High-strength high-barrier pe composite packaging film and preparation method thereof

Abstract

The application relates to the technical field of plastic film, in particular to a high-strength high-barrier PE composite packaging film and a preparation method thereof. The application obtains flame-retardant modified glass fiber by adding piperazine, 3-chloropropyl triethoxysilane, pretreated glass fiber, methyl phosphonic acid, modified glass fiber and pentaerythritol phosphate. The flame-retardant modified glass fiber is sequentially immersed in alpha-zirconium phosphate dispersion liquid, chitosan dispersion liquid, phytic acid dispersion liquid, chitosan dispersion liquid and phytic acid dispersion liquid to obtain flame-retardant reinforcing fiber. The flame-retardant reinforcing fiber and polyethylene resin are mixed, extruded and granulated to obtain high-performance polyethylene resin; and then the high-performance polyethylene resin, polypropylene resin, adhesive and ethylene-vinyl alcohol copolymer are sequentially prepared, blown into films, cut, and packaged to obtain the PE composite packaging film. The PE composite packaging film prepared by the application has excellent strength, flame retardance and barrier property, and therefore has a wide application prospect in the technical field of plastic film.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plastic film, in particular to a high-strength high-barrier PE composite packaging film and a preparation method thereof. BACKGROUND

[0002] In the modern packaging field, PE (polyethylene) composite packaging film has shown multi-dimensional important value due to its unique performance and wide application. On the one hand, the raw material cost of PE composite packaging film is relatively low, and the production process is relatively mature. Large-scale production can effectively reduce the unit cost. This makes it have a very high cost performance in the packaging market. Whether it is food, daily necessities or industrial product packaging, it can realize the packaging function at a lower cost, saving a lot of packaging expenses for enterprises and improving economic benefits. On the other hand, its good processing performance makes it can be printed, compounded and other secondary processing in various ways to meet the individualized packaging needs of different products, further expanding the market space and driving the development of related industries.

[0003] However, on the packaging production line, the packaging film will usually receive certain external forces such as stretching, extrusion and friction, so as to appear rupture or tearing and other phenomena. Therefore, in order to ensure the smooth progress of the packaging work, it is usually necessary to mechanically enhance the packaging film. In addition, in some special storage environment or transportation scene, there is a fire hazard, and the PE composite packaging film with flame retardant performance can slow down the burning speed when encountering a fire source, or even self-extinguish, thereby reducing the possibility of fire occurrence and the speed of fire spread, providing protection for personnel and property safety. Furthermore, PE composite packaging film is usually used for food packaging, pharmaceutical packaging, so it needs to improve its barrier performance to effectively block the invasion of oxygen, water vapor, odor and other substances.

[0004] In order to overcome the defects of the prior art, the present application provides a high-strength high-barrier PE composite packaging film and a preparation method thereof. SUMMARY

[0005] The purpose of the present application is to provide a high-strength high-barrier PE composite packaging film and a preparation method thereof to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A preparation method of a high-strength high-barrier PE composite packaging film, comprising the following steps:

[0008] Step one: under the nitrogen environment, piperazine is added to toluene, stirred at 105-110℃ until dissolved, then 3-chloropropyl triethoxysilane is added dropwise, after the dropwise addition is completed, the temperature is raised to 110-115℃ and refluxed for 5-6h, after the reaction is completed, it is cooled, filtered, washed, and rotary evaporated to remove the solvent to obtain piperazine siloxane; ethanol and deionized water are mixed uniformly, then sodium hydroxide aqueous solution is added to adjust the solution pH to 10-11, then piperazine siloxane and pretreated glass fiber are added, and stirred at 60-70℃ for 4-5h, after the reaction is completed, it is filtered, washed, and dried to obtain modified glass fiber;

[0009] Methyl phosphonic acid solution is added dropwise to the modified glass fiber solution, stirred for 1.5-2.0h, then the temperature is raised to 85-90℃ and continues to stir for 4-5h, then pentaerythritol phosphate solution is added dropwise and continues to stir for 15-18h, after the reaction is completed, it is rotary evaporated, filtered, washed, and dried to obtain flame-retardant modified glass fiber;

[0010] Step two: the flame-retardant modified glass fiber is sequentially immersed in α-zirconium phosphate dispersion, chitosan dispersion, phytic acid dispersion, chitosan dispersion, and phytic acid dispersion for 10-15min, and is dried for 3-5min after each immersion to obtain flame-retardant reinforcing fiber;

[0011] Step three: the flame-retardant reinforcing fiber and polyethylene resin are mixed and mixed at 180-200℃ for 15-20min, then extruded and granulated to obtain high-performance polyethylene resin; the high-performance polyethylene resin, polypropylene resin, adhesive, and ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film.

