Packaging composite film with good barrier property, high twisting strength and low rebound resilience and preparation method thereof

Abstract

The invention discloses a packaging composite film with good barrier property, high twisting strength and low rebound resilience and a preparation method thereof, and belongs to the technical field of composite film preparation. The PET / PP composite material comprises the following raw materials in parts by weight: 45-55 parts of PET, 25-40 parts of PP, 0.5-1 part of a heat stabilizer, 2-5 parts of an antioxidant and 2-3 parts of an ultraviolet light absorber. The flame retardant is prepared from 1-2 parts of hindered amine light stabilizer, 2-3 parts of lubricant, 4-6 parts of coupling agent, 5-10 parts of filler, 1-2 parts of flame retardant, 5-8 parts of cross-linking agent and 2-8 parts of bulking agent. By adding the compatibilizer PP-g-MAH, the compatibility of a PET / PP blending system can be improved, so that the rheological property and the mechanical property of the PET / PP blending system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite film preparation, and in particular relates to a composite film for packaging with good barrier properties, high kink strength and low resilience, and a preparation method thereof. Background Art

[0002] Twist-knot packaging is one of the most traditional candy packaging methods. It is one of the three major candy packaging methods along with pillow packaging and folding packaging. Among all candy packaging forms, pillow packaging accounts for about 70%, twist packaging accounts for about 15%, folding packaging accounts for about 10%, and other packaging forms account for about 5%. Twist-knot packaging is the oldest packaging method for candy packaging. At the beginning, the material used was paper (cellophane) and it was packaged manually. With the advent and promotion of mechanized pillow packaging machines, pillow packaging has become popular due to its low cost. However, pillow packaging products are monotonous and have basically no aesthetic packaging, which has limitations. Therefore, high-end and high-quality candies use more personalized twisted films or folding papers.

[0003] The rise of twist film has been going on for more than 20 years. At first, it was mainly produced from PVC twist and some imported cellophane. It was not until 2002-2003 that the new environmentally friendly PET twist film was researched and promoted to replace the toxic PVC twist products. However, for a long time, due to cost and profit reasons, PVC film did not completely withdraw from the food packaging industry. It was not until the impact of the plasticizer incident that various fields of society and factories realized the harmfulness of PVC twist products, and PET products were widely used.

[0004] It is an inevitable trend for PET twist film to replace PVC twist film. Its product performance has incomparable advantages. The advantages of PET twist film include environmental protection, economy, high efficiency, stable performance, safety and beauty. Environmental protection: PET twist film is made of polyester material, which is an environmentally friendly and recyclable product with no damage to the human body and the environment; while PVC products release dimethyl ethane when burned, which is a substance that can cause cancer in the human body. In Europe and the United States, PVC products are strictly prohibited from contacting food. Some Western European countries with the most stringent requirements even prohibit PVC film from being used for the outer packaging of children's products; Economic and efficient: Traditional PVC products must be above 28μ to have enough hardness and stiffness to meet the requirements of aluminum plating and printing, so as to show the rigid effect of the product. PET products can produce products of different thicknesses of 19μ, 23μ, and 25μ because they have sufficient strength and stiffness. Among them, 19μ is mainly used for manual packaging of dried meat, fresh fruit packaging or paper-plastic composite twist packaging. 23μ and 25μ are mainly used for candy and chocolate twist packaging; stable performance, high efficiency: the maximum speed of PVC machine packaging is 1000 pieces / minute, while PET can reach 2000 pieces / minute. Because PVC products are brittle and have poor flatness, the film width is generally controlled at about 60CM, while the limited printing film width of PET products can reach more than one meter. The printing speed of PET products can reach more than 200M / minute, while PVC cannot exceed 150M / minute. Therefore, PET products have obvious advantages in printing efficiency; beautiful and high-end: the aluminum layer of PET twist film is more solid. If protective resin (gold oil) is added appropriately during the printing process, the printed pattern can be bright and clear; at the same time, using the high rigidity and corrosion resistance of PET, partial aluminum washing or information layer pressing laser effect is carried out, and the printing effect has a strong three-dimensional sense, which greatly improves the grade of the packaged products.

