standard ASTM F1921. The thermal adhesion of Examples 1 to 4 and Comparative Example 5 is shown in Table 1.

[0050] Table 1. Thermal viscosity of Examples 1-4 and Comparative Example 5 at 80°C

[0051]

[0052] As can be seen from Table 1, the heat-resistant film layers of Examples 1 to 4 can all be used as anti-sticking agents, exhibiting low heat tackiness. Among them, Examples 3 and 4 represent the best modifications, ensuring that the packaging film does not generate heat stickiness during pasteurization, while its polarity also guarantees repulsion between it and the chicken skin tissue.

[0053] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A chicken meat packaging film facilitating detachment from chicken skin, the packaging film comprising, from the outer layer to the inner layer, a PA layer (1), a TIE layer (2), a PA layer (1), an EVOH layer (3), a PA layer (1), a TIE layer (2), a PE layer (4), and a heat-seal layer (5); the PA layer (1) and the EVOH layer (3), and the PE layer (4) and the heat-seal layer (5) are adapted to be connected by a multi-layer co-extrusion manner, characterized in that, The heat-sealing layer (5) is modified, the heat-sealing layer (5) contains 20% mLLDPE, 73.5%-76.5% EVA-18, 2%-5% SiO2, 1% dispersant and 0.5% antioxidant, the dispersant is ethylene bis-stearamide, and the antioxidant is a substance composed of hindered phenol and phosphite complex; the heat-sealing layer (5) is suitable for contacting with chicken skin, and the polarity of the heat-sealing layer (5) material repels the non-polarity of chicken skin tissue; the PE layer (4) is made of LLDPE.

2. The chicken meat packaging film facilitating detachment from chicken skin according to claim 1, wherein, The TIE layer (2) is formed to have a thickness of 10-20 μm.

3. A process for the preparation of a chicken packaging film according to any one of claims 1 to 2, characterized in that, The specific steps are as follows: S1, film blowing and cooling: a plurality of hoppers are arranged in front of the extruder, the raw materials are added into the hoppers in the order of PA layer (1), TIE layer (2), PA layer (1), EVOH layer (3), PA layer (1), TIE layer (2), PE layer (4) and heat-sealing layer (5), and after uniform mixing, the resins of the layers are melted at a melting temperature of 190-280 ℃, and then are extruded into the flow channels corresponding to the hoppers, and the melt is rapidly cooled by a water cooling device; S2, shaping: the film obtained in step S1 is clamped flat by a herringbone clamp to form a barrel film; S3, annealing: the film obtained in step S2 is drawn to an annealing stretching treatment system, and is preheated by an oven and repeatedly stretched and shaped by multiple rollers, wherein the annealing temperature ranges from 75 ℃ to 90 ℃, and the annealing roller pressure is 0.1-0.25 MPa.

4. A method for preparing a chicken packaging film that is easy to detach from chicken skin, as described in claim 3, characterized in that, In step S1, the heat-sealing layer (5) is modified, and the modification method is as follows: 20% mLLDPE, 73.5%-76.5% EVA-18, 2%-5% SiO2, 1% dispersant and 0.5% antioxidant are added by feeding, melting, mixing, extruding, cooling, and finally pelletizing to obtain the material particles of the heat-sealing layer.

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