Preparation method of a modified polypropylene film layer and its application in an aluminum-plastic film

Abstract

The present invention relates to the technical field of polypropylene film layers, and discloses a preparation method of a modified polypropylene film layer and its application in aluminum-plastic films. The present invention uses acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol, formaldehyde, aminopropyltriethoxysilane, nano-titanium dioxide, etc. as raw materials, and through addition reaction, Mannich reaction, hydrolysis and condensation reaction, modified nano-titanium dioxide is obtained. It is added to polypropylene for mixing, extrusion granulation, and casting film formation to obtain a modified polypropylene film layer. By using the benzoxazine structure, cyano structure and nano-titanium dioxide particles contained therein, the high-temperature resistance and mechanical properties of the polypropylene film layer are improved. The polypropylene film layer prepared by the present invention has excellent high-temperature resistance and mechanical properties after being verified by experiments, and has important application value in aluminum-plastic films.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene film layers, and specifically to a preparation method of a modified polypropylene film layer and its application in aluminum-plastic films. Background Art

[0002] The aluminum-plastic composite film, abbreviated as aluminum-plastic film, generally consists of an outer protective film, an outer adhesive, an aluminum foil, an inner adhesive, and an inner polypropylene film layer. It has good encapsulation properties, moisture resistance, corrosion resistance, etc., and is a key material for the encapsulation of soft-pack lithium battery cells. However, during the long-term use of the battery, the phenomenon of heating and overheating may occur, and there is even a risk of explosion at high temperatures. Therefore, in order to meet the need of the aluminum-plastic film for high temperature resistance, it is necessary to modify the materials in the aluminum-plastic film to enhance the high temperature resistance performance of the aluminum-plastic film.

[0003] Polypropylene is a thermoplastic synthetic resin with excellent properties, having advantages such as low density, non-toxicity, easy processing, and good insulation performance, and is widely used in fields such as chemical industry, electrical appliances, packaging materials, and building materials. Nano-titanium dioxide is an important inorganic functional material, having chemical stability, thermal stability, antibacterial properties, etc., and is widely used in fields such as cosmetics, plastics, and coatings. However, due to the extremely large specific surface free energy of nano-titanium dioxide, it is extremely easy to agglomerate during the application process. Therefore, it is necessary to modify and decorate its surface to improve its dispersibility and compatibility in polymers. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a preparation method of a modified polypropylene film layer and its application in aluminum-plastic films.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A preparation method of a modified polypropylene film layer, and the preparation method is as follows:

[0007] (1) Add acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol, and anhydrous aluminum chloride into a flask, heat to 70 - 80 °C, react for 15 - 24 h. After the reaction ends, perform vacuum distillation, wash successively with 10% dilute hydrochloric acid and saturated brine, and dry to obtain intermediate 1; the mass ratio of acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol, and anhydrous aluminum chloride is 1 - 1.5:1:0.2 - 0.4;

[0008] Under the catalysis of anhydrous aluminum chloride, acrylonitrile and 4,4'-diaminobiphenyl-2,2'-diol carry out an addition reaction to obtain intermediate 1, and the reaction process is as follows:

[0009]

[0010] (2) Add formaldehyde and 3-aminopropyltriethoxysilane into a flask containing chloroform solvent, stir evenly, then add Intermediate 1 thereto, heat up to 70 - 85 °C, react for 4 - 8 h. After the reaction ends, cool to room temperature, filter, rotary evaporate, and dry to obtain Intermediate 2; the mass ratio of formaldehyde, 3-aminopropyltriethoxysilane, and Intermediate 1 is 0.3 - 0.5:1.1 - 1.5:1;

[0011] Intermediate 2 is obtained by the Mannich reaction of the phenolic hydroxyl group contained in Intermediate 1 with formaldehyde and 3-aminopropyltriethoxysilane. The reaction process is as follows:

[0012]

[0013] (3) Add nano-titanium dioxide and Intermediate 2 into a flask containing 60 - 70% ethanol aqueous solution, ultrasonically disperse, adjust the pH to 3 - 4 with glacial acetic acid, stir and disperse at 40 - 50 °C for 1 - 2 h. After the reaction ends, wash with deionized water, filter, and dry to obtain modified nano-titanium dioxide; the mass ratio of nano-titanium dioxide to Intermediate 2 is 1:0.1 - 0.5;

[0014] Modified nano-titanium dioxide is obtained by the condensation reaction of the hydroxyl group contained in nano-titanium dioxide with the silicon hydroxyl group after hydrolysis of Intermediate 2. The reaction process is as follows:

[0015] Wherein is nano-titanium dioxide;

[0016] (4) Add polypropylene, nucleating agent, antioxidant, and modified nano-titanium dioxide into a high-speed mixer, mix for 2 - 5 min, then add it into a twin-screw extruder for extrusion granulation, dry, and form a film by casting to obtain a modified polypropylene film layer.