[0005] Therefore, the main material of twist packaging has been changed from the original PVC to the environmentally friendly material PET twist film. Although PET twist film has good transparency and glossiness, it can more intuitively and beautifully reflect the overall effect of the packaged items, and it does not contain halogen elements, conforms to food safety regulations, and is an option to replace the traditional PVC twist film. However, the PET twist film currently developed and produced has poor processing impact resistance, environmental stress cracking resistance and barrier properties need to be improved, and the material cost is high and the equipment investment is large, making it difficult to promote. PP (polypropylene) is a material with good toughness and is easy to process. The film prepared with it has the advantages of good quality and low price, but its good toughness and good deformation recovery make it generally difficult to be directly used in the preparation of twist film. However, under certain conditions, the mechanical properties and barrier properties of PET can be improved by adding PP, and the processing impact and environmental resistance of PET twist film can be improved.

[0006] Therefore, in the process of preparing PET twist film, how to use PP to modify PET so that the two can be effectively compounded to form a composite film with high twist strength and low resilience has become a problem that needs to be solved urgently. Summary of the invention

[0007] The first purpose of the present invention is to disclose a composite film for packaging with good barrier properties, high kink strength and low resilience. The composite film has good barrier properties, high kink strength and low resilience, and can package products well.

[0008] The second purpose of the present invention is to disclose a method for preparing a composite film for packaging with high kink strength and low resilience. While PP is used to improve the processing impact resistance, environmental stress cracking resistance and barrier properties of PET, PET can also improve the strength, heat resistance and surface hardness of PP. The two interact with each other to jointly improve the kink performance and barrier properties of the composite film.

[0009] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] A composite film for packaging with good barrier properties, high kink strength and low resilience. The raw materials include, by weight: 45-55 parts of PET, 25-40 parts of PP, 0.5-1 parts of heat stabilizer, 2-5 parts of antioxidant, 2-3 parts of ultraviolet absorber; 1-2 parts of hindered amine light stabilizer, 2-3 parts of lubricant, 4-6 parts of coupling agent, 5-10 parts of filler, 1-2 parts of flame retardant, 5-8 parts of cross-linking agent and 2-8 parts of compatibilizer.

[0011] Furthermore, in parts by weight, the raw materials include: 55 parts of PET, 40 parts of PP, 1 part of heat stabilizer, 5 parts of antioxidant, 2 parts of ultraviolet absorber; 2 parts of hindered amine light stabilizer, 3 parts of lubricant, 6 parts of coupling agent, 6 parts of filler, 2 parts of flame retardant, 5 parts of cross-linking agent and 8 parts of compatibilizer.

[0012] Furthermore, the heat stabilizer is FT-4288; the antioxidant is selected from one of diphenylamine and p-phenylenediamine; the ultraviolet absorber is selected from one of 2-hydroxy-4-methoxybenzophenone and 2-(2-hydroxy-3,5-bis(a,a-dimethylbenzyl)phenyl)benzotriazole; the hindered amine light stabilizer is selected from one of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester and tris(1,2,2,6,6-pentamethyl-4-hydroxypiperidinyl) phosphite.

[0013] Furthermore, the lubricant is pentaerythritol stearate; the coupling agent is isopropyl dioleyl (dioctyl phosphate) titanate; and the filler is silicon dioxide.

[0014] Furthermore, the cross-linking agent is oleamide; and the flame retardant is TDBPPE.

[0015] Furthermore, the compatibilizer is PP-g-MAH.

[0016] Furthermore, the method for preparing any of the above-mentioned composite films for packaging with good barrier properties, high kink strength and low resilience comprises the following steps:

[0017] (1) Add PET, FT-4288, diphenylamine, 2-hydroxy-4-methoxybenzophenone, benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, pentaerythritol stearate, isopropyl dioleyl acyloxy (dioctyl phosphate acyloxy) titanate, silica and TDBPPE into a high-speed mixer, mix at a speed of 250 r / min for 25-35 min, then transfer to an internal mixer, mix for 15-20 min, naturally cool to 70-90°C, take out and chop, and then cool to room temperature to obtain modified PET granules;

[0018] (2) The modified PET pellets, PP, oleamide and PP-g-MAH are mixed and added into a twin-screw extruder for extrusion granulation to obtain mixed pellets;

[0019] (3) The mixed pellets are placed in an extrusion casting machine and cast into a film with a thickness of 15 μm, and then double-sided corona treatment is performed and rolled up to obtain a PET-PP composite twisted film.

[0020] Furthermore, in step (1), the temperature of the internal mixer is 240-290° C., and the rotation speed is 50 r / min.

[0021] Furthermore, in the step (2), the extrusion temperature of the twin-screw extruder is 180-220°C.

