A high barrier boiling resistant aluminum-plated film and preparation method thereof

Abstract

The present application discloses a high-barrier, retort-resistant aluminum-plated film and a preparation method thereof, and relates to the field of aluminum-plated films. The high-barrier, retort-resistant aluminum-plated film comprises a base film layer, a first polyurethane coating, an aluminum-plated barrier layer, a second polyurethane coating and a heat-sealing layer; the base film layer is made of heat-resistant modified high-density polyethylene obtained by cross-linking high-density polyethylene, p-vinylbenzylamine and double-terminated acrylic silicone oil; the first polyurethane coating and the second polyurethane coating are both made of modified polyurethane coatings, and the modified polyurethane coatings include silicone-modified polyurethane coatings and water-based epoxy resin coatings; the heat-sealing layer is made of silicone-modified low-density polyethylene obtained by cross-linking low-density polyethylene and vinyl-terminated hydroxyl-terminated silicone oils. The aluminum-plated film of the present application can obtain an aluminum-plated film with high barrier properties through stable bonding between the layers. At the same time, since the layers themselves have good retort resistance, the bonding strength between the layers is less affected by temperature, and interlayer separation is not easy to occur during high-temperature retort.

Description

Technical Field

[0001] The present application relates to the field of aluminum-plated films, and in particular to a high-barrier and cooking-resistant aluminum-plated film and a preparation method thereof. Background Art

[0002] Aluminum-coated film is often used as a food packaging material, and usually includes a film substrate layer, an aluminized barrier layer and a heat-sealing layer arranged in sequence. The function of the aluminized barrier layer is to block external water vapor and oxygen to prevent water vapor and oxygen from spoiling the food in the package, which is beneficial to prolong the shelf life of the food.

[0003] Among them, the current aluminized film has the following problems: after high-temperature cooking, stratification easily occurs between the aluminized barrier layer and the film substrate layer and the heat-sealing layer, and the barrier performance of the aluminized film is significantly reduced, which is not conducive to effectively blocking water and oxygen. Summary of the invention

[0004] In order to improve the high temperature cooking resistance in the related art, the present application provides a high barrier cooking resistant aluminum-coated film and a preparation method thereof.

[0005] In the first aspect, a high barrier and boiling resistant aluminum-plated film of the present application adopts the following technical solution:

[0006] A high-barrier, retort-resistant aluminized film comprising a base film layer, a first polyurethane coating, an aluminized barrier layer, a second polyurethane coating and a heat-sealing layer;

[0007] The base film layer is made of heat-resistant modified high-density polyethylene obtained by cross-linking high-density polyethylene, p-vinylbenzylamine, and double-terminal acrylic ester silicone oil;

[0008] The first polyurethane coating and the second polyurethane coating are both made of modified polyurethane coating, wherein the modified polyurethane coating includes organosilicon-modified polyurethane coating and waterborne epoxy resin coating, and the weight ratio of the organosilicon-modified polyurethane coating to the waterborne epoxy resin coating is (3-4):1;

[0009] The heat sealing layer is made of low-density polyethylene and organosilicon-modified low-density polyethylene obtained by cross-linking reaction of vinyl-terminated and hydroxyl-terminated silicone oil.

[0010] Different from the existing aluminized films, the base film layer of the present application is made of heat-resistant modified high-density polyethylene obtained by modifying high-density polyethylene with p-vinylbenzylamine and double-ended acrylic silicone oil, and the heat-sealing layer is made of silicone-modified low-density polyethylene obtained by modifying low-density polyethylene with terminal vinyl and terminal hydroxyl silicone oil. The high-barrier and retort-resistant aluminized film has a first polyurethane coating added between the base film layer and the aluminized barrier layer, and a second polyurethane coating added between the aluminized barrier layer and the heat-sealing layer. At the same time, it is also specified that both the first polyurethane coating and the second polyurethane coating are modified polyurethane coatings made of organic modified polyurethane coatings and water-based epoxy resin coatings in a specific ratio.

[0011] Among them, the present application modifies high-density polyethylene by co-modifying vinylbenzylamine and double-terminated acrylic silicone oil, and at the same time improves the heat resistance and barrier properties of high-density polyethylene. The base film layer is prepared from the heat-resistant modified high-density polyethylene, which can simultaneously and effectively improve the high-temperature cooking resistance and barrier properties of the base film layer. The first polyurethane coating and the second polyurethane coating adopt a composition of a specific ratio of organosilicon-modified polyurethane coating and water-based epoxy resin coating. The organosilicon-modified polyurethane coating has high heat resistance, which is conducive to obtaining the first polyurethane coating and the second polyurethane coating that are resistant to high-temperature cooking. The addition of water-based epoxy resin can improve the bonding strength between the first polyurethane coating and the base film layer and the aluminum-plated barrier layer. The organosilicon-modified low-density polyethylene of the heat-sealing layer introduces organosilicon segments and hydroxyl groups from the end-vinyl and end-hydroxyl silicone oil. On the one hand, it appropriately improves the high-temperature cooking resistance of the heat-sealing layer, and on the other hand, it also improves the interface bonding strength between the heat-sealing layer and the second polyurethane coating, which is conducive to improving the stability between the heat-sealing layer and the second polyurethane coating.