[0017] Further, in the step (4), the nucleating agent is one of α-nucleating agent and β-nucleating agent; the antioxidant is one of antioxidant 168 and antioxidant 1010.

[0018] Further, in the step (4), the mass ratio of polypropylene, nucleating agent, antioxidant, and modified nano-titanium dioxide is 100:0.05 - 0.2:0.1 - 0.4:1 - 5.

[0019] Further, in the step (4), the extrusion temperature is 180 - 230 °C, the rotation speed is 300 - 500 r / min; the casting processing temperature is 210 - 230 °C.

[0020] Another object of the present invention is to provide the application of the polypropylene film layer of the present invention in an aluminum-plastic film.

[0021] The advantages of the present invention are as follows:

[0022] Using acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol, aminopropyltriethoxysilane, nano-titanium dioxide, etc. as raw materials, through addition reaction, Mannich reaction, hydrolysis and condensation reaction, modified nano-titanium dioxide is obtained. Its raw materials are easily available, the preparation method is simple, and the structure is novel. It is added to polypropylene and mixed, extruded and granulated, and cast into a film to obtain a modified polypropylene film layer.

[0023] The nano-titanium dioxide particles used in the present invention are prone to agglomeration. The present invention organifies it, reduces the degree of agglomeration, and increases its compatibility in organic substances. The present invention introduces it into the substrate, and the inorganic nano-rigid particles can restrict the movement of the substrate molecular chain, improve the heat distortion temperature under load of the modified polypropylene film layer, and further enhance the high-temperature resistance of the modified polypropylene film layer. In addition, the modified polypropylene film layer prepared in the present invention contains a benzoxazine structure and a cyano structure. When the benzoxazine structure is heated, it can absorb heat and form a cross-linked network structure by ring-opening, improving the high-temperature resistance of the material; and when the cyano group therein is heated, it can absorb heat and form highly cross-linked structures such as triazine rings and phthalocyanine rings, further enhancing the high-temperature resistance of the polypropylene film layer. The modified polypropylene film layer prepared in the present invention has excellent high-temperature resistance. Specific embodiments

[0024] The preparation method and application of the modified polypropylene film layer of the present invention will be further described below in conjunction with some specific embodiments. The specific examples are for further detailed description of the present invention and do not limit the protection scope of the present invention.

[0025] Example 1

[0026] (1) Add 6 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 2 g of anhydrous aluminum chloride to a flask, heat to 75 °C, react for 15 h, after the reaction is completed, perform vacuum distillation, wash with 10% dilute hydrochloric acid and saturated brine, and dry to obtain Intermediate 1.

[0027] (2) Add 0.8 g of formaldehyde and 2.5 g of aminopropyltriethoxysilane to a flask containing toluene solvent, stir evenly, then add 2 g of Intermediate 1 thereto, raise the temperature to 75 °C, react for 6 h, after the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain Intermediate 2.

[0028] (3) Add 10 g of nano-titanium dioxide and 1 g of Intermediate 2 to a flask containing 65% ethanol aqueous solution, ultrasonically disperse, adjust the pH to 3 with glacial acetic acid, stir and disperse at 45 °C for 2 h, after the reaction is completed, wash with deionized water and dry to obtain modified nano-titanium dioxide.

[0029] (4) Add 100 g of polypropylene, 0.1 g of β-nucleating agent, 0.3 g of antioxidant 168, and 1 g of modified nano-titanium dioxide into a high-speed mixer, mix for 4 min, then add it into a twin-screw extruder for extrusion granulation, where the extrusion temperature is 220 °C, the rotation speed is 400 r / min, dry it, and use the casting method to make a film with a processing temperature of 210 °C to obtain a modified polypropylene film layer.

[0030] Example 2

[0031] (1) Add 7.5 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 1.2 g of anhydrous aluminum chloride into a flask, heat to 80 °C, react for 20 h, after the reaction is completed, perform vacuum distillation, wash with 10% dilute hydrochloric acid and saturated brine, and dry to obtain Intermediate 1.

[0032] (2) Add 1 g of formaldehyde and 3 g of aminopropyltriethoxysilane into a flask containing toluene solvent, stir evenly, then add 2 g of Intermediate 1 into it, raise the temperature to 85 °C, react for 5 h, after the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain Intermediate 2.

[0033] (3) Add 10 g of nano-titanium dioxide and 2 g of Intermediate 2 into a flask containing 65% ethanol aqueous solution, ultrasonically disperse it, adjust the pH to 3 with glacial acetic acid, stir and disperse at 50 °C for 2 h, after the reaction is completed, wash with deionized water and dry to obtain modified nano-titanium dioxide.