[0022] Furthermore, in the step (3), the temperature of the extrusion casting machine is 200-220°C.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] 1) The present invention uses PP and PET to prepare a kink film. By adding a compatibilizer PP-g-MAH, the compatibility of the PET / PP blend system can be improved, thereby improving its rheological properties and mechanical properties. The addition of the compatibilizer not only improves the flow properties of the PET / PP alloy, but also reduces the effect of the shear rate on the apparent viscosity and reduces the temperature dependence of the material.

[0025] 2) The present invention can effectively reduce the melt viscosity of PET and improve its fluidity by adding a heat stabilizer to the raw materials; at the same time, the physical properties of PET are improved through its specific chemical structure, such as enhancing its impact resistance and increasing its thermal deformation temperature.

[0026] 3) The PET composite twist film prepared by the present invention has excellent physical properties and chemical stability, can meet the requirements of high-speed printing machines and twist packaging machines, and has good high temperature resistance and low shrinkage, ensuring its stability in high temperature environments and the tightness of packaging; in addition, the PET composite twist film also has antistatic properties and excellent printing quality, and is suitable for various packaging needs. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with specific embodiments.

[0028] Unless otherwise specified, the raw materials or components used in the following examples were purchased from commercial sources.

[0029] The methods for testing various properties of the composite films obtained in the following embodiments and comparative examples are as follows:

[0030] Tensile performance test: The electronic universal testing machine uses a special pneumatic clamp for film, and the force sensor range is 100N. The film is cut into 200mmx15mm specimens and its tensile performance is tested according to ASTMD638-03. The tensile speed is 500mm / min.

[0031] Optical performance test: light transmittance is tested according to GB / T2410-2008, and glossiness is tested according to ASTMD2457-2008.

[0032] Kink test: Fold a small piece of film sample once along the center line, fix one end of the film, rotate the other end 360 degrees, then release the sample to allow it to rebound freely, and finally measure the kink retention angle (RA).

[0033] Example 1

[0034] A composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following raw materials in parts by weight: 55 parts of PET (average molecular weight of 40,000-50,000), 25 parts of PP, 0.5 parts of FT-4288, 2 parts of p-phenylenediamine, 2 parts of 2-hydroxy-4-methoxybenzophenone, 3 parts of pentaerythritol stearate, 5 parts of isopropyl dioleyl (dioctyl phosphate) titanate, 5-10 parts of silicon dioxide, 2 parts of TDBPPE, 8 parts of oleamide and 5 parts of PP-g-MAH;

[0035] The preparation method of the composite film comprises the following steps:

[0036] (1) PET (average molecular weight of 40,000-50,000), FT-4288, p-phenylenediamine, 2-hydroxy-4-methoxybenzophenone, benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, pentaerythritol stearate, isopropyl dioleyl acyloxy (dioctylphosphoacyloxy) titanate, silica and TDBPPE were added into a high-speed mixer, mixed at a speed of 250 r / min for 25 min, and then transferred into an internal mixer, and mixed at 240°C and 50 r / min for 15 min, and then naturally cooled to 80°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0037] (2) The modified PET pellets, PP, oleamide and PP-g-MAH were mixed and added into a twin-screw extruder, and melt-extruded and granulated at 210°C and 250 r / min to obtain mixed pellets;

[0038] (3) The mixed pellets were placed in an extrusion casting machine and cast into a film with a thickness of 15 μm at 200° C., and then double-sided corona treatment was performed and rolled up to obtain a PET-PP composite twisted film.

[0039] Example 2

[0040] A composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following raw materials in parts by weight: 50 parts of PET (average molecular weight of 40,000-50,000), 30 parts of PP, 1 part of FT-4288, 5 parts of diphenylamine, 3 parts of 2-(2-hydroxy-3,5-bis(a,a-dimethylbenzyl)phenyl)benzotriazole; 2 parts of tris(1,2,2,6,6-pentamethyl-4-hydroxypiperidinyl)phosphite, 2 parts of pentaerythritol stearate, 4 parts of isopropyl dioleyl (dioctylphosphoyl) titanate, 8 parts of silicon dioxide, 2 parts of TDBPPE, 5 parts of oleamide and 8 parts of PP-g-MAH;

[0041] The preparation method of the composite film comprises the following steps:

[0042] (1) PET (average molecular weight of 40000-50000), FT-4288, diphenylamine, 2-(2-hydroxy-3,5-bis(a,a-dimethylbenzyl)phenyl)benzotriazole, tris(1,2,2,6,6-pentamethyl-4-hydroxypiperidinyl)phosphite, pentaerythritol stearate, isopropyl dioleyloxy(dioctylphosphoyloxy)titanate, silica and TDBPPE were added into a high-speed mixer, mixed at a speed of 250 r / min for 30 min, and then transferred into an internal mixer, and mixed at 260°C and 50 r / min for 15 min, then naturally cooled to 70°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0043] (2) The modified PET pellets, PP, oleamide and PP-g-MAH were mixed and added into a twin-screw extruder, and melt-extruded and granulated at 200°C and 250 r / min to obtain mixed pellets;

[0044] (3) The mixed pellets were placed in an extrusion casting machine and cast into a film with a thickness of 15 μm at 210° C., and then double-sided corona treatment was performed and rolled up to obtain a PET-PP composite twisted film.

[0045] Example 3

[0046] A composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following raw materials in parts by weight: 55 parts of PET (average molecular weight of 40,000-50,000), 40 parts of PP, 1 part of FT-4288, 5 parts of p-phenylenediamine, 2 parts of 2-hydroxy-4-methoxybenzophenone; 2 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, 3 parts of pentaerythritol stearate, 6 parts of isopropyl dioleyl (dioctylphospho) titanate, 6 parts of silicon dioxide, 2 parts of TDBPPE, 5 parts of oleamide and 8 parts of PP-g-MAH;

[0047] A method for preparing a composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following steps:

[0048] (1) PET (average molecular weight of 40,000-50,000), FT-4288, p-phenylenediamine, 2-hydroxy-4-methoxybenzophenone, benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, pentaerythritol stearate, isopropyl dioleyl acyloxy (dioctylphosphoacyloxy) titanate, silica and TDBPPE were added into a high-speed mixer, mixed at a speed of 250 r / min for 30 min, and then transferred into an internal mixer, and mixed at 240°C and 50 r / min for 15 min, and then naturally cooled to 90°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0049] (2) The modified PET pellets, PP, oleamide and PP-g-MAH were mixed and added into a twin-screw extruder, and melt-extruded and granulated at 220°C and 250 r / min to obtain mixed pellets;

[0050] (3) The mixed pellets were placed in an extrusion casting machine and cast into a film with a thickness of 15 μm at 210° C., and then double-sided corona treatment was performed and rolled up to obtain a PET-PP composite twisted film.

[0051] Example 4

[0052] A composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following raw materials in parts by weight: 48 parts of PET (average molecular weight of 40,000-50,000), 32 parts of PP, 1 part of FT-4288, 5 parts of diphenylamine, 3 parts of 2-hydroxy-4-methoxybenzophenone; 2 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, 3 parts of pentaerythritol stearate, 5 parts of isopropyl dioleyl (dioctylphosphonic acid) titanate, 7 parts of silicon dioxide, 2 parts of TDBPPE, 5 parts of oleamide and 8 parts of PP-g-MAH;

[0053] A method for preparing a composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following steps:

[0054] (1) PET (average molecular weight of 40,000-50,000), FT-4288, diphenylamine, 2-hydroxy-4-methoxybenzophenone, benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, pentaerythritol stearate, isopropyl dioleyl acyloxy (dioctylphosphoacyloxy) titanate, silica and TDBPPE were added into a high-speed mixer, mixed at a speed of 250 r / min for 35 min, and then transferred into an internal mixer, and mixed at 290°C and 50 r / min for 20 min, and then naturally cooled to 70°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0055] (2) The modified PET pellets, PP, oleamide and PP-g-MAH were mixed and added into a twin-screw extruder, and melt-extruded and granulated at 180°C and 250 r / min to obtain mixed pellets;

[0056] (3) The mixed pellets were placed in an extrusion casting machine and cast into a film with a thickness of 15 μm at 200° C., and then double-sided corona treatment was performed and rolled up to obtain a PET-PP composite twisted film.