[0012] More preferably, in step one, the preparation process of the pretreated glass fiber is: the glass fiber is ultrasonically washed with water for 10-15min, then immersed in 10-15wt% hydrochloric acid solution for 1.5-2.0h, and after the pretreatment is completed, it is washed with water, centrifuged, and dried to obtain the pretreated glass fiber.

[0013] More preferably, in step one, the molar ratio of piperazine to 3-chloropropyl triethoxysilane is (1.0-1.1):1; the mass ratio of piperazine siloxane to pretreated glass fiber is (1-2):1.

[0014] More preferably, in step one, methyl phosphonic acid is dissolved in N,N-dimethylformamide to obtain methyl phosphonic acid solution; the modified glass fiber is dispersed in N,N-dimethylformamide to obtain modified glass fiber solution; pentaerythritol phosphate is dissolved in N,N-dimethylformamide to obtain pentaerythritol phosphate solution; the mass ratio of methyl phosphonic acid, modified glass fiber, and pentaerythritol phosphate is (1.0-1.2):6:(1.7-2.0).

[0015] More preferably, in step two, zirconium alpha-phosphate is added to deionized water, stirred until uniform, and then the pH is adjusted to 7.0-7.5 to obtain a 2-3 wt% zirconium alpha-phosphate dispersion; chitosan is added to a 1.0-1.5 wt% acetic acid solution, stirred until uniform, and then a 2-3 wt% chitosan dispersion is obtained; phytic acid is added to deionized water, stirred until uniform, and then the pH is adjusted to 4.0-4.5 to obtain a 2-3 wt% phytic acid dispersion.

[0016] More preferably, in step three, the mass ratio of the flame-retardant reinforcing fiber and the polyethylene resin is (1.5-1.8):5.

[0017] More preferably, in step three, the PE composite packaging film has a layer structure from bottom to top: a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a high-performance polyethylene-polypropylene resin layer.

[0018] More preferably, the PE composite packaging film comprises 45.25% high-performance polyethylene-polypropylene resin, 3% adhesive, 3.5% ethylene-vinyl alcohol copolymer, 3% adhesive, and 45.25% high-performance polyethylene-polypropylene resin; wherein the high-performance polyethylene-polypropylene resin comprises 85% high-performance polyethylene resin and 15% polypropylene resin.

[0019] More preferably, in step three, the film blowing process has the following parameters: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 260-270℃, and the linear speed is 100-110 m / min; the die head temperature of the adhesive layer is 240-250℃, and the linear speed is 45-50 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 230-240℃, and the linear speed is 45-50 m / min.

[0020] The beneficial effects of the present application are as follows:

[0021] The present application is characterized in that, in step one, piperazine, 3-chloropropyl triethoxysilane, and pretreated glass fibers are added to obtain a modified glass fiber. This step uses a silane coupling agent to modify the pretreated glass fiber, effectively improving the dispersibility of the glass fiber, and introducing a piperazine structure on the surface of the glass fiber. Furthermore, methyl phosphonic acid and the piperazine structure on the surface of the modified glass fiber undergo acid-base neutralization reaction, and then pentaerythritol phosphate is added to continue the esterification reaction of the methyl phosphonic acid, thereby preparing a flame-retardant modified glass fiber.

[0022] On the one hand, both methyl phosphonic acid and pentaerythritol phosphate contain phosphorus elements, and phosphorus-based flame retardants have multiple flame-retardant mechanisms during the combustion process. In the initial stage of combustion, phosphorus-based compounds decompose under heat to generate phosphoric acid, metaphosphoric acid, and the like, and these acidic substances can promote the dehydration and carbonization of organic polymers to form a dense carbon layer. The carbon layer can isolate the transmission of oxygen and heat, preventing further combustion. In addition, glass fibers can play a role in supporting the framework in the flame-retardant system, preventing the expanded carbon layer from collapsing during the combustion process, maintaining the integrity and stability of the carbon layer, and further improving the flame-retardant performance of the material. On the other hand, glass fibers themselves have good mechanical strength, and the chemical bonds and new chemical structures formed during subsequent modification can further improve the interaction between glass fibers, promoting better dispersion of glass fibers in the matrix and forming a more uniform fiber network structure. When the material is subjected to external forces, individual fibers can work together to bear the load, thereby improving the overall strength and toughness of the material.