[0034] (4) Add 100 g of polypropylene, 0.15 g of α-nucleating agent, 0.3 g of antioxidant 168, and 2 g of modified nano-titanium dioxide into a high-speed mixer, mix for 5 min, then add it into a twin-screw extruder for extrusion granulation, where the extrusion temperature is 200 °C, the rotation speed is 500 r / min, dry it, and use the casting method to make a film with a processing temperature of 230 °C to obtain a modified polypropylene film layer.

[0035] Example 3

[0036] (1) Add 8.4 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 2.4 g of anhydrous aluminum chloride into a flask, heat to 70 °C, react for 16 h, after the reaction is completed, perform vacuum distillation, wash with 10% dilute hydrochloric acid and saturated brine, and dry to obtain Intermediate 1.

[0037] (2) Add 0.6 g of formaldehyde and 2.8 g of aminopropyltriethoxysilane to a flask containing toluene solvent, stir evenly, then add 2 g of intermediate 1 thereto, heat up to 80 °C, react for 4 h. After the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain intermediate 2.

[0038] (3) Add 10 g of nano-titanium dioxide and 3 g of intermediate 2 to a flask containing 70% ethanol aqueous solution, ultrasonically disperse, adjust the pH to 4 with glacial acetic acid, stir and disperse at 45 °C for 2 h. After the reaction is completed, wash with deionized water and dry to obtain modified nano-titanium dioxide.

[0039] (4) Add 100 g of polypropylene, 0.2 g of α-nucleating agent, 0.4 g of antioxidant 1010, and 3 g of modified nano-titanium dioxide to a high-speed mixer, mix for 2 min, then add it to a twin-screw extruder for extrusion granulation. The extrusion temperature is 200 °C, the rotation speed is 300 r / min, dry, and film is formed by casting method. The processing temperature is 220 °C to obtain a modified polypropylene film layer.

[0040] Example 4

[0041] (1) Add 8 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 1.2 g of anhydrous aluminum chloride to a flask, heat to 75 °C, react for 18 h. After the reaction is completed, perform vacuum distillation, wash with 10% dilute hydrochloric acid and saturated brine, and dry to obtain intermediate 1.

[0042] (2) Add 0.8 g of formaldehyde and 2.5 g of aminopropyltriethoxysilane to a flask containing toluene solvent, stir evenly, then add 2 g of intermediate 1 thereto, heat up to 70 °C, react for 6 h. After the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain intermediate 2.

[0043] (3) Add 10 g of nano-titanium dioxide and 4 g of intermediate 2 to a flask containing 60% ethanol aqueous solution, ultrasonically disperse, adjust the pH to 3 with glacial acetic acid, stir and disperse at 40 °C for 1 h. After the reaction is completed, wash with deionized water and dry to obtain modified nano-titanium dioxide.

[0044] (4) Add 100 g of polypropylene, 0.1 g of β-nucleating agent, 0.2 g of antioxidant 1010, and 4 g of modified nano-titanium dioxide to a high-speed mixer, mix for 4 min, then add it to a twin-screw extruder for extrusion granulation. The extrusion temperature is 180 °C, the rotation speed is 400 r / min, dry, and film is formed by casting method. The processing temperature is 210 °C to obtain a modified polypropylene film layer.

[0045] Example 5

[0046] (1) Add 9 g of acrylonitrile, 6 g of 4,4'-diaminobiphenyl-2,2'-diol, and 2 g of anhydrous aluminum chloride into a flask, heat to 75 °C, react for 24 h. After the reaction, perform vacuum distillation, wash with 10% dilute hydrochloric acid and saturated brine, and dry to obtain Intermediate 1.

[0047] (2) Add 1 g of formaldehyde and 2.2 g of aminopropyltriethoxysilane into a flask containing toluene solvent, stir evenly, then add 2 g of Intermediate 1 thereto, raise the temperature to 70 °C, react for 8 h. After the reaction, cool to room temperature, filter, rotary evaporate, and dry to obtain Intermediate 2.

[0048] (3) Add 10 g of nano-titanium dioxide and 5 g of Intermediate 2 into a flask containing 70% ethanol aqueous solution, ultrasonically disperse, adjust the pH to 3 with glacial acetic acid, stir and disperse at 50 °C for 2 h. After the reaction, wash with deionized water and dry to obtain modified nano-titanium dioxide.