[0012] In addition, the above-mentioned high barrier and cooking resistant aluminum-plated film of the present application can obtain an aluminum-plated film that effectively blocks oxygen and water vapor through the stable bonding between the layers. At the same time, since the layers themselves have good high temperature cooking resistance, the bonding strength between the layers is less affected by temperature, and the interlayer separation phenomenon is not easy to occur during high temperature cooking. Therefore, the aluminum-plated film of the present application has both high barrier and high temperature cooking resistance, and is a high barrier and cooking resistant aluminum-plated film.

[0013] Optionally, in the heat-resistant modified high-density polyethylene, the weight ratio of the high-density polyethylene, p-vinylbenzylamine, and double-ended acrylic silicone oil is 100:(8.8-10.4):(4.6-6.3).

[0014] Optionally, the method for preparing the heat-resistant modified high-density polyethylene comprises the following steps:

[0015] The first premix is ​​obtained by uniformly mixing high-density polyethylene, p-vinylbenzylamine, double-terminal acrylate silicone oil and a first initiator; the amount of the first initiator is 0.015%-0.03% of the amount of the high-density polyethylene; the first initiator is a composition of benzophenone and dicumyl peroxide, and the weight ratio of the benzophenone to the dicumyl peroxide is (1.5-2):1;

[0016] The premix is ​​subjected to radiation crosslinking to obtain a first radiation crosslinked product; the radiation crosslinking is performed at a wavelength of 280-300 nm and an irradiation intensity of 0.4-0.5 J / cm 2 The reaction was carried out for 3-4 hours under the conditions of

[0017] The first radiation cross-linked product is melt-extruded at 200-220° C. and then pelletized to obtain heat-resistant modified high-density polyethylene.

[0018] In the present application, the heat-resistant modified high-density polyethylene is prepared by the above method, which is conducive to obtaining heat-resistant modified high-density polyethylene with good heat resistance, barrier properties and stable performance.

[0019] Optionally, in the organosilicon-modified low-density polyethylene, the weight ratio of the low-density polyethylene to the vinyl-terminated hydroxyl-terminated silicone oil is 100:(6.5-8.5).

[0020] In the present application, in the organosilicon-modified low-density polyethylene, the weight ratio of low-density polyethylene to terminal vinyl-terminated hydroxyl-terminated silicone oil is within the above range, which is conducive to obtaining a heat-sealing layer with good heat resistance and high bonding strength with the second polyurethane coating.

[0021] Optionally, the method for preparing the organosilicon-modified low-density polyethylene comprises the following steps:

[0022] The low-density polyethylene, the vinyl-terminated hydroxyl-terminated silicone oil and the second initiator are uniformly mixed to obtain a second premix; the amount of the second initiator is 0.01%-0.015% of the amount of the low-density polyethylene, and the second initiator is a combination of benzophenone and dicumyl peroxide, and the weight ratio of the benzophenone to the dicumyl peroxide is (1-1.5):1;

[0023] The second premix is ​​subjected to radiation crosslinking to obtain a second radiation crosslinked product; the radiation crosslinking is performed at a wavelength of 250-260 nm and an irradiation intensity of 0.3-0.4 J / cm 2 The reaction was carried out for 3-4 hours under the conditions of

[0024] The second radiation cross-linked product is melt-extruded at 200-220° C. and then pelletized to obtain organosilicon-modified low-density polyethylene.

[0025] In the present application, the above method is used to prepare the organosilicon-modified low-density polyethylene, which is conducive to obtaining the organosilicon-modified low-density polyethylene with good heat resistance, high bonding strength with the second polyurethane coating and stable performance.

[0026] Preferably, based on raw materials, the organosilicon-modified polyurethane coating comprises isocyanate-terminated polyurethane prepolymer, alcohol hydroxyl-terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane in a weight ratio of 100:(1.2-2.6):(2.5-4.2).

[0027] In the present application, when the silicone-modified resin is used to prepare the silicone-modified polyurethane coating prepared by isocyanate-terminated polyurethane prepolymer, alcohol hydroxyl-terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane in the above weight ratio and the water-based epoxy resin, the modified polyurethane coating can be further reduced in thickness while ensuring the high barrier and high temperature cooking resistance of the aluminum-plated film.

[0028] Optionally, the isocyanate-terminated polyurethane prepolymer is obtained by reacting a polymeric diol with a diisocyanate in a molar ratio of 1:(1.3-1.6).

[0029] Optionally, the polymer diol is at least one of polytetramethylene glycol, polycarbonate glycol, polyoxypropylene glycol and polycaprolactone glycol.

[0030] Preferably, the preparation method of the organosilicon-modified polyurethane coating comprises the following steps:

[0031] Heat the polymer diol to 45-55°C, then add diisocyanate and organotin catalyst.