[0023] The application is characterized in that, in step two, the flame-retardant modified glass fibers are sequentially immersed in an alpha-zirconium phosphate dispersion, a chitosan dispersion, a phytic acid dispersion, a chitosan dispersion, and a phytic acid dispersion to obtain flame-retardant reinforcing fibers. The alpha-zirconium phosphate dispersion has negative charge characteristics, the chitosan dispersion has positive charge characteristics, and the phytic acid dispersion has negative charge characteristics. Therefore, after the flame-retardant modified glass fibers are sequentially immersed in the above dispersions in a certain order, they are combined with each other through electrostatic attraction, forming a stable multi-layer alternating flame-retardant structure. This stable structure is not easily damaged during combustion and can continuously exert a flame-retardant effect. Each layer can act as an independent barrier to block the transmission of heat, oxygen, and combustible gases. When the fibers encounter a fire source, the multi-layer structure can gradually exert its effect, effectively delaying the combustion process.

[0024] The application is characterized in that, in step three, the flame-retardant reinforcing fibers and polyethylene resin are mixed, extruded and granulated to obtain high-performance polyethylene resin; and the high-performance polyethylene resin, polypropylene resin, adhesive, and ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film. The PE composite packaging film includes high-performance polyethylene resin with excellent strength and flame retardancy, and ethylene-vinyl alcohol copolymer with excellent barrier properties, thus having a broad application prospect in the field of plastic film technology. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0026] Raw material sources:

[0027] Glass fiber, particle size 5 μm; α-zirconium phosphate, provided by Wuhan Lanya Bai Medicine Chemical Co., Ltd., model α; chitosan, provided by Hebei Chuangzhanyuan Biological Technology Co., Ltd., effective ingredient content 99%; adhesive, provided by Japan Mitsui, brand NF528H; ethylene-vinyl alcohol copolymer, provided by Japan Kolice, brand F104B; polyethylene resin, provided by Exxon Mobil, brand 2018MA; polypropylene resin, provided by Letian Chemical, brand PP510M.

[0028] Example 1: Step one: the glass fiber was ultrasonically washed for 15 min, then immersed in a 13wt% hydrochloric acid solution for pretreatment for 2.0 h, and after pretreatment, it was washed with water, centrifuged, and dried to obtain pretreated glass fiber;

[0029] Under a nitrogen environment, piperazine was added to toluene and stirred at 110°C until dissolved, then 3-chloropropyl triethoxysilane was added dropwise, and after the addition was completed, the temperature was raised to 115°C and refluxed for 6 h. After the reaction was completed, it was cooled, filtered, washed, and rotary evaporated to remove the solvent to obtain piperazine siloxane. Ethanol and deionized water were mixed uniformly, then sodium hydroxide aqueous solution was added to adjust the solution pH to 11, then piperazine siloxane and pretreated glass fiber were added, and stirred at 70°C for 5 h. After the reaction was completed, it was suction filtered, washed, and dried to obtain modified glass fiber. The reaction molar ratio of piperazine to 3-chloropropyl triethoxysilane was 1.1:1. The reaction mass ratio of piperazine siloxane to pretreated glass fiber was 1.5:1.

[0030] Methyl phosphonic acid was dissolved in N,N-dimethylformamide to obtain a methyl phosphonic acid solution. Modified glass fiber was dispersed in N,N-dimethylformamide to obtain a modified glass fiber solution. Pentaerythritol phosphate was dissolved in N,N-dimethylformamide to obtain a pentaerythritol phosphate solution. The methyl phosphonic acid solution was added dropwise to the modified glass fiber solution, stirred for 2.0 h, then the temperature was raised to 90°C and stirring was continued for 5 h. Then the pentaerythritol phosphate solution was added dropwise and stirring was continued for 18 h. After the reaction was completed, it was rotary evaporated, suction filtered, washed, and dried to obtain flame-retardant modified glass fiber. The reaction mass ratio of methyl phosphonic acid, modified glass fiber, and pentaerythritol phosphate was 1.1:6:1.8.

[0031] Step two: α-zirconium phosphate was added to deionized water, stirred uniformly, and then the pH was adjusted to 7.5 to obtain a 2.5wt% α-zirconium phosphate dispersion. Chitosan was added to a 1.3wt% acetic acid solution, stirred uniformly, and then a 2.5wt% chitosan dispersion was obtained. Phytic acid was added to deionized water, stirred uniformly, and then the pH was adjusted to 4.5 to obtain a 2.5wt% phytic acid dispersion.

