Flame-retardant waterproof packaging film material and preparation method thereof

Abstract

The invention discloses a flame-retardant waterproof packaging film material and a preparation method thereof, and relates to the technical field of packaging materials. The packaging film material is prepared from the following components in parts by weight: 100 parts of polypropylene, 10 to 15 parts of modified expanded vermiculite, 0.5 part of dicumyl peroxide and 15 parts of maleic anhydride grafted polypropylene, the expanded vermiculite is modified by amino trimethylene phosphonic acid and vinyl-terminated polyethylene glycol. Amino trimethylene phosphonic acid is complexed with magnesium and aluminum ions between expanded vermiculite layers by virtue of phosphonic acid groups, and flame-retardant elements phosphorus and nitrogen are introduced into the surface of a vermiculite laminate; and long-chain molecules of the vinyl-terminated polyethylene glycol expand interlayers, so that the compatibility of the vinyl-terminated polyethylene glycol with a matrix is improved, vinyl is introduced to the surface of the vinyl-terminated polyethylene glycol, and the vinyl-terminated polyethylene glycol is subsequently chemically combined with the resin matrix. The preparation process is completed in one step, the whole process is simple, and the strength, flame retardance and waterproof performance of the packaging film are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to a flame-retardant and waterproof packaging film and its preparation method. Background Technology

[0002] In current technology, vermiculite, due to its natural layered structure and good thermal stability, is considered a potential filler for improving the flame retardant and barrier properties of polyolefin materials. However, vermiculite's surface is rich in hydroxyl groups and exhibits hydrophilicity, resulting in a lack of compatibility with hydrophobic matrix materials such as polypropylene and polyethylene. When added directly, it is difficult to disperse evenly and tends to form agglomerates in the matrix. This not only fails to exert the physical barrier effect of its layered structure but also becomes a stress concentration point within the material, leading to a decline in mechanical properties.

[0003] To address this issue, vermiculite typically requires organic modification. However, existing modification methods are generally cumbersome, with lengthy processes and high control difficulty. Even after multiple steps, the interfacial bonding between the modified vermiculite and the polyolefin matrix remains unsatisfactory, the layers cannot be fully exfoliated, and its dispersion and interfacial anchoring strength in the matrix fail to meet practical application requirements.

[0004] Furthermore, commonly used modifiers only act as compatibilizers and do not possess flame-retardant elements themselves. Vermiculite exists only as a physical barrier in the material, with limited flame-retardant efficiency, requiring compounding with other flame retardants to meet usage requirements, which further increases the complexity of formulation design. More importantly, due to weak interfacial bonding, microscopic voids easily form between the filler and the matrix, allowing water molecules and oxygen to permeate along the interface, thus weakening the material's barrier properties. Therefore, how to simplify the modification process while simultaneously improving the interfacial compatibility between vermiculite and polyolefins, imparting chemical flame retardancy, and maintaining the original mechanical properties of the material has become an urgent problem to be solved in the current packaging film industry. Summary of the Invention

[0005] The purpose of this invention is to provide a flame-retardant and waterproof packaging film material and its preparation method, so as to solve the problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a flame-retardant and waterproof packaging film material, comprising, by weight, 100 parts of polypropylene, 10-15 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene. The modified expanded vermiculite is prepared as follows: aminotrimethylenephosphonic acid is prepared into an aqueous solution, the pH is adjusted to 4.5 with sodium hydroxide solution, sodium expanded vermiculite is added to it, and the mixture is stirred in a water bath at 60°C for 2 hours; then vinyl-terminated polyethylene glycol is added to the reaction system, and the mixture is stirred at 80°C for 6 hours; after the reaction is completed, the mixture is cooled to room temperature, filtered, and the filter cake is washed three times with anhydrous ethanol. The filter cake is then dried for 24 hours to obtain the modified expanded vermiculite.

[0007] Furthermore, the concentration of the aminotrimethylenephosphonic acid aqueous solution is 10 g / L.

[0008] Furthermore, the sodium hydroxide solution has a mass fraction of 10%.

[0009] Furthermore, the mass ratio of the sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid is 1:0.2-1:0.3.

[0010] Furthermore, the number average molecular weight of the terminal vinyl polyethylene glycol is 2000-4000.