[0032] Raising the temperature to 80-85°C for prepolymerization to obtain an isocyanate-terminated polyurethane prepolymer;

[0033] Add alcohol hydroxyl terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane to the isocyanate terminated polyurethane prepolymer, maintain the temperature at 80-85°C for chain extension reaction, and obtain an organosilicon modified polyurethane coating.

[0034] In the present application, the modified polyurethane coating is prepared by using the silicone-modified polyurethane coating prepared by the above-mentioned preparation method and the water-based epoxy resin coating, and an aluminum-plated film with high overall bonding strength and not prone to interlayer separation during high-temperature cooking can be obtained.

[0035] Optionally, the base film layer has a thickness of 10-20 μm, the first polyurethane coating has a thickness of 1-10 μm, the aluminum-plated barrier layer has a thickness of 40-50 angstroms, the second polyurethane coating has a thickness of 1-10 μm, and the heat-sealing layer has a thickness of 10-20 μm.

[0036] In the second aspect, the present application provides a method for preparing a high barrier and boiling resistant aluminum-plated film using the following technical solution: A method for preparing a high barrier and boiling resistant aluminum-plated film, comprising the following steps:

[0037] S1, melting the heat-resistant modified high-density polyethylene, casting a sheet, and longitudinally stretching to obtain the base film layer, coating one side of the base film layer with the modified polyurethane coating, and drying to form the first polyurethane coating on the base film layer;

[0038] S2, send the film material obtained in S1 into the vacuum aluminum plating equipment, heat the aluminum wire, and make the gaseous aluminum deposit on

[0039] forming the aluminum-plated barrier layer on the first polyurethane coating;

[0040] S3, coating the modified polyurethane coating on the side of the aluminum-plated barrier layer away from the first polyurethane coating, and after drying, forming the second polyurethane coating on the aluminum-plated barrier layer;

[0041] S4, melting and blow-molding the organosilicon-modified low-density polyethylene to obtain the heat-sealing layer, and compounding the heat-sealing layer on the side of the second polyurethane coating away from the aluminized barrier layer to obtain a high-barrier and cooking-resistant aluminized film.

[0042] The present application adopts the above method to prepare a high-barrier and cooking-resistant aluminum-plated film, which is beneficial to obtaining an aluminum-plated film with both high barrier and high-temperature cooking resistance.

[0043] In summary, the beneficial technical effects of the technical solution of this application are:

[0044] (1) The present application prepares a base film layer with high temperature cooking resistance and high barrier properties by modifying high density polyethylene with vinyl benzylamine and double-terminated acrylic ester silicone oil. The first polyurethane coating and the second polyurethane coating use a composition with a specific ratio of organosilicon-modified polyurethane coating and water-based epoxy resin coating. The organosilicon-modified polyurethane coating has high heat resistance, which is conducive to obtaining the first polyurethane coating and the second polyurethane coating that are resistant to high temperature cooking. The addition of water-based epoxy resin can improve the bonding strength between the first polyurethane coating and the base film layer and the aluminum-plated barrier layer. The organosilicon-modified low-density polyethylene of the heat-sealing layer introduces organosilicon segments and hydroxyl groups from the end-vinyl and end-hydroxy silicone oil, which on the one hand appropriately improves the high temperature cooking resistance of the heat-sealing layer, and on the other hand also improves the interfacial bonding strength between the heat-sealing layer and the second polyurethane coating, which is conducive to improving the stability between the heat-sealing layer and the second polyurethane coating. Among them, the above-mentioned high barrier and cooking resistant aluminum-plated film of the present application can obtain an aluminum-plated film that effectively blocks oxygen and water vapor through the stable combination of each layer. At the same time, since each layer itself has good high temperature cooking resistance, the bonding strength between the layers is less affected by temperature, and the interlayer separation phenomenon is not easy to occur during high temperature cooking. Therefore, the aluminum-plated film of the present application has both high barrier and high temperature cooking resistance performance, and is a high barrier and cooking resistant aluminum-plated film.

[0045] (2) In the present application, when the silicone-modified resin is prepared by mixing isocyanate-terminated polyurethane prepolymer, alcohol hydroxyl-terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane in the above weight ratio with water-based epoxy resin to prepare the modified polyurethane coating, the thickness of the first polyurethane coating and the second polyurethane coating can be further reduced while ensuring the high barrier and high temperature cooking resistance of the aluminum-plated film. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of a high-barrier, cooking-resistant aluminum-plated film of the present application.

[0047] Description of reference numerals:

[0048] 1. Base film layer; 2. First polyurethane coating; 3. Aluminum-plated barrier layer; 4. Second polyurethane coating; 5. Heat-sealing layer. DETAILED DESCRIPTION

[0049] The application is further explained below in conjunction with specific experiments. Among them, the high-density polyethylene is a product of Korean brand FB3000; the double-ended acrylic ester silicone oil adopts a product with a viscosity of 70-80mPa.s from Kermik; the water-based epoxy resin coating adopts the GS-water-based epoxy resin of Guangshen Technology; the silanol-terminated silicone oil is a product with a Kermik model of SC-VH10; the alcohol-hydroxyl-terminated silicone oil adopts Kermik's double-ended hydroxypropyl silicone oil, with a molecular weight in the range of 3000-4000; the polytetrahydrofuran ether glycol adopts PTMEG2000; the low-density polyethylene adopts a product of Yanshan Petrochemical with a model of LD100AC; the vinyl-terminated hydroxyl-terminated silicone oil adopts a product with a Kermik model of SC-VH10.