[0032] The flame-retardant modified glass fiber is sequentially immersed in the alpha-zirconium phosphate dispersion solution, the chitosan dispersion solution, the phytic acid dispersion solution, the chitosan dispersion solution, and the phytic acid dispersion solution for 15 min, and is dried for 5 min after each immersion, to obtain the flame-retardant reinforcing fiber;

[0033] Step three: the flame-retardant reinforcing fiber and the polyethylene resin are mixed, and are mixed and kneaded at 200℃ for 20 min, and are then extruded and granulated to obtain the high-performance polyethylene resin; the reaction mass ratio of the flame-retardant reinforcing fiber and the polyethylene resin is 1.6:5;

[0034] The high-performance polyethylene resin, the polypropylene resin, the adhesive, and the ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film; the PE composite packaging film has a film layer structure from bottom to top, which is a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a high-performance polyethylene-polypropylene resin layer; the PE composite packaging film comprises 45.25% of the high-performance polyethylene-polypropylene resin, 3% of the adhesive, 3.5% of the ethylene-vinyl alcohol copolymer, 3% of the adhesive, and 45.25% of the high-performance polyethylene-polypropylene resin; the high-performance polyethylene-polypropylene resin comprises 85% of the high-performance polyethylene resin and 15% of the polypropylene resin;

[0035] The film blowing process is as follows: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 270℃, and the linear speed is 110 m / min; the die head temperature of the adhesive layer is 250℃, and the linear speed is 50 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 240℃, and the linear speed is 50 m / min.

[0036] Example 2: Step one: the glass fiber is ultrasonically washed for 13 min, and then is immersed in a 13wt% hydrochloric acid solution for pretreatment for 1.7 h; after the pretreatment, the glass fiber is washed with water, centrifuged, and dried to obtain pretreated glass fiber;

[0037] Under a nitrogen environment, piperazine is added to toluene, stirred at 107℃ until dissolved, and then 3-chloropropyl triethoxysilane is added dropwise; after the dropwise addition is completed, the temperature is increased to 112℃ for reflux reaction for 5.5 h; after the reaction is completed, the solution is cooled, filtered, washed, and rotary evaporated to remove the solvent to obtain piperazine siloxane; ethanol and deionized water are mixed uniformly, and then a sodium hydroxide aqueous solution is added to adjust the pH of the solution to 10.5; then piperazine siloxane and pretreated glass fiber are added, and stirred at 65℃ for 4.5 h; after the reaction is completed, the mixture is filtered, washed, and dried to obtain modified glass fiber; the reaction molar ratio of piperazine and 3-chloropropyl triethoxysilane is 1.1:1; the reaction mass ratio of piperazine siloxane and pretreated glass fiber is 1.5:1;

[0038] The methylphosphonic acid is dissolved in N,N-dimethylformamide to obtain a methylphosphonic acid solution; the modified glass fiber is dispersed in N,N-dimethylformamide to obtain a modified glass fiber solution; the pentaerythritol phosphate is dissolved in N,N-dimethylformamide to obtain a pentaerythritol phosphate solution; the methylphosphonic acid solution is added dropwise into the modified glass fiber solution, and stirred for 1.7 hours, then the temperature is increased to 87 DEG C and the stirring is continued for 4.5 hours, then the pentaerythritol phosphate solution is added dropwise and the stirring is continued for 17 hours, after the reaction is completed, the rotary evaporation, suction filtration, washing and drying are performed to obtain the flame-retardant modified glass fiber; wherein the reaction mass ratio of the methylphosphonic acid, the modified glass fiber and the pentaerythritol phosphate is 1.1:6:1.8;

[0039] Step two: the alpha-zirconium phosphate is added into deionized water, and after stirring uniformly, the pH is adjusted to 7.3 to obtain a 2.5wt% alpha-zirconium phosphate dispersion; the chitosan is added into a 1.3wt% acetic acid solution, and after stirring uniformly, a 2.5wt% chitosan dispersion is obtained; the phytic acid is added into deionized water, and after stirring uniformly, the pH is adjusted to 4.2 to obtain a 2.5wt% phytic acid dispersion;

[0040] The flame-retardant modified glass fiber is sequentially immersed in the alpha-zirconium phosphate dispersion, the chitosan dispersion, the phytic acid dispersion, the chitosan dispersion and the phytic acid dispersion for 13 minutes, and after each immersion, it is dried for 4 minutes to obtain the flame-retardant reinforcing fiber;

[0041] Step three: the flame-retardant reinforcing fiber and the polyethylene resin are mixed, and the mixing is performed at 190 DEG C for 17 minutes, and then the extrusion granulation is performed to obtain the high-performance polyethylene resin; the reaction mass ratio of the flame-retardant reinforcing fiber and the polyethylene resin is 1.6:5;

[0042] The high-performance polyethylene resin, the polypropylene resin, the adhesive and the ethylene-vinyl alcohol copolymer are sequentially prepared into a PE composite packaging film through batching, film blowing, slitting and packaging; the PE composite packaging film comprises, from bottom to top, a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer and a high-performance polyethylene-polypropylene resin layer; the PE composite packaging film comprises 45.25% high-performance polyethylene-polypropylene resin, 3% adhesive, 3.5% ethylene-vinyl alcohol copolymer, 3% adhesive and 45.25% high-performance polyethylene-polypropylene resin; wherein the high-performance polyethylene-polypropylene resin comprises 85% high-performance polyethylene resin and 15% polypropylene resin;

[0043] The film blowing process is as follows: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 265 DEG C, and the linear speed is 105 m / min; the die head temperature of the adhesive layer is 245 DEG C, and the linear speed is 47 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 235 DEG C, and the linear speed is 47 m / min.