[0011] Furthermore, the amount of the terminal vinyl polyethylene glycol added is 20-30% of the mass of the sodium expanded vermiculite.

[0012] Furthermore, the preparation method of the sodium-modified expanded vermiculite is as follows: the expanded vermiculite is crushed and passed through a 300-mesh sieve. The sieve material is added to a sodium chloride solution with a concentration of 1 mol / L. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:15-1:20. The mixture is stirred and reacted in a constant temperature water bath at 80℃ for 6 hours. After the reaction is completed, the mixture is filtered, and the filter cake is washed with deionized water until no chloride ions are detected. The filter cake is dried to constant weight to obtain sodium-modified expanded vermiculite.

[0013] Furthermore, the preparation method of the packaging film material is as follows: by weight, polypropylene, modified expanded vermiculite, dicumyl peroxide, and maleic anhydride-grafted polypropylene are added to a high-speed mixer and mixed for 10 minutes at a speed of 500 rpm; the mixture is added to a twin-screw extruder for melt blending and extrusion; the extruded strip is cooled with water, granulated, and dried to obtain cylindrical polypropylene granules with a diameter of 2-4 mm and a length of 3-5 mm; the polypropylene granules are added to a single-screw extrusion blown film mill for extrusion; after the film bubble stabilizes, it is wound up to obtain the polypropylene packaging film material.

[0014] Furthermore, the preparation method of the maleic anhydride-grafted polypropylene is as follows: by weight, 100 parts of polypropylene, 3-8 parts of maleic anhydride, and 0.3-0.8 parts of dicumyl peroxide are added to a high-speed mixer and mixed for 5-10 minutes at a speed of 300-500 rpm; the mixture is added to a twin-screw extruder for melt grafting reaction, and the extruded strip is cooled with water, pelletized, and dried to obtain maleic anhydride-grafted polypropylene.

[0015] Furthermore, the thickness of the packaging film is preferably 50 μm, but can be customized according to different requirements.

[0016] Furthermore, the polypropylene, F280S, is sourced from Shanghai Petrochemical.

[0017] Furthermore, the expanded vermiculite is sourced from Shijiazhuang Qiaocan Mineral Products Co., Ltd., and its specifications can be customized according to requirements, thus eliminating the need for a crushing step.

[0018] Furthermore, the terminal vinyl polyethylene glycol is sourced from Shanghai Celluloid Chemical Co., Ltd., and is customized according to molecular weight requirements.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) This invention prepares modified expanded vermiculite as a filler and adds it to polypropylene base material to obtain packaging film material to achieve flame retardant and waterproof effects. This invention selects aminotrimethylene phosphonic acid and vinyl-terminated polyethylene glycol to modify expanded vermiculite. Aminotrimethylene phosphonic acid relies on phosphonic acid groups to form complexes with magnesium and aluminum ions between expanded vermiculite layers, introducing phosphorus and nitrogen elements into the surface of vermiculite layers; the long-chain molecules of vinyl-terminated polyethylene glycol enter the already expanded interlayer to further open it, improving its compatibility with the matrix while introducing vinyl groups into its surface.

[0020] (2) The expanded vermiculite selected in this invention has a loose layered structure after high-temperature treatment, which can more effectively form a physical barrier inside the matrix. The phosphorus and nitrogen elements in aminotrimethylene phosphonic acid are anchored to the surface of expanded vermiculite by chemical bonds. When heated, phosphoric acid is generated to promote the dehydration of the substrate into carbon, which together with the layers of expanded vermiculite to form a dense protective carbon layer.

[0021] (3) The modified expanded vermiculite sheets are uniformly dispersed in the matrix. The tortuous path formed by its loose and open structure can more effectively extend the water molecule penetration path and significantly reduce the water vapor permeability. In addition, the introduction of end-vinyl polyethylene glycol makes the expanded vermiculite and the polyolefin matrix interface tightly bonded, and its end vinyl groups form a chemical bond with the matrix resin, realizing the stable anchoring of the filler and the interface reinforcement. While obtaining flame retardant and waterproof properties, the packaging film can still maintain good mechanical strength and toughness, and the overall performance is stable and reliable.