[0050] Preparation Example

[0051] [Preparation Example 1-1]

[0052] Heat-resistant modified high-density polyethylene, the raw materials include 100kg high-density polyethylene, 8.8kg p-vinylbenzylamine, 6.3kg double-ended acrylate silicone oil and 0.015kg first initiator, wherein the first initiator is a combination of benzophenone and diisopropylbenzene peroxide, and the weight ratio of benzophenone to diisopropylbenzene peroxide is 2:1.

[0053] The method for preparing the base film layer 1 comprises the following steps:

[0054] Uniformly mixing high-density polyethylene, p-vinylbenzylamine, double-terminal acrylate silicone oil and a first initiator to obtain a first premix;

[0055] The premix is ​​cross-linked under irradiation conditions of a wavelength of 280 nm and an irradiation intensity of 0.5 J / cm2 for 3 hours to obtain a first irradiation cross-linked product;

[0056] The first radiation cross-linked product is melt-extruded at 200° C. and then pelletized to obtain heat-resistant modified high-density polyethylene.

[0057] [Preparation Example 1-2]

[0058] Heat-resistant modified high-density polyethylene, the raw materials include 100kg high-density polyethylene, 10.4kg p-vinylbenzylamine, 4.6kg double-ended acrylate silicone oil and 0.03kg first initiator, wherein the first initiator is a combination of benzophenone and diisopropylbenzene peroxide, and the weight ratio of benzophenone to diisopropylbenzene peroxide is 1.5:1.

[0059] The method for preparing the base film layer 1 comprises the following steps:

[0060] Uniformly mixing high-density polyethylene, p-vinylbenzylamine, double-terminal acrylate silicone oil and a first initiator to obtain a first premix;

[0061] The premix is ​​cross-linked for 4 hours under the conditions of a wavelength of 300 nm and an irradiation intensity of 0.4 J / cm2 to obtain a first irradiation cross-linked product;

[0062] The first radiation cross-linked product is melt-extruded at 220° C. and then pelletized to obtain heat-resistant modified high-density polyethylene.

[0063] [Preparation Example 1-3]

[0064] The modified high-density polyethylene is different from [Preparation Example 1-1] in that p-vinylbenzylamine is replaced by an equal amount of double-terminal acrylate silicone oil.

[0065] [Preparation Example 1-4]

[0066] The modified high-density polyethylene is different from [Preparation Example 1-1] in that the double-ended acrylate silicone oil is replaced by an equal amount of p-vinylbenzylamine.

[0067] [Preparation Example 2-1]

[0068] The modified polyurethane coating is prepared by uniformly mixing the silicone modified polyurethane coating and the waterborne epoxy resin coating in a weight ratio of 3:1.

[0069] Among them, the raw materials of the silicone-modified polyurethane coating include 100kg of isocyanate-terminated polyurethane prepolymer, 1.8kg of alcohol hydroxyl-terminated silicone oil and 3.4kg of ethylenediamine; the isocyanate-terminated polyurethane is obtained by reacting polytetramethylene ether diol and isophorone diisocyanate under the catalysis of dibutyltin dilaurate, the molar ratio of polytetramethylene ether diol to isophorone diisocyanate is 1:1.3, and the amount of dibutyltin dilaurate is 0.01% of polytetramethylene ether diol.

[0070] Specifically, in this preparation example, the preparation method of the organosilicon-modified polyurethane coating comprises the following steps:

[0071] The polytetramethylene glycol was heated to 45°C, and then isophorone diisocyanate and dibutyltin dilaurate were added, and the temperature was raised to 80°C for prepolymerization reaction for 2 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0072] According to the ratio, add alcohol hydroxyl terminated silicone oil and ethylenediamine to the isocyanate terminated polyurethane prepolymer, maintain 80°C for chain extension reaction for 2h, and obtain silicone modified polyurethane coating.

[0073] [Preparation Example 2-2]

[0074] The modified polyurethane coating is prepared by uniformly mixing the silicone modified polyurethane coating and the waterborne epoxy resin coating in a weight ratio of 3:1.

[0075] Among them, the raw materials of the silicone-modified polyurethane coating include 100kg of isocyanate-terminated polyurethane prepolymer, 1.8kg of silanol-terminated silicone oil and 3.4kg of 3.3'-dimethyl-4.4'-diaminodiphenylmethane; the isocyanate-terminated polyurethane is obtained by reacting polytetramethylene ether diol and isophorone diisocyanate under the catalysis of dibutyltin dilaurate, the molar ratio of polytetramethylene ether diol to isophorone diisocyanate is 1:1.3, and the amount of dibutyltin dilaurate used is 0.01% of polytetramethylene ether diol.