[0049] (4) Add 100 g of polypropylene, 0.05 g of α-nucleating agent, 0.1 g of antioxidant 1010, and 5 g of modified nano-titanium dioxide into a high-speed mixer, mix for 5 min, then add it into a twin-screw extruder for extrusion granulation, where the extrusion temperature is 230 °C, the rotation speed is 500 r / min, dry, and form a film by casting method, the processing temperature is 220 °C to obtain a modified polypropylene film layer.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that: in step (4), nano-titanium dioxide is used instead of modified nano-titanium dioxide.

[0052] Use a universal electronic testing machine to test the tensile properties of the polypropylene film layer, then place the polypropylene film layer in an oven at 100 °C for thermal aging for 24 h, and test the tensile properties after thermal aging.

[0053] Table 1:

[0054]

[0055] As can be seen from the table, the tensile properties of Example 1 before and after thermal aging are better than those of Comparative Example 1. This is because in Example 1, it not only contains heat-resistant benzoxazine structure and cyano structure, which can enhance the tensile properties after thermal aging, but also, in Example 1, the nano-titanium dioxide is organically modified and can be evenly dispersed in the polypropylene film layer. When the film is stretched by an external force, the two ends of the inorganic particles are subjected to tensile stress from the polymer matrix, while the middle is subjected to compressive stress. Due to the interaction of forces, it is beneficial to the generation of yield, thereby improving its tensile properties. However, the nano-titanium dioxide in Comparative Example 1 is unmodified. Therefore, its mechanical properties are inferior to those of Example 1; in Examples 1-5, as the amount of modified nano-titanium dioxide increases, its tensile properties before and after thermal aging also increase. The maximum tensile strength before thermal aging can reach 50.8 MPa, and the maximum tensile strength after thermal aging can reach 47.1 MPa. The polypropylene film layer prepared by the present invention has excellent mechanical properties and heat resistance.

[0056] The heat resistance of the modified polypropylene film layer was tested using a thermogravimetric analyzer. Under a nitrogen atmosphere, the temperature was raised from room temperature to 800 °C at a heating rate of 20 °C / min.

[0057] Table 2:

[0058] Initial decomposition temperature / °C Example 1 432 Example 2 439 Example 3 451 Example 4 456 Example 5 448 Comparative Example 1 415

[0059] As can be seen from the table, the modified polypropylene film layer prepared by the present invention has good heat resistance. The modified polypropylene film layer prepared by the present invention has an important application prospect in the aluminum-plastic film.

[0060] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A method for preparing a modified polypropylene film layer, characterized in that: The preparation method is: (1) Add acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol and anhydrous aluminum chloride into a flask, wherein the mass ratio of acrylonitrile, 4,4'-diaminobiphenyl-2,2'-diol and anhydrous aluminum chloride is 1-1.5:1:0.2-0.4, heat to 70-80°C, react for 15-24 hours, and after the reaction is completed, distill under reduced pressure, wash with 10% dilute hydrochloric acid and saturated brine in turn, and dry to obtain intermediate 1; (2) Add formaldehyde and aminopropyltriethoxysilane to a flask containing chloroform solvent, stir evenly, and then add intermediate 1 thereto, wherein the mass ratio of formaldehyde, aminopropyltriethoxysilane and intermediate 1 is 0.3-0.5:1.1-1.5:1, heat to 70-85°C, react for 4-8h, and after the reaction is completed, cool to room temperature, filter, rotary evaporate, and dry to obtain intermediate 2; (3) Add nano titanium dioxide and intermediate 2 into a flask containing 60-70% ethanol aqueous solution, perform ultrasonic dispersion, adjust the pH to 3-4 with glacial acetic acid, stir and disperse at 40-50°C for 1-2h, wash with deionized water after the reaction, filter and dry to obtain modified nano titanium dioxide; (4) Add polypropylene, nucleating agent, antioxidant and modified nano titanium dioxide into a high-speed mixer and mix for 2-5 minutes. Then add the mixture into a twin-screw extruder for extrusion granulation, dry it and form a film by casting to obtain a modified polypropylene film layer.

2. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (3), the mass ratio of nano titanium dioxide to intermediate 2 is 1:0.1-0.

5.

3. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (4), the nucleating agent is one of an α-nucleating agent and a β-nucleating agent; and the antioxidant is one of an antioxidant 168 and an antioxidant 1010.

4. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (4), the mass ratio of polypropylene, nucleating agent, antioxidant and modified nano titanium dioxide is 100:0.05-0.2:0.1-0.4:1-5.

5. The method for preparing a modified polypropylene film layer according to claim 1, characterized in that: In the above (4), the extrusion temperature is 180-230°C, the rotation speed is 300-500r / min; and the casting processing temperature is 210-230°C.

6. Use of the polypropylene film layer prepared by the preparation method according to any one of claims 1 to 5 in aluminum-plastic film.

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