[0022] (4) This invention utilizes two organic compounds to modify expanded vermiculite. The preparation process is completed in one step, and the overall process is simple and easy to control. While improving the dispersion state and interfacial bonding strength of expanded vermiculite in polyolefins, it also improves the strength, flame retardancy and waterproof performance of packaging film. Detailed Implementation

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

[0024] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The testing methods for various indicators of a flame-retardant and waterproof packaging film material prepared in the following embodiments are as follows: Strength: The tensile strength and elongation at break of the samples prepared in the examples and comparative examples were tested in accordance with the standard GB / T 1040.1-2018.

[0025] Flame retardancy: The samples prepared in the examples and comparative examples were tested for flame retardancy using the vertical burning method of standard ANSI / UL-94-2009 (UL-94).

[0026] Water resistance: The contact angle of the samples prepared in the examples and comparative examples was measured using a German DAtaphysics OCA25 contact angle meter at room temperature. The amount of water used was 2.0 μL. The contact angle of the samples was measured 5 times and the average value was taken.

[0027] Example 1 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve material and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:15. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH to 10% sodium hydroxide solution. 4.5 Add sodium-modified expanded vermiculite, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.2, and stir in a water bath at 60°C for 2 hours; then add terminal vinyl polyethylene glycol to the reaction system, with a number average molecular weight of 2000, and the amount added is 20% of the mass of sodium-modified expanded vermiculite, and continue stirring at 80°C for 6 hours; after the reaction is completed, cool to room temperature, filter, wash the filter cake three times with anhydrous ethanol, and dry the filter cake in a vacuum drying oven at 50°C for 24 hours to obtain modified expanded vermiculite; (2) By weight, 100 parts of polypropylene, 3 parts of maleic anhydride and 0.3 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 5 minutes at a speed of 300 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 minutes. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 10 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. Set the screw speed to 250 rpm. The material resides in the extruder for 3 minutes; after water cooling, pelletizing, and drying, the extruded strip yields cylindrical polypropylene granules with a diameter of 2 mm and a length of 3 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, with the extruder temperature set to 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 180℃ in zone 4, and the die temperature set to 175℃; the screw speed is 40 rpm, the traction speed is 8 m / min, and the film bubble is wound up after stabilization to obtain a polypropylene packaging film with a thickness of 50 μm.

[0028] Example 2 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.25. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 3000 was added to the reaction system, and its addition amount was 25% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then placed in a vacuum drying oven at 50°C and dried for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0029] Example 3 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve material and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:20. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is completed, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH to 10% sodium hydroxide solution. 4.5 Add sodium-modified expanded vermiculite, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.3, and stir in a water bath at 60°C for 2 hours; then add terminal vinyl polyethylene glycol to the reaction system, with a number average molecular weight of 4000, and the amount added is 30% of the mass of sodium-modified expanded vermiculite, and continue stirring at 80°C for 6 hours; after the reaction is completed, cool to room temperature, filter, wash the filter cake three times with anhydrous ethanol, and dry the filter cake in a vacuum drying oven at 50°C for 24 hours to obtain modified expanded vermiculite; (2) By weight, 100 parts of polypropylene, 8 parts of maleic anhydride and 0.8 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 10 minutes. The mixer speed was 500 rpm. The mixture was added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175℃ in zone 1, 180℃ in zone 2, 190℃ in zone 3 and 185℃ in zone 4, the die head temperature was 180℃, the screw speed was 300 rpm, and the material residence time in the extruder was 3 minutes. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 15 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 300 rpm. The material resides in the extruder for 4 minutes; after water cooling, pelletizing, and drying, the extruded strip yields cylindrical polypropylene granules with a diameter of 4 mm and a length of 5 mm; the polypropylene granules are then added to a single-screw extrusion blown film mill, with the extruder temperature set to 170℃ in zone 1, 180℃ in zone 2, 190℃ in zone 3, and 190℃ in zone 4, and the die temperature set to 185℃; the screw speed is 60 rpm, the traction speed is 15 m / min, and the film bubble is wound up after stabilization to obtain a polypropylene packaging film with a thickness of 50 μm.