[0044] Example 3: Step one: ultrasonic washing of glass fiber for 10 min, then immerse in 13wt% hydrochloric acid solution for 1.5h pretreatment, after pretreatment, washed, centrifuged, dried, and then pretreated glass fiber was obtained;

[0045] Under the nitrogen environment, piperazine was added to toluene, stirred at 105℃ until dissolved, then 3-chloropropyl triethoxysilane was added dropwise, after the end of dropwise addition, the temperature was raised to 110℃ and refluxed for 5h, after the reaction was completed, it was cooled, filtered, washed, and the solvent was removed by rotary evaporation to obtain piperazine siloxane; ethanol and deionized water were mixed uniformly, then sodium hydroxide aqueous solution was added to adjust the solution pH to 10, then piperazine siloxane and pretreated glass fiber were added, and stirred at 60℃ for 4h, after the reaction was completed, it was filtered, washed, and dried to obtain modified glass fiber; the reaction molar ratio of piperazine and 3-chloropropyl triethoxysilane was 1.1:1; the reaction mass ratio of piperazine siloxane and pretreated glass fiber was 1.5:1;

[0046] Methyl phosphonic acid was dissolved in N,N-dimethylformamide to obtain a methyl phosphonic acid solution; the modified glass fiber was dispersed in N,N-dimethylformamide to obtain a modified glass fiber solution; pentaerythritol phosphate was dissolved in N,N-dimethylformamide to obtain a pentaerythritol phosphate solution; the methyl phosphonic acid solution was added dropwise to the modified glass fiber solution, stirred for 1.5h, then the temperature was raised to 85℃ and continued to stir for 4h, then the pentaerythritol phosphate solution was added dropwise and continued to stir for 15h, after the reaction was completed, it was rotary evaporated, filtered, washed, and dried to obtain flame-retardant modified glass fiber; the reaction mass ratio of methyl phosphonic acid, modified glass fiber, and pentaerythritol phosphate was 1.1:6:1.8;

[0047] Step two: zirconium alpha-phosphate was added to deionized water, stirred uniformly, and then the pH was adjusted to 7.0 to obtain a 2.5wt% zirconium alpha-phosphate dispersion; chitosan was added to a 1.3wt% acetic acid solution, stirred uniformly, and then a 2.5wt% chitosan dispersion was obtained; phytic acid was added to deionized water, stirred uniformly, and then the pH was adjusted to 4.0 to obtain a 2.5wt% phytic acid dispersion;

[0048] The flame-retardant modified glass fiber was sequentially immersed in the zirconium alpha-phosphate dispersion, chitosan dispersion, phytic acid dispersion, chitosan dispersion, and phytic acid dispersion for 10 min, and was dried for 3 min after each immersion to obtain a flame-retardant reinforcing fiber;

[0049] Step three: the flame-retardant reinforcing fiber and polyethylene resin were mixed, and then mixed at 180℃ for 15 min, and then extruded and granulated to obtain a high-performance polyethylene resin; the reaction mass ratio of the flame-retardant reinforcing fiber and the polyethylene resin was 1.6:5;

[0050] A high-performance polyethylene resin, a polypropylene resin, an adhesive, and an ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film; the PE composite packaging film has a film layer structure from bottom to top of a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a high-performance polyethylene-polypropylene resin layer; the PE composite packaging film comprises 45.25% of the high-performance polyethylene-polypropylene resin, 3% of the adhesive, 3.5% of the ethylene-vinyl alcohol copolymer, 3% of the adhesive, and 45.25% of the high-performance polyethylene-polypropylene resin; the high-performance polyethylene-polypropylene resin comprises 85% of a high-performance polyethylene resin and 15% of a polypropylene resin;

[0051] The film blowing process is as follows: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 260℃, and the linear speed is 100 m / min; the die head temperature of the adhesive layer is 240℃, and the linear speed is 45 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 230℃, and the linear speed is 45 m / min.