[0076] Specifically, in this preparation example, the preparation method of the organosilicon-modified polyurethane coating comprises the following steps:

[0077] The polytetramethylene glycol was heated to 45°C, and then isophorone diisocyanate and dibutyltin dilaurate were added, and the temperature was raised to 80°C for prepolymerization reaction for 2 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0078] According to the ratio, silanol-terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane were added to the isocyanate-terminated polyurethane prepolymer, and the chain extension reaction was carried out at 80° C. for 2 h to obtain a silicone-modified polyurethane coating.

[0079] [Preparation Example 2-3]

[0080] The modified polyurethane coating is prepared by uniformly mixing the silicone modified polyurethane coating and the waterborne epoxy resin coating in a weight ratio of 3:1.

[0081] Among them, the raw materials of the silicone-modified polyurethane coating include 100kg of isocyanate-terminated polyurethane prepolymer, 1.8kg of alcohol hydroxyl-terminated silicone oil and 3.4kg of 3.3'-dimethyl-4.4'-diaminodiphenylmethane; the isocyanate-terminated polyurethane is obtained by reacting polytetramethylene ether diol and isophorone diisocyanate under the catalysis of dibutyltin dilaurate, the molar ratio of polytetramethylene ether diol to isophorone diisocyanate is 1:1.3, and the amount of dibutyltin dilaurate is 0.01% of polytetramethylene ether diol.

[0082] Specifically, in this preparation example, the preparation method of the organosilicon-modified polyurethane coating comprises the following steps:

[0083] The polytetramethylene glycol was heated to 45°C, and then isophorone diisocyanate and dibutyltin dilaurate were added, and the temperature was raised to 80°C for prepolymerization reaction for 2 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0084] According to the proportion, alcohol hydroxyl terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane were added to the isocyanate terminated polyurethane prepolymer, and the chain extension reaction was carried out at 80° C. for 2 h to obtain a silicone modified polyurethane coating.

[0085] [Preparation Example 3-1]

[0086] The raw materials of the organosilicon-modified low-density polyethylene include 100 kg of low-density polyethylene, 6.5 kg of vinyl-terminated hydroxyl-terminated silicone oil and 0.01 kg of a second initiator. The second initiator is a combination of benzophenone and diisopropylbenzene peroxide, and the weight ratio of benzophenone to diisopropylbenzene peroxide is 1:1.

[0087] The preparation method of organosilicon-modified low-density polyethylene comprises the following steps:

[0088] Uniformly mixing low-density polyethylene, vinyl-terminated hydroxyl-terminated silicone oil and dibutyltin dilaurate to obtain a second premix;

[0089] The second premix is ​​subjected to irradiation crosslinking for 3 hours at a wavelength of 250 nm and an irradiation intensity of 0.4 J / cm2 to obtain a second irradiation crosslinked product;

[0090] The second radiation cross-linked product is melt-extruded at 200° C. and then pelletized to obtain organosilicon-modified low-density polyethylene.

[0091] [Preparation Example 3-2]

[0092] The raw materials of the organosilicon-modified low-density polyethylene include 100 kg of low-density polyethylene, 8.5 kg of vinyl-terminated hydroxyl-terminated silicone oil and 0.015 kg of a second initiator. The second initiator is a combination of benzophenone and diisopropylbenzene peroxide, and the weight ratio of benzophenone to diisopropylbenzene peroxide is 1.5:1.

[0093] The preparation method of organosilicon-modified low-density polyethylene comprises the following steps:

[0094] Uniformly mixing low-density polyethylene, vinyl-terminated hydroxyl-terminated silicone oil and dibutyltin dilaurate to obtain a second premix;

[0095] The second premix is ​​subjected to irradiation crosslinking for 4 hours at a wavelength of 260 nm and an irradiation intensity of 0.3 J / cm2 to obtain a second irradiation crosslinked product;

[0096] The second radiation cross-linked product was melt-extruded at 220° C. and then pelletized to obtain organosilicon-modified low-density polyethylene.

[0097] Example

[0098] [Example 1]

[0099] A high barrier and boiling resistant aluminum film, reference Figure 1, including a base film layer 1, a first polyurethane coating 2, an aluminized barrier layer 3, a second polyurethane coating 4 and a heat-sealing layer 5 which are arranged in sequence, wherein the base film layer 1 has a thickness of 18 μm, the first polyurethane coating 2 has a thickness of 10 μm, the aluminized barrier layer 3 has a thickness of 45 angstroms, the second polyurethane coating 4 has a thickness of 10 μm, and the heat-sealing layer 5 has a thickness of 18 μm.