[0057] Example 5

[0058] A composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following raw materials in parts by weight: 55 parts of PET (average molecular weight of 40,000-50,000), 38 parts of PP, 0.5-1 parts of FT-4288, 2-5 parts of p-phenylenediamine, 2 parts of 2-hydroxy-4-methoxybenzophenone; 1 part of tris(1,2,2,6,6-pentamethyl-4-hydroxypiperidinyl)phosphite, 3 parts of pentaerythritol stearate, 4 parts of isopropyl dioleyl (dioctylphospho) titanate, 6 parts of silicon dioxide, 1 part of TDBPPE, 7 parts of oleamide and 5 parts of PP-g-MAH;

[0059] A method for preparing a composite film for packaging with good barrier properties, high kink strength and low resilience, comprising the following steps:

[0060] (1) PET (average molecular weight of 40,000-50,000), FT-4288, p-phenylenediamine, 2-hydroxy-4-methoxybenzophenone, tris(1,2,2,6,6-pentamethyl-4-hydroxypiperidinyl)phosphite, pentaerythritol stearate, isopropyl dioleyloxy (dioctylphosphoyloxy) titanate, silica and TDBPPE were added into a high-speed mixer, mixed at a speed of 250 r / min for 35 min, and then transferred into an internal mixer, and mixed at 250°C and 50 r / min for 15 min, and then naturally cooled to 75°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0061] (2) The modified PET pellets, PP, oleamide and PP-g-MAH were mixed and added into a twin-screw extruder, and melt-extruded and granulated at 210°C and 250 r / min to obtain mixed pellets;

[0062] (3) The mixed pellets were placed in an extrusion casting machine and cast into a film with a thickness of 15 μm at 200° C., and then double-sided corona treatment was performed and rolled up to obtain a PET-PP composite twisted film.

[0063] Comparative Example 1

[0064] The 15 μm thick PET twist film was prepared by conventional methods.

[0065] Comparative Example 2

[0066] A composite film for packaging, comprising the following raw materials in parts by weight: 55 parts of PET (average molecular weight of 40,000-50,000), 1 part of FT-4288, 5 parts of p-phenylenediamine, 3 parts of pentaerythritol stearate, 6 parts of isopropyl dioleyl (dioctyl phosphate) titanate, 6 parts of silicon dioxide, 2 parts of TDBPPE, 5 parts of oleamide and 8 parts of PP-g-MAH;

[0067] The preparation method of the above-mentioned composite film for packaging comprises the following steps:

[0068] (1) PET (average molecular weight of 40,000-50,000), FT-4288, p-phenylenediamine, pentaerythritol stearate, isopropyl dioleyl (dioctyl phosphate) titanate, silica, TDBPPE, oleamide and PP-g-MAH were added into a high-speed mixer, mixed at a speed of 250 r / min for 30 min, and then transferred into an internal mixer, and mixed at 240°C and 50 r / min for 15 min, and then naturally cooled to 90°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0069] (2) The modified PET pellets were placed in an extrusion casting machine and cast into a 15 μm thick film at 210°C, and then double-sided corona treatment was performed and rolled up to obtain a PET twist film.

[0070] Comparative Example 3

[0071] A composite film for packaging, comprising the following raw materials in parts by weight: 55 parts of PET (average molecular weight of 40,000-50,000), 1 part of FT-4288, 5 parts of p-phenylenediamine, 2 parts of 2-hydroxy-4-methoxybenzophenone; 2 parts of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, 3 parts of pentaerythritol stearate, and 6 parts of isopropyl dioleyl acyloxy (dioctyl phosphate acyloxy) titanate;

[0072] The preparation method of the above-mentioned composite film for packaging comprises the following steps:

[0073] (1) PET (average molecular weight of 40,000-50,000), FT-4288, p-phenylenediamine, 2-hydroxy-4-methoxybenzophenone, benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, pentaerythritol stearate and isopropyl dioleyl acyloxy (dioctyl phosphate acyloxy) titanate were added into a high-speed mixer, mixed at a speed of 250 r / min for 30 min, and then transferred to an internal mixer, and mixed at 240°C and 50 r / min for 15 min, and then naturally cooled to 90°C, taken out and chopped, and then cooled to room temperature to obtain modified PET pellets;

[0074] (3) The mixed pellets were placed in an extrusion casting machine and cast into a film with a thickness of 15 μm at 210° C., and then double-sided corona treatment was performed and rolled up to obtain a PET twist film.

[0075] The kinked films obtained in the above-mentioned embodiments and comparative examples were subjected to tensile property test, optical property test and kinking test respectively, and the test results are shown in Table 1 below.

[0076]

[0077] It can be seen from the data in Table 1 that the composite twisted films prepared in Examples 1 to 5 are superior to the comparative examples in tensile strength, optical properties and twisting properties, indicating that the composite twisted films prepared in the present invention have better advantages as packaging materials. The PET used in the present invention can improve the strength, modulus, heat resistance and surface hardness of PP, while PP can improve the processing impact resistance, environmental stress cracking resistance and barrier properties of PET. The purpose is to strengthen, toughen and harden the material, while improving its wear resistance, pressure resistance and drop resistance.