[0052] Comparative Example 1: Step two is removed, and the remaining steps are the same as those in Example 1, and the specific steps are as follows: Step one: the glass fibers are ultrasonically washed for 15 min, then immersed in a 13wt% hydrochloric acid solution for pretreatment for 2.0 h, and after the pretreatment, the glass fibers are washed with water, centrifuged, and dried to obtain pretreated glass fibers;

[0053] Under a nitrogen atmosphere, piperazine is added to toluene and stirred at 110℃ until dissolved, then 3-chloropropyl triethoxysilane is added dropwise, and after the addition is completed, the temperature is raised to 115℃ for reflux reaction for 6 h. After the reaction is completed, the solution is cooled, filtered, washed, and rotary evaporated to remove the solvent to obtain piperazine siloxane. Ethanol and deionized water are mixed uniformly, then a sodium hydroxide aqueous solution is added to adjust the pH of the solution to 11, then piperazine siloxane and pretreated glass fibers are added, and the mixture is stirred at 70℃ for 5 h. After the reaction is completed, the mixture is suction filtered, washed, and dried to obtain modified glass fibers. The reaction molar ratio of piperazine to 3-chloropropyl triethoxysilane is 1.1:1, and the reaction mass ratio of piperazine siloxane to pretreated glass fibers is 1.5:1.

[0054] The methylphosphonic acid is dissolved in N,N-dimethylformamide to obtain a methylphosphonic acid solution; the modified glass fiber is dispersed in N,N-dimethylformamide to obtain a modified glass fiber solution; the pentaerythritol phosphate is dissolved in N,N-dimethylformamide to obtain a pentaerythritol phosphate solution; the methylphosphonic acid solution is added dropwise into the modified glass fiber solution, stirring and reacting for 2.0 h, then the temperature is increased to 90℃ and the reaction is continued for 5 h, then the pentaerythritol phosphate solution is added dropwise and the reaction is continued for 18 h, after the reaction is completed, rotary evaporation, suction filtration, washing and drying are performed to obtain the flame-retardant modified glass fiber; wherein the reaction mass ratio of the methylphosphonic acid, the modified glass fiber and the pentaerythritol phosphate is 1.1:6:1.8;

[0055] Step two: the flame-retardant modified glass fiber and the polyethylene resin are mixed and mixed at 200℃ for 20 min, and then extruded and granulated to obtain the high-performance polyethylene resin; the reaction mass ratio of the flame-retardant modified glass fiber and the polyethylene resin is 1.6:5;

[0056] The high-performance polyethylene resin, the polypropylene resin, the adhesive and the ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut and packaged to obtain a PE composite packaging film; the PE composite packaging film has a film layer structure from bottom to top, which is a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a high-performance polyethylene-polypropylene resin layer; the PE composite packaging film comprises 45.25% of the high-performance polyethylene-polypropylene resin, 3% of the adhesive, 3.5% of the ethylene-vinyl alcohol copolymer, 3% of the adhesive and 45.25% of the high-performance polyethylene-polypropylene resin; wherein the high-performance polyethylene-polypropylene resin comprises 85% of the high-performance polyethylene resin and 15% of the polypropylene resin;

[0057] The film blowing process is as follows: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 270℃, and the linear speed is 110 m / min; the die head temperature of the adhesive layer is 250℃, and the linear speed is 50 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 240℃, and the linear speed is 50 m / min.

[0058] Comparative Example 2: steps one and two are removed, and the rest is the same as Example 1, and the specific steps are as follows: Step one: the glass fiber and the polyethylene resin are mixed and mixed at 200℃ for 20 min, and then extruded and granulated to obtain the high-performance polyethylene resin; the reaction mass ratio of the glass fiber and the polyethylene resin is 1.6:5;

[0059] The high-performance polyethylene resin, the polypropylene resin, the adhesive, and the ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film; the PE composite packaging film has a film layer structure from bottom to top, which is sequentially a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a high-performance polyethylene-polypropylene resin layer; the PE composite packaging film comprises 45.25% of the high-performance polyethylene-polypropylene resin, 3% of the adhesive, 3.5% of the ethylene-vinyl alcohol copolymer, 3% of the adhesive, and 45.25% of the high-performance polyethylene-polypropylene resin; and the high-performance polyethylene-polypropylene resin comprises 85% of the high-performance polyethylene resin and 15% of the polypropylene resin.

[0060] The film blowing process is as follows: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 270℃, and the linear speed is 110 m / min; the die head temperature of the adhesive layer is 250℃, and the linear speed is 50 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 240℃, and the linear speed is 50 m / min.