[0100] The preparation method of high-barrier boiling-resistant aluminum-plated film comprises the following steps:

[0101] S1, melting the heat-resistant modified high-density polyethylene prepared in [Preparation Example 1-1], casting a sheet, and longitudinally stretching to obtain a base film layer 1, coating one side of the base film layer 1 with the modified polyurethane coating prepared in [Preparation Example 2-1], and drying to form a first polyurethane coating 2 on the base film layer 1 to obtain a primer film;

[0102] S2, send the film material obtained in S1 into the vacuum aluminum plating equipment, heat the aluminum wire, and make the gaseous aluminum deposit on

[0103] An aluminum-plated barrier layer 3 is formed on the first polyurethane coating 2;

[0104] S3, coating the modified polyurethane coating prepared in [Preparation Example 2-1] on the side of the aluminum-plated barrier layer 3 away from the first polyurethane coating 2, and after drying, forming a second polyurethane coating 4 on the aluminum-plated barrier layer 3;

[0105] S4. The organosilicon-modified low-density polyethylene obtained in [Preparation Example 3-1] is melted and blow-molded to obtain a heat-sealing layer 5, and the heat-sealing layer 5 is compounded on the side of the second polyurethane coating 4 away from the aluminized barrier layer 3 to obtain a high-barrier and cooking-resistant aluminized film.

[0106] [Example 2]

[0107] A high barrier and boiling resistant aluminum film, reference Figure 1 , including a base film layer 1, a first polyurethane coating 2, an aluminized barrier layer 3, a second polyurethane coating 4 and a heat-sealing layer 5 which are arranged in sequence, wherein the base film layer 1 has a thickness of 18 μm, the first polyurethane coating 2 has a thickness of 10 μm, the aluminized barrier layer 3 has a thickness of 45 angstroms, the second polyurethane coating 4 has a thickness of 10 μm, and the heat-sealing layer 5 has a thickness of 18 μm.

[0108] The preparation method of high-barrier boiling-resistant aluminum-plated film comprises the following steps:

[0109] S1, melting the heat-resistant modified high-density polyethylene prepared in [Preparation Example 1-2], casting a sheet, and longitudinally stretching to obtain a base film layer 1, coating one side of the base film layer 1 with the modified polyurethane coating prepared in [Preparation Example 2-1], and drying to form a first polyurethane coating 2 on the base film layer 1 to obtain a primer film;

[0110] S2, send the film material obtained in S1 into the vacuum aluminum plating equipment, heat the aluminum wire, and make the gaseous aluminum deposit on

[0111] An aluminum-plated barrier layer 3 is formed on the first polyurethane coating 2;

[0112] S3, coating the modified polyurethane coating prepared in [Preparation Example 2-1] on the side of the aluminum-plated barrier layer 3 away from the first polyurethane coating 2, and after drying, forming a second polyurethane coating 4 on the aluminum-plated barrier layer 3;

[0113] S4. The organosilicon-modified low-density polyethylene obtained in [Preparation Example 3-2] is melted and blow-molded to obtain a heat-sealing layer 5, and the heat-sealing layer 5 is compounded on the side of the second polyurethane coating 4 away from the aluminized barrier layer 3 to obtain a high-barrier and cooking-resistant aluminized film.

[0114] [Example 3]

[0115] A high-barrier, cooking-resistant aluminum-plated film, which differs from [Example 1] in that: the thickness of the first polyurethane coating 2 is 1 μm, and the thickness of the second polyurethane coating 4 is 1 μm.

[0116] [Example 4]

[0117] A high-barrier, cooking-resistant aluminum-plated film, which differs from [Example 3] in that the modified polyurethane coating used in steps S1 and S3 is the modified polyurethane coating prepared in [Preparation Example 2-2].

[0118] [Example 5]

[0119] A high barrier and cooking resistant aluminum-plated film, which differs from [Example 3] in that: the modified polyurethane coating in steps S1 and S3 is the modified polyurethane coating prepared in [Preparation Example 2-3].

[0120] Comparative Example

[0121] [Comparative Example 1]

[0122] An aluminum-plated film, which differs from [Example 1] in that: the heat-resistant modified high-density polyethylene in step S1 is replaced by the heat-resistant modified high-density polyethylene prepared in [Preparation Example 1-3].

[0123] [Comparative Example 2]

[0124] An aluminum-plated film, which differs from [Example 1] in that: the heat-resistant modified high-density polyethylene in step S1 is replaced by the heat-resistant modified high-density polyethylene prepared in [Preparation Example 1-4].

[0125] [Comparative Example 3]

[0126] An aluminum-plated film, which differs from [Example 1] in that the modified polyurethane coating in steps S1 and S3 is replaced by the organosilicon-modified polyurethane coating prepared in [Preparation Example 2-1].

[0127] [Comparative Example 4]

[0128] An aluminum-plated film, which differs from [Example 1] in that the modified polyurethane coating in steps S1 and S3 is replaced by a water-based epoxy resin coating.

[0129] [Comparative Example 5]

[0130] An aluminum-plated film, which differs from [Example 1] in that the organosilicon-modified low-density polyethylene in step S4 is replaced by low-density polyethylene.