[0078] Among them, the tensile strength and kink retention angle of the composite kinked film prepared in Example 3 are higher than those of other examples, indicating that in the preparation process of the composite material, appropriately increasing the content of PP and the proportion of the compatibilizer can effectively improve the kink strength and tensile properties of the kinked composite film. The reason may be that by adding the compatibilizer PP-g-MAH, the compatibility of the PET / PP blend system can be improved, thereby improving its rheological properties and mechanical properties. The addition of the compatibilizer not only improves the flow properties of the PET / PP alloy, but also reduces the effect of the shear rate on the apparent viscosity, and reduces the material's dependence on temperature.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A composite film for packaging with good barrier properties, high kink strength and low resilience, characterized in that: In terms of weight, the raw materials include: 45-55 parts of PET, 25-40 parts of PP, 0.5-1 parts of heat stabilizer, 2-5 parts of antioxidant, 2-3 parts of ultraviolet absorber; 1-2 parts of hindered amine light stabilizer, 2-3 parts of lubricant, 4-6 parts of coupling agent, 5-10 parts of filler, 1-2 parts of flame retardant, 5-8 parts of cross-linking agent and 2-8 parts of compatibilizer.

2. The composite film for packaging having good barrier properties, high kink strength and low resilience according to claim 1, characterized in that: In terms of weight, the raw materials include: 55 parts of PET, 40 parts of PP, 1 part of heat stabilizer, 5 parts of antioxidant, 2 parts of ultraviolet absorber; 2 parts of hindered amine light stabilizer, 3 parts of lubricant, 6 parts of coupling agent, 6 parts of filler, 2 parts of flame retardant, 5 parts of cross-linking agent and 8 parts of compatibilizer.

3. The composite film for packaging having good barrier properties, high kink strength and low resilience according to claim 1, characterized in that: The heat stabilizer is FT-4288; the antioxidant is selected from one of diphenylamine and p-phenylenediamine; the ultraviolet absorber is selected from one of 2-hydroxy-4-methoxybenzophenone and 2-(2-hydroxy-3,5-bis(a,a-dimethylbenzyl)phenyl)benzotriazole; the hindered amine light stabilizer is selected from one of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester and tris(1,2,2,6,6-pentamethyl-4-hydroxypiperidinyl) phosphite.

4. The composite film for packaging having good barrier properties, high kink strength and low resilience according to claim 1, characterized in that: The lubricant is pentaerythritol stearate; the coupling agent is isopropyl dioleic acid acyloxy (dioctyl phosphate acyloxy) titanate; and the filler is silicon dioxide.

5. The composite film for packaging having good barrier properties, high kink strength and low resilience according to claim 1, characterized in that: The cross-linking agent is oleamide; and the flame retardant is TDBPPE.

6. The composite film for packaging having good barrier properties, high kink strength and low resilience according to claim 1, characterized in that: The compatibilizer is PP-g-MAH.

7. A method for preparing a composite film for packaging having good barrier properties, high kink strength and low resilience as claimed in any one of claims 1 to 6, characterized in that: Here are the steps: (1) Add PET, FT-4288, diphenylamine, 2-hydroxy-4-methoxybenzophenone, benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidinyl) ester, pentaerythritol stearate, isopropyl dioleyl acyloxy (dioctyl phosphate acyloxy) titanate, silica and TDBPPE into a high-speed mixer, mix at a speed of 250 r / min for 25-35 min, then transfer to an internal mixer, mix for 15-20 min, naturally cool to 70-90°C, take out and chop, and then cool to room temperature to obtain modified PET granules; (2) The modified PET pellets, PP, oleamide and PP-g-MAH are mixed and added into a twin-screw extruder for extrusion granulation to obtain mixed pellets; (3) The mixed pellets are placed in an extrusion casting machine and cast into a film with a thickness of 15 μm, and then double-sided corona treatment is performed and rolled up to obtain a PET-PP composite twisted film.

8. The method according to claim 7, characterized in that: In the step (1), the temperature of the internal mixer is 240-290° C., and the rotation speed is 50 r / min.

9. The method according to claim 7, characterized in that: In the step (2), the extrusion temperature of the twin-screw extruder is 180-220°C.

10. The method according to claim 7, characterized in that: In the step (3), the temperature of the extrusion casting machine is 200-220°C.

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