[0030] Example 4 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.25. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 4000 was added to the reaction system, and the amount added was 25% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then dried in a vacuum drying oven at 50°C for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0031] Example 5 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.25. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 2000 was added to the reaction system, and the amount added was 25% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then dried in a vacuum drying oven at 50°C for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0032] Example 6 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.25. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 3000 was added to the reaction system, and the amount added was 20% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then dried in a vacuum drying oven at 50°C for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0033] Example 7 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.2. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 3000 was added to the reaction system, and the amount added was 30% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then dried in a vacuum drying oven at 50°C for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0034] Example 8 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.25. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 3000 was added to the reaction system, and its addition amount was 25% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then placed in a vacuum drying oven at 50°C and dried for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0035] Example 9 (1) After crushing the expanded vermiculite, pass it through a 300-mesh sieve. Take the sieve residue and add it to a 1 mol / L sodium chloride solution. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:17.5. Stir the reaction in an 80℃ constant temperature water bath for 6 hours. After the reaction is complete, filter the solution and wash the filter cake with deionized water until no chloride ions are detected. Place the filter cake in a 60℃ vacuum drying oven and dry it to constant weight to obtain sodium-modified expanded vermiculite. Prepare an aqueous solution of aminotrimethylenephosphonic acid with a concentration of 10 g / L and adjust the pH with a 10% sodium hydroxide solution. To a depth of 4.5, sodium-modified expanded vermiculite was added, with a mass ratio of sodium-modified expanded vermiculite to aminotrimethylenephosphonic acid of 1:0.3. The mixture was stirred in a water bath at 60°C for 2 hours. Then, terminal vinyl polyethylene glycol with a number average molecular weight of 3000 was added to the reaction system, and its addition amount was 25% of the mass of sodium-modified expanded vermiculite. The mixture was stirred at 80°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol. The filter cake was then placed in a vacuum drying oven at 50°C and dried for 24 hours to obtain modified expanded vermiculite. (2) By weight, 100 parts of polypropylene, 5.5 parts of maleic anhydride and 0.55 parts of dicumyl peroxide were added to a high-speed mixer and mixed for 7.5 min at a speed of 400 rpm. The mixture was then added to a twin-screw extruder for melt grafting reaction. The extruder temperature was set to 175°C in zone 1, 180°C in zone 2, 190°C in zone 3 and 185°C in zone 4, the die head temperature was 180°C, the screw speed was 300 rpm, and the material residence time in the extruder was 3 min. After water cooling, pelletizing and drying, maleic anhydride grafted polypropylene was obtained. (3) By weight, take 100 parts of polypropylene, 12.5 parts of modified expanded vermiculite, 0.5 parts of dicumyl peroxide, and 15 parts of maleic anhydride-grafted polypropylene and add them to a high-speed mixer and mix for 10 minutes at a speed of 500 rpm. Add the mixture to a twin-screw extruder for melt blending and extrusion. Set the extruder temperature to 170°C in zone 1, 180°C in zone 2, 190°C in zone 3, 190°C in zone 4, 185°C in zone 5, and 180°C at the die head. The screw speed is 275 rpm. The residence time in the extruder is 3.5 min; after water cooling, pelletizing and drying, the extruded strip is used to obtain cylindrical polypropylene granules with a diameter of 3 mm and a length of 4 mm; the polypropylene granules are added to a single-screw extrusion blown film mill, the extruder temperature is set to 165℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3 and 185℃ in zone 4, and the die temperature is 180℃; the screw speed is 50 rpm and the traction speed is 11.5 m / min. After the film bubble stabilizes, it is wound up to obtain a polypropylene packaging film with a thickness of 50 μm.

[0036] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that unmodified expanded vermiculite powder was used in the preparation of the flame-retardant and waterproof packaging film material, while the other steps were the same as in Example 2.

[0037] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that in the preparation process of the flame-retardant and waterproof packaging film, the expanded vermiculite powder is only modified with aminotrimethylene phosphonic acid, without the addition of vinyl-terminated polyethylene glycol, and the remaining steps are the same as in Example 2.

[0038] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that in the preparation process of the flame-retardant and waterproof packaging film, the expanded vermiculite powder is only modified with end-vinyl polyethylene glycol, without the addition of aminotrimethylenephosphonic acid, and the remaining steps are the same as in Example 2.