[0061] Comparative Example 3: The preparation of the flame-retardant reinforcing fiber is removed, and the remaining steps are the same as those in Example 1, and the specific steps are as follows: Step 1: The polyethylene resin, the polypropylene resin, the adhesive, and the ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film; the PE composite packaging film has a film layer structure from bottom to top, which is sequentially a polyethylene resin+polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a polyethylene resin+polypropylene resin layer; the PE composite packaging film comprises 45.25% of the polyethylene resin+polypropylene resin, 3% of the adhesive, 3.5% of the ethylene-vinyl alcohol copolymer, 3% of the adhesive, and 45.25% of the polyethylene resin+polypropylene resin; and the polyethylene resin+polypropylene resin comprises 85% of the polyethylene resin and 15% of the polypropylene resin.

[0062] The film blowing process is as follows: the die head temperature of the polyethylene resin+polypropylene resin layer is 270℃, and the linear speed is 110 m / min; the die head temperature of the adhesive layer is 250℃, and the linear speed is 50 m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 240℃, and the linear speed is 50 m / min.

[0063] Detection test:

[0064] Mechanical property test: The PE composite packaging film prepared in the application is cut into a test sample with a size of 170×20×0.5 mm, and the tensile strength is tested by a universal tensile testing machine, and the tensile rate is set to 20 mm / min.

[0065] Flame retardant performance test: according to GB / T 2406.2-2009 "Plastics - Determination of the burning behavior of plastics - Part 2: guidance on test methods", the PE composite packaging film prepared by the application is cut into a sample with a size of 120x50x0.5mm, and an oxygen index instrument is used to test and record the oxygen index value.

[0066] Barrier performance test: according to GB / T 1038-2000 "Plastics - Determination of the burning behavior of plastics - Part 2: guidance on test methods", the PE composite packaging film prepared by the application is used as a sample to test the oxygen transmission rate. The results are as follows:

[0067]

[0068] Conclusion: the amount of examples 1-3 remains unchanged, only the reaction parameters are modified. From the experimental data, the performance of the sample does not change significantly.

[0069] Comparative example 1: step two is removed, and the rest is the same as example 1. From the experimental data, compared with example 1, the tensile strength is reduced to 85.7MPa, and the oxygen index is reduced to 25.2%. The analysis reason is: step two modifies the glass fiber by adding piperazine, 3-chloropropyl triethoxysilane, methyl phosphonic acid, and pentaerythritol phosphate, etc. to obtain a flame-retardant modified glass fiber. Therefore, the flame-retardant modified glass fiber has good flame-retardant performance and mechanical strength, so after removing it, the tensile strength and oxygen index are reduced.

[0070] Comparative example 2: steps one and two are removed, and the rest is the same as example 1. From the experimental data, compared with example 1, the tensile strength is reduced to 83.3MPa, and the oxygen index is reduced to 21.3%. The analysis reason is: comparative example 2 further removes the multi-layer alternating flame-retardant structure based on comparative example 1, so the flame-retardant performance is further reduced, and the oxygen index is reduced to 21.3%.

[0071] Comparative example 3: the preparation of flame-retardant reinforcing fibers is removed, and the rest is the same as example 1. From the experimental data, compared with example 1, the tensile strength is reduced to 76.7MPa, and the oxygen index is reduced to 20.8%. The analysis reason is: comparative example 3 further removes the reinforcing glass fiber based on comparative example 2, so the mechanical properties of the sample decrease, and the tensile strength is reduced by 76.7MPa.

[0072] It is to be noted that, in the present text, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0073] Finally, it should be noted that the above-mentioned only constitutes preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications, equivalent substitutions, improvements and the like of the technical solutions described in the foregoing embodiments can still be made. Any modifications, equivalent substitutions, improvements and the like made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for preparing a high strength high barrier PE composite packaging film, characterized by: The method comprises the following steps: Step one: under the nitrogen environment, piperazine is added into toluene, stirred at 105-110℃ until dissolved, then 3-chloropropyl triethoxysilane is added dropwise, after the dropwise addition is completed, the temperature is increased to 110-115℃ and refluxed for 5-6h, after the reaction is completed, the solution is cooled, filtered, washed, and the solvent is removed by rotary evaporation to obtain piperazine siloxane; ethanol and deionized water are mixed uniformly, then sodium hydroxide aqueous solution is added to adjust the pH of the solution to 10-11, then piperazine siloxane and pretreated glass fiber are added, and the mixture is stirred and reacted at 60-70℃ for 4-5h, after the reaction is completed, the mixture is filtered, washed, and dried to obtain modified glass fiber; Methyl phosphonic acid solution is added dropwise into the modified glass fiber solution, and the mixture is stirred and reacted for 1.5-2.0h, then the temperature is increased to 85-90℃ and the mixture is continuously stirred and reacted for 4-5h, then pentaerythritol phosphate solution is added dropwise and the mixture is continuously stirred and reacted for 15-18h, after the reaction is completed, the mixture is rotary evaporated, filtered, washed, and dried to obtain flame-retardant modified glass fiber; Step two: the flame-retardant modified glass fiber is sequentially immersed in α-zirconium phosphate dispersion, chitosan dispersion, phytic acid dispersion, chitosan dispersion, and phytic acid dispersion for 10-15min, and is dried for 3-5min after each immersion to obtain flame-retardant reinforcing fiber; Step three: the flame-retardant reinforcing fiber and polyethylene resin are mixed, and the mixture is mixed at 180-200℃ for 15-20min, then is extruded and granulated to obtain high-performance polyethylene resin; the high-performance polyethylene resin, polypropylene resin, adhesive, and ethylene-vinyl alcohol copolymer are sequentially prepared, blown into a film, cut, and packaged to obtain a PE composite packaging film.