[0131] Performance testing

[0132] (1) Oxygen permeation test: According to GB / T 1038.1-2022 "Plastic film and sheet gas permeability test method Part 1: Differential pressure method", the oxygen permeation of the packaging film in each embodiment and comparative example was tested at 145°C for different times. The smaller the oxygen permeation, the better the oxygen barrier performance. Note: After the aluminum-coated film is delaminated, the delamination is noted, and the water vapor permeation test is not performed after delamination.

[0133] (2) Water vapor transmission rate test: According to GB / T 26253-2010 "Determination of water vapor transmission rate of plastic films and sheets - infrared detector method", the water vapor transmission rate of the packaging films in each embodiment and comparative example after being steamed at 145°C for different time periods was tested. The smaller the water vapor transmission rate, the better the water vapor barrier performance. Note: If the aluminum-coated film is delaminated, the delamination is noted, and the water vapor transmission rate test is not performed after delamination.

[0134] Table 1

[0135]

[0136] Table 2

[0137]

[0138] By comparing Example 1 with Comparative Examples 1-2, it can be seen that Comparative Example 1 uses double-terminal acrylate silicone oil alone to modify high-density polyethylene to prepare base film layer 1, Comparative Example 2 uses p-vinylbenzylamine alone to modify high-density polyethylene to prepare base film layer 1, and Example 1 uses double-terminal acrylate silicone oil and p-vinylbenzylamine to modify high-density polyethylene to prepare base film layer 1. Combined with the data in Table 1-2, it can be seen that after the aluminized film in Comparative Example 1 was steamed at 145°C for 30 minutes, the aluminized film was delaminated. The reason is that the bonding strength between the base film layer 1 and the first polyurethane coating 2 is poor, that is, the aluminized film in Comparative Example 1 cannot be steamed at high temperature for a long time. No obvious delamination was found in the aluminized film in Comparative Example 2 after high-temperature steaming at 145°C for 60 minutes, but the oxygen barrier and water vapor barrier of the aluminized film in Comparative Example 2 are significantly lower than those of the aluminized film in Example 1. The aluminized film in Example 1 can be cooked in a high temperature environment of 145°C for 60 minutes without delamination, and the aluminized film after high temperature cooking still has excellent oxygen barrier and water vapor barrier properties. It can be seen that the modification of high-density polyethylene with double-terminal acrylate silicone oil and p-vinylbenzylamine can obtain an aluminized film with both high temperature cooking resistance and high barrier properties.

[0139] Comparing Example 1 with Comparative Examples 3-4, it can be seen that: Comparative Example 3 uses only silicone modified polyurethane coating to prepare the first polyurethane coating 2 and the second polyurethane coating 4, and Comparative Example 4 uses only water-based epoxy resin coating to prepare the first polyurethane coating 2 and the second polyurethane coating 4, while Example 1 uses a composition of silicone modified polyurethane coating and water-based epoxy resin coating in a specific ratio to prepare the first polyurethane coating 2 and the second polyurethane coating 4. Combined with the data in Table 1-2, it can be seen that after the aluminum-plated films in Comparative Examples 3 and 4 were steamed at 145°C for 30 minutes, the aluminum-plated films were delaminated, because the bonding strength between the base film layer 1 and the first polyurethane coating 2, and between the heat-sealing layer 5 and the second polyurethane coating 4 was poor. That is, using a composition of silicone modified polyurethane coating and water-based epoxy resin coating in a specific ratio to prepare the first polyurethane coating 2 and the second polyurethane coating 4 is conducive to obtaining an aluminum-plated film with both high temperature steaming resistance and high barrier properties.

[0140] Comparison of Example 1 and Comparative Example 5 shows that: Comparative Example 5 directly uses low-density polyethylene to prepare the heat-sealing layer 5, while Example 1 uses organosilicon-modified low-density polyethylene obtained by modifying low-density polyethylene with end-vinyl and end-hydroxyl silicone oil to prepare the heat-sealing layer 5. Combined with the data in Table 1-2, it can be seen that after the aluminum-plated film in Comparative Example 5 was steamed at 145°C for 30 minutes, the aluminum-plated film was delaminated, because the bonding strength between the heat-sealing layer 5 and the second polyurethane coating 4 was poor. Therefore, using organosilicon-modified low-density polyethylene obtained by modifying low-density polyethylene with end-vinyl and end-hydroxyl silicone oil to prepare the heat-sealing layer 5 is conducive to obtaining an aluminum-plated film with both high-temperature steaming resistance and high barrier properties.

[0141] By comparing Example 1 and Examples 3-5, it can be seen that the difference between Example 1 and Example 3 is that the thickness of the first polyurethane coating 2 and the second polyurethane coating 4 are different, and the thickness of the first polyurethane coating 2 and the second polyurethane coating 4 in Example 3 is small. The difference between Examples 3-5 is that the organosilicon-modified polyurethane coating used in the modified polyurethane coating is different. Among them, the organosilicon-modified polyurethane coating in Example 3 is made of isocyanate-terminated polyurethane prepolymer, alcohol hydroxyl-terminated silicone oil and ethylenediamine, the organosilicon-modified polyurethane coating in Example 4 is made of isocyanate-terminated polyurethane prepolymer, silicone hydroxyl-terminated silicone oil and 3.3'-dimethyl-4.4'diaminodiphenylmethane, and the organosilicon-modified polyurethane coating in Example 5 is made of isocyanate-terminated polyurethane prepolymer, alcohol hydroxyl-terminated silicone oil and 3.3'-dimethyl-4.4'diaminodiphenylmethane. Combined with the data in Table 1-2, it can be seen that the aluminum-plated film in Example 5 can maintain high temperature cooking resistance and high barrier properties while having a thinner overall thickness.