[0039] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that in the preparation process of the flame-retardant and waterproof packaging film, the expanded vermiculite powder is modified by replacing the end-vinyl polyethylene glycol with ordinary polyethylene glycol. The remaining steps are the same as in Example 2.

[0040] Comparative Example 5 The difference between Comparative Example 5 and Example 2 is that the amount of modified expanded vermiculite added during the preparation of the flame-retardant and waterproof packaging film is halved, specifically 6 parts, while the remaining steps are the same as in Example 2.

[0041] Example of effect Table 1 below shows the performance analysis results of a flame-retardant and waterproof packaging film material using Examples 1 to 9 and Comparative Examples 1 to 5 of the present invention.

[0042] Table 1 It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A flame-retardant and waterproof packaging film, characterized in that, By weight, it includes 100 parts polypropylene, 10-15 parts modified expanded vermiculite, 0.5 parts dicumyl peroxide, and 15 parts maleic anhydride-grafted polypropylene. The modified expanded vermiculite is prepared as follows: aminotrimethylenephosphonic acid is prepared into an aqueous solution, the pH is adjusted to 4.5 with sodium hydroxide solution, sodium expanded vermiculite is added to it, and the mixture is stirred in a water bath at 60°C for 2 hours; then vinyl-terminated polyethylene glycol is added to the reaction system, and the mixture is stirred at 80°C for 6 hours; after the reaction is completed, the mixture is cooled to room temperature, filtered, and the filter cake is washed three times with anhydrous ethanol. The filter cake is then dried for 24 hours to obtain the modified expanded vermiculite.

2. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The concentration of the aminotrimethylenephosphonic acid aqueous solution is 10 g / L.

3. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The sodium hydroxide solution has a mass fraction of 10%.

4. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The mass ratio of sodium expanded vermiculite to aminotrimethylenephosphonic acid is 1:0.2-1:0.

3.

5. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The number average molecular weight of the terminal vinyl polyethylene glycol is 2000-4000.

6. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The amount of vinyl-terminated polyethylene glycol added is 20-30% of the mass of sodium expanded vermiculite.

7. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The preparation method of the sodium-modified expanded vermiculite is as follows: the expanded vermiculite is crushed and passed through a 300-mesh sieve. The sieve material is added to a sodium chloride solution with a concentration of 1 mol / L. The solid-liquid mass ratio of the expanded vermiculite to the sodium chloride solution is 1:15-1:

20. The mixture is stirred and reacted in a constant temperature water bath at 80℃ for 6 hours. After the reaction is completed, the mixture is filtered, and the filter cake is washed with deionized water until no chloride ions are detected. The filter cake is dried to constant weight to obtain sodium-modified expanded vermiculite.

8. The flame-retardant and waterproof packaging film material according to claim 1, characterized in that, The preparation method of the packaging film material is as follows: by weight, polypropylene, modified expanded vermiculite, dicumyl peroxide, and maleic anhydride-grafted polypropylene are added to a high-speed mixer and mixed for 10 minutes at a speed of 500 rpm; the mixture is added to a twin-screw extruder for melt blending and extrusion; the extruded strip is cooled with water, granulated, and dried to obtain cylindrical polypropylene granules with a diameter of 2-4 mm and a length of 3-5 mm; the polypropylene granules are added to a single-screw extrusion blown film mill for extrusion; after the film bubble stabilizes, it is wound up to obtain the polypropylene packaging film material.

9. A flame-retardant and waterproof packaging film material according to claim 8, characterized in that, The preparation method of maleic anhydride-grafted polypropylene is as follows: by weight, take 100 parts of polypropylene, 3-8 parts of maleic anhydride, and 0.3-0.8 parts of dicumyl peroxide and add them to a high-speed mixer and mix for 5-10 minutes at a speed of 300-500 rpm; add the mixture to a twin-screw extruder for melt grafting reaction, and after water cooling, pelletizing, and drying, maleic anhydride-grafted polypropylene is obtained.

10. A flame-retardant and waterproof packaging film material according to claim 8, characterized in that, The thickness of the packaging film is preferably 50 μm, but can be customized according to different requirements.

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