2. The preparation method of the high-strength high-barrier PE composite packaging film according to claim 1, characterized in that: In step one, the preparation process of the pretreated glass fiber is as follows: the glass fiber is ultrasonically washed with water for 10-15min, then is immersed in 10-15wt% hydrochloric acid solution for pretreatment for 1.5-2.0h, and after the pretreatment is completed, the glass fiber is washed with water, centrifuged, and dried to obtain the pretreated glass fiber.

3. The preparation method of the high-strength high-barrier PE composite packaging film according to claim 1, characterized in that: In step one, the molar ratio of piperazine to 3-chloropropyl triethoxysilane is (1.0-1.1):1; the mass ratio of piperazine siloxane to pretreated glass fiber is (1-2):

1.

4. The preparation method of the high-strength high-barrier PE composite packaging film according to claim 1, characterized in that: In step one, methyl phosphonic acid is dissolved in N,N-dimethylformamide to obtain methyl phosphonic acid solution; the modified glass fiber is dispersed in N,N-dimethylformamide to obtain modified glass fiber solution; and pentaerythritol phosphate is dissolved in N,N-dimethylformamide to obtain pentaerythritol phosphate solution; the mass ratio of methyl phosphonic acid, modified glass fiber, and pentaerythritol phosphate is (1.0-1.2):6:(1.7-2.0).

5. The method for preparing a high-strength, high-barrier PE composite packaging film according to claim 1, characterized in that: In step two, α-zirconium phosphate is added into deionized water, stirred uniformly, and then the pH is adjusted to 7.0-7.5 to obtain 2-3wt% α-zirconium phosphate dispersion; chitosan is added into 1.0-1.5wt% acetic acid solution, stirred uniformly, and then 2-3wt% chitosan dispersion is obtained; and phytic acid is added into deionized water, stirred uniformly, and then the pH is adjusted to 4.0-4.5 to obtain 2-3wt% phytic acid dispersion.

6. The method for preparing a high-strength, high-barrier PE composite packaging film according to claim 1, characterized in that: In step three, the mass ratio of the fire-retardant reinforcing fiber and the polyethylene resin is (1.5-1.8):

5.

7. The method for preparing a high-strength, high-barrier PE composite packaging film according to claim 1, characterized in that: In step three, the PE composite packaging film has a film layer structure from bottom to top: a high-performance polyethylene-polypropylene resin layer, an adhesive layer, an ethylene-vinyl alcohol copolymer layer, an adhesive layer, and a high-performance polyethylene-polypropylene resin layer.

8. The method for preparing a high-strength, high-barrier PE composite packaging film according to claim 7, characterized in that: The PE composite packaging film comprises 45.25% high-performance polyethylene-polypropylene resin, 3% adhesive, 3.5% ethylene-vinyl alcohol copolymer, 3% adhesive, and 45.25% high-performance polyethylene-polypropylene resin; wherein the high-performance polyethylene-polypropylene resin comprises 85% high-performance polyethylene resin and 15% polypropylene resin.

9. The method for preparing a high-strength, high-barrier PE composite packaging film according to claim 1, characterized in that: In step three, the film blowing process is as follows: the die head temperature of the high-performance polyethylene-polypropylene resin layer is 260-270℃, and the linear speed is 100-110m / min; the die head temperature of the adhesive layer is 240-250℃, and the linear speed is 45-50m / min; and the die head temperature of the ethylene-vinyl alcohol copolymer layer is 230-240℃, and the linear speed is 45-50m / min.

10. A high strength, high barrier PE composite packaging film, characterized in that, Prepared by the preparation method according to any one of claims 1-9. Prepared by the preparation method according to any one of claims 1-9.

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