[0142] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high barrier and boiling resistant aluminum-plated film, characterized in that: It comprises a base film layer (1), a first polyurethane coating (2), an aluminum-plated barrier layer (3), a second polyurethane coating (4) and a heat-sealing layer (5); The base film layer (1) is made of heat-resistant modified high-density polyethylene obtained by cross-linking high-density polyethylene, p-vinylbenzylamine, and double-terminal acrylic ester silicone oil; The first polyurethane coating (2) and the second polyurethane coating (4) are both made of modified polyurethane coatings, wherein the modified polyurethane coatings include organosilicon-modified polyurethane coatings and waterborne epoxy resin coatings, and the weight ratio of the organosilicon-modified polyurethane coatings to the waterborne epoxy resin coatings is (3-4):1; The heat seal layer (5) is made of low-density polyethylene and organosilicon-modified low-density polyethylene obtained by cross-linking vinyl-terminated hydroxyl-terminated silicone oil; The preparation method of the heat-resistant modified high-density polyethylene comprises the following steps: The first premix is ​​obtained by uniformly mixing high-density polyethylene, p-vinylbenzylamine, double-terminal acrylate silicone oil and a first initiator; the weight ratio of the high-density polyethylene, p-vinylbenzylamine and double-terminal acrylate silicone oil is 100: (8.8-10.4): (4.6-6.3); Performing radiation cross-linking on the premix to obtain a first radiation cross-linked product; Melting and extruding the first radiation cross-linked product, and then pelletizing it to obtain heat-resistant modified high-density polyethylene; The preparation method of the organosilicon-modified low-density polyethylene comprises the following steps: The second premix is ​​obtained by uniformly mixing low-density polyethylene, vinyl-terminated hydroxyl-terminated silicone oil and a second initiator; the weight ratio of the low-density polyethylene to the vinyl-terminated hydroxyl-terminated silicone oil is 100: (6.5-8.5); performing radiation cross-linking on the second premix to obtain a second radiation cross-linked product; Melting and extruding the second radiation cross-linked product, and then pelletizing it to obtain organosilicon-modified low-density polyethylene; In terms of raw materials, the silicone-modified polyurethane coating comprises an isocyanate-terminated polyurethane prepolymer, an alcohol hydroxyl-terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane in a weight ratio of 100:(1.2-2.6):(2.5-4.2); the isocyanate-terminated polyurethane prepolymer is obtained by reacting a polymerized diol with a diisocyanate in a molar ratio of 1:(1.3-1.6).

2. The high barrier and boiling resistant aluminum-plated film according to claim 1, characterized in that: The polymer diol is at least one of polytetramethylene glycol, polycarbonate glycol, polyoxypropylene glycol and polycaprolactone glycol.

3. The high barrier and boiling resistant aluminum-plated film according to claim 1, characterized in that: The preparation method of the organosilicon-modified polyurethane coating comprises the following steps: Heat the polymer diol to 45-55°C, then add diisocyanate and organotin catalyst. Raising the temperature to 80-85°C for prepolymerization to obtain an isocyanate-terminated polyurethane prepolymer; Add alcohol hydroxyl terminated silicone oil and 3.3'-dimethyl-4.4'-diaminodiphenylmethane to the isocyanate terminated polyurethane prepolymer, maintain the temperature at 80-85°C for chain extension reaction, and obtain an organosilicon modified polyurethane coating.

4. The method for preparing a high barrier and boiling resistant aluminum-plated film according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, melting the heat-resistant modified high-density polyethylene, casting it into a sheet, and longitudinally stretching it to obtain the base film layer (1), coating one side of the base film layer (1) with the modified polyurethane coating, and drying it to form the first polyurethane coating (2) on the base film layer (1); S2, send the film material obtained in S1 into the vacuum aluminum plating equipment, heat the aluminum wire, and make the gaseous aluminum deposit on The aluminum-plated barrier layer (3) is formed on the first polyurethane coating (2); S3, coating the modified polyurethane coating on the side of the aluminum-plated barrier layer (3) facing away from the first polyurethane coating (2), and after drying, forming the second polyurethane coating (4) on the aluminum-plated barrier layer (3); S4, melting and blow-molding the organosilicon-modified low-density polyethylene to obtain the heat-sealing layer (5), and compounding the heat-sealing layer (5) on the side of the second polyurethane coating (4) away from the aluminized barrier layer (3) to obtain a high-barrier and cooking-resistant aluminized film.

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